失神经支配骨骼肌退变组织形态学及电生理实验研究

目的研究大鼠失神经支配骨骼肌组织形态学及其电生理变化，为临床寻找检测肌肉萎缩程度的方法及更好防治肌肉萎缩提供理论基础。方法选用成年ＳＤ大鼠，切断胫神经建立失神经支配腓肠肌实验模型。测定萎缩肌肉湿重、肌细胞直径及截面积，观察骨骼肌运动终板及肌肉纤颤电位波幅与频数变化。结果４周内肌肉湿重下降最快，以后逐渐减慢并维持于一定水平，而肌细胞直径及截面积呈持续性下降；在４周内运动终板改变不明显，６周后退变逐渐加重，１６周后消失；２周时肌肉纤颤电位波幅最大，１２周后进行性下降，２０周时有半数以上大鼠出现电静息，频数与波幅值变化规律相一致。结论肌肉湿重、肌细胞直径及截面积可作为反映肌肉萎缩的组织形态学指标，而后两者更为可靠；肌肉纤颤电位波幅与频数可作为电生理指标，周围神经损伤后修复手术越早越好，应力争在运动终板消失前进行。

EXPERIMENTAL STUDY OF MORPHOLOGY AND ELECTROPHYSIOLOGY ON DENERVATED SKELETAL MUSCLE

Objective In order to provide the scientific basis to find out a practical and effective method to evaluate the degree of muscle atrophy and a better method of prevention and treatment of skeletal muscle atrophy.Methods Fourty two adult Spray Dawley rats were used and the model of denervated gastrocnemius muscle was established by cutting off the tibial nerve. The muscle wet weight, diameter and cross section area of myocyte were measured. The motor end plate, fibrillation potential amplitude and frequency of denervated skeletal muscle were observed. Results The muscle wet weight rapidly reduced within 4 weeks. Afterwards, it maintained about 30 per cent of normal value,and the diameter and cross section area of myocyte progressively reduced.The motor end plate slightly changed within 4 weeks, but its degeneration accelerated in 6 weeks and disappeared after 16 weeks. The fibrillation potential amplitude was maxium at 2 weeks and it progressively reduced after 12 weeks of muscle denervation. The changes of amplitude and frequency were consistent with the degeneration of end plate.Conclusion The muscle wet weight, diameter and cross section area of myocyte, fibrillation potential amplitude and frequency could be considered as the morphological and electrophysiological indexes of muscle atrophy degree.It's suggested that the repairing operation of peripheral nerve should be performed before the disappearance of motor end plate.