周围神经损伤后背根神经节神经元及M1、M2型巨噬细胞变化

CHANGES OF DORSAL ROOT GANGLION NEURONS AND M1 AND M2 MACROPHAGES AFTER PERIPHERAL NERVE INJURY

目的观察大鼠坐骨神经损伤后背根神经节神经元数目变化及M1、M2型巨噬细胞浸润情况。方法暴露大鼠右侧坐骨神经,于梨状肌下缘0.5cm处切断并原位吻合,左侧作为空白对照。术后1d、3d、1周、2周、4周、6周、8周剪取两侧背根神经节,石蜡切片后行甲苯胺蓝染色及免疫组织化学染色,观察背根神经节神经元数目及M1、M2型巨噬细胞的浸润情况。结果与左侧相比,术后1d、3d、1周、2周、4周、6周、8周时,右侧背根神经节神经元数目分别减少0.2%、1.9%、8.6%、23.0%、29.0%、31.0%、31.0%。术后1d右侧背根神经节内可见少量M1型巨噬细胞浸润,术后3d时M1型巨噬细胞数增多,术后1周时达顶峰,之后开始逐渐减少,至术后6周,再无M1型巨噬细胞浸润;M2型巨噬细胞于术后1周开始浸润,术后2周时右侧背根神经节内M2型巨噬细胞数达顶峰,之后逐渐减少,术后8周无M2型巨噬细胞浸润。左侧背根神经节内始终未见M1、M2型巨噬细胞浸润。结论大鼠坐骨神经损伤后,相应背根神经节感觉神经元数目在4周内逐渐减少,损伤初期以M1型巨噬细胞浸润为主,损伤中期以M2型巨噬细胞浸润为主。

Objective To observe the changes of the number of neurons in the dorsal root ganglion and the infiltration of M1 and M2macrophage in rats with sciatic nerve injury. Methods The right sciatic nerves of rats were cut and in situ endto-end anastomosis done at 0.5cm of the lower edge of the pear shaped muscle and the left sciatic nerves were exposed only to save as a blank control.Both sides of the dorsal root ganglions were removed-1d,3d,1w,2w,4w,6wand 8wafter operation.Paraffin sections by toluidine blue staining and immunohistochemical staining were done to observe the changes on the number of neurons in the dorsal root ganglion and the infiltration of M1 and M2macrophage in rats with sciatic nerve injury. Results Compared with the control side,the number of neurons in the right dorsal root ganglion was respectively decreased by 0.2%,1.9%,8.6%,23.0%,29.0%,31.0%,and 31.0% after 1d,3d,1w,2w,4w,6wand 8wof operation.One day after surgery,a small amount of type M1 macrophage infiltration could be seen in the right dorsal root ganglion,and three days after surgery,the number of M1 macrophage increased,and reached the peak one week after surgery,and then gradually decreased.No more M1 macrophage infiltration was found six weeks after surgery.M2 macrophages began to infiltrate one week after surgery,and reached the peak two weeks after surgery,then decreased gradually.The infiltration disappeared eight weeks after surgery.There were no M1 and M2macrophage infiltrations were found in the control side of the dorsal root ganglion during the whole period. Conclusion The number of corresponding sensory neurons in the dorsal root ganglion was gradually decreased within 4weeks after sciatic nerve injury in rats.At the beginning of the damage,M1 macrophages played the key role,and in the middle stage of the damage,the M2 macrophage infitration was the main.