局灶性脑缺血后鼠脑组织tPA基因表达及其与细胞凋亡

EXPRESSION OF tPA GENE AND CELL APOPTOSIS FOLLOWING FOCAL CEREBRAL ISCHEMIA IN RAT

目的 探讨局灶性脑缺血后组织型纤溶酶原激活物 (t PA)基因的表达及其与细胞凋亡的关系。 方法 用原位杂交和免疫组织化学方法检测 t PA基因在大鼠局灶性脑缺血 (大脑中动脉阻塞 )后的表达 ,用 TUNEL 法检测缺血不同时间的细胞凋亡状况。 结果 脑缺血 6 h缺血中心部位的胶质细胞和梗死灶周边缺血半影区的神经元均观察到 t PA免疫反应性信号 ,在大脑皮层后肢体区、顶皮层区、海马区和齿状回可见凋亡细胞 ,但缺血 18h缺血侧神经元及胶质细胞未见 t PA免疫反应性信号 ,仅齿状回有凋亡细胞。 结论 t PA蛋白在脑缺血 6 h缺血侧表达增高 ,局灶性脑缺血后神经元死亡有细胞凋亡的参与 ,该凋亡可能与 t PA基因表达和缺血时间有一定关联。

Objective\ To study the expression of tissue plasminogen activator(tPA) gene and the relationship with cell apoptosis following focal cerebral ischemia in rat.Methods\ The samples of focal cerebral ischemia(middle cerebral artery occlusion,MCA occlusion) were analyzed by using in situ hybridization (ISH) and immunohistochemical(IHC) methods.Apoptotic neurons were detected by using TdT\|mediated dUTP nick end labeling (TUNEL).Results\ In the rats 6h after MCA occlusion,posititive immunostaining of tPA was detected in endothelial cells of small blood vessels,meninges,chorioid,in the glial cells at the zone of ischemic core and neurons at the infarct border zone,apoptotic cells were observed in parietal and hindlimb cerebral cortex,hippocumpus and dentate gyrus,but in the rats 18h after MCA occlusion,immunoreactivity of tPA was not detected in the neurons and glial cells of the ischemic hemisphere,and apoptotic cells were only found in dentate gyrus.Conclusions\ Expression of tPA protein in ischemic site 6h after MCA occlusion is higher than that of nonischemic site.Cell apoptosis was involved in neuronal death following focal cerebral ischemia,and the apoptosis might be related with expression of tPA gene and the time after cerebral ischemia.