LED photobiomodulation therapy associated with heterologous fibrin biopolymer optimizes wound repair in rats

Purpose: The skin is a complex organ that covers the entire surface of the body. Any situation that interrupts the integrity of the skin, whether by accidents, trauma, disease, or surgery, is defined as a skin wound. This study aimed to evaluate the effect of LED photobiomodulation therapy associated or not with heterologous fibrin biopolymer to repair skin wounds in rats. Methods: Full-thickness skin wounds were induced on the back of 84 Wistar rats and they were randomly divided into 4 groups: control group (CG), LED group (LED), heterologous fibrin biopolymer group (HFB), and LED + heterologous fibrin biopolymer group (LED + HFB). The animals were euthanized at 7, 14, and 21 days after surgery. In the macroscopic findings, it was observed in the control group, mild local inflammation, evidenced between the 5th and 6th day after the injury, not manifested in the other groups. The analysis of the wound reduction index showed that the treated groups presented greater wound reduction in the three periods evaluated. Results: The results of the degree of inflammation showed that the LED and LED + HFB groups showed a predominance of chronic inflammation, while the control group showed a predominance of diffuse acute inflammation. The quantity of type I collagen was bigger after 7 days in the LED and LED + HFB groups, and at 14 and 21 days this type of collagen appears more intensely in the group that used only HFB. For the traction force at 7 days of the experiment, the treated groups showed better performance, while at 14 and 21 days the group that used only the biopolymer obtained greater strength in the suture region. Conclusion: Treatments using HFB and LED, either isolated or associated, stimulated the wound repair process in rats. HFB promote collagen maturation. © 2023, The Author(s), under exclusive licence to The Brazilian Society of Biomedical Engineering.