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THOR on YouTube38 papers for you this month starting with a review from Harvard on LLLT for hair loss, a clinical trial on osteoarthritis*, a trial on wound healing post tooth extraction on HIV+ patients* (see rant below), a review of laser vs needles on myofascial trigger points, effect of laser vs needle acupuncture on the CNS, an extensive report on auricular laser acupuncture, a trial using red LED light on muscle activity. I also found 19 LED studies studies that got missed in previous literature watches so I have added those (so you get 57 papers ins all in this literature watch) and that brings the total number of LED research papers in my collection to 260.
Low-level laser (light) therapy (LLLT) for treatment of hair loss.
Avci P, Gupta GK, Clark J, Wikonkal N, Hamblin MR
Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, Massachusetts 02114; Department of Dermatology, Harvard Medical School, Boston, Massachusetts 02115; Department of Dermatology, Venereology and Dermato-Oncology, Semmelweis University School of Medicine, Budapest 1085, Hungary.
OBJECTIVE: Alopecia is a common disorder affecting more than half of the population worldwide. Androgenetic alopecia, the most common type, affects 50% of males over the age of 40 and 75% of females over 65. Only two drugs have been approved so far (minoxidil and finasteride) and hair transplant is the other treatment alternative. This review surveys the evidence for low-level laser therapy (LLLT) applied to the scalp as a treatment for hair loss and discusses possible mechanisms of actions. METHODS AND MATERIALS: Searches of PubMed and Google Scholar were carried out using keywords alopecia, hair loss, LLLT, photobiomodulation. RESULTS: Studies have shown that LLLT stimulated hair growth in mice subjected to chemotherapy-induced alopecia and also in alopecia areata. Controlled clinical trials demonstrated that LLLT stimulated hair growth in both men and women. Among various mechanisms, the main mechanism is hypothesized to be stimulation of epidermal stem cells in the hair follicle bulge and shifting the follicles into anagen phase. CONCLUSION: LLLT for hair growth in both men and women appears to be both safe and effective. The optimum wavelength, coherence and dosimetric parameters remain to be determined. Lasers Surg. Med. 9999:1-8, 2013. (c) 2013 Wiley Periodicals, Inc.
Lasers Surg Med 2013 Aug 23
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Effect of low-level laser therapy in patients with chronic knee osteoarthritis: a single-blinded randomized clinical study.
Alghadir A, Omar MT, Al-Askar AB, Al-Muteri NK
Department of Rehabilitation Health Sciences, College of Applied Medical Sciences, King Saud University, P.O. Box. 10219, Riyadh, 11433, Saudi Arabia.
The aim of this study was to investigate the effect of low-level laser therapy (LLLT) on pain relief and functional performance in patients with chronic knee osteoarthritis (OA). Forty patients with knee OA were randomly assigned into active laser group (n = 20) and placebo laser group (n = 20). The LLLT device used was a Ga-As diode laser with a power output of 50 mW, a wavelength of 850 nm, and a diameter beam of 1 mm. Eight points were irradiated and received dosage of 6 J/point for 60 s, with a total dosage of 48 J/cm2 in each session. The placebo group was identical but treated without emission of energy. LLLT was applied two times per week over the period of 4 weeks. Outcome measurements included pain intensity at rest and at movement on visual analog scale, knee function using Western Ontario McMaster Universities Osteoarthritis Index scale, and ambulation duration. These measurements were collected at baseline and post-intervention. The results showed significant improvements in all assessment parameters in both groups compared to baseline. Active laser group showed significant differences in pain intensity at rest and movement, knee function, and ambulation duration when compared with the placebo group. Therefore, LLLT seemed to be an effective modality for short-term pain relief and function improvement in patients with chronic knee OA.
Lasers Med Sci 2013 Aug 3
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Tissue laser biostimulation promotes post-extraction neoangiogenesis in HIV-infected patients.
Halon A, Donizy P, Dziegala M, Dobrakowski R, Simon K
Department of Pathomorphology and Oncological Cytology, Wroclaw Medical University, Borowska 213, 50-556, Wroclaw, Poland, ahalon2@gmail.com.
The aim of the study was to assess the rate of neoangiogenesis in extraction wound healing following exposure to biostimulating laser therapy and to analyze the correlation between parameters of neoangiogenesis as reflected by the number and surface area of newly formed blood vessels and clinical parameters such as gender, position of a tooth in the oral cavity, and CD4 lymphocyte count. Twenty-seven patients with confirmed HIV infection were enrolled in the study (6 women, 21 men). Eighty-nine teeth were extracted; 45 sockets were exposed to 6 J laser radiation (laser parameters were set as follows: wavelength, 820 nm; output, 200 mW; dose, 6 J/cm2; spot size, 38 mm2; continuous radiation) for five consecutive days following tooth extraction, and the remaining extraction wounds were left to heal spontaneously without laser irradiation. Antigen CD34 was assessed by immunohistochemistry as a marker of angiogenesis, and its expression was examined by computer-assisted histomorphometric image analysis. As a result, we report that biostimulating laser therapy in HIV-infected patients of varying degrees of immunodeficiency greatly accelerated post-extraction neoangiogenesis, regardless of the patient’s gender, tooth position, number of roots, or number of CD4 lymphocytes in the blood. Application of low-level laser therapy for the treatment of tooth extraction wounds in HIV(+) patients greatly enhanced the formation of new blood vessels, which in turn promoted wound healing.
Lasers Med Sci 2013 Aug 6
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Myofascial trigger point therapy: laser therapy and dry needling.
Uemoto L, Nascimento de Azevedo R, Almeida Alfaya T, Nunes Jardim Reis R, Depes de Gouvea CV, Cavalcanti Garcia MA
Faculdade de Odontologia (Departamento de Odontotecnica), UFF, Rua Sao Paulo, 28. Campos do Valonguinho, Centro, Niteroi, RJ, CEP: 24020-150, Brazil, lucianauemoto@hotmail.com.
The aim of the present review is to discuss two forms of treatment for myofascial pain: laser therapy and dry needling. Although studies have reported the deactivation of myofascial trigger points with these two methods, clinical trials demonstrating their efficacy are scarce. The literature reports greater efficacy with the use of laser over dry needling. It has been suggested that improvements in microcirculation through the administration of laser therapy may favor the supply of oxygen to the cells under conditions of hypoxia and help remove the waste products of cell metabolism, thereby breaking the vicious cycle of pain, muscle spasm and further pain. While laser therapy is the method of choice for patients with a fear of needles and healthcare professionals inexperienced with the dry needling technique, further controlled studies are still needed to prove the greater efficacy of this method.
Curr Pain Headache Rep 2013 Sep 17(9) 357
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Effects of infrared-LED illumination applied during high-intensity treadmill training in postmenopausal women.
Paolillo FR, Milan JC, Aniceto IV, Barreto SG, Rebelatto JR, Borghi-Silva A, Parizotto NA, Kurachi C, Bagnato VS
Optics Group from Instituto de Fisica de Sao Carlos, University of Sao Paulo, Sao Paulo, Brazil. fer.nanda.rp@hotmail.com
BACKGROUND DATA: Technology and physical exercise can enhance physical performance during aging. OBJECTIVE: The purpose of this study was to investigate the effects of infrared-light-emitting diode (LED) illumination (850 nm) applied during treadmill training. MATERIALS AND METHODS: Twenty postmenopausal women participated in this study. They were randomly divided into two groups. The LED group performed treadmill training associated with infrared-LED illumination (n=10) and the control group performed only treadmill training (n=10). The training was performed during 3 months, twice a week during 30 min at intensities between 85 and 90% of maximal heart rate. The irradiation parameters were 31 mW/cm(2), treatment time 30 min, 14,400 J of total energy and 55.8 J/cm(2) of fluence. Physiological, biomechanical, and body composition parameters were measured at the baseline and after 3 months. RESULTS: Both groups improved the time of tolerance limit (Tlim) (p<0.05) during submaximal constant-speed testing. The peak torque did not differ between groups. However, the results showed significantly higher values of power [from 56+/-10 to 73+/-8 W (p=0.002)] and total work [from 1,537+/-295 to 1,760+/-262 J (p=0.006)] for the LED group when compared to the control group [power: from 58+/-14 to 60+/-15 W (p>/=0.05) and total work: from 1,504+/-404 to 1,622+/-418 J (p>/=0.05)]. The fatigue significantly increased for the control group [from 51+/-6 to 58+/-5 % (p=0.04)], but not for the LED group [from 60+/-10 to 60+/-4 % (p>/=0.05)]. No significant differences in body composition were observed for either group. CONCLUSIONS: Infrared-LED illumination associated with treadmill training can improve muscle power and delay leg fatigue in postmenopausal women.
Photomed Laser Surg 2011 Sep 29(9) 639-45
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Differential brain effects of laser and needle acupuncture at LR8 using functional MRI.
Quah-Smith I, Williams MA, Lundeberg T, Suo C, Sachdev P
School of Psychiatry, University of New South Wales and Neuropsychiatric Institute (NPI), Prince of Wales Hospital, , Sydney, New South Wales, Australia.
OBJECTIVE: While needle acupuncture is a well-accepted technique, laser acupuncture is being increasingly used in clinical practice. The differential effects of the two techniques are of interest. We examine this in relation to brain effects of activation of LR8, a putative acupuncture point for depression, using functional MRI (fMRI). METHODS: Sixteen healthy participants were randomised to receive low intensity laser acupuncture to LR8 on one side and needle acupuncture to the contralateral LR8. Stimulation was in an on-off block design and brain patterns were recorded under fMRI. RESULTS: Significant activation occurred in the left precuneus during laser acupuncture compared with needle acupuncture and significant activation occurred in the left precentral gyrus during needle acupuncture compared with laser acupuncture. CONCLUSIONS: Laser and needle acupuncture at LR8 in healthy participants produced different brain patterns. Laser acupuncture activated the precuneus relevant to mood in the posterior default mode network while needle acupuncture activated the parietal cortical region associated with the primary motor cortex. Further investigations are warranted to evaluate the clinical relevance of these effects.
Acupunct Med 2013 Sep 31(3) 282-9
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Effect of low-power gallium-aluminum-arsenium noncoherent light (640 nm) on muscle activity: a clinical study.
Kelencz CA, Munoz IS, Amorim CF, Nicolau RA
Institute of Research and Development (IP&D), Universidade do Vale do Paraiba (UNIVAP), Paraiba, Brazil. carloskelencz@terra.com.br
BACKGROUND DATA: Studies have shown the significant effects of electromagnetic irradiation in the visible region, with laser as an irradiation source. However, the effect of LEDs (light-emitting diodes) irradiation in similar wavelengths is not known. OBJECTIVE: The purpose of this clinical study was to verify the effects of the LED (640 nm with 40 nm full bandwidth at half maximum) on muscle activity. METHODS: The study was done with 30 test subjects, of both genders, aged 23 +/- 3 years, with a mean weight of 60 kg, divided into three groups (n = 10). Fatigue was induced through the maximum power of a bite, for 60 s in two overlaid occlusal platforms, coupled to a load cell and to a biologic signal-acquisition device. LED irradiation of the right masseter muscle was applied to all subjects. The left muscle received placebo treatment. Irradiation was applied in eight points on the right masseter muscle (transcutaneous), 1.044 J per point, 2.088 J per point, or 3.132 J per point, 0.116 W, 0.522 cm(2) spot size, 0.816 cm spot O, continuous wave, perpendicular to the skin. RESULTS: An increase in muscle activity was observed after irradiation with 1.044 J per point (p < 0.05). A significant increase (p < 0.01) in the time before fatigue was observed in the irradiated muscle with 2.088 J per point, without a change in the force of contraction (p > 0.05). This change was not observed with 1.044 J per point and 3.132 J per point. The results suggest a dose-dependent relation with this kind of noncoherent irradiation in the red region of the electromagnetic spectrum in the muscle-fatigue process. CONCLUSION: It was concluded that LED can be used as a clinical tool to increase muscle activity (1.044 J per point) and to prevent fatigue (2.088 J per point), without change in the muscle force.
