Biostimulation of wound healing by low‐energy laser irradiation A review

Conlan, Michael J.; Rapley, John W.; Cobb, Charles M.

doi:10.1111/j.1600-051x.1996.tb00580.x

Cited by 428 publications

(318 citation statements)

References 22 publications

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“…These findings suggest that this protocol of light Laser irradiation is able to downregulate the inflammatory response and favor the acceleration of biological events responsible for the healing process. Similar findings attesting a remarkable anti-inflammatory activity of LLLT in other different protocols have been previously reported 14,15 . Additionally, LLLT apparently influenced the dynamic of the immunoinflammatory response at early stages of wound healing process, once it clearly induced switching of the leukocyte infiltration pattern (neutrophilic to lymphoplasmacytic infiltration) into the damaged tissue of irradiated wounds.…”

Section: Discussionsupporting

confidence: 91%

Effect of low level laser on sutured wound healing in rats

et al. 2011

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Purpose:To evaluate the effect of low-level laser therapy (LLLT) ë904 nm on healing of surgical wounds in rats. Methods: Forty male Wistar rats were used, divided into four groups, underwent incision along the lines Alba covering skin, subcutaneous and muscle abdominal, sutured continuously for nylon 5-0. Eight and fifteen days after the surgery process, the repairing area was removed and histological sections were stained with hematoxylin-eosin to assess cellularity inflammatory, Masson´s Trichrome and Picrossirus to quantify the collagen fibers and immunohistochemical technique for counting newly formed vessels. The data were compared statistically using analysis of variance ANOVA, with a "post-hoc Tukey test, p <0.05. Results: Low-level laser therapy reduced the intensity of the inflammatory reaction and influenced the dynamic of the immunoinflammatory response by inducing switching of the leukocyte infiltration pattern (neutrophilic to lymphoplasmacytic infiltration). Also stimulate the deposition and enhance the organization of collagen fibers, featuring a delicate collagen type III. Furthermore, it appeared to a significant increase in the average number of newly formed vessels (p = 0.00 and p = 0.02, respectively). Conclusion: Low-level laser therapy resulted in modulate of the inflammatory response, enhanced deposition of collagen fibers and increase in the average number of newly formed vessels. Key words: Wound Healing. Lasers, Semiconductor. Collagen. Macrophages. Rats. RESUMO Objetivo:Avaliar o efeito da terapia laser de baixa potência (TLBP) ë904 nm na cicatrização de feridas cirúrgicas em ratos. Métodos: Foram utilizados 40 ratos Wistar, machos, divididos em quatro grupos, submetidos à incisão na linha Alba abrangendo pele, subcutâneo e musculatura abdominal, suturados continuamente por fios de nylon 5-0. Oito e quinze dias após o procedimento cirúrgico, a área de reparo foi removida e os cortes histológicos foram corados com hematoxilina-eosina para avaliar celularidade do infiltrado inflamatório, Tricrômico de Masson e Picrosirius para quantificar as fibras de colágeno e técnica imuno-histoquímica para a contagem de vasos neoformados. Os dados foram comparados estatisticamente pela análise de variância ANOVA, com "teste de Tukey post-hoc, p <0,05. Resultados: A terapia laser de baixa potência reduziu a intensidade da reação inflamatória e influenciou a dinâmica da resposta imuno por induzir a mudança do padrão de infiltração de leucócitos (neutrófilos a infiltração mononuclear). Como também estimula a deposição e melhora padrão organizacional das fibras colágenas, apresentando um delicado colágeno tipo III. Além disso, verificou-se um aumento significativo no número médio de vasos neoformados (p = 0,00 e p = 0,02, respectivamente). Conclusão: A terapia laser de baixa potência modula a resposta inflamatória, com melhor deposição de fibras colágenas e aumento do número médio de vasos neoformados. Descritores: Cicatrização de Feridas. Lasers Semicondutores. Colágeno. Macrófagos. Ratos. -Act...

