外周神经切断后诱发脊髓运动神经元细胞凋亡的形态学研究

Morphological changes of motor neurons of spinal cord after peripheral nerve injury

目的 观察外周神经切断损伤后，脊髓前角运动神经元发生细胞凋亡的形态学变化。方法 采用切断成年SD大鼠左侧坐骨神经后，近端双重结扎的实验模型，分别在术后3、7、14和21d取材。应用苏木精伊红染色光镜下观察凋亡细胞的形态学变化；利用透射电镜观察不同时期凋亡细胞的超微结构变化，TUNEL染色观察脊髓前角神经元中标记阳性细胞的形态变化。结果 坐骨神经切断后3和21d，在脊髓前角可见到典型凋亡细胞，1—2周为细胞凋亡的高峰期，而且在同一时间点可以检测到处于不同阶段的凋亡细胞和典型的凋亡小体。结论 外周神经轴突损伤诱发脊髓前角运动神经元发生细胞凋亡有很重要的形态学改变。

Objective To investigate the morphological changes of apoptosis in motor neurons of spinal cord following transection of the peripheral nerve in adult rats. nehtods Twenty-five adult Sprague-Dawley rats were randomly divided into operation group and normal group. The sciatic nerve injuried model was set up and double ligation of the proximal stump. The rats were sacrificed on the 3rd, 7th, 14th and 21st postoperative day respectively. The spinal cord of IA to L6 was harvested, and the cells of motor neuron of spinal cord were observed under light microscope and electronmicroscope. Meanwhile, the TUNEL technique was applied for detection of apoptotic motor neurons. Results The typical apoptotic cells could be observed during 3rd to 21st day after operation. The number of apoptotic cells reached a peak a week later. What＇ s more, apoptotic cells staying in different stages and typical apoptotic body could be found at the same time. Conclusion Apoptosis of motor neurons of spinal cord is an important morphological change after transection of the peripheral nerve.