Photomed Laser Surg 2010 Oct 28(5) 647-52
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Laser therapy in a soft-shelled turtle (Pelodiscussinensis) for the treatment of skin and shell ulceration. A case report.
Kraut S, Fischer D, Heuser W, Lierz M
Dominik Fischer, Klinik fur Vogel, Reptilien, Amphibien und Fische, Justus-Liebig-Universitat Giessen, Frankfurter Strasse 91-93, 35392 Giessen, Germany, Email: dominik.fischer@vetmed.uni-giessen.de.
Skin and shell diseases in aquatic turtles are often associated with several underlying causes. The presented case report describes aetiology including differential diagnoses, diagnostic procedures and therapy of a soft-shelled turtle (Pelodiscus sinensis) suffering from a septicaemic ulcerative dermatitis. Central aspect hereby is the positive curing effect of laser therapy on skin and shell lesions.
Tierarztl Prax Ausg K Kleintiere Heimtiere 2013 Aug 20 41(4) 261-6
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Auricular acupuncture with laser.
Round R, Litscher G, Bahr F
Frank Bahr Research Group “Auriculomedicine and Pharmacopuncture”, Stronach Research Unit for Complementary and Integrative Laser Medicine, Research Unit of Biomedical Engineering, Anesthesia and Intensive Care Medicine, and the TCM Research Center Graz, Medical University of Graz, Auenbruggerplatz 29, 8036 Graz, Austria.
Auricular acupuncture is a method which has been successfully used in various fields of medicine especially in the treatment of pain relief. The introduction of lasers especially low-level lasers into medicine brought besides the already existing stimulation with needles and electricity an additional technique to auricular acupuncture. This literature research looks at the historical background, the development and the anatomical and neurological aspects of auricular acupuncture in general and auricular laser acupuncture in detail. Preliminary scientific findings on auricular acupuncture with laser have been described in detail and discussed critically in this review article. The results of the studies have shown evidence of the effect of auricular laser acupuncture. However, a comparison of these studies was impossible due to their different study designs. The most important technical as well as study parameters were described in detail in order to give more sufficient evidence and to improve the quality of future studies.
Evid Based Complement Alternat Med 2013 2013 984763
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The Use of Low Level Light Therapy in the Treatment of Androgenetic Alopecia and Female Pattern Hair Loss.
Gupta A Dr, Daigle D
Mediprobe Research Inc, 645 Windermere Road, London, Ontario, Canada, ON N6K 1L6, 519-657-4222, 519-657-4233.
Abstract Androgenetic alopecia (AGA) or female pattern hair loss (FPHL) is the most common form of hair loss in men and women. Despite its common occurrence, our understanding of the etiology of AGA and FPHL remains incomplete. As such, traditional therapies demonstrate modest efficacies and new therapies continue to be sought. Low-level light therapy (LLLT) is a relatively new technique used to promote hair growth in both men and women with AGA and FPHL. Currently, there exist several LLLT devices marketed for the treatment of alopecia, which claim to stimulate hair growth; yet marketing these devices only requires that safety, not efficacy, be established. A handful of studies have since investigated the efficacy of LLLT for alopecia with mixed results. These studies suffered from power, confounding, and analysis issues which resulted in a high risk of bias in LLLT studies. Due to the paucity of well-conducted randomized controlled trials, the efficacy of LLLT devices remains unclear. RCTs of LLLT conducted and reported according to the Consolidated Standards of Reporting Trials (CONSORT) statement would greatly increase the credibility of the evidence and clarify the ambiguity of the effectiveness of LLLT in the treatment of AGA and FPHL.
J Dermatolog Treat 2013 Aug 7
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Blue and red light combination LED phototherapy for acne vulgaris in patients with skin phototype IV.
Lee SY, You CE, Park MY
Department of Dermatology, National Medical Center, Seoul, Republic of Korea.
BACKGROUND AND OBJECTIVES: Blue light is effective for acne treatment, inducing photodynamic destruction of Propionibacterium acnes (P. acnes). This study was designed to investigate the efficacy of combined blue and red light-emitting diode (LED) phototherapy for acne vulgaris. MATERIALS AND METHODS: Twenty-four patients with mild to moderately severe facial acne were treated with quasimonochromatic LED devices, alternating blue (415 nm) and red (633 nm) light. The treatment was performed twice a week for 4 weeks. Objective assays of the skin condition were carried out before and after treatment at each treatment session. Clinical assessments were conducted before treatment, after the 2nd, 4th, and 6th treatment sessions and at 2, 4, and 8 weeks after the final treatment by grading and lesion counting. RESULTS: The final mean percentage improvements in non-inflammatory and inflammatory lesions were 34.28% and 77.93%, respectively. Instrumental measurements indicated that the melanin levels significantly decreased after treatment. Brightened skin tone and improved skin texture were spontaneously reported by 14 patients. CONCLUSION: Blue and red light combination LED phototherapy is an effective, safe and non-painful treatment for mild to moderately severe acne vulgaris, particularly for papulopustular acne lesions.
Lasers Surg Med 2007 Feb 39(2) 180-8
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Low level laser therapy in the treatment of aphthous ulcer.
Anand V, Gulati M, Govila V, Anand B
Department of Periodontics, Babu Banarasi Das College of Dental Sciences, Babu Banarasi Das University, Chinhat, Lucknow, Uttar Pradesh, India.
Recurrent aphthous stomatitis (RAS) is one of the most common and painful ulcerative lesions of the oral cavity, but until now no cure has been recognized for it. Two patients diagnosed with minor RAS were treated in a single sitting with low level laser therapy using 940-nm diode laser. The lesions healed completely within 3-4 days and a follow-up for 1 showed no recurrence in these patients. According to the results of this study, low level laser therapy can decrease the healing time, pain intensity, size, and recurrence of the lesion in patients with minor RAS, and hence can be considered the most appropriate treatment modality for minor RAS, with greatest clinical effectiveness.
Indian J Dent Res 2013 Mar-Apr 24(2) 267-70
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Facial rejuvenation and light: our personal experience.
Trelles MA, Mordon S, Calderhead RG
Instituto Medico Vilafortuny, Antoni de Gimbernat Foundation, Cambrils, Spain. imv@laser-spain.com
The treatment of ageing skin remains a very hot topic, and many systems have been reported as having varying degrees of success. Nonablative lasers were developed to avoid the problematic and uncomfortable sequelae following laser ablative resurfacing, and while there was no downtime, there was also poor patient satisfaction. The same was true of the intense pulsed light systems. The use of different modalities in various combinations was found to offer much better results, however, such as a 595-nm pulsed dye laser followed by a 1,450-nm diode laser, and so on, all used at subablative thresholds. The recent entry of blue and infrared tunable plasma light and light-emitting diodes into the skin rejuvenation arena has attracted a great deal of attention. The authors suggest that no single modality can accomplish all the complex events required for effective skin rejuvenation, suggest that combination phototherapy is the best approach combined with an adjunctive epidermal care regimen, and demonstrate their development of this methodology.
Lasers Med Sci 2007 Jun 22(2) 93-9
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Fibrosis Inhibition of Photobiomodulation Promoted Regeneration.
Li XE, Zhu L, Liu TC
Laboratory of Laser Sports Medicine, South China Normal University , Guangzhou, China .
Photomed Laser Surg 2013 Aug 14
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Effect of LED light spectra on starvation-induced oxidative stress in the cinnamon clownfish Amphiprion melanopus.
Choi CY, Shin HS, Choi YJ, Kim NN, Lee J, Kil GS
Division of Marine Environment & BioScience, Korea Maritime University, Busan 606-791, Republic of Korea. choic@hhu.ac.kr
The present study aimed to test starvation-induced oxidative stress in the cinnamon clownfish Amphiprion melanopus illuminated by light-emitting diodes (LEDs): red (peak at 630 nm), green (peak at 530 nm), and blue (peak at 450 nm) within a visible light. We investigated the oxidative stress induced by starvation for 12 days during illumination with 3 LED light spectra through measuring antioxidant enzyme (superoxide dismutase [SOD] and catalase [CAT]) mRNA expression and activity; CAT western blotting; and measuring lipid peroxidation [LPO]), plasma H(2)O(2), lysozyme, glucose, alanine aminotransferase (AlaAT), aspartate aminotransferase (AspAT), and melatonin levels. In green and blue lights, expression and activity of antioxidant enzyme mRNA were significantly lower than those of other light spectra, results that are in agreement with CAT protein expression level by western blot analysis. Also, in green and blue lights, plasma H(2)O(2), lysozyme, glucose, AlaAT, AspAT, and melatonin levels were significantly lower than those in other light spectra. These results indicate that green and blue LEDs inhibit oxidative stress and enhance immune function in starved cinnamon clownfish.
Comp Biochem Physiol A Mol Integr Physiol 2012 Nov 163(3-4) 357-63
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Effect of light-emitting diode (LED) therapy on the development of osteoarthritis (OA) in a rabbit model.
Oshima Y, Coutts RD, Badlani NM, Healey RM, Kubo T, Amiel D
Department of Orthopaedic Surgery, University of California San Diego, La Jolla CA 92093-0863, USA. yasushi@sj8.so-net.ne.jp
OBJECTIVE: The objective of this study was to evaluate whether light-emitting diodes (LEDs) could be effective in a noninvasive, therapeutic device for the treatment of osteoarthritic (OA) knee joints. DESIGN: Five weeks following the anterior cruciate ligament transection (ACLT) of mature New Zealand White rabbits, the animal knees were exposed to LED stimulation at intervals of 10 min/day, 5 days/week for 5 weeks in the experimental group (n=7). The device used high intensity red and infrared (IR) LEDs with a total amount of energy delivered to the skin of 2.4 J/cm(2). Animals were sacrificed at 9 weeks postoperatively. Femoral surface gross morphology was evaluated with a modified Outerbridge classification and mRNA expression of catabolic and anabolic markers from femoral condyle cartilage and synovial tissue was assessed using RT-PCR. A control group was harvested 9 weeks following untreated ACLT. RESULTS: Gross morphometry of the control group showed four Grade II, two Grade III and one Grade IV (average 2.6) condyles macroscopically. The experimental group showed two Grade I and five Grade II (average 1.7) (Table 1). mRNA expression of aggrecan in the cartilage showed no difference between the groups, however type II collagen expression increased in the experimental group compared with control. TNF-alpha expression was significantly decreased in the experimental group compared to control. CONCLUSIONS: There was general preservation of the articular surface and decreased levels of inflammation in the osteoarthritic joints with the application of LED therapy. This may provide potential application as a noninvasive treatment.
Biomed Pharmacother 2011 Jun 65(3) 224-9
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Red-light light-emitting diode irradiation increases the proliferation and osteogenic differentiation of rat bone marrow mesenchymal stem cells.
