Avaliação da ação do laser, Led e da terapia fotodinâmica na cicatrização de queimaduras em pele: estudo clínico e histológico em ratos

Abstract

The aim of this study was to evaluate the influence of the red laser, infrared, photodynamic therapy and LED on the healing of wound burns through the clinical and histological analysis in rats. Therefore, 100 animals were randomly divided into five groups: G 1- untreated controlled (CTR), G2- red laser (LVER), G3- infrared laser (LINF), G4- photodynamic therapy (TFD) and G5- green led (LED). The induction of wound burns was obtained by applying a squared metal instrument, previously heated on a torch for 40 seconds, on the back of the rats for 20 seconds. The treatment of the experimental groups was the irradiation of red light (10J/cm2, 10s, and 40mW &#955;660 nm), infrared (10J/cm2, 10s, and 40mW &#955;780 nm), green LED (60J/cm2, 10s, &#955;520 to 550 nm) and photodynamic therapy (10J/cm2, and 40mW &#955;660 nm) that was associated with 0.5 µg/mL of methylene blue .The applications were punctually applied on four coincident points of the wound angles. At each point was added 10J/cm2 totaling 40J/cm2 except from the green LED that was applied 60J/cm², totaling 240J/cm2 per session. The applications were daily until the day before the animal sacrifice that occurred respectively ,considering the group classification, in 3, 7, 14 and 21 days when was applied an overdose of intraperitoneal anesthetic on the animals. The samples were removed and clinically examined then processed and stained with HE and Sirius red for analysis under light microscopy and polarized light, respectively. Animals treated with LVER, LINF, TFD (p <0.001) and LED (p <0.05), stimulated the production and maturation of collagen. Besides the fact that the animals from the group ate better and drink more water if compared to the other untreated controlled group (p<0.001). In conclusion, the red laser, infrared, photodynamic therapy and green led stimulated the healing process in third degree burns in rats.