Photomedicine and Laser Surgery

Histological Assessment of the Effect of Laser Irradiation on Skin Wound Healing in Rats

Aug 2006, Vol. 24, No. 4: 480-488

Peter Gál Department of Medical Biophysics, Faculty of Medicine, Pavol Jozef šafárik University in Ko[scaron]ice, Košice, Slovak Republic.

Boris Vidinský Department of Medical Biophysics, Faculty of Medicine, Pavol Jozef šafárik University in Ko[scaron]ice, Košice, Slovak Republic.

Tomáš Toporcer Department of Medical Biophysics, Faculty of Medicine, Pavol Jozef šafárik University in Ko[scaron]ice, Košice, Slovak Republic.

Michal Mokrý Department of Medical Biophysics, Faculty of Medicine, Pavol Jozef šafárik University in Ko[scaron]ice, Košice, Slovak Republic.

ŠTefan Mozeš, D.V.M., Ph.D. Institute of Animal Physiology, Slovak Academy of Sciences, Košice, Slovak Republic.

FrantišEk Longauer, M.D., Ph.D. Department of Forensic Medicine, Faculty of Medicine, Pavol Jozef šafárik University in Košice, Košice, Slovak Republic.

Prof. Ján Sabo, Ph.D. Department of Medical Biophysics, Faculty of Medicine, Pavol Jozef šafárik University in Ko[scaron]ice, Košice, Slovak Republic.

Objective: The purpose of this study was to evaluate, from the histological point of view, the effect of diode laser irradiation on skin wound healing in Sprague-Dawley rats.

Background Data: Various biological effects have been described in different studies after low-level laser therapy (LLLT).

Methods: Two parallel full thickness skin incisions were performed on the back of each rat (n = 49) and immediately sutured. After surgery, one wound of each rat was exposed to laser irradiation (continuous mode, 670 nm, daily dose 30 J/cm2), whereas the parallel wound was not irradiated and served as control. Both wounds were removed 24, 48, 72, 96, 120, 144, and 168 h after surgery and routinely fixed and embedded in paraffin sections, stained with hematoxylin and eosin, van Gieson, periodic acid Schiff + periodic acid Schiff diastase, Mallory's phosphotungstic hematoxylin, and azur and eosin, and histopathologically evaluated.

Results: As compared to nonirradiated control wounds, laser stimulation shortened the inflammatory phase as well as accelerated the proliferative and maturation phase, and positively stimulated the regeneration of injured epidermis and the reparation of injured striated muscle.

Conclusion: LLLT at 670 nm positively influences all phases of rat skin wound healing.

Photomedicine and Laser Surgery

Comparison between Wound Healing in Induced Diabetic and Non diabetic Rats after Low-Level Laser Therapy

Aug 2006, Vol. 24, No. 4: 474-479

Sylvia Bicalho Rabelo , D.D.S., M.S.D. Instituto de Pesquisa e Desenvolvimento (IP&D), Universidade do Vale do Paraiba (UNIVAP), São José dos Campos, São Paulo, Brazil.

Dr. Antonio Balbin Villaverde , Ph.D. Instituto de Pesquisa e Desenvolvimento (IP&D), Universidade do Vale do Paraiba (UNIVAP), São José dos Campos, São Paulo, Brazil.

Renataamadei Nicolau , D.D.S., Ph.D. Instituto de Pesquisa e Desenvolvimento (IP&D), Universidade do Vale do Paraiba (UNIVAP), São José dos Campos, São Paulo, Brazil.

Miguel A. Castillo Salgado , Ph.D. Faculdade de Odontologia (FOSJC), Universidade Estadual Paulista (UNESP), São José dos Campos, São Paulo, Brazil.

Milene Da Silva Melo , M.S.D. Instituto de Pesquisa e Desenvolvimento (IP&D), Universidade do Vale do Paraiba (UNIVAP), São José dos Campos, São Paulo, Brazil.

Marcos Tadeu T. Pacheco , Ph.D. Instituto de Pesquisa e Desenvolvimento (IP&D), Universidade do Vale do Paraiba (UNIVAP), São José dos Campos, São Paulo, Brazil.

Objective: The aim of this work was to compare the effect of low-level laser therapy (LLLT) on the wound healing process in nondiabetic and diabetic rats.

