神经轴突二次损伤对健侧颈7神经根移位术疗效影响的实验研究

目的以大鼠健侧颈，神经根移位术为动物模型，比较健侧颈7神经根移位术后神经轴突一次和二次损伤对中枢神经元及周围神经的影响差异。方法清洁级雌性SD大鼠60只，随机分成3组。A组为健侧颈，神经根移位术二次完成组；B组为健侧颈7神经根移位术一次完成组；C组为正常对照组。术后通过脊髓神经元计数、肌电图检查、神经肌肉组织学检查、肌张力测定和运动终板形态学检查进行综合评价。结果健侧颈，神经根移位术后36周，脊髓前角α运动神经元和背根神经节感觉元的数目A组较B组减少。但A组的再生神经纤维数目增加，而肌电图检查潜伏期延长。2组间肌张力、肌湿重、肌纤维截面积等无明显差异。结论神经轴突二次损伤，可减少中枢神经元数目，但再生神经纤维增加，最终对肌肉形态与肌张力的恢复无明显影响。

An experimental study on the influence of secondary axotomy on contralateral C7 transfer

Objective To study the influence of single axotomy and double axotomy on spinal neurons and peripheral nerves in a rat contralateral C7 transfer model. Methods Sixty adult female Sprague-Dawley rats were randomly divided into A, B, and C group. In group A, contralateral C7 transfer to the musculecutaneous nerve via ulnar nerve graft was done in 2 stages with an interval of 12 weeks. In group B, the neurotization was done in one stage. Group C served as control. Thirty-six weeks after the first operation, spinal neuron count, eleetrophysiolngical, examination, neuromorphometry, muscle morphometry, and motor endplate detection of biceps brachii were carried out to evaluate the outcomes of each group. Results There were smaller numbers of motor neurons in anterior horn of the spinal cord and smaller numbers of sensory neurons in the dorsal root ganglia of group A animals. However there were more regenerating nerve fibers in group A than in group B. There was no difference in muscle tension, muscle wet weight and muscle morphometry between group A and group B. Conclusion Secondary axotomy can cause the decrease in central motor neurons. However, there is an increase in regenerating nerve fibers. The ultimate recovery of muscle morphometry and muscle function is not affected.