大鼠全脑缺血再灌注损伤后调控基因Bcl-2、Bax的表达及与细胞凋亡的关系

The relationship between the expression of Bcl-2, Bax protein and apoptosis after cerebral ischemia reperfusion injury

目的：本研究旨在探讨Bcl-2及Bax蛋白在大鼠全脑缺血再灌注损伤中的变化及与细胞凋亡的关系。方法：雄性Wistar大鼠56只，随机分为假手术组、缺血15分钟再灌注1、6、12、24、48、72小时组。采用大鼠四条血管阻断方法制备大鼠全脑缺血再灌注模型。采用TUNEL法观察不同再灌注时间组海马CA1区细胞凋亡的变化。采用免疫组化法观察Bcl-2及Bax蛋白表达水平的变化。结果：脑缺血损伤后随再灌注时间延长凋亡细胞逐渐增多，至再灌注48小时达到高峰，72小时后减少。Bcl-2表达至再灌注12小时达高峰，再灌注24～72小时组逐渐减弱。Bax表达至48小时达高峰，再灌注72小时减少。结论：Bcl-2于再灌注早期表达增强，Bax于再灌注中期表达增强，Bcl-2／Bax比例失衡可能是大鼠全脑缺血再灌注后神经细胞凋亡的机制之一。

Objective： The aim of this research is to study the relationship between the expression of Bcl-2, Bax protein and neuronal apoptosis after ischemia reperfusion. Methods： Fifty-six male wistar rats were used in this study. Four-vessel occlusion was used to establish the global cerebral ischemia reperfusion model in the study groups. The brain of rat was removed inl, 6,12,, 24, 48, 72 hours respectively after reperfusion. The time-course expression of Bcl-2, Bax protein was detected in hippocampus by using immunohistochemical method in different time spots after reperfusion. Meanwhile, change of neuron apoptosis in hippocampus were detected by the TdT-mediated dUTP-biotin nick end labeling （TUNEL） method in the different time of reperfusion. Results： The number of apoptotic cells increased with the development of reperfusion within 1 -48 hours and reached peak at 48h. The expression of Bcl-2 protein appeared at lh after reperfusion, peaked at 12h, and decreased in 24-72h. Immunoreactivity of Bax protein increased with time after reperfusion with peak expression at 48h. The ratio of Bcl-2/Bax gradually increased at the beginning of reperfusion and approached peak at 12h and decreased in the following time. Conclusion.. The neuronal cell apoptosis may play an important role in cerebral ischemia reperfusion injury, while the change of Bcl-2/Bax ratio would play a important role in regulating the neuronal survival or death during reperfusion.