Background Data: Among the clinical symptoms caused by diabetes mellitus, a delay in wound healing is a potential risk for patients. It is suggested that LLLT can improve wound healing.

Methods: The tissue used for this study was extracted from animals suffering from diabetes, which was induced by Streptozotocin^®, and from nondiabetic rats. Animals were assembled into two groups of 25 rats each (treated and control) and further subdivided into two groups: diabetic (n = 15) and nondiabetic (n = 10). A full-thickness skin wound was made on the dorsum area, with a round 8-mm holepunch. The treated group was irradiated by a HeNe laser at 632.8 nm, with the following parameters: 15 mW, exposition time of 17 sec, 0.025 cm² irradiated area, and energy density of 10 J/cm². Square full-thickness skin samples (18 mm each side, including both injured and noninjured tissues) were obtained at 4, 7, and 15 days after surgery and analyzed by qualitative and quantitative histological methods.

Results: Quantitative histopathological analysis confirmed the results of the qualitative analysis through histological microscope slides. When comparing tissue components (inflammatory cells, vessels and fibroblast/area), we found that treated animals had a less intense inflammatory process than controls.

Conclusion: Results obtained by both qualitative and quantitative analyses suggested that irradiation of rats with HeNe (632.8 nm), at the tested dose, promoted efficient wound healing in both nondiabetic and diabetic rats as, compared to the control group.

Photoengineering of Tissue Repair in Skeletal and Cardiac Muscles

Apr 2006, Vol. 24, No. 2: 111-120 , Photomedicine and Laser Surgery

 

Dr. Uri Oron, Ph.D.

Department of Zoology, The George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, Israel.

This review discusses the application of He-Ne laser irradiation to injured muscles at optimal power densities and optimal timing, which was found to significantly enhance (twofold) muscle regeneration in rats and, even more, in the cold-blooded toads. Multiple and frequent (daily) application of the laser in the toad model was found to be less effective than irradiation on alternate days. It was found that in the ischemia/reperfusion type of injury in the skeletal leg muscles (3 h of ischemia), infrared Ga-Al-As laser irradiation reduced muscle degeneration, increased the cytoprotective heat shock proteins (HSP-70i) content, and produced a twofold increase in total antioxidants. In vitro studies on myogenic satellite cells (SC) revealed that phototherapy restored their proliferation. Phototherapy induced mitogen-activated protein kinase/extracellular signalregulated protein kinase (MAPK/ERK) phosphorylation in these cells, probably by specific receptor phosphorylation. Cell cycle entry and the accumulation of satellite cells around isolated single myofibers cultured in vitro was also stimulated by phototherapy. Phototherapy also had beneficial effects on mouse, rat, dog and pig ischemic heart models. In these models, it was found that phototherapy markedly and significantly reduced (50–70%) the scar tissue formed after induction of myocardial infarction (MI). The phototherapeutic effect was associated with reduction of ventricular dilatation, preservation of mitochondria and elevation of HSP- 70i and ATP in the infarcted zone.

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Protection of Skeletal Muscles from Ischemic Injury: Low-Level Laser Therapy Increases Antioxidant Activity

Jun 2005, Vol. 23, No. 3: 273-277, Photomedicine and Laser Surgery

Dorit Avni, M.Sc.

Department of Zoology, The George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, Israel.

Sara Levkovitz, Ph.D.

Department of Zoology, The George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, Israel.

Lidya Maltz, M.Sc.

Department of Zoology, The George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, Israel.

Uri Oron, Ph.D.

Department of Zoology, The George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, Israel.

Objective: The aim of this study was to investigate the effect of low-level laser therapy (LLLT) on ischemic-reperfusion (I-R) injury in the gastrocnemius muscle of the rat. Background Data: Ischemic injury in skeletal muscle is initiated during hypoxia and is aggravated by reoxygenation during blood reperfusion and accumulation of cytotoxic reactive oxygen superoxides. LLLT has been found to biostimulate various biological processes, such as attenuation of ischemic injury in the heart. Materials and Methods: The injury was induced in the gastrocnemius muscles of 106 rats by complete occlusion of the blood supply for 3 h, followed by reperfusion. Another group of intact rats served to investigate the effect of LLLT on intact nonischemic muscles. Creatine phosphokinase, acid phosphatase, and heat shock protein were determined 7 days after I-R injury and antioxidant levels 2 h after reperfusion.

