Apilarnil Improves Early Histological Repair and Biomechanical Strength During Experimental Femoral Fracture Healing in Rats.

Fracture healing remains a major challenge in orthopedic practice, and natural bioactive products have attracted increasing interest as supportive agents for bone regeneration. Apilarnil (drone larvae homogenate), a bee-derived natural product with antioxidant and anti-inflammatory properties, has not previously been investigated in fracture healing. This study evaluated the effects of oral apilarnil on experimental femoral fracture healing in rats. Forty-two male Wistar Albino rats underwent standardized closed femoral fracture fixation with intramedullary Kirschner wire stabilization and were randomly assigned to either a control group or an apilarnil-treated group receiving 400 mg/kg/day orally. Animals were sacrificed on postoperative days 15, 30, and 45. Fracture healing was assessed radiologically using the Lane and Sandhu scoring system, histopathologically using the Huo scoring system, and biomechanically by a three-point bending test. Histopathological scores were significantly higher in the apilarnil group on postoperative day 15 (p = 0.042), whereas no significant differences were observed at later time points. Biomechanical testing demonstrated significantly greater fracture strength in the apilarnil-treated group on postoperative days 30 (p = 0.001) and 45 (p = 0.004), while radiological scores did not differ significantly between groups throughout the study. These findings suggest that apilarnil may support fracture healing by enhancing early tissue repair and improving the biomechanical properties of healing bone, warranting further experimental and clinical investigation.