不同程度失神经支配后眼轮匝肌和口轮匝肌运动终板的形态学研究

Morphology of orbicularis muscle and orbicularis oris motor end plat of experimentally denervated and reinnervated guinea pigs facial nerve

目的探讨不同程度失神经支配后眼轮匝肌(眼肌)和口轮匝肌(口肌)运动终板的形态学变化。方法建立豚鼠右侧面神经阻断15 s、30 s和切断的动物模型。于术后1周和1月切取口肌和眼肌患侧和健侧组织,应用乙酰胆碱酯酶组织化学染色,分析光镜和电镜下口肌和眼肌运动终板的病理变化,探讨乙酰胆碱酯酶活性变化与肌肉种属和肌纤维类型的关系。结果光镜下,正常情况下,眼肌和口肌的AchE活性接近;神经损伤1周时,眼肌和口肌AchE活性均没有明显变化;神经损伤1月时,口肌AchE活性仍没有明显变化,而眼肌出现变化:断组<30 s组<15 s组。电镜下,正常组MEP接头褶宽大,AchE阳性反应产物为均匀一致的高电子密度颗粒,定位于突触前膜和突触后膜。失神经支配后1周,突触后膜和神经末梢萎缩,初级和次级皱褶均变浅,眼肌与口肌MEP结构相似。失神经支配后1月口肌,断组,初级和次级皱褶继续变浅;15 s和30 s组,初级突触间隙接近正常。失神经支配后1月眼肌,30 s组和断组初级和次级皱褶继续变浅,有些次级皱褶消失。结论不同程度神经支配后,口肌MEP处的AchE含量一定时间内保持稳定,MEP处的AchE活性变化与肌肉种属和肌纤维类型不同有关。面肌间受伤存在差异,支持面神经瘫部分评价系统的合理性。

Objective To Explore the morphological changes of the orbicularis muscle and orbicularis oris motor end plate（MEP）of experimentally denervated and reinnervated guinea pigs facial nerve.Methods The animal model was estabished that the guinea pig right facial nerve block for 15 seconds,30 seconds,and cut.Cut ipsilateral and contralateral tissue of orbicularis muscle and orbicularis oris a week and a month after surgery.we analyse the pathological changes of MEP in orbicularis muscle and orbicularis oris by acetylcholinesterase（AchE） staining in light microscope（LM） and electron microscope（EM）,discuss the relationship among AchE activity,muscular species and types.Results In normal group,the AchE activity in orbicularis muscle and orbicularis oris is similar.When the facial nerve is injuried for 1 week,the AchE activity in orbicularis muscle and orbicularis oris hasn＇t changed apparently.When the facial nerve is injuried for 1 month,the AchE activity in orbicularis oris hasn＇t changed apparently all the same,however,it has changed in orbicularis muscle,excision group 30 s15 s.In EM,in normal group,the junctional fold is expanse,AchE positive outcome is high electronic dense granule which locate in anterior and posterior member of the synapse.When the facial nerve is injuried for 1 week,posterior member of the synapse and motor nerve ending become atrophy,primary synaptic fold and secondary synaptic fold become shallow,the MEP structure of orbicularis muscle and orbicularis oris is similar.When the facial nerve is injuried for 1 month,in excision group,orbicularis oris primary synaptic fold and secondary synaptic fold become shallower continually.In group of 15 s and 30 s,orbicularis oris primary synaptic cleft is similar to normal.In the group of 30 s and excision,orbicularis muscle primary synaptic fold and secondary synaptic fold become shallower continually,a number of the secondary synaptic fold disappear.Conclusion When denervated in different degree,the MEP AchE activity of orbicularis oris maintain for a long time;the change of MEP AchE activity is related to the muscle species and the myofiber type;there is different changes in the facial muscles that makes a conclusion that the partially evaluating system of facial palsy is reasonable.