Li WT, Leu YC, Wu JL
Department of Biomedical Engineering, Chung Yuan Christian University, Chung-Li, Taiwan, Republic of China. wtli@cycu.edu.tw
OBJECTIVE: The objective of this study was to investigate the effects on the proliferation and osteogenic differentiation of rat mesenchymal stem cells (MSCs) by using red-light light-emitting diode (LED) irradiation. BACKGROUND DATA: Low-level light irradiation (LLLI) has been shown to enhance proliferation and cytokine secretion of a number of cells. MSCs are capable of regenerating various mesenchymal tissues and are essential in supporting the growth and differentiation of hematopoietic stem cells within the bone marrow. MATERIALS AND METHODS: Rat bone marrow MSCs were treated with single or multiple doses of LLLI from an LED array (630 nm) at the irradiances of 5 and 15 mW/cm(2), and radiant exposures of 2 and 4 J/cm(2). The proliferation, clonogenic potential, and osteogenic differentiation of MSCs were evaluated after illumination. RESULTS: The growth of MSCs was enhanced by red-light LLLI, and the effect became more obvious at low cell density. A single dose of LLLI led only to a short-term increase in MSCs proliferation. A maximal increase in cell proliferation was observed with multiple exposures of LLLI at 15 mW/cm(2) and 4 J/cm(2). The number of colony-forming unit fibroblasts increased when cells were illuminated under the optimal parameter. During osteogenesis, significant increases (p < 0.01) in both alkaline phosphatase and osteocalcin expressions were found in the MSCs that received light irradiation. CONCLUSION: Our data demonstrated that MSCs proliferation was enhanced by multiple exposures to LLLI from 630-nm LEDs, and cell growth depended on the plating density. Furthermore, multiple dose of LLLI could enhance the osteogenic potential of rat MSCs.
Photomed Laser Surg 2010 Aug 28 Suppl 1 S157-65
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Near-infrared light protect the photoreceptor from light-induced damage in rats.
Qu C, Cao W, Fan Y, Lin Y
Department of Ophthalmology, Sichuan Academy of Medical Sciences, Sichuan, China.
BACKGROUND: A project originally developed for NASA plant growth experiments in space demonstrating the Light-Emitting Diode (LED) could promote the wound healing. Further study showed that the LED’s could protect cells by stimulating the basic energy processes in the mitochondria of each cell. OBJECTIVE: The purpose of this study was to assess the effects of 670 nm LED to protect the photoreceptor from the light-induced damage in a rodent model. METHODS: SD rats were randomly assigned to one of eight groups: untreated control group, the LED-treated control group, three light-induced damage groups, and three LED-protected groups. The rats were exposed to constant light for 3 h of different illuminations of 900, 1,800 and 2,700 lux, respectively. The LED treatment (50 mW) were done for 30 min, 3 h before the light damage and 0, 24 and 48 h after the light damage. Using the electroretinogram as a sensitive indicator of retinal function, and the histopathologic change was showed as a proof of the protective effect of LED treatment. RESULTS: The 900 lux illumination for 3 h did not cause damage to the retina of rats, however, the 1,800 lux illumination for 3 h caused significant damage to ONL of an approximate half retina, which caused the swing of ERG b wave to be 431 muV. With the LED protection: the damage of ONL was near 1/6 of retina, which was significantly reduced than the ones without LED protection (P < 0.01); and the swing of ERG b wave was recorded to be 1,011 muV, which was increased significantly than the ones without LED protection (P < 0.01). The illumination of 2,700 lux for 3 h caused severe damage to the rats’ retinas and the LED could not protect them significantly in both of morphology and function (P > 0.05, P > 0.05). CONCLUSIONS: 670 nm LED treatment has an evident protective effect on retinal cells against light-induced damage, which may be an innovative and non-invasive therapeutic approach to prevent or to delay age-related macular degeneration.
Adv Exp Med Biol 2010 664 365-74
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Effects of low level red-light irradiation on the proliferation of mesenchymal stem cells derived from rat bone marrow.
Li WT, Leu YC
Department of Biomedical Engineering, Chung-Yuan Christian University, Chung-Li, 32023 Taiwan, ROC. wtli@be.cycu.edu.tw
Mesenchymal stem cells (MSCs) are capable of regenerating various mesenchymal tissues and are essential in supporting the growth and differentiation of hematopoietic stem cells within the bone marrow microenvironment in vivo. To achieve clinically meaningful numbers of cells, many approaches have been used to maintain the differentiation potentialities and expand enough cells for clinical treatments. Previously, we have reported that low level light irradiation (LLLI) using 630 nm light emitting diodes (LEDs) could enhance replicative and colony formation potentials of MSCs derived from human bone marrow. The purpose was to study the effect on the proliferation of MSCs derived from the rat bone marrow by red light LLLI (630 nm) under different parameters of irradiation. The irradiance used was 5, 10 or 15 mW/cm2, and the radiant exposure was 2 or 4 J/cm2. Rat MSCs were irradiated at room temperature with single and multiple exposures. The results showed that the proliferation of MSCs plated at the low density (100 cells/well) and high density (1000 cells/well) was enhanced by multiple exposures of red-light LED treatment. The rate of proliferation of MSCs plated at the high density was not as high as those plated at the low density. The optimal parameter for LLLI was at irradiance of 15 mW/cm2, and radiant exposure of 4 J/cm2. The effect on the proliferation of cells by single dose irradiation was temporary. Multiple stimuli may be necessary for the enhancement of cell growth.
Conf Proc IEEE Eng Med Biol Soc 2007 2007 5830-33
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Effect of low-level laser therapy on metalloproteinase MMP-2 and MMP-9 production and percentage of collagen types I and III in a papain cartilage injury model.
Alves AC, Albertini R, Dos Santos SA, Leal-Junior EC, Santana E, Serra AJ, Silva JA Jr, de Carvalho PD
Postgraduate Program in Rehabilitation Sciences, Universidade Nove de Julho (UNINOVE), Sao Paulo, Sao Paulo, Brazil.
Osteoarthritis (OA) resulting from injury or disease is associated with increased levels of several matrix metalloproteinases (MMPs), which degrade all components of the complex extracellular matrix in the cartilage. The objective of this study is to investigate the effect of low-level laser therapy (LLLT) on papain-induced joint damage in rats by histopathology and analysis of metalloproteinase 2 and 9 production. Sixty male Wistar rats were randomly distributed into four groups of 15 animals: (1) non-injury negative control, (2) injury positive control, (3) treated with LLLT at 50 mW, and (4) treated with LLLT at 100 mW. OA was induced in animals using papain (4 % solution) followed by treatment with LLLT. After 7, 14, and 21 days, the animals were euthanized. The articular lavage was collected and centrifuged; then, the supernatant was stored prior to protein analysis by western blot. The material was stained with hematoxylin and eosin for histopathological analysis, and Picrosirius Red was used to estimate the percentage of collagen fibers. To determine normal distribution, ANOVA and Tukey’s post hoc test were used for comparison between and within each group at each time period. All data are expressed as mean and standard deviation values, with the null hypothesis considered as p < 0.05. Both laser groups (50 and 100 mW) were effective in tissue repair, decreasing collagen type III expression and increasing type I expression in all experimental periods; however, LLLT at 50 mW reduced metalloproteinase 9 more than at 100 mW in 21 days. LLLT at 50 mW was more efficient in the modulation of matrix MMPs and tissue repair.
Lasers Med Sci 2013 Aug 29
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The effect of low-level laser therapy on the healing of hard palate mucosa and the oxidative stress status of rats.
Firat ET, Dag A, Gunay A, Kaya B, Karadede MI, Ersoz Kanay B, Ketani A, Evliyaoglu O, Uysal E
Department of Periodontology, Faculty of Dentistry, Dicle University, Diyarbakir, Turkey.
OBJECTIVE: The biostimulation effects of low-level laser therapy (LLLT) have been demonstrated recently. This study investigated the effects of LLLT on palatal mucoperiosteal wound healing and oxidative stress status in rats. MATERIAL AND METHOD: Forty-two male Wistar rats weighing 250-300 g were used in this study. A standardized full-thickness wound was created in the mucoperiosteum of the hard palates of the rats using a 3-mm-diameter biopsy punch. Treatment using a GaAlAs laser at a wavelength of 940 nm and a dose of 10 J/cm2 was initiated after surgery and repeated on the 2nd, 4th, and 6th days post-surgery. Seven animals from each group were sacrificed on the 7th, 14th, and 21st days after surgery. Total antioxidant status and total oxidative status were measured in serum. RESULTS: The histopathological findings revealed reduced numbers of inflammatory cells on the 7th day, increased mitotic activity of fibroblasts on the 14th and 21st day, and the same degree of collagen synthesis and vascularization on the days 7, 14, and 21 in the LLLT group compared with the control group. No significant differences in total oxidative status and total antioxidant status were observed between the groups. CONCLUSION: LLLT using a GaAlAs laser at a wavelength of 940 nm and a dose of 10 J/cm2 elicited a positive healing effect on palatal mucoperiosteal wounds likely via the induction of fibroblasts. The oxidative stress status was not affected by LLLT.
J Oral Pathol Med 2013 Aug 19
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670nm Photobiomodulation as a Novel Protection against Retinopathy of Prematurity: Evidence from Oxygen Induced Retinopathy Models.
Natoli R, Valter K, Barbosa M, Dahlstrom J, Rutar M, Kent A, Provis J
The John Curtin School of Medical Research, Australian National University, Canberra, Australian Capital Territory, Australia ; ARC Centre of Excellence in Vision Science, Australian National University, Canberra, Australian Capital Territory, Australia ; ANU Medical School, Australian National University, Canberra, Australian Capital Territory, Australia.
INTRODUCTION: To investigate the validity of using 670nm red light as a preventative treatment for Retinopathy of Prematurity in two animal models of oxygen-induced retinopathy (OIR). MATERIALS AND METHODS: During and post exposure to hyperoxia, C57BL/6J mice or Sprague-Dawley rats were exposed to 670nm light for 3 minutes a day (9J/cm(2)). Whole mounted retinas were investigated for evidence of vascular abnormalities, while sections of neural retina were used to quantify levels of cell death using the TUNEL technique. Organs were removed, weighed and independent histopathology examination performed. RESULTS: 670nm light reduced neovascularisation, vaso-obliteration and abnormal peripheral branching patterns of retinal vessels in OIR. The neural retina was also protected against OIR by 670nm light exposure. OIR-exposed animals had severe lung pathology, including haemorrhage and oedema, that was significantly reduced in 670nm+OIR light-exposed animals. There were no significance differences in the organ weights of animals in the 670nm light-exposed animals, and no adverse effects of exposure to 670nm light were detected. DISCUSSION: Low levels of exposure to 670nm light protects against OIR and lung damage associated with exposure to high levels of oxygen, and may prove to be a non-invasive and inexpensive preventative treatment for ROP and chronic lung disease associated with prematurity.
PLoS One 2013 8(8) e72135
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LED and laser photobiomodulation in the prevention and treatment of oral mucositis: experimental study in hamsters.
Freire MD, Freitas R, Colombo F, Valenca A, Marques AM, Sarmento VA
Federal University of Bahia, Rua Araujo Pinho, 62 Canela, Salvador, Bahia, 40110-150, Brazil, rosariofreire@ufba.br.
