Photobiomodulation, Photomedicine, and Laser Surgery Volume 38, Number 7, 2020 ª Mary Ann Liebert, Inc. Pp. 419–424 DOI: 10.1089/photob.2019.4754
Effect of Photobiomodulation Therapy (660 nm) on Wound Healing of Rat Skin Infected by Staphylococcus
Zi-Xuan Wang, PhD, MD,1,2 and Seong-Hwan Kim, PhD, MD2
Objective: To assess the impact of photobiomodulation (PBM) therapy on healing of infected wounds and document the microscopic findings throughout the recovery process.
Background: Previous studies have suggested that PBM accelerates wound healing and reduces inflammation and pain. However, the ideal protocol and ultimate value of PBM treatment for infected wounds are controversial.
Materials and methods: Eight-month-old male rats were randomly divided into the control group, the nonirradiation group, or the irradiation group. A 1 cm diameter skin excision was made. The wounds of the nonirradiated and irradiated rats were inoculated with a suspension of Staphylococcus aureus. We then performed 7 days of PBM therapy at a wavelength of 660 nm for 35 min/day. On day 8, the rats were sacrificed for histological assessment. Sections were stained with hematoxylin and eosin, Masson trichrome, and a proliferating cell nuclear antigen (PCNA) kit. Defect diameter was calculated using the Visus Image Analysis System.
Results: The irradiated group had more epithelial cells and richer granulation tissue compared to those in the other groups. The irradiation group had a significantly smaller defect size than the nonirradiation group ( p < 0.01) and the control group ( p < 0.05). The amount of collagen was highest in the irradiation group and was graded as 3, 2, and 3+ in the control, nonirradiation, and irradiation groups, respectively. The percentage of PCNA in the control group was significantly lower than that in the other two groups ( p < 0.05).
Conclusions: PBM therapy (660 nm) promoted cell proliferation and collagen synthesis, thereby improving the wound healing response to an S. aureus infection. Keywords: 660 nm, photobiomodulation therapy, wound healing, infection, Staphylococcus
Journal of Photochemistry & Photobiology, B: Biology
Photobiomodulatory effects of superpulsed 904 nm laser therapy on bioenergetics status in burn wound healing
Anju Yadav, Asheesh Gupta ⁎, Gaurav K. Keshri, Saurabh Verma, Sanjeev K. Sharma, Shashi Bala Singh Defence Institute of Physiology and Allied Sciences (DIPAS), DRDO, Lucknow Road, Timarpur, Delhi 110 054, India
article info abstract Article history: Received 7 April 2016 Received in revised form 16 June 2016 Accepted 17 June 2016 Available online xxxx
Burn wounds exhibit impaired healing as the progression through the normal sequential stages of tissue repair gets hampered by epidermal barrier disruption, compromised blood circulation, abrogated defence mechanism, pathologic inflammation, and septicemia. Our earlier results reported that superpulsed 904 nm LLLT enhanced healing and attenuated inflammatory response in burn wounds. The present study investigated the effect of superpulsed 904 nm LLLT (200 ns pulse width; 100 Hz; 0.7 mW mean output power; 0.4 mW/cm2 average irradiance) on biochemical and molecular markers pertaining to bioenergetics and redox homeostasis on fullthickness burn wounds in experimental rats.
Results indicated that superpulsed laser irradiation for 7 days post-wounding propelled the cellular milieu towards aerobic energy metabolism as evidenced by significantly enhanced activities of key energy regulatory enzymes viz. HK, PFK, CS and G6PD, whereas LDH showed reduced activity as compared to the non-irradiated controls. LLLT showed a significant increased CCO activity and ATP level. Moreover, LLLT also regulated redox homeostasis as evidenced by enhanced NADPH levels and decreased NADP/NADPH ratio. Western blot analysis demonstrated that LLLT produced an up-regulation of GLUT1, pAMPKα and down-regulation of glycogen synthase1 (GS1). Our findings suggest that superpulsed 904 nm LLLT augments burn wound healing by enhancing intracellular energy contents through modulation of aerobic metabolism for maximum energy output. Bioenergetic activation and maintenance of redox homeostasis could be one of the noteworthy mechanisms responsible for the beneficial NIR photobiomodulatory effect mediated through superpulsed 904 nm LLLT in burn wound healing.
© 2016 Published by Elsevier B.V.
Photomedicine and Laser Surgery. April 2010, 28(2): 281-283. doi:10.1089/pho.2009.2489.
