目的　探讨坐骨神经高速弹丸震荡伤后腰段脊髓运动神经元及胶质细胞凋亡规律。方法　 6 5只大耳白兔分为正常对照组、高速弹丸震荡伤组 (震荡伤组 )和切割伤组。震荡伤组致伤靶点为兔右大腿外侧坐骨神经体表投影线中点 ,切割伤组在同一水平切断右坐骨神经。应用DNA电泳、原位末端标记法 (TUNEL)染色和流式细胞仪进行细胞凋亡定性定量检测。　结果　震荡伤组伤后 2周运动神经元数明显减少 ;伤后 1,2周 ,可见TUNEL阳性运动神经元及胶质细胞 ,DNA电泳出现凋亡梯形带 ,流式细胞仪检测可见亚二倍体峰 ;震荡伤组伤后 1,2周 ,细胞凋亡百分比分别为 10 .6 %和 2 6 .4 %。切割伤组仅在 4周时有少量阳性运动神经元。　结论　与切割伤组比较 ,震荡伤组细胞凋亡发生早、数量多 ,凋亡是坐骨神经高速弹丸震荡伤后运动神经元数量减少的主要机制 Objective To investigate the regularity of apoptosis of lumbar spinal motor neurons and glial cells after shock injury of sciatic nerve. Methods Sixty five white rabbits were divided into normal control group, high-speed projectile shock group (shock group) and cleft group. Shock injury group wound target rabbit right thigh lateral sciatic nerve surface projection line midline, cut the injury group at the same level cut off the right sciatic nerve. DNA electrophoresis, TUNEL staining and flow cytometry were used for qualitative and quantitative detection of apoptosis. Results The number of motor neurons decreased significantly at 2 weeks after injury in injured group. TUNEL-positive motor neurons and glial cells were seen at 1 and 2 weeks after injury, and the apoptotic trapezoidal band appeared on DNA electrophoresis. The flow cytometry showed sub-doubling Body peak. The percentages of apoptosis in injured group were 10.6% and 26.4% respectively at 1 and 2 weeks after injury. The cut injury group only had a small amount of positive motor neurons at 4 weeks. Conclusion Compared with the incision injury group, the apoptosis of shock injury group occurs earlier and more frequently. Apoptosis is the main mechanism of the decreased number of motor neurons after shock injury of the sciatic nerve high-speed projectile