Caspase-3激活的DNA酶与局灶性脑缺血神经元再灌注损伤的关系研究

Relationship between expression of caspase-activated DNase and neuronal injury during focal reversible ischemia in rat brain

目的在半胱氨酸蛋白酶-3(caspase-3)抑制剂的干预下,探讨大鼠局灶性脑缺血再灌注后半胱氨酸蛋白酶-3激活的DNA酶(caspase-activated DNase,CAD)表达变化与神经元损伤的关系。方法线拴法建立大鼠大脑中动脉闭塞及再通模型,侧脑室给予抑制剂,应用HE、免疫组化、原位末端标记(TUNEL)染色及电镜观察大鼠大脑中动脉栓塞1 h后再灌注6 h、12 h、24 h、48 h、72 h时caspase-3和CAD蛋白的表达及神经元凋亡程度的变化。结果模型组蛋白与凋亡细胞的时空动态变化趋势基本一致;干预组各指标趋于平坦,6 h后波峰均有下降。结论caspase-3后继CAD的激活参与了鼠脑再灌注神经元的凋亡,caspase-3抑制剂能一定程度降低缺血再灌注后神经元凋亡,起到神经保护作用。

Objective To investigate the relationship between the expression variations of caspase-activated DNase （CAD） protein and the neuronal apoptosis in rat cerebral cortex injured after focal cerebral ischemia-reperfusion with the intervention of caspase-3 inhibitor（Ac-DEVD-CHO） against neuronal injury.Methods The focal cerebral ischemia and repeffusion model was prepared by thread embolism of unilateral middle cerebral artery（MCA）. The expression of protein and neuronal apoptosis in the temporal parietal cortex regions injured by ischemia for 1 h then repeffusions at 6, 12, 24,48,72 h points were studied by using HE staining, immunohistochemistry, in situ apoptotic detection （TUNEL method） and electron microscope technique. And then the effects of caspase-3 inhibitor given via intraventricular injection on these variations were also assessed. Results In ischemia-reperfusion group, the change of apoptotic cells was accordant with that of protein expression. As for the treatment.group, the trend of above parameters tends to be mild, and the peak expression of these parameters were lower than that in ischemia and reperfusion group after 6 h point. Conclusion The expression of caspase-3 followed by the activa-ted of CAD protein participates the process of neuronal apoptosis in rat brains subjected to transient focal cerebral ischemia. Treatment with easpase-3 inhibitor to a certain extent inhibits the activation of caspases-3 and CAD, reduces the number of apoptotic cell after focal cerebral ischemia and repeffusion, thus plays a protective role in ischemic brain damage.