Results: Laser irradiation (Ga-As, 810 nm) was applied to the muscles immediately and 1 h following blood supply occlusion. It was found that laser irradiation markedly protects skeletal muscles from degeneration following acute I-R injury. This was evident by significantly (p < 0.05) higher content of creatine phosphokinase activity and lower (p < 0.05) activity of acid phosphatase in the LLLT-treated muscles relative to the injured non-irradiated ones. The content of antioxidants and heat shock proteins was also higher (p < 0.05) in the LLLT-treated muscles relative to that of injured non-irradiated muscles.

Conclusion: The present study describes for the first time the ability of LLLT to significantly prevent degeneration following ischemia/reperfusion injury in skeletal muscles, probably by induction of synthesis of antioxidants and other cytoprotective proteins, such as hsp-70i. The elevation of antioxidants was also evident in intact muscle following LLLT. The above phenomenon may also be of clinical relevance in scheduled surgery or microsurgery requiring extended tourniquet applications to skeletal muscle followed by reperfusion.

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Kawalec J S, Hetherington J, Pfennigwerth C et al.

Effect of a diode laser on wound healing by using diabetic and nondiabetic mice.

Journal of Foot and Ankle Surgery. 2004; 43 (4): 214-220.

The purpose of this study was to evaluate therapy with a high power 980 nm GaAlAs laser for wound healing. Using genetically diabetic and non-diabetic mice, two 6 mm wounds were created on the back of each mouse by using a punch biopsy. The mice were assigned to 1 of 4 subgroups for laser treatment at different fluence and frequency of treatment: 5 W (18 J/cm²) every 2 days, 5 W (18 J/cm²) every 4 days, 10 W (36 J/cm²) every 2 days, and 10 W (36 J/cm²) every 4 days. In addition, control mice were used and the wounds were allowed to heal naturally. Wound healing was evaluated on days 5, 12, and 19 by percentage of wounds healed and percent wound closure. A maximum of 5 mice per subgroup were killed at days 7, 14, and 21, and histology was conducted on the wound sites. For diabetic mice receiving 5 W every 2 days, the percentage of wounds healed after 19 days was 100% versus 40% in the control group. Only 20% of wounds in the 10 W diabetic subgroups achieved healing during the same period. For the subgroups whose wounds did not completely heal, all but the 10 W every 2 days subgroup had average closure of >90%. The 100% closure for the 5 W every 2 days subgroup was significantly greater than the other subgroups. For non-diabetic mice, 100% of the wounds in the 5 W every 4 days and control subgroups were completely healed, whereas 90% of the wounds from the 5 W every 2 days and the 10 W every 4 days subgroups were completely healed. In the latter 2 subgroups, wound closure was 99.4% and 98.8%, respectively. These differences were not significant. The histological results confirmed these findings.

In conclusion, treatment at 18 J/cm² shows a beneficial effect on wound healing in diabetic mice and does not have a detrimental effect in non-diabetic mice.

Wound healing of animal and human body sport and traffic accident injuries using low-level laser therapy treatment: a randomized clinical study of seventy-four patients with control group.

Simunovic Z; Ivankovich AD; Depolo A

Journal of clinical laser medicine & surgery; VOL: 18 (2); p. 67-73 /200004/

Department of Anesthesiology, La Caritá Medical Center, Laser Center, Locarno, Switzerland. info@lasermedico.ch

BACKGROUND AND OBJECTIVE: The main objective of current animal and clinical studies was to assess the efficacy of low level laser therapy (LLLT) on wound healing in rabbits and humans.

STUDY DESIGN/MATERIALS AND METHODS: In the initial part of our research we conducted a randomized controlled animal study, where we evaluated the effects of laser irradiation on the healing of surgical wounds on rabbits. The manner of the application of LLLT on the human body are analogous to those of similar physiologic structure in animal tissue, therefore, this study was continued on humans.

