成年大鼠面神经低位切断后面运动神经元的死亡进程及GDNF的保护作用

Protective role of GDNF in adult rat facial motoneurons following facial nerve injury

目的观察大鼠面神经低位切断伤后,大鼠面运动神经元死亡的时间进程和胶质细胞源性神经营养因子(GDNF)局部应用对伤后面运动神经元的作用。方法手术制作大鼠右侧面神经的低位切断伤+GDNF模型,左侧为切断伤+PBS液对照。用HE、甲苯胺蓝染色技术观测面运动神经元死亡情况及其形态学变化。结果面神经低位切断伤可引起面运动神经元死亡且于伤后4周时达到高峰。损伤后1、2、4、6周时,GDNF侧神经元数量明显多于对照侧(P<0.01)。伤后2、4、6周时,GDNF侧的神经元数量较第1周时均减少(P<0.01),而第4周与第6周的神经元数量差异无统计学意义(P>0.05)。结论局部应用GDNF对低位切断伤后的面运动神经元有显著的保护作用,这种作用在损伤4周内完全发挥。

Objective To observe the protective effects of topical application of glial-cell-derived neurotrophic factor （GDNF） on facial motoneurons following facial nerve injury in adult rats. Methods Thirty-two adult rats underwent the distal amputation of bilateral facial nerves, and then received topical application of GDNF on the right and phosphate buffered solution （PBS） on the left. The motor neurons of facial nuclei were observed by HE and toluidine blue stain over 6 weeks. Results The death of facial motoneurons were induced by the facial nerve insult, especially in the 4th week. The motoneuron counts were significantly higher in GDNF treatment side than those in PBS side at 4 timepoints （P 〈 0.01）. The motoneuron counts in GDNF treatment side decreased after one week （P 〈 0.01）, but there were no statistical differences in the motoneuron counts between the 4th and 6th week （P 〉0.05）. Conclusion Local application of GDNF improves the survival of facial motoneurons during 4 weeks following distal insult of facial nerves.