PURPOSE: This paper aims to evaluate the effects of laser (660 nm) and light-emitting diode (LED) (670 nm) irradiation in the cheek pouch mucosa of hamsters with oral mucositis (OM) induced by chemotherapy (Che) with 5-fluorouracil (5-FU). MATERIALS AND METHODS: In the preventive groups, the photobiomodulation was started 1 day before the drug administration and was performed every 48 h (Ia, IIa, Ib, and IIb). In the therapeutic groups (IIIa, IIIb, IVa, and IVb), the irradiations were started on the third day after the Che d(0) and was performed every 48 h. In both groups, animals were sacrificed 7 or 14 days after Che. In the positive control groups, the hamsters were subjected to Che but did not receive irradiation, and they were sacrificed in 7 days (Va) or 14 days (Vb). In the negative control groups, no procedures were done and the animals were sacrificed 7 days (Vc) or 14 days (Vd) after the experiment started. RESULTS: The results indicated loss of body mass, xerostomia, and alopecia in the animals subjected to Che and the healing of OM to different degrees after the photobiomodulation treatment. Histologically, the positive control and experimental groups showed inflammation, predominately with lymphocytes and plasma cells, which tended to diminish with time. Epithelial atrophy, hyperemia, fibroblast proliferation, and vascular congestion were also observed at those intervals. CONCLUSIONS: The best results were obtained from the preventive laser and LED photobiomodulation groups; both treatments were effective in diminishing the OM lesions. CLINICAL RELEVANCE: A noninvasive and effective method with sparse side effects of OM would be desirable for use in cancer centers around the world.
Clin Oral Investig 2013 Aug 15
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Effects of low-intensity laser therapy over mini-implants success rate in pigs.
Garcez AS, Suzuki SS, Martinez EF, Iemini MG, Suzuki H
Sao Leopoldo Mandic Dental Research Center, Campinas, SP, Brazil, garcez.segundo@gmail.com.
The success rate of miniscrews when used as temporary orthodontic anchorage is relatively high, but some factors could affect its clinical success such as inflammation around the miniscrew. Low-intensity laser therapy has been widely used for biostimulation of tissue and wound healing specially for its anti-inflammatory effects. The purpose of this study was to evaluate the effect of low-intensity laser therapy over the miniscrew success rate. Five Landrace’s pigs received 50 miniscrews on the buccal side of the mandible and on the palate of the maxilla. All the miniscrews were immediately loaded with 250 gf. The laser group were irradiated with a 780-nm diode laser with 70 mWs for 1 min (dose = 34 J/cm2); the contralateral side was used as the control group. The miniscrews were photographed and analyzed clinically every week to determine their stability and presence of local inflammation. After 3 weeks, histological analysis and fluorescent microscopy were performed to compare the laser and the control side. Clinical results showed a success rate of 60 % for the control group and 80 % for the laser-treated group. The histological analysis and fluorescent microscopy demonstrated that the laser group had less inflammatory cells than the control group and the bone neoformation around the miniscrew was more intense. Low-intensity laser therapy increased the success rate of orthodontic miniscrews, probably due to anti-inflammatory effect and bone stimulation.
Lasers Med Sci 2013 Aug 9
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The effects of diode laser (660 nm) on the rate of tooth movements: an animal study.
Shirazi M, Ahmad Akhoundi MS, Javadi E, Kamali A, Motahhari P, Rashidpour M, Chiniforush N
Department of Orthodontics, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran.
Low-level laser has been indicated to have the capability to facilitate the differentiation of the osteoclastic and osteoblastic cells which are responsible for the bone remodeling process. The aim of this study was to evaluate the effects of InGaAlP laser with a wavelength of 660 nm on the rate of tooth movement and histological status. Thirty male Wistar rats of 7 weeks old were selected for this study. The rats were randomly divided into two groups of 15 each to form the experimental (laser-irradiated) and control (non-irradiated) groups. The control group received unilateral orthodontic appliance design (one quadrant), but the laser-irradiated group received split-mouth design, with orthodontic appliance on both sides and laser irradiation on one side only (group b) and on the contralateral side (group c). The orthodontic appliance consisted of a NiTi closed coil spring with a length of 5 mm which was ligated to maxillary molar and incisor. A total of 60 g of force was applied to the rat molar. The diode laser (660 nm) was irradiated with an output power of 25 mW in continuous mode for a total time of 5 min in the laser-irradiated group. After 14 days of orthodontic tooth movement, the amount of tooth movements was measured. In the laser-irradiated group, the amount of tooth movement was significantly greater than that of the non-irradiated group (2.3-fold), but there was no significant difference between the non-irradiated and indirectly irradiated groups. Histopathological studies revealed that the number of osteoclasts in the laser-irradiated group was significantly greater than that of the non-irradiated group (1.5-fold) while this number was almost the same in the non-irradiated and indirectly irradiated groups. The results suggested that low-level laser can accelerate the rate of bone remodeling. However, in order to utilize the low-level laser as an adjunct in orthodontic practice on patients, further research studies are needed for finding the appropriate dosage for the human tissues.
Lasers Med Sci 2013 Aug 7
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Comparison of light-emitting diode wavelength on activity and migration of rabbit ACL cells.
Seo YK, Park JK, Song C, Kwon SY
Department of Medical Biotechnology, Dongguk University, Seoul, 100-715, South Korea.
The purpose of this study was to evaluate the biological response and gene expression of New Zealand White Rabbit anterior cruciate ligament (ACL) fibroblasts for different wave lengths of light-emitting diode (LED) irradiation. In other words, this study was undertaken to evaluate the effects of different wavelengths of LED irradiation on cell growth, expression of extracellular matrix and growth factors, migration, and expression of actin and integrin. Proliferation assay showed that red (630 nm, 9.5 J/cm2) and green LED (530 nm, 9.8 J/cm2) irradiated cells were more increased than control group but there was no difference between the control group and the blue LED (460 nm, 27 J/cm2) irradiated group. Moreover, the expression of insulin-like growth factor, transforming growth factor-beta (TGF-beta1), and collagen I were significantly increased in the red and green LED-irradiated group, but the expression of collagen was decreased in the blue LED-irradiated group. The results of staining showed that collagen and TGF-beta1 were weaker in the control group and blue LED-irradiated cells, but stronger in the red and green LED-irradiated cells. Also, in the red and green LED-irradiated group, the expression of actin and integrin was not changed compared to the control group, but the expression of actin and integrin was decreased in the blue irradiated group. This study revealed that irradiation with a wavelength of 460 nm (blue LED) is cytotoxic to ACL cells, but irradiation with nontoxic fluencies of 530 (green LED) and 630 nm (red LED) wavelengths induced cell growth in cultured ACL cells.
Lasers Med Sci 2013 Apr 25
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Effect of monochromatic visible light on intracellular superoxide anion production and mitochondrial membrane potential of B16F1 and B16F10 murine melanoma cells.
Sato K, Minai Y, Watanabe H
Department of Life Science, College of Agriculture, Tamagawa University, 6-1-1 Tamagawa Gakuen, Machida, Tokyo, Japan.
We have investigated the effect of visible light on animal cells using light-emitting diodes to emit monochromatic visible light (red, yellow, green and blue light). To explore the relevant mechanism of apoptosis, we assessed the intracellular superoxide anion production and mitochondrial membrane potential (DeltaPsim) of B16F1 and B16F10 murine melanoma cells after monochromatic light irradiation. Blue light caused DeltaPsim depolarization subsequent to elevation of intracellular superoxide production. However, red and yellow light had no affect on both cell lines. Green light induced DeltaPsim collapse only in B16F1 melanoma cells. DeltaPsim is a key indicator of mitochondrial function, therefore its disruption causes mitochondria-dependent apoptosis. Thus, blue light causes mitochondrial dysfunction and subsequent cell death.
Cell Biol Int 2013 Jun 37(6) 633-7
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Blue LED inhibits the growth of Porphyromonas gingivalis by suppressing the expression of genes associated with DNA replication and cell division.
Chui C, Hiratsuka K, Aoki A, Takeuchi Y, Abiko Y, Izumi Y
Department of Periodontology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.
BACKGROUND AND OBJECTIVES: Blue light has been employed or investigated in both the medical and dental fields. Many studies have so far been reported a bactericidal effect of blue light emitting diodes (LED). However, it is still unclear whether exposure to blue LED kills or inhibits the growth of bacteria. We therefore investigated the effect of blue LED irradiation on the growth of Porphyromonas gingivalis compared with the effects of red LED. MATERIALS AND METHODS: P. gingivalis cell suspensions were irradiated with blue or red LED (135 J/cm2) anaerobically, incubated for various lengths of time, and then the total RNAs were isolated. The RNA degradation and gene expression levels of stress-related proteins in blue or red LED-irradiated samples were examined using the RNA integrity number (RIN) and RT-PCR, respectively. Quantitative RT-PCR was done to investigate the gene expression profiles associated with chromosome replication and cell division. RESULTS: Exposure to blue LED delayed the growth of P. gingivalis, while red LED did not. The RIN value indicated no RNA degradation in either the blue or red LED-irradiated samples. In addition, the gene expression levels of stress-related molecules remained either constant or increased 15 minutes after the blue LED irradiation compared to that before irradiation, thus suggesting that blue LED may not kill P. gingivalis cells. However, the blue LED irradiation did lead to a remarkably decreased expression of genes associated with chromosomal DNA replication and cell division after 5 minutes; exposure to the red LED did not. CONCLUSION: The inhibition of the growth of P. gingivalis by blue LED may therefore be induced not by a bactericidal effect, but instead due to a bacteriostatic effect mediated by the suppression of the genes associated with chromosomal DNA replication and cell division at the transcriptional level.
Lasers Surg Med 2012 Dec 44(10) 856-64
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Nitrergic response to Clostridium perfringens infection in the rat brain regions: effect of red light irradiation.
Movsesyan HA, Alchujyan NKh, Movsesyan NH, Guevorkian AG, Hairapetyan HL, Barsegyan KA, Kevorkian GA
H.Buniatian Institute of Biochemistry NAS RA, 5/1 P. Sevak St., 0014, Yerevan, Republic of Armenia.
A single intraperitoneal injection of a gram-positive pathogen Clostridium perfringens (Cp) causes a remarkable down-regulation the constitutive nitric oxide synthase (cNOS) with a simultaneous increase in the activity of inducible NOS (iNOS) and the level of reactive nitrogen species in the rat brain major regions (cortex, striatum, hippocampus and hypothalamus) at 48 h post-administration of Cp. Treatment by both a semiconductor laser (SCL) and/or a light-emitting diode (LED) with same wavelength, energy density and time exposure (continuous wave, lambda=654 nm, fluence=1.27 J/cm(2), time exposure=600 s) could modulate brain nitrergic response following Cp-infection. Besides, unlike the LED, the SCL-irradiation prevents the cNOS inhibition in all the studied brain regions and might be useful in restoring its function in neurotransmission and cerebral blood flow, along with providing a protective effect against nitrosative stress-induced iNOS-mediated injury in the brain regions.
Cent Nerv Syst Agents Med Chem 2012 Jun 12(2) 146-52
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Gene expression under laser and light-emitting diodes radiation for modulation of cell adhesion: Possible applications for biotechnology.
Karu T, Pyatibrat L
Laboratory of Laser Biology and Medicine, Institute of Laser and Information Technologies of Russian Academy of Sciences, Troitsk 142190, Moscow Region, Russian Federation. tkaru@isan.troitsk.ru
Experimental data about the modulation of adhesion and proliferation of anchorage-dependent HeLa cells with monochromatic or quasimonochromatic radiation in red to near-infrared region are presented. Cell adhesion and proliferation can be increased by irradiation with light of certain wavelengths (maxima in action spectrum are 619, 675, 740, 760, and 820 nm) or decreased when the activity of photoacceptor (cytochrome c oxidase in mitochondrial respiratory chain) is inhibited by chemicals before the irradiation. This modality allows controlling the number of attached and/or proliferating cells. Possible biotechnology applications of this method are outlined.