Clinical study was performed on 74 patients with injuries to the following anatomic locations: ankle and knee, bilaterally, Achilles tendon; epicondylus; shoulder; wrist; interphalangeal joints of hands, unilaterally. All patients had had surgical procedure prior to LLLT. Two types of laser devices were used: infrared diode laser (GaAlAs) 830 nm continuous wave for treatment of trigger points (TPs) and HeNe 632.8 nm combined with diode laser 904-nm pulsed wave for scanning procedure. Both were applied as monotherapy during current clinical study. The results were observed and measured according to the following clinical parameters: redness, heat, pain, swelling and loss of function, and finally postponed to statistical analysis via chi2 test.

RESULTS: After comparing the healing process between two groups of patients, we obtained the following results: wound healing was significantly accelerated (25%-35%) in the group of patients treated with LLLT. Pain relief and functional recovery of patients treated with LLLT were significantly improved comparing to untreated patients.

ose and wavelength of laser light have influence on the repair of cutaneous wounds.

Mendez TM; Pinheiro AL; Pacheco MT; Nascimento PM; Ramalho LM

Journal of clinical laser medicine & surgery; VOL: 22 (1); p. 19-25 /200402/

IP&D, Univap & School of Dentistry, Universidade do Vale do Paraíba, São José dos Campos, São Paulo, Brazil.

OBJECTIVE: The objective of the present study was to compare histologically the effect of GaAlAs (lambda 830 nm, phi approximately 2 mm(2), 35 mW) and InGaAlP (lambda 685 nm, phi approximately 2 mm(2), 35 mW) lasers, alone or in association with doses of 20 or 50 J/cm(2) on cutaneous wounds in the dorsum of the Wistar rat.

Background Data: The healing time of surgical wounds is of extreme importance and it is usually associated with a post-operative period free of infection and with less pain and inflammation.

MATERIALS AND METHODS: Sixty Wistar rats were divided into seven groups: Group I - control (non-irradiated); Group II - lambda 685 nm, 20 J/cm(2); Group III - lambda 830 nm, 20 J/cm(2); Group IV - lambda 685 nm and lambda 830 nm, 20 J/cm(2); Group V - lambda 685 nm, 50 J/cm(2)); Group VI - lambda 830 nm, 50 J/cm(2); and Group VII - lambda 685 nm and 830 nm, 50 J/cm(2). The animals were sacrificed 3, 5, and 7 days after surgery.

RESULTS: Light microscopic analysis using H&E and Picrosírius stains showed that, at the end of the experimental period, irradiated subjects showed increased collagen production and organization when compared to non-irradiated controls. Inflammation was still present in all groups at this time.

Influence of low level laser therapy on wound healing and its biological action upon myofibroblasts.

Medrado AR; Pugliese LS; Reis SR; Andrade ZA

Lasers in surgery and medicine; VOL: 32 (3); p. 239-44 /2003/

Laboratory of Experimental Pathology, Oswaldo Cruz Foundation-Salvador, Bahia, Brazil. alenamedrado@hotmail.com

BACKGROUND AND OBJECTIVE: In re-evaluating the effects of laser therapy in wound healing, the role of extracellular matrix elements and myofibroblasts, was analyzed.

STUDY DESIGN/MATERIALS AND METHODS: Cutaneous wounds were inflicted on the back of 72 Wistar rats. Low level laser was locally applied with different energy densities. Lesions were analyzed after 24, 48, 72 hours and 5, 7, and 14 days. Tissues were studied by histology, immunohistochemistry, and electron microscopy.

Low-level laser therapy (LLLT) efficacy in post-operative wounds.

Herascu N; Velciu B; Calin M; Savastru D; Talianu C

Photomedicine and laser surgery; VOL: 23 (1); p. 70-3 /200502/

National Institute of Research and Development for Optoelectronics INOE 2000, 1 Atomistilor St., PO Box MG5, 077125, Magurele-Bucharest, Romania. herescu@inoe.inoe.ro

OBJECTIVE: The aim of this paper was to investigate the efficacy of low-level laser radiation (LLLR) with wavelength of 904 nm on the stimulation of the healing process of postoperative aseptic wounds (early scar).

BACKGROUND DATA: Low-level laser therapy (LLLT) has been increasingly used to treat many disorders, including wounds. However, despite such increased clinical usage, there is still controversy regarding the efficacy of this wound treatment in curent clinical practice. METHODS: LLLT has been used to treat cutting plague in the right instep and on the left foot. Both resulted from sutured wounds. The clinical evaluation by semiquantitative methods is presented. RESULTS: Clinical evaluation showed that the healing process of these postoperatively treated wounds has occurred and that the functional recovery of the patients (i.e., return to their ordinary life) was faster than without treatment.

