Anti-inflammatory effect of low-intensity laser on the healing of third-degree burn wounds in rats

Abstract

Third-degree burn wounds are considered severe injuries because they destroy all the skin layers and may affect subcutaneous tissues, fasciae, muscles, and bones. To favor the healing process of the injured tissues, it is very useful to diminish the occurrence of the inflammatory process. The present study was aimed at comparing the effect of different energetic densities of AlGaInP laser on the inflammatory process and in the healing of third-degree burn wounds in Wistar rats. This study was approved by the Ethics Committee, in which 36 adult male rats were selected and suffered the induction of third-degree burn injury. These rats were divided as follows: group 1-control (treated with silver sulfadiazine), group 2-received energy density of 3J/cm(2), and group 3-received energy density of 6J/cm(2). All animals daily received an occlusive bandage with silver sulfadiazine and 8% papain. The laser therapy was performed alternatively three times a week. The animals were evaluated on the 3rd, 7th, 14th, and 21st days after the initial lesion and euthanized for the macroscopic, histologic, and morphometric analysis. A higher production of collagen was observed at 7days and a greater re-epithelialization at 21days in group 3 (6J/cm(2)). Furthermore, the latter when compared to the other groups presented macroscopically a better aspect of the scar at 21days with more granulation tissue and fibrosis. We conclude that the AlGaInP laser used in dosages of 3 and 6J/cm(2) favors the healing of third-degree burn wounds induced in rats.