Promoting Fracture Healing Effect Of NGF On Tibia Fracture With Peripheral Nerve Injury In Early-Stage

Objective: To study the effect of peripheral nerve injury and NGF on fracture healing, and investigate the mechanism of how NGF influence fracture repairing.Method: A total 48 male Wistar rats were operated on and got a closed transverse tibia fracture in middle, then randomly divided into 4 groups. A1 group: sodium chloride, A2 group: sodium chloride + peripheral nerve injury , B1 group: NGF,B2 group: NGF + peripheral nerve injury. Animals were executed after 2,4 weeks. Callus size was evaluated by wet weight and radiograph , the callus microstructure was measured by bone histomorphometery.Result: The callus formation on the nerve injury sides (A2, B2)was much more than that on the innervated sides(A1,B1),but the increased callus had more osteoid, less in mineralized bone and normal bone trabecular structure. Local injection of NGF(B1,B2) can inhibit the metabolism of osteoclast, increase bone volume, widen the bone trabecular , mature the callus.Conclusion: Peripheral nervous system has an effect on bone metabolism, Intact innervation is essential for normal fracture healing. Nerve injury can induce mechanically insufficient callus and inhibit the rehabilitation of fracture. During fracture, weather nerve injury or not, Local injection of NGF can have a passive effect.