Temperature-controlled 830-nm low-level laser therapy of experimental pressure ulcers.

Lanzafame RJ; Stadler I; Coleman J; Haerum B; Oskoui P; Whittaker M; Zhang RY

Photomedicine and laser surgery; VOL: 22 (6); p. 483-8 /200412/

The Laser Center, Rochester General Hospital, Rochester, New York, USA. ray.lanzafame@viahealth.org

OBJECTIVE: This study was performed to evaluate the effectiveness of near-infrared low-level laser therapy (LLLT) treatment of pressure ulcers under temperature-controlled conditions.

BACKGROUND DATA: Little information is available regarding the potential thermal effects of near-infrared photo-radiation during LLLT.

METHODS: Pressure ulcers were created in C57BL mice by placing the dorsal skin between two round ceramic magnetic plates (12.0 x 5.0 mm, 2.4 g, 1 K Gauss) for three 12-h cycles. Animals were divided into three groups (n = 9) for daily light therapy (830 nm, CW, 5.0 J/cm(2)) on days 3-13 post ulceration in both groups A and B. A special heat-exchange device was applied in Group B to maintain a constant temperature at the skin surface (30 degrees C).

Group C served as controls, with irradiation at 5.0 J/cm(2) using an incandescent light source. Temperature of the skin surface, and temperature alterations during treatment were monitored. The wound area was measured and the rate and time to complete healing were noted.  

RESULTS: The maximum temperature change during therapy was 2.0 +/- 0.64 degrees C in Group A, 0.2 +/- 0.2 degrees C in Group B and 3.54 degrees C +/- 0.72 in Group C. Complete wound closure occurred at

18 +/- 4 days in Groups A and B

The influence of low-level laser therapy on biomodulation of collagen and elastic fibers.

Pugliese LS; Medrado AP; Reis SR; Andrade Zde A

Pesquisa odontologica brasileira =Brazilian oral research; VOL: 17 (4); p. 307-13 /2003 Oct-Dec/

Department of Basic Science, Foundation for the Development of Science, Salvador

The study of low-level laser therapy upon extracellular matrix elements is important to understand the wound healing process under this agent. However, little is known about the interference of laser light in relation to collagen and elastic fibers.

Cutaneous wounds were performed on the back of 72 Wistar rats and a Ga-Al-As low-level laser was punctually applied with different energy densities. The animals were killed after 24, 48, 72 hours and 5, 7 and 14 days. Tissues were stained with hematoxilin-eosin, sirius red fast green and orcein and then analyzed. It was observed that the treated group exhibited larger reduction of edema and inflammatory infiltrate.

Photobiomodulation improves cutaneous wound healing in an animal model of type II diabetes.

Byrnes KR; Barna L; Chenault VM; Waynant RW; Ilev IK; Longo L; Miracco C; Johnson B; Anders JJ

Photomedicine and laser surgery; VOL: 22 (4); p. 281-90 /200408/

Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA. krb27@georgetown.edu

OBJECTIVE: We investigated the effects of photobiomodulation (PBM) on cutaneous wound healing in an animal model of type II diabetes, Psammomys obesus (Sand Rats).

were done to establish optimal treatment parameters for this model. Following creation of bilateral full-thickness skin wounds, non-diabetic Sand Rats were treated with PBM of differing dosages. Wound healing was assessed according to wound closure and histological characteristics of healing. Optimal treatment parameters were then used to treat type II diabetic Sand Rats while a diabetic control group received no irradiation. In order to elucidate the mechanism behind an improvement in wound healing, expression of basic fibroblast growth factor (bFGF) was assessed.

RESULTS: Significant improvement in wound healing histology and wound closure were found following treatment with 4 J/cm(2) (16 mW, 250-sec treatments for 4 consecutive days; p < 0.05). The 4 J/cm(2) dosage significantly improved histology and closure of wounds in the diabetic group in comparison to the non-irradiated diabetic group. Quantitative analysis of bFGF expression at 36 h post-injury revealed a threefold increase in the diabetic and non-diabetic Sand Rats after PBM.