IUBMB Life 2011 Sep 63(9) 747-53
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Effects of LED light spectra on oxidative stress and the protective role of melatonin in relation to the daily rhythm of the yellowtail clownfish, Amphiprion clarkii.
Shin HS, Lee J, Choi CY
Division of Marine Environment & BioScience, Korea Maritime University, Busan 606-791, Republic of Korea.
The present study aimed to test the effects of melatonin on oxidative stress in the yellowtail clownfish, Amphiprion clarkii, as produced by light emitting diodes (LEDs): red, green, and blue. We investigated the effects of the different LEDs on oxidative stress by measuring the mRNA expression of arylalkylamine N-acetyltransferase (AANAT2), the expression and activities of antioxidant enzymes (superoxide dismutase, SOD (EC 1.15.1.1); and catalase, CAT (EC 1.11.1.6)), and plasma H2O2 and plasma melatonin levels. In red light, the expression of AANAT2, SOD, and CAT mRNA was significantly higher than those under the other light spectra. SOD and CAT activities and plasma H2O2 and melatonin levels were also significantly higher for the red spectra than those for the other light spectra. These results indicate that red light induces oxidative stress. To investigate the effects of melatonin on oxidative stress, we injected melatonin into live fish (in vivo) or treated cultured pineal organ (in vitro) with melatonin. We found that AANAT2, SOD, and CAT mRNA expression levels, SOD and CAT activities, and plasma H2O2, lipid peroxidation (LPO) and melatonin levels were significantly lower than those for the controls. Therefore, our results indicate that red light induces oxidative stress and melatonin plays the role of a strong antioxidant in yellowtail clownfish.
Comp Biochem Physiol A Mol Integr Physiol 2011 Oct 160(2) 221-8
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Laser-guided repair of complex bile duct strictures.
van Gulik T, Beek J, de Reuver P, Aronson D, van Delden O, Busch O, Gouma D
Department of Surgery, Academic Medical Center, Amsterdam, The Netherlands. t.m.vangulik@amc.uva.nl
BACKGROUND: The repair of bile duct strictures (BDS) requires identification of healthy bile duct proximal to the stenosis. Identification may be difficult in complex bile duct injuries after cholecystectomy or partial liver resection. AIM: We describe a technique to identify the prestenotic bile duct using the sentinel light of a laser fiber passed through the catheter after percutaneous transhepatic biliary drainage (PTD). METHODS: Seven patients were seen with hepatic duct or segmental BDS after (extended) right hemihepatectomy (4), cholecystectomy (2) or previous hepaticojejunostomy (1). All patients underwent preoperative PTD for imaging of stricture site and drainage. During operation for repair, a laser fiber (0.2-0.6 mm) connected to a (low-power) red light-emitting diode laser was passed through the PTD catheter into the proximal end of the stricture. RESULTS: In 6 patients, the prestenotic bile duct was identified and exposed with the aid of the sentinel light of the laser fiber. Roux-en-Y hepaticojejunostomy was carried out in all patients. Postoperative cholangiographies showed complete restoration of biliary continuity. In one patient, positioning of the laser fiber failed because of angulation of the PTD catheter. CONCLUSION: Laser-guided identification of prestenotic bile duct facilitates exposure of the stricture site without unnecessary and usually difficult dissection in complex postoperative BDS.
Dig Surg 2009 26(5) 358-63
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Low-Level Laser Therapy Rescues Dendrite Atrophy via Upregulating BDNF Expression: Implications for Alzheimer’s Disease.
Meng C, He Z, Xing D
MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631, China.
Downregulation of brain-derived neurotrophic factor (BDNF) in the hippocampus occurs early in the progression of Alzheimer’s disease (AD). Since BDNF plays a critical role in neuronal survival and dendrite growth, BDNF upregulation may contribute to rescue dendrite atrophy and cell loss in AD. Low-level laser therapy (LLLT) has been demonstrated to regulate neuronal function both in vitro and in vivo. In the present study, we found that LLLT rescued neurons loss and dendritic atrophy via upregulation of BDNF in both Abeta-treated hippocampal neurons and cultured APP/PS1 mouse hippocampal neurons. Photoactivation of transcription factor CRE-binding protein (CREB) increased both BDNF mRNA and protein expression, since knockdown CREB blocked the effects of LLLT. Furthermore, CREB-regulated transcription was in an ERK-dependent manner. Inhibition of ERK attenuated the DNA-binding efficiency of CREB to BDNF promoter. In addition, dendrite growth was improved after LLLT, characterized by upregulation of Rac1 activity and PSD-95 expression, and the increase in length, branching, and spine density of dendrites in hippocampal neurons. Together, these studies suggest that upregulation of BDNF with LLLT by activation of ERK/CREB pathway can ameliorate Abeta-induced neurons loss and dendritic atrophy, thus identifying a novel pathway by which LLLT protects against Abeta-induced neurotoxicity. Our research may provide a feasible therapeutic approach to control the progression of AD.
J Neurosci 2013 Aug 14 33(33) 13505-17
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Application of a Low-Level Laser Therapy and the Purified Protein from Natural Latex (Hevea brasiliensis) in the Controlled Crush Injury of the Sciatic Nerve of Rats: A Morphological, Quantitative, and Ultrastructural Study.
Dias FJ, Issa JP, Iyomasa MM, Coutinho-Netto J, Calzzani RA, Iyomasa DM, Sousa LG, de Almeida SR, Cury DP, Watanabe IS
Department of Anatomy, Institute of Biomedical Sciences, University of Sao Paulo, 2415 Avenida Professor Lineu Prestes, 05508-900 Sao Paulo, SP, Brazil.
This study analyzed the effects of a low-level laser therapy (LLLT, 15 J/cm(2), 780 nm wavelength) and the natural latex protein (P1, 0.1%) in sciatic nerve after crush injury (15 Kgf, axonotmesis) in rats. Sixty rats (male, 250 g) were allocated into the 6 groups (n = 10): CG-control group; EG-nerve exposed; IG-injured nerve without treatment; LG-crushed nerve treated with LLLT; PG-injured nerve treated with P1; and LPG-injured nerve treated with LLLT and P1. After 4 or 8 weeks, the nerve samples were processed for morphological, histological quantification and ultrastructural analysis. After 4 weeks, the myelin density and morphological characteristics improved in groups LG, PG, and LPG compared to IG. After 8 weeks, PG, and LPG were similar to CG and the capillary density was higher in the LG, PG, and LPG. In the ultrastructural analysis the PG and LPG had characteristics that were similar to the CG. The application of LLLT and/or P1 improved the recovery from the nerve crush injury, and in the long term, the P1 protein was the better treatment used, since only the application of LLLT has not reached the same results, and these treatments applied together did not potentiate the recovery.
Biomed Res Int 2013 2013 597863
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Protective effect of low-level laser therapy (LLLT) on acute zymosan-induced arthritis.
Carlos FP, de Paula Alves da Silva M, de Lemos Vasconcelos Silva Melo E, Costa MS, Zamuner SR
Universidade Nove de Julho, Rua Vergueiro, 234, Sao Paulo, Sao Paulo, Brazil.
The aim of this study was to evaluate the effect of low-level laser therapy on acute zymosan-induced arthritis, with respect to the laser action on inflammatory cells influx, release of pro-inflammatory mediators, metalloproteinases activity into the joint cavity and the cartilage repair process. Arthritis was induced in male Wistar rats (250-280 g) by intra-articular injection of zymosan (1 mg dissolved in 50 mul of a sterile saline solution) into one rear knee joint. Animals were irradiated immediately, 1 and 2 h after zymosan administration with a semiconductor laser InGaAIP (660 nm, 10 mW, 2.5 J/cm2, 10 s). In the positive control group, animals were injected with the anti-inflammatory drug dexamethasone 1 h prior to the zymosan administration. Treatment with laser significantly inhibited leukocytes influx, the release of IL-1 and IL-6 and also the activity of metalloproteinase-2 and 9, into the joint cavity. In conclusion, laser therapy was effective in reducing inflammation to sites of injury and inhibit activation of proteases (gelatinase) suggesting less degradation of collagen tissue in experimental model of acute arthritis.
Lasers Med Sci 2013 Aug 10
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Thermal Effects of Transcranial Near-Infrared Laser Irradiation on Rabbit Cortex.
Chen Y, De Taboada L, O’Connor M, Delapp S, Zivin JA
University of California San Diego, Department of Neuroscience, 9500 Gilman Drive MTF321, La Jolla, CA 92093-0624. Electronic address: jzivin@ucsd.edu.
BACKGROUND AND PURPOSE: Transcranial near-infrared laser therapy (TLT) improves stroke outcome in animal models. Adequate laser doses are necessary to exert therapeutic effects. However, applying higher laser energy may cause cortical tissue heating and exacerbate stroke injury. The objective of this study is to examine the thermal effect and safety of transcranial near-infrared laser therapy. METHODS: Diode laser with a wavelength of 808nm was used to deliver different power densities to the brain cortex of rabbits. Cortical temperature was monitored and measured using a thermal probe during the 2min transcranial laser irradiation. Neuro-pathological changes were examined with histological staining 24hrs after laser treatment. RESULTS: Transcranial laser irradiation for 2min at cortical power densities of 22.2 and 55.6 mW/cm2 with continuous wave (CW) did not increase cortical temperature in rabbits. With the same treatment regime, cortical power density at 111.1 mW/cm2 increased brain temperature gradually by 0.5 degrees C over the 2min exposure and returned to baseline values within 1-2min post-irradiation. Separately, histological staining was evaluated after triple laser exposure of 22.2 mW/cm2 CW and 111.1 mW/cm2 pulse wave (PW) and showed normal neural cell morphology. CONCLUSIONS: The present study demonstrated that the TLT powers currently utilized in animal stroke studies do not cause cortical tissue heating and histopathological damage.
Neurosci Lett 2013 Aug 7
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Effects of Laser Irradiation on Pulp Cells Exposed to Bleaching Agents.
Lima AF, Basso FG, Ribeiro AP, Bagnato VS, Hebling J, Marchi GM, de Souza Costa CA
Department of Restorative Dentistry, Piracicaba Dental School, University of Campinas – UNICAMP, Avenida Limeira, 901, 13404-903, Piracicaba, SP, Brazil; Department of Restorative Dentistry, Nove de Julho University, Rua Vergueiro, 235, 01504-000, Sao Paulo, SP, Brazil.
The aim of the present study was to evaluate the effect of low-level laser therapy (LLLT) on odontoblast-like cells exposed to a bleaching agent. MDPC-23 cells were seeded in wells of 24-well plates. Eight groups were established according to the exposure to the bleaching agent and LLLT (0, 4, 10, and 15 J/cm2 ). Enamel-dentin discs were adapted to artificial pulp chambers, which were individually placed in wells containing DMEM. A bleaching agent (35% hydrogen peroxide-BA35%HP) was applied on enamel (15 min) to obtain the extracts (DMEM + BA35%HP components diffused through enamel/dentin discs). The extracts were applied (1 h) to the cells, and then subjected to LLLT. Cell viability (MTT assay), alkaline phosphatase (ALP) activity, as well as gene expression of ALP, fibronectin (FN), and collagen type I, were evaluated. The bleaching procedures reduced the cell viability, ALP activity, and gene expression of dentin proteins. Laser irradiation did not modulate the cell response; except for FN, since LLLT decreased the gene expression of this protein by the cells exposed to the BA35%HP. It can be concluded that BA35%HP decreased the odontoblasts activities that were not recovered by the irradiation of the damaged cells with a low-level laser parameters tested. This article is protected by copyright. All rights reserved.
