坐骨神经非冻结性冷损伤后背根神经节细胞的凋亡

The study on non-freezing cold injury induced apoptosis of dorsal root ganglion in the sciatic nerve

目的观察大鼠坐骨神经在非冻结性低温作用后,腰段脊髓L4-L6背根神经节(dorsal root ganglion,DRG)凋亡神经元的数量以及形态学改变,探讨周围神经非冻结性冷损伤致DRG神经元凋亡的情况。方法雄性Wistar大鼠33只,随机分为1周组、2周组、3周组,每组11只。每只大鼠取任意一侧坐骨神经为实验侧,给予冷损伤(4℃,2h),对照侧坐骨神经同样方法暴露,不给予低温处理。根据坐骨神经和DRG的病理变化,分别取两侧的L4、L5、L6背根神经节于低温结束后1周、2周、3周采用流式细胞仪(Annexin/PI法)和Tunel法对DRG神经元凋亡进行定量和定性检测。结果流式细胞仪(Annexin/PI法)定量测定结果显示,实验侧凋亡率明显高于对照侧。Tunel法检测发现受冷侧的DRG出现典型的Tunel染色阳性的早期凋亡细胞,半定量测定显示实验侧DRG神经元凋亡率明显高于对照侧。两种方法均显示受冷后1周开始凋亡细胞增多,2周时到达高峰,3周时略下降。结论非冻结性低温可以造成坐骨神经对应的L4、L5、L6DRG神经元出现凋亡,凋亡的高峰出现在冷损伤后2周,以早期凋亡为主。凋亡可能是坐骨神经冷损伤的机制之一。

Objective To detect the presence of the apoptotic sensory neurons in rat dorsal root ganglion （DRG） following non-freezing cold injury of the sciatic nerve. Methods Thirty three male Wistar rats were randomly divided into three grnups （7 d group, 14 d group, 21 d group; n = 11 each）. The sciatic nerves were cooled to 4 ℃ for2 hours and the control side underwent sham operation. The pathological examination was performed on L4-6 DRGs at 7, 14, and 21 d post operation. The apoptotic sensory neurons of IA-6 DRGs were detected using FCM （ Annexin/PI） and TUNEL staining. Results The apoptotic sensory neurons of L4-6 DRGs were revealed after non-freezing cold injury of the rat sciatic nerve. FCM （Annexin/PI） and TUNEL quantitative analysis indicated that the apoptotic neurons significantly increased in rat dorsal root ganglion （DRG） at 7 d, 14 d, and 21 d post operation following non-freezing cold injury of the sciatic nerve. TUNEL qualitative analysis further confirmed pathological characters of neuron apoptosis in L4-6 DRGs. The apoptotic neurons began to increase from 7^th day, reached peak at 14th day, and then decreased slightly at 21 d following operation. Conclusions Non-freezing cold injury on sciatic nerves can cause the sensory neurons apoptosis of L4-6 DRGs.