Efeitos do biopolímero de fibrina heterólogo e fotobiomodulação no reparo de feridas cutâneas em ratos

Abstract

Cutaneous wounds are a public health problem in Brazil and worldwide with a negative impact on the lives of thousands of people, that raise treatment costs and make it difficult to maintain the sustainability of health systems. The aim of the present study was to evaluate the effect of LED-mediated-photobiomodulation therapy associated or not with the use of heterologous fibrin biopolymer (HFB) on the repair of cutaneous wounds in rats. Male Wistar rats were randomly divided into 4 groups of 21 animals as follows: control group (CG) whose wounds were treated with 0.9% saline solution; LED group (LED) whose wounds were irradiated with LED (660 nm, 166 mW, 60 s, 9.96 J); heterologous fibrin biopolymer group (HFB) whose wounds were treated exclusively with HFB; group LED + heterologous fibrin biopolymer (LED + HFB) whose wounds were irradiated with LED and HFB was applied. Two full-thickness cutaneous wounds were created on the back of each animal: a longitudinal wound measuring 3 cm and a circular wound with the diameter of 2 cm. The applications of LED and HFB were performed immediately after injury and followed an interval period of 72 hours between the posterior applications as described: with 2 applications for the 7-day groups, 4 applications for the 14-day groups and 6 applications for the 21-day groups. Animal euthanasia occurred in three different time periods: 7, 14 and 21 days after surgery. Macroscopic analysis, morphometric analysis of the wound repair index, descriptive histological and histomorphometric analysis, collagen quantification and tensile strength analysis. In the macroscopic findings, it was possible to observe the absence of necrosis, odor, presence of fibrosis or fluid in the lesion cavity in all experimental groups. Particularly In the control group, there was mild local inflammation evidenced between the fifth and sixth day after injury, that did not manifest in the other groups. The analysis of the wound repair index demonstrated that the treated groups presented greater wound reduction in the three periods of evaluation. Histopathological analysis revealed that the treatments presented a better repair process in comparison to the control group. Comparing the applied treatments, it was observed that only in the HFB group the dermis exhibited a denser extracellular matrix after 21 days. The collagen evaluation demonstrated that all treatments induced greater collagen deposition and maturation when compared to the control group. However, at 14 and 21 days the HFB group presents greater deposition of collagen type I and collagen maturation. The analysis of the traction force at 7 days of experiment showed better performance of the treated groups, while at 14 and 21 days the group that used HFB had greater resistance in the suture region. The results indicate that treatments using HFB and LED, either isolated or associated, stimulated the wound repair process in rats.