机械性鼠脑皮层下横切后皮层神经元凋亡

Cortical neuron apoptosis after mechanical subcortical transection in rats

目的 :探讨在机械性脑白质损伤后皮层神经元凋亡及其分布特征 .方法 :制作大脑皮层下横切动物模型 ,于致伤后不同时间处死动物 ,用TUNEL原位末端标记和病理组织学方法观察损伤区及相应皮层神经元变化规律 .结果 :致伤后 ,损伤部神经元出现坏死 ,胶质细胞增多 ,大脑Ⅱ～V层神经元多出现萎缩 .伤后 12h ,相应皮层内即出现散在凋亡神经元 ,后渐增多 ,7d后又趋减少 ,伤后 19d皮层内仍可检出凋亡神经元 ,而在损伤区凋亡神经元少见 ,其时间分布呈一单峰状曲线 .结论 :脑白质损害时 ,损伤相应部位皮层神经元主要表现为凋亡 ,分布于第Ⅱ～V层 .

AIM: To investigate the characteristics of cell apoptosis in cortex after mechanical white matter injury. METHODS: Twenty-six SD rats suffering mechanical subcortical transection were killed at different time points post-injury, and the brains were obtained. The change of cells in lesion area and cortex was observed by HE staining, buffered-methylen blue staining and TUNEL in situ end-labeling. RESULTS: Histopathological examination showed neuronal necrosis and glial cell proliferation in lesion site, while many neurons withered in the layer Ⅱ-Ⅴ of the corresponding cortex . Apoptotic neurons could be detected in the corresponding cortex as early as the 12th h post-injury. The number increased with time, peaked during 5th-7th d, and then declined. In the 19th d, the apoptotic neurons still could be detected in the corresponding cortex, while few apoptotic neurons were found in lesion area, and the time was presented in a single-wave-curve. CONCLUSION: The main pathological change of cortical neurons is not necrosis, but apoptosis after mechanical white matter injury. The apoptotic neurons are anatomically located in the corresponding cortical layer Ⅱ-Ⅴ.