Photochem Photobiol 2013 Aug 12
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The effect of low-level laser on bone healing in critical size defects treated with or without autogenous bone graft: an experimental study in rat calvaria.
de Almeida AL, Medeiros IL, Cunha MJ, Sbrana MC, de Oliveira PG, Esper LA
Department of Prosthodontics, Bauru School of Dentistry, University of Sao Paulo, Bauru, SP, Brazil.
OBJECTIVE: The objective of this study was to evaluate the effect of low-level laser (LLL) on bone healing process in surgically created critical size defects in rat calvaria treated with or without autogenous bone graft (AB). MATERIAL AND METHODS: The study was conducted on 40 male rats (Rattusnorvegicus, albinus, Wistar), weighing 250-300 g. For accomplishment of the experimental procedures, the rats were anesthetized with an intramuscular injection of xylazine (0.02 ml/kg) and ketamine hydrochloride (0.4 ml/kg). Acritical size defect with 5-mm diameter was created. The animals were divided into four groups: Group C (Control- filled with blood clot), Group LLL, Group AB (autogenous bone graft), Group AB + LLL (autogenous bone graft and LLL). The animals treated with LLL received applications of LLL at the infrared spectrum wavelength (lambda = 810 nm) and energy density of 6 J/cm2 per point, 60 s per point, adding up to five points on the entire created defect. The animals were euthanized at 30 days postoperatively. After decalcification, each specimen was longitudinally divided into two blocks, exactly along the center of the original surgical defect, processed and embedded in paraffin. Longitudinal serial sections with 6-mum thickness were made, initiating from the center of the original surgical defect. The sections were stained with hematoxylin and eosin (HE) for light microscopy analysis for histomorphometric analysis. RESULTS: Group C presented smaller quantity of new bone formation than Groups LLL (P < 0.01), AB (P < 0.01), and AB + LLL (P < 0.01). CONCLUSIONS: Utilization of LLL favored the healing process in rat calvaria. The quantity of new bone formation with use of the LLL was similar to the autogenous bone graft.
Clin Oral Implants Res 2013 Aug 6
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Assessment of Changes in Mineral Components in Bone Repair After Laser Therapy and Pharmacotherapy by mu-EDX: A New Potential Tool in Medical Diagnostics.
de Abreu GM, Santo AM, Martin AA, Arisawa EA
1 Laboratory of Biomedical Vibrational Spectroscopy – LEVB, Research and Development Institute – IP&D, Vale do Paraiba University-UNIVAP, Sao Jose dos Campos , SP, Brazil .
Abstract Background data: Energy-dispersive microspectroscopy X-ray fluorescence (mu-EDX) is a non-destructive, multi-element analytical method. This technique is able to quickly perform a qualitative and semiquantitative evaluation of several sorts of samples with minimal or no previous sample preparation. Low-level laser therapy (LLLT) and synthetic calcitonin have been used to promote osteogenesis and to accelerate the repair process in bone lesions. Objective: The aim of this study was to evaluate qualitatively and semiquantitatively biochemical changes in the composition of the bone tissue during the repair process in rats by the analytical measurement tool, mu-EDX. Methods: We created a surgical bone defect in 60 Wistar rats with induced osteoporosis treated with calcitonin, LLLT, and a combination of both. The animals were divided into four groups. In groups Ca and CaLa, calcitonin, 2 UI/kg, i.m., was administered on alternate days. LLLT (20 J/cm(2), 10 mW, 830 nm, 6 sec, every 48 hours) was applied to the La and CaLa groups. The experimental times were 7, 14, and 21 days. After euthanasia, the specimens were measured for inorganic chemical compounds with mu-EDX. Results and Conclusions: This study showed that it was possible to perform qualitative and semiquantitative analysis of inorganic components of biological samples with this technique during the bone repair process using different experimental treatment protocols. CaLa specimens showed the relation between calcium and phosphorus (Ca/P) closest to stoichiometric hydroxyapatite.
Photomed Laser Surg 2013 Aug 31(8) 378-85
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Osteoblast differentiation of amniotic fluid-derived stem cells irradiated with visible light.
Higuchi A, Shen PY, Zhao JK, Chen CW, Ling QD, Chen H, Wang HC, Bing JT, Hsu ST
Department of Chemical and Materials Engineering, National Central University, Jhongli, Taoyuan, Taiwan. higuchi@ncu.edu.tw
The effect of visible light irradiation on the expression of pluripotent genes (Oct-4, Sox2, and Nanog) in amniotic fluid-derived stem cells (AFSCs) and on the osteogenic differentiation ability of AFSCs was investigated using light-emitting diodes (LEDs) at 0-2 mW/cm(2) in various wavelengths: [blue (470 nm), green (525 nm), yellow (600 nm), and red (630 nm)]. Pluripotent gene expression in AFSCs was up-regulated by visible light irradiation from a LED for more than 6 h. Green light irradiation of AFSCs up-regulated the expression of pluripotent genes more significantly than irradiation with other light. The osteogenic differentiation of AFSCs was facilitated by green and blue light irradiation. Facilitated differentiation into osteogenic cells by visible light irradiation was not mediated by reactive oxygen species (ROS); alkaline phosphatase activity (a marker of early osteogenic differentiation) and gene expression of osteopontin (a marker of late osteogenic differentiation) did not change significantly between AFSCs in differentiation medium with or without a ROS scavenger (vitamin C). The mitogen-activated protein kinase/extracellular signal-regulated protein kinase pathway, as well as other unknown signaling pathways, may be responsible for the activation of signaling pathways that facilitate the differentiation of AFSCs into osteogenic cells on light irradiation.
Tissue Eng Part A 2011 Nov 17(21-22) 2593-602
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The effects of low-level laser irradiation on bone tissue in diabetic rats.
Patrocinio-Silva TL, de Souza AM, Goulart RL, Pegorari CF, Oliveira JR, Fernandes K, Magri A, Pereira RM, Araki DR, Nagaoka MR, Parizotto NA, Renno AC
Department of Biotechnology, Federal University of Sao Carlos, Rod Washington Luis, Km 235, Monjolinho, Sao Carlos, Sao Paulo, Brazil, 13565-902.
Diabetes mellitus (DM) leads to a decrease in bone mass and increase the risk of osteoporosis and in this context, many treatments have shown to accelerate bone metabolism. It seems that low-level laser therapy (LLLT) is able of stimulating osteoblast activity and produced increased biomechanical properties. However, its effects on bone in diabetic rats are not fully elucidated. The aim of this study was to evaluate the effects of LLLT on bone formation, immunoexpression of osteogenic factors, biomechanical properties and densitometric parameters in diabetic rats. Thirty male Wistar rats were randomly distributed into three experimental groups: control group, diabetic group, and laser-treated diabetic group. DM was induced by streptozotocin (STZ) and after 1 week laser treatment started. An 830-nm laser was used, performed for 18 sessions, during 6 weeks. At the end of the experiment, animals were euthanized and tibias and femurs were defleshed for analysis. Extensive resorptive areas as a result of osteoclasts activity were noticed in DG when compared to control. Laser-treated animals showed an increased cortical area. The immunohistochemical analysis revealed that LLLT produced an increased RUNX-2 expression compared to other groups. Similar RANK-L immunoexpression was observed for all experimental groups. In addition, laser irradiation produced a statistically increase in fracture force, bone mineral content (BMC) and bone mineral density compared to DG. The results of this study indicate that the STZ model was efficient in inducing DM 1 and producing a decrease in cortical diameter, biomechanical properties and in densitometric variables. In addition, it seems that LLLT stimulated bone metabolism, decreased resorptive areas, increased RUNX-2 expression, cortical area, fracture force, BMD, and BMC. Further studies should be developed to provide additional information concerning the mechanisms of action of laser therapy in diabetic bone in experimental and clinical trials.
Lasers Med Sci 2013 Aug 29
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Effect of LED-mediated-photobiomodulation therapy on orthodontic tooth movement and root resorption in rats.
Ekizer A, Uysal T, Guray E, Akkus D
Department of Orthodontics, Faculty of Dentistry, Erciyes University, Kayseri, Turkey, dtekizer@hotmail.com.
The aim of this experimental study was to evaluate the effects of light-emitting diode-mediated-photobiomodulation therapy (LPT), on the rate of orthodontic tooth movement (TM) and orthodontically induced root resorption, in rats. Twenty male 12-week-old Wistar rats were separated into two groups (control and LPT) and 50 cN of force was applied between maxillary left molar and incisor with a coil spring. In the treatment group, LPT was applied with an energy density of 20 mW/cm2 over a period of 10 consecutive days directly over the movement of the first molar teeth area. The distance between the teeth was measured with a digital caliper on days 0 (T0), 10 (T1), and 21 (T2) on dental cast models. The surface area of root resorption lacunae was measured histomorphometrically using digital photomicrographs. Mann-Whitney U and Wilcoxon tests were used for statistical evaluation at p < 0.05 level. TM during two different time intervals (T1-T0 and T2-T1) were compared for both groups and a statistically significant difference was found in the LPT group (p = 0.016). The TM amount at the first time period (1.31 +/- 0.36 mm) was significantly higher than the second time period (0.24 +/- 0.23 mm) in the LPT group. Statistical analysis showed significant differences between two groups after treatment/observation period (p = 0.017). The magnitude of movement in the treatment group was higher (1.55 +/- 0.33 mm) compared to the control group (1.06 +/- 0.35 mm). Histomorphometric analysis of root resorption, expressed as a percentage, showed that the average relative root resorption affecting the maxillary molars on the TM side was 0.098 +/- 0.066 in the LPT group and 0.494 +/- 0.224 in the control group. Statistically significant inhibition of root resorption with LPT was determined (p < 0.001) on the TM side. The LPT method has the potential of accelerating orthodontic tooth movement and inhibitory effects on orthodontically induced resorptive activity.
Lasers Med Sci 2013 Aug 29
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Effects of laser acupuncture on longitudinal bone growth in adolescent rats.
Yeom M, Kim SH, Lee B, Zhang X, Lee H, Hahm DH, Sohn Y, Lee H
Acupuncture and Meridian Science Research Center, College of Korean Medicine, Kyung Hee University, Seoul 130-701, Republic of Korea.
Longitudinal bone growth is the results of chondrocyte proliferation and hypertrophy and subsequent endochondral ossification in the growth plate. Recently, laser acupuncture (LA), an intervention to stimulate acupoint with low-level laser irradiation, has been suggested as an intervention to improve the longitudinal bone growth. This study investigated the effects of laser acupuncture on growth, particularly longitudinal bone growth in adolescent male rats. Laser acupuncture was performed once every other day for a total of 9 treatments over 18 days to adolescent male rats. Morphometry of the growth plate, longitudinal bone growth rate, and the protein expression of BMP-2 and IGF-1 in growth plate were observed. The bone growth rate and the heights of growth plates were significantly increased by laser acupuncture. BMP-2 but not IGF-1 immunostaining in growth plate was increased as well. In conclusion, LA promotes longitudinal bone growth in adolescent rats, suggesting that laser acupuncture may be a promising intervention for improving the growth potential for children and adolescents.
Evid Based Complement Alternat Med 2013 2013 424587
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Modulating effect of low level-laser therapy on fibrosis in the repair process of the tibialis anterior muscle in rats.
