Wistar大鼠脊神经根拔除后脊髓前角NOS和GFAP的表达

Expression of NOS and GFAP in spinal cord of ventral root-avulsed rat

目的观察Wistar大鼠脊神经根拔除后脊髓前角NOS阳性表达运动神经元和GFAP阳性表达神经胶质细胞的关系。方法对4-6周龄Wistar大鼠进行椎管外拔除第4腰神经根,术后1、3、5、7周灌注固定后,取L3-L5脊髓节段做冰冻切片,进行Nissl染色和一氧化氮合酶(NOS)、胶质纤维酸性蛋白(GFAP)进行免疫荧光标记。结果拔除后第1周内,运动神经元大量死亡,存活的运动神经元为对照侧的60%。而第3、5周持续缓慢下降,直到第7周存活率为对照侧的40%。NOS阳性表达运动神经元在损伤后第1周开始出现,第3周达到峰值,第5周开始下降。GFAP阳性表达神经胶质细胞在拔除后第1周损伤侧明显增加,第3周达到高峰,而第5、7周一直维持于高水平。结论脊神经根拔除后,GFAP阳性神经胶质细胞增加,可能参与了损伤后神经的修复及维持神经再生的微环境。

Objective To observe the relationship between the expressions of nitric oxide synthetase （NOS） and glial fibrillary acidic protein （GFAP） in spinal cord of ventral root-avulsed rat. Methods The L4 ventral roots were avulsed by an extravertebral extraction procedure in Wistar rats aged 4-6 weeks, the L3-L5 segments of spinal cord were taken out after 1,3,5,7 weeks of survival time. NOS and GFAP were detected using immunofluorescent labeling technique for confocal laser microscopy. Results A drastic cell loss of motor neurons occurred during the first week, the surviving motor neurons fell to approximately 60% of the control side. Subsequent motor neurons loss proceeded slowly, as the surviving cells decreased to 40% at seven weeks. The NOS-positive motor neurons appeared at first week, reached the summit at 3 weeks, decreased at 5 weeks. The expression levels of GFAP were increased significantly 1 week after avulsion, reached the peak at 3 weeks, maintained the high level of expression at 5 weeks and 7 weeks. Conclusion The GFAP-positive astrocytes may contribute to the survival of nerve cells and the repair of damaged neural tissues after ventral root avulsion.