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Section: Discussionsupporting

confidence: 91%

Effect of low level laser on sutured wound healing in rats

et al. 2011

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“…Increased amount of collagen fibers was reported previously following several laser therapy protocols. 30,38,39 Similarly, studies carried out using polarized light sources also reported positive biomodulatory effects on wound healing. 22,40,41 Polarized light may reproduce nearly 80% of the effects of the laser, but nonpolarized light may not.42 Polarization has also been suggested as an important factor on tissue responses.26,43 Despite earlier reports suggesting that laser light may inhibit or have no effect on wound healing, meticulous analysis of evidence and problems on the parameters used30,44-48 or consequence of the systemic effect of the laser therapy remain.…”

Section: Discussionmentioning

confidence: 99%

Polarized Light (400–2000 nm) and Non-ablative Laser (685 nm): A Description of the Wound Healing Process Using Immunohistochemical Analysis

Pinheiro

Pozza

Oliveira

et al. 2005

Photomedicine and Laser Surgery

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Objective: This study aimed to describe, through morphologic and cytochemical analysis, the healing process of wounds submitted (or not) to laser therapy (λ685 nm) or polarized light (λ400-2000 nm). Background Data: There are many reports on different effects of several types of phototherapies on the treatment of distinct conditions, amongst them, on wound healing. Laser therapy and the use of polarized light are still controversial despite successive reports on their positive effects on several biological processes. Methods: Thirty male Wistar rats, approximately 4 months old, were used, and standardized excisional wounds were created on their dorsum. The wounds were irradiated in four equidistant points with laser light or illuminated with polarized light, both with doses of 20 or 40 J/cm2. Group 1 acted as untreated controls. Animals were irradiated every 48 h during 7 days, starting immediately after surgery, and were humanely killed on the 8th post-operative day. Specimens were taken and routinely processed and stained with H&E, and for descriptive analysis of myofibroblasts and collagen fibers, the specimens were imunnomarked by smooth muscle α-actin and picrosirius stain. Results: Control specimens showed the presence of ulceration, hyperemia, discrete edema, intense, and diffuse inflammation, collagen deposition was irregular, and myofibroblasts were seen parallel to the wound margins. Wounds treated by laser therapy with a dose of 20 J/cm2 showed mild hyperemia, inflammation varied from moderate to intense, the number of fibroblasts was large, and the distribution of collagen fibers was more regular. Increasing the dose to 40 J/cm2 evidenced exuberant neovascularization, severe hyperemia, moderate to severe inflammation, large collagen deposition, and fewer myofibroblasts. On subjects illuminated with polarized light with a dose of 20 J/cm2, mild to moderate hyperemia was detectable, and collagen matrix was expressive and unevenly distributed; a larger number of myofibroblasts was present and no re-epithelialization was seen. Increasing the dose resulted in mild to moderate hyperemia, no reepithelialization was seen, edema was discrete, and inflammation was moderate. Conclusion: The use of 685-nm laser light or polarized light with a dose of 20 J/cm2 resulted in increased collagen deposition and better organization on healing wounds, and the number of myofibroblast was increased when polarized light is used.

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“…Previous studies have reported-beneficial effects of LLLT on chronic wound healing, in healthy and nonhealthy rats, as well as in some other small animals. 7,10,[19][20][21][22] Since blood flow is increased in the microcirculation during laser therapy, this could explain the enhancement of wound healing and reduced pain. 6,7 Others have suggested that LLLT is beneficial for wound healing in diabetics.…”

Section: Discussionmentioning

confidence: 99%

“…14 Laser parameters (such as wavelength, time of exposure, and dosage) used for in vivo studies of the effect of LLLT on wound healing have not been standardized yet. 11,20 It is difficult to compare results from different experiments when laser parameters are variable.…”

Section: Introduction Dmentioning

confidence: 99%

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

Rabêlo

Villaverde

Nicolau

et al. 2006

Photomedicine and Laser Surgery

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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 cm 2 irradiated area, and energy density of 10 J/cm 2 . 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. 474

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Biostimulation of wound healing by low‐energy laser irradiation A review

Abstract: This paper reviews studies on the basic principles of biostimulation of wound healing by various low-energy lasers. It looks at the mechanism of action of biostimulation as well as the laser's effect on cell proliferation, collagen synthesis, and would healing.

Cited by 428 publications

References 22 publications

Effect of low level laser on sutured wound healing in rats

Effect of low level laser on sutured wound healing in rats

Polarized Light (400–2000 nm) and Non-ablative Laser (685 nm): A Description of the Wound Healing Process Using Immunohistochemical Analysis

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

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