Alves AN, Fernandes KP, Melo CA, Yamaguchi RY, Franca CM, Teixeira DF, Bussadori SK, Nunes FD, Mesquita-Ferrari RA
Universidade Nove de Julho – UNINOVE, Sao Paulo, SP, Brazil.
The treatment of muscle injuries is a common practice at rehabilitation centers. Low-level laser therapy (LLLT) has demonstrated positive effects regarding the modulation of the inflammatory response, the enhancement of the tissue repair process and the prevention of fibrosis. The aim of the present study was to evaluate the effects of LLLT on morphological aspects of muscle tissue, collagen remodeling and activity of matrix metalloproteinase 2 (MMP-2) in rat skeletal muscle following acute injury. Wistar rats were divided into five groups: (1) control group (n = 10), (2) sham group (n = 10), (3) LLLT group (n = 30), (4) non-treated injury group (n = 30) and (5) injury + LLLT group (n = 30). Cryoinjury was performed on the belly of the tibialis anterior (TA) muscle. LLLT was performed daily with an AlGaAs laser (780 nm; beam spot of 0.04 cm2, output power of 40 mW, power density of 1 W/cm2, energy density of 10 J/cm2 and 10-s exposure time). Animals were euthanized at 1, 3 and 7 days. The TA muscles were removed and weighed. Morphological aspects were evaluated using H & E staining. The amount and distribution of collagen fibers were evaluated by picrosirius staining. Characterization and activity of MMP-2 were evaluated by zymography and Western blot techniques, respectively. The results revealed that LLLT induced a reduction in inflammatory infiltrate and myonecrosis after 1 day, an increase in the number of blood vessels after 3 and 7 days as well as an increase in the number of immature muscle fibers and MMP-2 gelatinase activity after 7 days. In conclusion, LLLT has a positive effect on the inflammatory process, MMP2 activity and collagen organization and distribution in the repair process of rat skeletal muscle.
Lasers Med Sci 2013 Aug 28
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Pulsed LLLT improves tendon healing in rats: a biochemical, organizational, and functional evaluation.
Guerra FD, Vieira CP, Dos Santos de Almeida M, Oliveira LP, Claro AC, Simoes GF, de Oliveira AL, Pimentel ER
Department of Structural and Functional Biology, Institute of Biology, University of Campinas-UNICAMP, CP 6109, 13083-970, Campinas, SP, Brazil, dgflavia@yahoo.com.br.
In the last decades, the tendon injuries have increased substantially. Previous results suggested that low-level laser treatment (LLLT) promotes synthesis of extracellular matrix and improves the functional properties of the tendon. The aim of this study was to evaluate the effects of different protocols of LLLT on partially tenotomized tendons. Adult male rats were divided into the following: G1-intact, G2-injured, G3-injured + LLLT (4 J/cm2 continuous), G4-injured + LLLT (4 J/cm2 at 20 Hz). G2, G3, and G4 were euthanized 8 days after injury. G5-injured, G6-injured + LLLT (4 J/cm2 continuous), and G7-injured + LLL (4 J/cm2 at 20 Hz until the seventh day and 2 kHz from 8 to 14 days). G5, G6, and G7 were euthanized on the 15th day. Glycosaminoglycan (GAG) level was quantified by dimethylmethylene blue method and analyzed on agarose gel. Toluidine blue (TB) stain was used to observe metachromasy. CatWalk system was used to evaluate gait recovery. Collagen organization was analyzed by polarization microscopy. The GAG level increased in all transected groups, except G5. In G6 and G7, there was a significant increase in GAG in relation to G5. In G3 and G4, the presence of dermatan sulfate band was more prominent than G2. TB stains showed intense metachromasy in the treated groups. Birefringence analysis showed improvement in collagen organization in G7. The gait was significantly improved in G7. In conclusion, pulsed LLLT leads to increased organization of collagen bundles and improved gait recovery.
Lasers Med Sci 2013 Aug 28
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Effects of LED phototherapy on relative wound contraction and reepithelialization during tissue repair in hypothyroid rats: morphometric and histological study.
Paraguassu GM, da Guarda MG, Xavier FC, Cangussu MC, Rodriguez TT, Ramalho MJ, Pinheiro AL, Ramalho LM
School of Dentistry, Federal University of Bahia, Avenida Araujo Pinho, 62. Canela, Salvador, BA, CEP 40140-110, Brazil.
The aim of this study was to assess morphometrically and histologically, the effects of light-emitting diode (LED) (lambda630 +/- 20 nm) phototherapy on reepithelialization and wound contraction during tissue repair in hypothyroid rats. Thyroid hormone deficiency has been associated with disorders of tissue repair. LED phototherapy has been studied using several healing models, but their usefulness in the improvement of hypothyroidism wound healing remains unknown. Under general anesthesia, a standard surgical wound (1 cm2) was produced on the dorsum of 48 male Wistar rats divided into four groups of 12 animals each: EC-control euthyroid, ED-euthyroid + LED, HC-control hypothyroid, and HD-Hypothyroid + LED. The irradiation started immediately after surgery and was repeated every other day for 7 and 14 days. Photographs of the wound were taken at the day of the surgical procedure and on days 8 and 15 after surgery, when animals’ deaths occurred. The specimens were removed, routinely processed, and stained with hematoxylin/eosin. Seven days after the surgery, it was possible to observe statistically significant reductions in the wound area of the irradiated euthyroid group, in comparison to hypothyroid group, irradiated and non-irradiated (ANOVA, p < 0.05). The reepithelialization was significantly higher in the euthyroid and hypothyroid groups irradiated with LED than in the non-irradiated groups (Fisher’s test, p < 0.05). No significant difference was found in the experimental period of 14 days among the groups. The hypothyroidism delayed wound healing and the LED phototherapy, at these specific parameters, improved the process of reepithelialization in the presence of hypothyroidism.
Lasers Med Sci 2013 Aug 24
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New Bone Formation around Implants Inserted on Autologous and Xenografts Irradiated or not with IR Laser Light: A Histomorphometric Study in Rabbits.
Soares LG, Magalhaes EB Junior, Magalhaes CA, Ferreira CF, Marques AM, Pinheiro AL
Center of Biophotonics, Dental School, UFBA – Federal University of Bahia, Salvador,BA, Brazil.
Use of biomaterials and light on bone grafts has been widely reported. This work assessed the influence of low-level laser therapy (LLLT) on bone volume (BV) and bone implant contact (BIC) interface around implants inserted in blocks of bovine or autologous bone grafts (autografts), irradiated or not, in rabbit femurs. Twenty-four adult rabbits were divided in 8 groups: AG: autograft; XG: xenograft; AG/L: autograft + laser; XG/L: xenograft + laser; AG/I: autograft + titanium (Ti) implant; XG/I: xenograft + Ti implant; AG/I/L: autograft + Ti implant + laser; and XG/I/L: xenograft + Ti implant + laser. The animals received the Ti implant after incorporation of the grafts. The laser parameters in the groups AG/L and XG/L were lambda=780 nm, 70 mW, CW, 21.5 J/cm 2 , while in the groups AG/I/L and XG/I/L the following parameters were used: lambda=780 nm, 70 mW, 0.5 cm 2 (spot), 4 J/cm 2 per point (4), 16 J/cm 2 per session, 48 h interval x 12 sessions, CW, contact mode. LLLT was repeated every other day during 2 weeks. To avoid systemic effect, only one limb of each rabbit was double grafted. All animals were sacrificed 9 weeks after implantation. Specimens were routinely stained and histomorphometry carried out. Comparison of non-irradiated and irradiated grafts (AG/L versus AG and XG/L versus XG) showed that irradiation increased significantly BV on both grafts (p=0.05, p=0.001). Comparison between irradiated and non-irradiated grafts (AG/I/L versus AG/I and XG/I/L versus XG/I) showed a significant (p=0.02) increase of the BIC in autografts. The same was seen when xenografts were used, without significant difference. The results of this investigation suggest that the use of LLLT is effective for enhancing new bone formation with consequent increase of bone-implant interface in both autologous grafts and xenografts.
Braz Dent J 2013 May-Jun 24(3) 218-223
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Comparative study of the effects of laser photobiomodulation and extract of Brassica oleracea on skin wounds in wistar rats: A histomorphometric study.
Goncalves RV, Sarandy MM, da Matta SL, Novaes RD, Pinto MV
Department of Basic Science Area Health, Federal University of Juiz de Fora, Brazil. Electronic address: reggysvilela@yahoo.com.br.
The objective of this study was to investigate the effect of a photobiomodulation laser and Brassica oleracea on tissue morphology in skin wounds. The parameters analyzed were type I and III collagen fibers, and thickness and surface density of the epithelial tissue, as well as how quickly the wound closed. Five skin wounds 12mm in diameter were made on the backs of the animals, which were randomized into four groups (8 animals each). Saline Group: 0.9% saline solution; Ointment Group (extract of Cabbage, B. oleracea, 10% lanolin); Balsam Group (10% glycolic extract of B. oleracea emulsion oil); L60 Group (laser GaAsAl 60J/cm2). The applications were made daily during a 20-day treatment, and every 4 days tissue from different wounds was removed. The reduction in the size of the wounds on the 4th, 8th, 12th and 16th days was significantly greater in the treated groups compared to the control group. At all the time points analyzed, there was a greater proportion of collagen in the Balsam and L60 groups (p<0.05). There was also a greater proliferation of epithelial cells in the L60 and Balsam groups after 20 days of treatment (p<0.05). The healing extract and laser 60j/cm2 exerted a great effect on collagen proliferation in stimulating scar tissue maturation.
Pathol Res Pract 2013 Jul 31
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Effects of increased low-level diode laser irradiation time on extraction socket healing in rats.
Park JB, Ahn SJ, Kang YG, Kim EC, Heo JS, Kang KL
Department of Periodontology, School of Dentistry, Kyung Hee University, Seoul, South Korea.
In our previous studies, we confirmed that low-level laser therapy (LLLT) with a 980-nm gallium-aluminum-arsenide diode laser was beneficial for the healing of the alveolar bone in rats with systemic disease. However, many factors can affect the biostimulatory effects of LLLT. Thus, we attempted to investigate the effects of irradiation time on the healing of extraction sockets by evaluating the expressions of genes and proteins related to bone healing. The left and right first maxillary molars of 24 rats were extracted. Rats were randomly divided into four groups in which extraction sockets were irradiated for 0, 1, 2, or 5 min each day for 3 or 7 days. Specimens containing the sockets were examined using quantitative real-time reverse transcription polymerase chain reaction and western blotting. LLLT increased the expressions of all tested genes, Runx2, collagen type 1, osteocalcin, platelet-derived growth factor-B, and vascular endothelial growth factor, in a time-dependent manner. The highest levels of gene expressions were in the 5-min group after 7 days. Five minutes of irradiation caused prominent increases of the expression of all tested proteins after both 3 and 7 days. The expression level of each protein in group 4 was higher by almost twofold compared with group 1 after 7 days. Laser irradiation for 5 min caused the highest expressions of genes and proteins related to bone healing. In conclusion, LLLT had positive effects on the early stages of bone healing of extraction sockets in rats, which were irradiation time-dependent.
Lasers Med Sci 2013 Aug 9
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Local fundus response to blue (LED and laser) and infrared (LED and laser) sources.
