Os efeitos do laser hélio-neônio de baixa intensidade na cicatrização de lesões cutâneas induzidas em ratos

Abstract

Objective: To evaluate the effects of low-level helium-neon (HeNe) laser on cutaneous wound healing in rats. Methods: Sixty Wistar rats were divided into control group and experimental group. A sutured longitudinal, dorsal-medial incision was made, with simple separate stitches. The experimental group was irradiated daily in three areas of the wound with HeNe laser (5mW maximum continuous power, 632.8 nm wavelength, 4 j/cm 2 energy density and 0.015 cm 2 laser beam area) for 36 seconds. The areas were evaluated on the third, seventh and fourteenth days postoperative. Histological sections were stained with hematoxylin-eosin to determine the type of inflammatory reaction according to the protocol by Vizzotto et al. (2003)* and with Picrosirius to identify types I and III collagen and the collagen maturation index (CMI). Immunohistochemical detection was employed with anti-CD45-LCA to recognize the inflammatory cells. Results: Both groups had the same inflammatory pattern. The experimental group had fewer inflammatory cells at the three evaluation times (p<0.001) with faster reduction in the number of leukocytes. The experimental group had greater total collagen density on the third day (p=0.001), with more type III collagen (p=0.001) and more type I collagen (p=0.001). There was no significant difference in the CMI. Conclusion: Low-level laser irradiation does not change the quality of the inflammatory response, but it does reduce its intensity; it increases collagen deposition in the early stages of the healing process and does not interfere with collagen maturation.Key words: wound healing; low-level laser therapy; helium-neon laser; collagen. ResumoObjetivo: Avaliar os efeitos do laser de baixa potência hélio e neônio (HeNe) na cicatrização de feridas cutâneas de ratos. Métodos: Sessenta ratos Wistar foram divididos em grupos controle e experimento. Utilizou-se ferida incisional, longitudinal, dorso-mediana, suturada com pontos separados simples. No grupo experimento, as feridas foram irradiadas diariamente com aparelho de laser de HeNe com potência contínua máxima de 5mW, comprimento de onda de 632,8 nm, visível com densidade de energia de 4j/cm 2 , área de raio do laser de 0,015cm 2 , durante 36 segundos, em três pontos da lesão. As feridas foram avaliadas no 3º, no 7º e no 14º dia de pós- (p<0,001), com diminuição mais rápida do número de leucócitos. Verificou-se que as do grupo experimento tinham maior densidade de colágeno total no 3º dia (p=0,001), com mais colágeno III (p=0,001) e mais colágeno I (p=0,001). Não houve diferença significativa no IMaC. Conclusão: A irradiação com laser de baixa intensidade não modifica a qualidade da reação inflamatória, mas diminui a intensidade dela; aumenta a deposição do colágeno no início do processo cicatricial e não interfere na maturação da cicatriz.Palavras-chave: cicatrização de feridas; laserterapia de baixa intensidade; laser de gases Hélio e Neônio; colágeno.* Vizzotto jr AO, Noronha L, Scheffel LHD, Campos ACL. Influência da cisplatina administrada n...

Development and validation of an algorithm for laser application in wound treatment

“…It is known that laser therapy is a wound treatment, since it accelerates tissue proliferation, increases vascularity in the wound area, and the formation of more organized granulation tissue, favoring rapid healing of the wound. However, criteria for its application are necessary 5 , 8 - 9 , 14 .…”

Action of AlGaInP laser and high frequency generator in cutaneous wound healing. A comparative study

“…Studies suggest that LPL, as well as HF, facilitate tissue repair of cutaneous wounds 7,9,12,16,[19][20][21] . Similar results, especially in relation to the laser, were found in this study.…”

“…Studies show that the LPL 7,12,13,[19][20][21] , as well as HF 9,16 , accelerate the tissue repair process for wounds, after incisional lesion, being relevant in the treatment of skin disorders, once the AlGaInP laser reduces the inflammatory reaction and provides better quality and greater speed in the repair process of soft tissue 11,15 , while the HF can intervene in the oxidoreduction balance with germicide, bactericide and antiseptic properties in the cicatrization process 9,16 . Given this, the goal was to have a macroscopic, histological and histomorphometric assessment of the process for cutaneous wound cicatrization in mice, by using AlGaInP Laser therapy compared to treatment with HF.…”

Effects of low-level laser therapy on wound healing

“…In addition, it contributes to increase the motility of epithelial cells, the amount of granulation tissue and may reduce the synthesis of inflammatory mediators [2][3][4][5] . Its action can be observed on the reduction of the area of skin wounds in humans and animals, although the adoption of physical variables involved in the treatments is still not a consensus among authors [6][7][8][9] .…”