Up-regulation of CNTFR in the facial motor neurons following facial nerve regeneration in rat and the regulated role of TGF-β, BMP-2

Abstract

Objective: CNTFR was observed in the facial motor neuro ns following facial nerve regeneration, to investigate the changes of its expressi on. Methods:facial nerve was cut off from stylomastoid fo remen,TGF-β and rhBMP-2 was injected into adjacent region. CNTFR immunohistoch emical reaction was conducted. Difference of the amount of CNTFR in seven groups was determined by Computer Image Analysis System. Results: The expression of CNTFR increased during regeneration. After one week, it's c ontent reached maximum, then reduced gradually. In one month group, it's content reached second maximum. In three month group, the expression level of CNTFR was n't detected. TGF-βgroup could increase the expression of CNTFR during nerve re generation.Conclusions: The CNTFR may act as important pro tective role during facial nerve regeneration. TGF-β acts as indirect neurotrop hic factor in facial nerve injury.

目的: 探讨睫状神经营养因子受体CNTFR 在面神经切断后的蛋白表达及转化生长因子( TGF- B) 及重组骨形成蛋白- 2( rhBMP- 2) 对其的表达影响。方法: 将面神经切断后分别注入TGF- B、rhBMP- 2 及生理盐水。取不同时期的面神经核组织切片标本, 采用免疫组化染色和计算机图像分析仪对不同时期中面神经核CNTFR 的表达进行定量分析。结果: 面神经切断后, CNT FR 在术后一天开始表达, 一周后面神经元中CNT FR 的含量达到最大。术后二周出现下调。术后一个月又有所提高, 从而出现第二个高峰。此后逐渐下降。TGF- B 处理组在面神经损伤后期CNT FR 的表达高于生理盐水组。结论: 面神经运动神经元损伤及再生过程中, 内源性CNTFR 的表达提高使神经元损伤后增加CNTF 的摄入, 减少了面神经元的死亡, 为神经元的恢复及神经轴突的延伸具有促进作用。而TGF- B对CNT FR 的表达具有一定的促进作用。对面神经核运动神经元起着间接的营养作用。