The Effect of Equal Daily Dose Achieved by Different Power Densities of Low-Level Laser Therapy at 635 and 670 nm on Wound Tensile Strength in Rats: A Short Report
Tomáš Vasilenko,1 Martin Slezák,1 Ivan Kováč, 1 Zuzana Bottková,1 Ján Jakubčo, 1 Martina Kostelníková,1 Zoltán Tomori, Ph.D.,2 and Peter Gál, M.Sc.1,3,4 1 Department of Medical Biophysics, Pavol Jozef Šafárik University, Košice, Slovak Republic. 2 Department of Biophysics, Institute of Experimental Physics, Slovak Academy of Sciences, Košice, Slovak Republic. 3 Department of Pathological Anatomy, University of Veterinary Medicine, Košice, Slovak Republic. 4 Department of Biomedical Research, The East-Slovak Institute for Cardiovascular Diseases, Košice, Slovak Republic. Address correspondence to: Peter Gál Department of Biomedical Research The East-Slovak Institute for Cardiovascular Diseases Ondavská ul.č. 8, 040 11 Košice
Abstract Objective: The aim of our study was to compare the effects of different power densities of LLLT at 635 and 670 nm achieving a daily dose of 5 J/cm2 on wound tensile strength (TS) in rats. Background Data: Optimal parameters of low-level laser therapy (LLLT) are still unknown.
Materials and Methods: Under general anesthesia, one full-thickness skin incision was performed on the back of each rat (n= 40) and immediately closed using an intradermal running suture. Rats were separated into five groups depending on treatment parameters: (1) sham irradiated control group (SIC); (2) 635nm laser-treated group at 4mW/cm2 (L-635/4); (3) 635nm laser-treated group at 15mW/cm2 (L-635/15); (4) 670nm laser-treated group at 4 mW/cm2 (L-670/4); and (5) 670nm laser-treated group at 15mW/cm2 (L-670/15). The total daily dose was 5J/cm2 . Seven days after surgery each wound was removed for wound TS measurement.
Results: The lowest wound TS results were measured in the SIC rats (10.5± 2.8 g/mm2 ). Higher wound TS results were measured in group L-670/15 (11.5± 2.5g/mm2 ) and group L-635/4 (11.7± 4.3 g/mm2 ) rats, while significantly higher results were found in group L-670/4 (15.8 ± 4.4 g/mm2 ) and group L-635/15 (15.9± 4.8g/mm2 ). The differences were significant between certain groups (p< 0.01: SIC vs. L-635/15, SIC vs. L-670/4; p< 0.05: L635/4 vs. L-635/15, L-635/4 vs. L-670/4, L-635/15 vs. L-670/15, L-670/4 vs. L-670/15). Conclusion: Both red lasers significantly increased wound TS at selected parameters. Whereas the 635nm laser significantly improved wound healing by using the higher power density, the 670nm laser improved healing using a lower power density.
Photomedicine and Laser Surgery, Volume: 28 Issue 2: April 7, 2010
Effects of 780-nm Low-level Laser Therapy with a Pulsed Gallium Aluminum Arsenide Laser on the Healing of a Surgically Induced Open Skin Wound of Rat
Mohammad Bayat, Ph.D., Afsaneh Azari, M.Sc., and Mohammad Ghasem Golmohammadi, Ph.D. Physical Therapy Research Group, Academic Center for Education, Culture, and Research, Iran Medical Science Branch University, Vanak, Tehran, Iran. Address correspondence to: Mohammad Bayat, Ph.D. Physical Therapy Research Group Academic Center for Education Culture and Research P.O. Box 16315-447 Vanak, Tehran, Iran
Abstract Objective: The aim of the present investigation is to evaluate the effects of a 780-nm lowlevel laser on open skin wound healing.
Background Data: Optimal parameters of low-level laser therapy (LLLT) for wound healing are discussed. Methods: One full-thickness skin wound was surgically induced in the dorsum skin of 30 rats. The rats were divided into two groups. Rats in the experimental group were daily treated with a gallium aluminum arsenide (GaAlAs) laser (2J/cm2 , λ= 780nm, pulse frequency of 2336Hz). Rats in the sham-exposed group received LLLT with switched off equipment. After 4, 7, and 15 days, wounds were checked by histological and biomechanical methods. Data were analyzed by the Mann– Whitney U-test.
Results: Fibroblasts, endothelium of blood vessels, blood vessel sections, and maximum stress were significantly increased, whereas macrophages were significantly decreased, compared with those of the sham-exposed group.