Dawson W, Nakanishi-Ueda T, Armstrong D, Reitze D, Samuelson D, Hope M, Fukuda S, Matsuishi M, Ozawa T, Ueda T, Koide R
Department of Ophthalmology, University of Florida, 1600 SW Archer Road, Gainesville, FL 32610-0284, U.S.A. wdawson@eye1.eye.ufl.edu
Light damage research began during the early years of laser light exploration. There is a clear and significant literature that identifies an easily demonstrated retina-pigment epithelium pathology which is associated with short wavelength exposures below 520 nm. Recent interest has expanded because of the growing evidence for a blue light contribution to the retina aging process by way of a poorly understood chemical process(es) that involve circulation, oxidative reactions and the spectral absorption properties of the pigment epithelium. New powerful sources of relatively inexpensive blue energy have become available as a family of light emitting diodes. In this experiment, we examined funduscopic, angiographic and scanning laser tomographic measures of the retinal-pigment epithelium response to LED and laser spectral blue and infrared emissions closely matched in wavelengths and delivered under carefully matched circumstances. Ten retinas in normal young rhesus monkeys were locally exposed to various energy density values at 458 nm (Argon laser) ranging from 5 to 54 J cm(-2). Eight rhesus eyes were exposed to LED irradiation with a peak wavelength of 460 nm ranging from 9 to 62 J cm(-2). Similarly, a matched infrared (IR) laser and IR LED pair were used to expose an additional ten eyes for comparison of the long wavelengths. IR irradiance ranged from 21 to 306 J cm(-2). There was no response to IR exposure in any of the eyes. Blue light exposure results were measured from the color fundus photographs, scanning laser tomographs and early- and late-phase fluorescein angiogram responses at 2 and 30 days after the exposure. Results scores were accumulated for the four measures at the two time periods. The resulting lesion scores when plotted against the exposure in J cm(-2)showed no demonstrable effect at irradiance lower than 10 J cm(-2)and near 100% effectiveness for irradiance greater than 30 J cm(-2). The most sensitive and enduring indicator of change was the late fluorescein angiograms. Nonparametric statistical analysis of the scores from the two samples support the conclusion that there is no difference in the consequences of LED and laser light exposures under these matched conditions.
Exp Eye Res 2001 Jul 73(1) 137-47
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Melatonin modulates the action of near infrared radiation on cell adhesion.
Karu TI, Pyatibrat LV, Ryabykh TP
Institute of Laser and Informatic Technologies, Russian Academy of Sciences, Troitsk, Moscow Region, Russia. tkaru@isan.troitsk.ru
The adhesion of human cervical cancer (HeLa) cells to a glass matrix is evaluated following their irradiation in a suspension with a pulsed near-infrared (IR) light-emitting diode (wavelength 820 nm, pulse repetition frequency 10 Hz, irradiation dose 16-120 J/m2) when melatonin (4 x 10(-11) to 4 x 10(-5) m) is added to cell suspension immediately before or after the irradiation. Also, the dependence of visible-to-near-IR radiation (600-840 nm, 52 J/m2) on cell adhesion (action spectrum) is recorded in absence and presence of melatonin (4 x 10(-6) m). It is found that melatonin in pharmacological concentrations (but not in physiological range) inhibited cell adherence. Irradiation of cells before or after melatonin treatment normalizes cell adhesion to control level. Melatonin in pharmacological concentrations eliminates stimulation of cell attachment induced by irradiation. Pre-treatment (but not post-treatment) with melatonin in the physiological concentration eliminates cell adhesion stimulation induced by irradiation. Melatonin modifies the light action spectrum significantly in near IR region (760-840 nm only). Thus, the peak at 820-830 nm characteristic for the light action spectrum is fully reduced.
J Pineal Res 2003 Apr 34(3) 167-72
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Phototherapy with low-level laser influences the proliferation of endothelial cells and vascular endothelial growth factor and transforming growth factor-beta secretion.
Szymanska J, Goralczyk K, Klawe JJ, Lukowicz M, Michalska M, Goralczyk B, Zalewski P, Newton JL, Gryko L, Zajac A, Rosc D
Department of Lasertherapy and Physiotherapy, Ludwik Rydygier Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Torun, Poland. j.szymanska@cm.umk.pl.
The healing process and the angiogenesis associated with it, is a very important but currently poorly understood area. Low level laser therapy (LLLT) has been reported to modulate the process of tissue repair by stimulation of cellular reaction such as migration, proliferation, apoptosis and cellular differentiation. The aim of this work was to evaluate the influence of laser radiation in the range of visible and infrared light on the proliferation of vascular endothelial cells in vitro and the secretion of angiogenic factors: vascular endothelial growth factor (VEGF)-A and transforming growth factor (TGF)-beta. Vascular human endothelial cells (Ecs) were exposed to radiation with laser beam of the wavelengths: 635 nm (1.875 mW/cm(2)) and 830 nm (3.75 mW/cm(2)). Depending on the radiation energy density, the experiment was conducted in four groups : I) the control group (no radiation, 0 J/cm(2)); II) 635 nm – the energy density was 2 J/cm(2); III) 635 nm – 4 J/cm(2); IV635 nm – 8 J/cm(2), II) 830 nm – the energy density was 2 J/cm(2); III) 830 nm – 4 J/cm(2); IV) 830 nm – 8 J/cm(2). The proliferation and concentration of VEGF-A and TGF-beta were examined. LLLT with wavelength 635 nm increases endothelial cell proliferation. Significant increase in endothelial cell proliferation and corresponding decrease in VEGF concentration may suggest the role for VEGF in this process. The wavelength of 830 nm was associated with a decrease in TGF-beta secretion.
J Physiol Pharmacol 2013 Jun 64(3) 387-91
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Enhancement of monoclonal antibody production in CHO cells by exposure to He-Ne laser radiation.
Ghaleb R, Naciri M, Al-Majmaie R, Maki A, Al-Rubeai M
School of Chemical and Bioprocess Engineering, Conway Institute for Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin, Ireland.
This study tested the effectiveness of laser biostimulation in small-scale cultures in vitro. We investigated the response of recombinant CHO cells, which are used for the production of monoclonal antibody, to low level laser radiation. The cells were irradiated using a 632.8 nm He-Ne laser in a continuous wave mode at different energy doses. We incubated the irradiated cells in small batch cultures and assessed their proliferation and productivity at various time intervals. Compared to untreated cells, the irradiated cells showed a significant increase in antibody production. Moreover, the results showed that laser irradiation did not affect viability and slightly enhanced proliferation rate.
Cytotechnology 2013 Aug 14
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Effects of light-emitting diode radiations on human retinal pigment epithelial cells in vitro.
Chamorro E, Bonnin-Arias C, Perez-Carrasco MJ, Munoz de Luna J, Vazquez D, Sanchez-Ramos C
Neuro-Computing and Neuro-Robotics Research Group, Universidad Complutense de Madrid, Madrid, Spain. eva.chamorro@opt.ucm.es
Human visual system is exposed to high levels of natural and artificial lights of different spectra and intensities along lifetime. Light-emitting diodes (LEDs) are the basic lighting components in screens of PCs, phones and TV sets; hence it is so important to know the implications of LED radiations on the human visual system. The aim of this study was to investigate the effect of LEDs radiations on human retinal pigment epithelial cells (HRPEpiC). They were exposed to three light-darkness (12 h/12 h) cycles, using blue-468 nm, green-525 nm, red-616 nm and white light. Cellular viability of HRPEpiC was evaluated by labeling all nuclei with DAPI; Production of reactive oxygen species (ROS) was determined by H2DCFDA staining; mitochondrial membrane potential was quantified by TMRM staining; DNA damage was determined by H2AX histone activation, and apoptosis was evaluated by caspases-3,-7 activation. It is shown that LED radiations decrease 75-99% cellular viability, and increase 66-89% cellular apoptosis. They also increase ROS production and DNA damage. Fluorescence intensity of apoptosis was 3.7% in nonirradiated cells and 88.8%, 86.1%, 83.9% and 65.5% in cells exposed to white, blue, green or red light, respectively. This study indicates three light-darkness (12 h/12 h) cycles of exposure to LED lighting affect in vitro HRPEpiC.
Photochem Photobiol 2013 Mar-Apr 89(2) 468-73
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Effects of red light-emitting diode irradiation on dental pulp cells.
Holder MJ, Milward MR, Palin WM, Hadis MA, Cooper PR
Oral Biology, School of Dentistry, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK.
Light irradiation activates a range of cellular processes in a variety of cell types, including stem cells, and can promote tissue repair. This study investigated the effects of light-emitting diode (LED) exposure on dental pulp cells (DPCs). Dose response analysis at 20-second intervals up to 120 seconds demonstrated that a LED array emitting 653-nm red light stimulated significantly increased cell growth at 3 and 7 days post-irradiation with 40 (149 mJ/cm(2)) and 60 (224 mJ/cm(2)) seconds of radiant exposure. Double-dosing cells at days 1 and 4 of a 7-day culture period with 60-second (224 mJ/cm(2)) LED exposure significantly increased cell growth compared with a single dosing regime. BrdU analysis demonstrated significantly increased proliferation rates associated with significantly increased ATP, nitric oxide (NO), and mitochondrial metabolic activity. LED-stimulated NO levels were not reduced by inhibition of NO-synthase activity. Light exposure also rescued the inhibition of mitochondrial dysfunction and increased levels of in vitro mineralization compared with control. Media exchange experiments indicated that autocrine signaling was not likely responsible for red-light-induced DPC activity. In conclusion, data analysis indicated that 653-nm LED irradiation promoted DPC responses relevant to tissue repair, and this is likely mediated by increased mitochondrial activity.
J Dent Res 2012 Oct 91(10) 961-6
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Treatment of acne vulgaris in pregnant patients.
Pugashetti R, Shinkai K
Department of Dermatology, University of California, San Francisco, San Francisco, California.
The management of acne vulgaris in the setting of pregnancy raises important clinical considerations regarding the efficacy and safety of acne treatments in this special patient population. Particular challenges include the absence of safety data, discrepancy in safety data between different safety rating systems, and lack of evidence-based recommendations for the treatment of acne during pregnancy. Nonetheless, many therapeutic options exist, and the treatment of acne in pregnant women can be safely and often effectively accomplished. For mild or moderate disease, patients can be treated with topical antimicrobial agents, anti-inflammatory agents, as well as glycolic and salicylic acid. Several topical agents, notably benzoyl peroxide, previously viewed as potentially dangerous are cited by many sources as being considered safe. When necessary, systemic therapies that can be safely added include penicillins, amoxicillin, cephalosporins, erythromycin, clindamycin, and tetracyclines or sulfonamides, depending on the stage of fetal development. Adjunct therapy may include phototherapy or laser treatments. Physicians should work with this often highly motivated, safety-conscious patient population to tailor an individualized treatment regimen. This treatment regimen will likely shift throughout the different stages of fetal development, as distinct safety considerations are raised prior to conception as well as during each of the trimesters of pregnancy. Important considerations regarding acne management in breast-feeding mothers is also discussed.
Dermatol Ther 2013 Jul 26(4) 302-11
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Visible light treatment of photoaging.
Dierickx CC, Anderson RR
Skin and Laser Surgery Center, Beukenlaan 52, 2850 Boom, Belgium. cdierickx@cdierickx.be
Recently, a number of new devices have been developed specifically to improve the visible signs of aging in a noninvasive way. These include visible or near-infrared lasers, intense pulsed light sources (IPL), light-emitting diode (LED), and radiofrequency devices. This paper reviews the use of visible light sources and examines the attributes of specific systems for noninvasive skin rejuvenation.
Dermatol Ther 2005 May-Jun 18(3) 191-208
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