外源性睫状神经营养因子对离断面神经修复的实验研究

Role of ciliary neurotrophic factor in regeneration of severed facial nerve of cats

目的探讨应用外源性睫状神经营养因子(CNTF)对成年猫面神经损伤后的再生修复作用。方法猫颞骨内面神经横断损伤后端端对合,局部应用CNTF作实验组,对照组用同等量生理盐水(SAL);于术后2、4和8周各组进行电生理、免疫组织化学细胞化学技术结合免疫电镜观察及形态学分析。结果术后2周两组电刺激面神经均未诱发面肌兴奋,有髓纤维计数实验组(834±326)、对照组(235±152)t检验(P<0.05),有显著意义。术后4周CNTF组,面神经复合肌动作电位潜伏期实验组(7.832±2.695)、对照组(16.120±3.516);有髓神经纤维数实验组(1435±318)、对照组(957±269),有显著性差异。术后8周CNTF组,面神经复合肌动作电位潜伏期实验组(3.125±0.156)、对照组(3.095±0.178),有髓神经纤维数实验组(1695±283)、对照组(1543±320),t检验(P>0.05),两组差异均无明显意义。但髓鞘厚度较均匀、结构尚完整,轴突再生明显,雪旺细胞增多。结论局部应用CNTF在正常猫神经损伤的较早期(4周左右)有促进再生修复作用,但远期作用尚不明确。

Objective To study the role of extrinsic （CNTF） in the regeneration of severed facial nerve in cats. Method The facial nerve in temporal bone of adult cats were severed and the severed ends were connected with CNTF or saline applied at the connection. Electrophysiological examination and immunocytochemistry were performed with immunoelectron microscope for morphological analysis at 2, 4 and 8 weeks after the operation. Results Two weeks after operation, both CNTF and saline groups failed to exhibit muscular excitement by facial nerve stimulation, but the amount of myelinated nerve fibers had statistical difference between the two groups （P〈0.05）. At 4 weeks, the latency of the facial muscle excitement was 7.832 ±2.695 ms in CNTF group and 16.120±3.516 ms in saline group, and the average number of myelinated axons was significantly different between the two groups （1 435±318 vs 957±269, P〈0.05）. At the 8th weeks, the latency of facial muscle excitement was reduced to 3.125±0.165 ms in CNTF group and to a comparable level of 3.095 ±0.178 ms in saline group （P〉0.05）, and the average number ofmyelinated axons increased to 1 695±283 and 1 543±320 respectively in the two groups （P〉0.05）. Significant increase of Schwann cells was noted in both groups at this stage. Conclusion Local application of CNTF may enhance facial early-stage nerve regeneration in adult cats, but its long-term effects remain unclear.