大鼠面神经核运动神经元的分布及神经损伤再支配后的变化

Distribution of rat facial motoneurons and its reorganization following nerve reinnervation

目的 研究正常和面神经损伤后再支配条件下大鼠面神经不同分支神经元的分布。方法 采用荧光素逆行双标法观察正常情况下面神经颊支和下颌缘支神经元的分布 ,以及神经损伤发生再支配后二者分布方式的变化。结果 正常情况下 ,发出颊支的神经元与发出下颌缘支的神经元位于面神经核中间内侧和外侧亚核 ,呈完全交迭分布 ;两种神经元排列紧密 ,但未见双标记神经元。面神经切断吻合后 4个月 ,颊支神经元与下颌缘支神经元仍主要呈交迭分布 ,但标记的神经元数明显减少 ,神经元排列松散 ,部分颊支和下颌缘支神经元分布到背侧、腹内侧和内侧亚核。面神经切断吻合后 6个月 ,颊支神经元与下颌缘支的分布方式与面神经吻合后 4个月时基本相同 ,但标记的神经元数明显增多 ,并见 1%～ 2 %的双标记神经元。结论 正常情况下面神经核内颊支神经元与下颌缘支神经元分布方式提示在颊支和下颌缘支的远端可能存在广泛的交通 ;

Objective To examine the distribution of rat facial motoneurons contributing different branches under normal situation and when nerve reinnervation occured following facial nerve axotomy.Methods The normal distribution of motoneurons innervated both buccal and marginal mandibular branches and its reorganization after facial nerve reinnervation was observed using retrograde labeling with fluorescein.Results Under normal situation,the motoneurons contributing buccall and marginal mandibular branches were primarily distributed in the intermedial and lateral subnucleus in facial nucleus and almost completely overlapped.The two types labeled neurons organized closely,but there were no double-labeled neurons.Although the motoneurons contributing buccall and marginal mandibular branches were primarily overlapped 4 month post-anastomosis,the number of the labeled neurons obviously decreased and the organization got more scattered.There were 10% of buccall branches,5% of marginal mandibular motoneurons in the dorsal subnuleus,1% of buccall and 4% of marginal mandibular in dorsal ventral and medial subnucleus.The distribution pattern of the motoneurons 6 month post-anastomosis was similar to that of 4 month post-anastomosis,but the number of the labeled neurons increased,and there were 1%-2% double-labeled neurons.Conclusion The distribution pattern of motoneurons innervated both buccal and marginal mandibular branches indicates that it should exist wide-spread communicating branches,and its reorganization after facial nerve reinnervation suggests that misdirected regeneration occurs among motoneurons innervating different branches.