Efeitos da terapia de fotobiomodulação sobre a reparação tecidual em animais após queimadura de terceiro grau

Abstract

Burns are thermal lesions of the organic tissue that result in loss of skin integrity and consequent changes in the mechanophysiological conditions of the tissues. When third degree, the burns are deeper and have more serious consequences, with greater difficulty in the regeneration process. Photobiomodulation Therapy (FBM) induces better production of collagen fibers and enables shorter wound contraction time to neo-formed tissue. The aim of this study was to evaluate the influence of 658nm, 830nm and 904nm wavelength FBM on tissue repair in an experimental third degree burn model in rats. Wistar rats (males) from the UNIFAL Central Campus Bioterium were used. All experiments followed the established ethical standards for experimentation with agreed animals. A third degree burn of 3 cm in diameter was performed in the dorsal region of the animal. 128 animals were divided into four groups: G658 (received 658nm FBM), G830 (received 830nm FBM), G904 (received 904nm FBM) and GC (Control). Each group was evaluated on the 3rd, 7th, 14th and 21st days after the burn, receiving respectively one, three, six and nine FBM applications. For application in all groups, a fluency of 4J/cm² was used, at 8 points at the edge of the lesion and one at the center. Surface skin temperature analysis was performed by infrared thermography camera. Blood vessel and inflammatory cell counts were performed by histological analysis after the samples were stained with hematoxylin and eosin (HE). For collagen counting, picrosirius red staining was performed. After inflammatory cell count, a significant intragroup difference was observed in G658 (p = 0.006) and G904 (p <0.0001). Quantification of type III collagen differences were found in G568 (p <0.0001), G830 (p = 0.02) and CG (p <0.0001), in the intergroup analysis, the 3PO days of analysis (p = 0.004 ) and 7PO (p <0.0001) showed significant differences between the groups. At 7PO, G658 showed an increase in blood vessels compared to CG. At 21PO, G658 showed a higher number of blood vessels compared to G904 (p = 0.02) and CG (p = 0.005). At 21PO the CG presented higher skin temperature compared to G904 (p = 0.02). It can be concluded that 658nm FBM is more effective in tissue repair after 3rd degree burn.