梯度灌注对沙土鼠全脑缺血神经元凋亡的保护作用

Neural apoptotic protection study of graded reperfusion for gerbil global cerebral ischemia

目的 观察梯度灌注时间和灌注量对全脑组织缺血损害的恢复程度和凋亡基因的表达 ,探讨梯度灌注的脑保护作用。方法 将沙土鼠随机分 4组 ,实验组夹闭两侧颈总动脉 ,造成沙土鼠全脑缺血模型 ,夹闭 10min后 ,开放 10min ,开放不同脑血流量 (1/4、1/2、1/1)和单纯血液稀释后分别观察缺血海马CA区凋亡蛋白Bcl x/l和Bax的表达 ,海马区神经元的凋亡形态学改变和缺血区大脑半球的改善状况。结果 开放 10min ,1/2脑血流量时Bcl x/l蛋白表达较一次性再灌注明显上调 (P <0 .0 5 ) ,而Bax表达下调。海马CA区缺血损害改善最明显 ,开放 10min、全脑血流量一次性开放时海马CA区损害最严重。结论 梯度灌注流量有明显的抗脑缺血海马区神经元凋亡作用 ;低灌注流量有较好的改善脑缺血作用 ;夹闭 10min后 ,开放 1/2脑血流量 ,开放 10min的效果比一次性再灌注开放效果要好。

Objective To study the effects of graded reperfusion(GR) duration and volume on the ischemic injures in brain and the expression of apoptotic gene so as to explore the preventive effect of GR.Methods The gerbil global ischemic models were made by 10 min occlusion of bilateral carotid artery and randomly divided into 4 groups.The expression of apoptotic genes Bcl x/l and Bax after reperfusion for 10 min and at different reperfusion flows (1/4,1/2,1/1) was detected.The morphological changes in hippocampus CA1 region were observed.Results The expression of Bcl x/l gene after reperfusion for 10 min and at 1/2 reperfusion blood flow was significantly up regulated,while the expression of Bax down regulated as compared with that after reperfusion for 10 min only ( P < 0.05). The ischemic injures in hippocampus CA1 region was most significantly improved.The injures in hippocampus CA1 region after reperfusion for 10 and at 1/1 reperfusion blood flow was the most severe.Conclusion GR effectively upregulated the Bcl x/l expression in hippocampus CA region and had antiapoptotic effects.Low reperfusion flow improved ischemic ischemia.Ten min reperfusion and 1/2 reperfusion blood flow after clamping for 10 min was better than other reperfusion ways.