面神经不同受损模型中神经元病理变化的比较研究

Comparative study of pathological changes of neurons in different facial nerve injury model

目的研究大鼠面神经不同致伤模式下面神经元变化的差异，为针对不同研究目的选择动物模型提供依据，同时为临床神经损伤的修复提供理论基础。方法建立大鼠面神经茎SLTL处压榨、切断、抽脱模型；根据取材时间的不同，分为术后1、2．7、14、28d组，行Cresyl Violet和胆碱乙酰转移酶（CHAT）免疫组化染色，观察受损侧面神经核团内神经元空间在形态学上的变化，比较不同模型中受损神经元的差异，对核团区ChAT阳性神经元进行计数，并以手术侧与对照侧阳性神经元总数的比值表达活性神经元比率，进行统计学分析。结果压榨伤后，神经元并不表现出凋亡的形态学特征，仅在早期合成ChAT能力下降，随后又逐渐恢复。切断组和抽脱组的神经元功能为永久性失活，但切断组失活的神经元在28d内仅发生凋亡前形态学变化，并未类似于抽脱组彻底死亡。结论面神经切断伤模型消除了靶器官对受损神经元的逆向性营养作用，且神经元在早期未发生彻底性死亡，而是进入功能上的“休眠”状态，更有利于研究面神经损伤后的核团因素。

Objective To study the changes of facial neurons in different injury models to provide basis for selecting animal models accoding to different research aims and provide theoretical basis for repairing nerve injury in clinic systematically. Methods Rat facial nerve models of crush, axotomy and avulsion at stylomastoidforaman were established; the experimental groups were divided into postoperative 1 day, 2 days, 7 days, 14 days and 28 days groups according to different harvesting time. Then Cresyl Violet and immunohistochemisty staining of choline aeetyltransferase （CHAT） were performed to observe the morphological differences of neurons between the control side and injury side of facial nucleus, comparing the differences of damaged neurons in different models. The positive neurons to the ChAT on both sides of facial nucleus were counted. The viable rate of neurons was presented by the ratios of neuron numbers on both sides and the statistical analysis was performed. Results Facial motor neurons in crush group didn＇t appeared any apoptotic morphological character except the synthetic capability of ChAT decreased early and then recuperated gradually. Although a large number of neurons in both axotomy and avulsion groups lost their activation for good, the inactived neurons in the axotomy group just showed a series of changes of pro-apoptosis within 28 days after facial nerve axotomy; while the same changes was not happened in the avulsion group. Conclusion Injured neurons didn＇t die just entered into the ＂dormant＂ state of function at the early stage of facial nerve axotomy model. Furthermore, it is more helpful for the research of facial motor nucleus because the reverse nutritional role from target organ was eliminated in this model.