Conclusion: Pulsed LLLT with a 780-nm GaAlAs laser significantly accelerates the process of healing of surgically induced, full-thickness skin wounds in rat.
Photomedicine and Laser Surgery, : 28 Issue 2: April 7, 2010
Laser Photobiomodulation of Wound Healing in Diabetic and Non-Diabetic Mice: Effects in Splinted and Unsplinted Wounds
Tzu-Yun Chung, B MedSc,1 Philip V. Peplow, Ph.D.,1 and G. David Baxter, DPhil2 1 Department of Anatomy & Structural Biology, University of Otago, Dunedin, New Zealand. 2 Centre for Physiotherapy Research, School of Physiotherapy, University of Otago, Dunedin, New Zealand. Address correspondence to: Dr. Philip Peplow Department of Anatomy and Structural Biology University of Otago PO Box 56 Dunedin 9013, New Zealand
Objective: The aim of this investigation was to compare the healing of laser-irradiated and non-irradiated wounds covered by an occlusive dressing in mice. Background data: Many previous studies of the effects of laser irradiation of experimental wounds in mice and rats did not cover the wounds so that healing occurred mainly by contraction. Healing of covered wounds is slower and mimics more closely wound healing in humans.
Materials and Methods: Forty-seven diabetic and twenty non-diabetic mice were used. A single wound (5 mm diameter) was created on the left flank of each animal and covered by Tegaderm HP dressing (Day 1). Wounds were irradiated (660nm) for 20s using a lower power (18mW) or higher power (80mW) laser starting immediately post-wounding for seven consecutive days (0.36 or 1.6J/day); untreated wounds served as controls. Animals were euthanized on Day 8, 10, or 14. Wound specimens were cut and stained using haematoxylin and eosin, and picrosirius red, and examined by microscopy.
Results: Results confirmed that wound healing was impaired in diabetic mice. Analysis of the data demonstrated that Tegaderm HP dressing had retarded contraction (splinted the wounds) in a large proportion of diabetic mice and, to a lesser extent, in non-diabetic mice. Healing of splinted wounds was delayed compared to unsplinted wounds, but laser irradiation (1.6J/day, 7 days) stimulated healing by reepithelization and granulation tissue formation.
Conclusion: These are the first findings of laser-mediated stimulation of healing in splinted wounds. Further studies are needed
The Efficacy of Laser Therapy in Wound Repair: A Meta-Analysis of the Literature
LYNDA D. WOODRUFF, P.T., Ph.D.,1 JULIE M. BOUNKEO, M.S.,1 WINDY M. BRANNON, M.S.,1 KENNETH S. DAWES, Jr., M.S.,1 CAMERON D. BARHAM, M.S.,1 DONNA L. WADDELL, Ed.D., R.N., C.S.,2 and CHUKUKA S. ENWEMEKA, Ph.D., FACSM3,4
Objective: We determined the overall effects of laser therapy on tissue healing by aggregating the literature and subjecting studies meeting the inclusion and exclusion criteria to statistical meta-analysis. Background Data: Low-level laser therapy (LLLT) devices have been in use since the mid sixties, but their therapeutic value remains doubtful, as the literature seems replete with conflicting findings.
Materials and Methods: Pertinent original research papers were gathered from library sources, online databases and secondary sources. The papers were screened and coded; those meeting every inclusion and exclusion criterion were subjected to meta-analysis, using Cohen’s d. statistic to determine the treatment effect size of each study.
Results: Twentyfour studies with 31 effect sizes met the stringent inclusion and exclusion criteria. The overall mean effect of laser therapy on wound healing was highly significant (d = +2.22). Sub-analyses of the data revealed significant positive effects on wound healing in animal experiments (d = +1.97) as well as human clinical studies (d = +0.54). The analysis further revealed significant positive effects on specific indices of healing, for example, acceleration of inflammation (d = +4.45); augmentation of collagen synthesis (d = +1.80); increased tensile strength (d = +2.37), reduced healing time (d = +3.24); and diminution of wound size (d = +0.55). The Fail-Safe number associated with the overall effect of laser therapy was 509; a high number representing the number of additional studies—in which laser therapy has negative or no effect on wound healing—required to negate the overall large effect size of +2.22. The corresponding Fail-Safe number for clinical studies was 22.
Conclusion: We conclude that laser therapy is an effective tool for promoting wound repair.