Study of the effects and mechanism of allogeneic platelet-rich plasma gel on layered skin flaps

This study investigated the effects of allogeneic PRP gel on layered flap transplantation in Sprague-Dawley (SD) rats and explored its underlying mechanisms, providing a theoretical foundation for improving clinical layered flap success rates. Seventy-two SD rats were randomly assigned to three groups: layered flap + PRP gel (PRP group), layered flap + saline (control group), and traditional flap + saline (sham group), with 24 rats per group. PRP gel was applied during surgery in the PRP group, while saline was used in the sham and control groups. Skin tissue necrosis, temperature fluctuations, and edema were recorded at 6 h, and on days 1, 3, and 5 post-surgery. Growth factors and inflammatory-related indicators in the skin tissue were analyzed on day 3 post-surgery. Layered skin flap grafts exhibited greater susceptibility to necrosis compared to traditional flaps (F = 13.754, P<0.001 on 3th day; F = 10.593, P<0.001 on 5th day). PRP gel enhanced the expression of vascular endothelial growth factor (F = 9.775, P<0.001), CD31 (F = 13.181, P＜0.001), platelet-derived growth factor (F = 6.273, P <0.001), and transforming growth factor beta (F = 8.365, P<0.001), promoting angiogenesis (F = 17.617, P<0.001). Additionally, PRP reduced the expression of IL-18 (F = 38.143, P<0.001), IL-1β (t = 4.575, P<0.001), NLRP3 (F = 13.016, P<0.001), and caspase-1 (t = 6.248, P<0.001), thereby mitigating inflammation. These effects contributed to improved layered flap survival rates. Allogeneic PRP gel facilitated neovascularization and reduced inflammation and decreased the necrotic area in the layered skin flap following flap transplantation. The mechanism likely involves the upregulation of local growth factors.