外源性神经生长因子对失神经大鼠股骨生物力学的影响

背景：现已发现在骨折愈合过程中有神经生长因子的表达，且外源性神经生长因子有促进骨折愈合的作用。目的：拟观察外源性神经生长因子对去神经大鼠失用性骨质疏松股骨生物力学的影响。设计、时间及地点：随机对照动物实验，于2006-03/05在成都体育学院运动医学系动物实验室完成。材料：2月龄SD雄性大鼠50只，体质量（180.2±10.2）g，用于建立失神经失用性骨质疏松模型。方法：50只大鼠随机抽签法分为5组。假手术组不切除坐骨神经和股神经，每天注射等体积的生理盐水；其他各组均切除大鼠右侧坐骨神经和股神经，去神经组每天注射等体积的生理盐水；被动运动组每天用自行设计的被动训练仪按设定的节奏和运动量对其患肢进行被动运动；神经生长因子组注射外源性神经生长因子2 U/(kg?d)；被动运动与神经生长因子联合组被动运动方式和注射方式分别同被动运动组和神经生长因子组。主要观察指标：30 d 后取材，剥离右侧股骨进行生物力学检测，包括最大载荷、破断载荷、结构刚度、能量吸收，弹性模量、极限强度、最大应变。结果：50只SD大鼠均进入结果分析。与假手术组相比，去神经组各指标均明显降低（P < 0.01）；被动运动与神经生长因子联合组最大载荷和弹性模量下降（P < 0.05）；被动运动组、神经生长因子组最大载荷、结构刚度、弹性模量均降低（P < 0.05）。与去神经组相比，被动运动与神经生长因子联合组除能量吸收和极限强度指标差异不明显外，其他指标均明显偏高（P < 0.01）。结论：去神经后骨失去肌肉应力作用，股骨力学性能下降，神经的修复和再生有利于防止或延缓骨质疏松的发生。

Effect of exogenous nerve growth factor on femoral biomechanics of denervated rats

BACKGROUND: Nerve growth factor (NGF) expresses in the process of fracture healing, and exogenous NGF can promote the healing.OBJECTIVE: To investigate the effect of exogenous NGF on the biomechanics of the femur in denervated rats with disuse osteoporosis.DESIGN, TIME AND SETTING: Randomized control animal experiments were performed in the Animal Laboratory, School of Medicine, Chengdu Sport University from March to May in 2006.MATERIALS: Fifty SD male rats of 2 months old, weighing (180.2±10.2) g, were used to establish the disuse osteoporosis rat model.METHODS: Fifty rats were randomly divided into five groups. Sham operation group was injected with saline, without the excision of sciatic nerve and femoral nerve. Other four groups were all induced disuse osteoporosis by the excision of sciatic nerve and femoral nerve. Denervation group was injected with saline. Passive movement group was processed into the movement according to the set rhythm and exercise amount. NGF group was injected with 2 U/(kg?d) exogenous NGF. Combination group underwent the intervene of both passive movement group and NGF group.MAIN OUTCOME MEASURES: Right femur was harvested at 30 days to evaluate the biomechanical indices, including the maximum load, breaking load, structure stiffness, energy absorption, modulus of elasticity, ultimate strength and maximum strain.RESULTS: All 50 rats were involved in the final analysis. Compared with sham group, the biomechanical indices were remarkably reduced in the denervation group (P < 0.01); The maximum load and modulus of elasticity in the combination group were both decreased (P < 0.05); In the passive movement group and NGF group, the maximum load, structure stiffness and modulus of elasticity were all reduced (P < 0.05); Except energy absorption and ultimate strength, other indices of passive movement group and NGF group were remarkably increased compared with the denervation group (P < 0.01).CONCLUSION: After the denervation, the muscular stress has been lost and femoral mechanical property decreases, nerve repair and regeneration will benefit to prevent or delay the appearance of osteoporosis.