喉返神经再生中乙酰胆碱受体免疫电镜观察

The electron microscopic study of AchR and ultrastructure of neuromuscular junction in recurrent laryngeal nerve reinnervation

目的 了解喉返神经再生时N 乙酰胆碱受体 (N Acetylcholinereceptor,N AchR)的分布及含量改变。方法 采用透射免疫电镜结合图像分析技术观察喉返神经再生过程中神经肌肉接头(neuromuscularjunction ,NMJ)及其N AchR的超微结构。结果 术后 3周突触前膜结构基本消失而后膜结构尚完整 ,N AchR含量较健侧增多 ,为健侧 1 2 8倍。术后 6周再生神经长入NMJ,但与突触后膜接触面积小 ,N AchR含量处于最低状态 ,为健侧 0 47倍。术后 12周NMJ结构较前成熟 ,N AchR含量增加为健侧 0 72倍。术后 18和 2 4周神经末梢与突触后膜接触良好 ,N AchR继续增多并趋稳定 ,分别为健侧 0 83和 0 81倍。结论 提示周围神经再生时N AchR含量与再生神经恢复程度有关。

Objective The purpose of this study was to observe the distribution of Acetylcholine receptor (AchR) and ultrastructural changes of the neuromuscular junction after laryngeal reinnervation Methods α bungarotoxin horseradish peroxidase (α BT HRP) conjugate electron microscopic immunocytochemical methods and computer analysis of intensity of immunocytochemical reaction were applied to observe the distribution and relative quantity of junctional N AchR Results The results showed that the synaptic nerve terminals and presynaptic membrane were segmentally disrupted and almost disappeared completely and were replaced by Schwann's cells at 3 weeks after neurorrhaphy At 6 weeks, some of the regenerating axons grew to the neuromuscular junctions and all the muscle fibers were reinnervated at 12 weeks But the original postsynaptic membranes were only partially in contact with the regenerated nerve terminals These conditions persisted until 18 weeks after neurorrhaphy, when remyelination was found in the vicinity of the neuromuscular junctions The N AchR reaction product on the postsynaptic membrane were increased greatly about 1 28 times more than the normal at 3 weeks after neurorrhaphy The reactive products decreased greatly which was only 0 47% of that in the normal at 6 weeks It remained low until 12 weeks after neurorrhaphy, which was 0 72% of the normal side It increased obviously to 0 83 times of normal sides at 18 weeks and didn't changed there after Conclusion The state of reinnervation determines the quantity of neuromuscular junctional N AchR