Objective: To observe the pathway of regenerative axons of spinal motoneurons following differently injury of brachial plexus and to investigate the correlation of the pathway of regenerative axons and the recovery of motor function. Method: A total of sixty adult male SD rats were randomly divided into five groups: nerve root cut group (rct), nerve root crush group (rch), neural stem cut group (sct), neral stem crush group (sch) and the control group. Two months later, the functional recovery was evaluated by using grooming test. Fluorogold labled regenerative motoneurons retrogradely when injected into the motor or sensory branch of musculocutaneous nerve. Three days later, the C5-7 spinal cord were harvested and then the regenerative motoneurons were numbered. Result: The regenerative motoneurons reinnervated motor branch were much more than that sensory branch in all five groups. With the functional recovery, the percentage of above grading 4 in the four injured groups rct, rch, sch, sct is 0, 17％, 50％, 75％, respectively. Conclusion: Regenerative axons of spinal motoneurons reinnervate the motor branch after BPI. The extent of motor functional recovery is different after different injuries, and it is correlated with the pathway and the numbers of regenerative axons.%目的:观察臂丛神经不同损伤后脊髓前角运动神经元再生轴突的路径选择,探讨运动功能恢复与再生的关系.方法:选用60只健康成年雄性SD大鼠,随机分为5组:根性切断组、根性挫伤组、干性切断组、干性挫伤组和对照组.术后2个月进行Grooming实验,检测其患肢运动功能的恢复.肌皮神经肌支或皮支注射荧光金逆行追踪标记,3天后取脊髓C5-7节段标本,计数再生脊髓运动神经元数.结果:各组肌支标记的神经元数均远多于皮支.运动功能恢复4级以上百分比,根性切断组(0)<根性挫伤组(17%)<干性切断组(50%)<干性挫伤组(75%)<对照组(100%).结论:臂丛神经损伤后脊髓前角运动神经元再生轴突的路径为肌支路径.不同损伤后功能恢复的程度不同,其与再生轴突的路径及再生轴突的数量有关.
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