Skin grafting consists in a surgical procedure where a skin segment is transported from one region of the body to another, with applicability in different scenarios such as burns, neoplastic excisions and others. However, the procedure failure may occur due to a frequent complication, the tissue necrosis. Therefore, resources are sought to improve the skin graft integration, seeking to minimize this important complication. In this sense, photobiomodulation (PBM) has been investigated, considering its relevant effects on the healing process such as neovascularization stimulation, fibroblastic proliferation and modulation of inflammatory mediators. However, until now, there are no studies that have performed open bed irradiation, before skin replacement, to prepare it for receiving the tissue and aiming to be a PBM promising application.

Evaluate and compare the effects of laser PBM, at red and infrared wavelengths, in the total skin graft integration process, in rats.

Eighteen Wistar rats were used, allocated in three groups: red laser (660nm), infrared laser (808nm), and control. In all groups, a 5x3 cm skin segment was removed, followed by panniculus carnosus muscle dissection. In the control group, the skin was replaced on the bed after a 180º rotation. In the laser groups, the bed first received irradiation with fluence of 25 J/cm² and irradiance of 2,500 mW/cm², in a total of 6 points, and then the skin was replaced in the same way. Euthanasia occurred on the 7th postoperative day, when photographic captures and skin tissue samples were collected for macroscopic analysis of tissue necrosis and descriptive histology, respectively. Statistical analysis was carried out using the Levene and Shapiro-Wilk tests, followed by Anova-Two-way test with Tukey post hoc and a significance level of 5%.

The macroscopic analysis showed that the control, laser 660nm and laser 808nm groups had mean necrosis percentages of 26.30%, 16.01% and 37.29%, respectively. It was observed that the 660nm group reached a lower percentage, proving to be more effective than the 808nm laser group (p=0.0022), but there was no statistical difference when compared to the control. In the histological analysis, it was noted that the control and 660nm groups presented similar fibrosis formation and granulation tissue, with no presence of granulation tissue in the 808nm group. Furthermore, moderate inflammatory infiltrate was identified in the control group, weak in the 660nm group, and intense in the 808nm group.

The control and 660nm laser groups obtained similar results in macroscopic and microscopic analyses, while the 660nm laser showed superior performance compared to the 808nm laser group in skin graft integration.

This study presents an innovative character in that it performs irradiation of the open bed before skin grafts replacement, acting as a starting point for future research. More studies are needed for a better understanding of this PBM application, seeking to optimize the skin grafting procedure using a low-cost therapeutic resource with high applicability.