Combined PRP injections increases S100B expression in nerve injury repair

Background and objectives. Peripheral nerve injuries present a wide array of symptoms depending on severity and the affected nerves. Despite extensive understanding of injury mechanisms and regeneration, treatments that ensure complete functional recovery remain limited. The use of biological therapies such as platelet-rich plasma (PRP) has increased in the treatment of neurological disorders. This study aimed to analyze S100B protein expression as a biomarker of nerve regeneration following axonotmesis injury after PRP administration and to compare the efficacy of PRP delivered via three different methods. Materials and methods. In this post-test-only design, twenty-five Wistar rats with sciatic nerve injury were randomly allocated into five groups (n = 5): K1 (sham operation, negative control), K2 (nerve injury with saline injection, positive control), and three treatment groups receiving PRP: local (P1), intraperitoneal (P2), and a combination of local and intraperitoneal (P3). Axonotmesis was induced by clamping the sciatic nerve for 60 seconds. S100B expression was evaluated by immunohistochemical examination using anti-S100B monoclonal antibodies, and the percentage of expression was calculated. Results. The PRP-treated groups showed greater S100B expression than the K1 and K2 control groups. Among them, the group receiving PRP via the combined route exhibited significantly higher expression than those receiving PRP either locally or intraperitoneally (p = 0.000). Conclusions. S100B expression was significantly increased in the group treated with both local and intraperitoneal PRP, compared to groups receiving PRP through a single route, suggesting enhanced nerve regeneration.