预缺血通过NMDA受体抑制海马CA1区Bcl-2磷酸化的研究

Ischemia Preconditioning Depressed Bcl-2 Phosphorylation Through NMDA Recepter in Hippocampal CA1 Region

目的:研究预缺血以及联合给予预缺血和NMDA(N-甲基-D-天冬氨酸)受体抑制剂MK801后对大鼠海马CA1区Bcl-2的磷酸化以及海马CA1区锥体细胞凋亡的影响。方法:采用SD大鼠四动脉结扎全脑缺血及预缺血模型,给药组大鼠在预缺血前1h给予腹腔注射MK801 3mg/kg。用免疫印迹法分析不同处理下大鼠海马CA1区Bcl-2的蛋白表达及其磷酸化水平,焦油紫染色法分析海马CA1区锥体细胞的凋亡情况。结果:脑缺血再灌注组相对于Sham组Bcl-2的磷酸化水平以及海马CA1区锥体细胞的凋亡水平显著增高,预缺血组相对于缺血再灌注组Bcl-2的磷酸化水平以及海马CA1区锥体细胞的凋亡水平显著降低;而预缺血前给予MK801组相对于预缺血组Bcl-2磷酸化水平以及海马CA1区锥体细胞的凋亡水平显著增高;而Bcl-2的蛋白表达水平在以上不同处理条件下均无明显变化。结论:NMDA受体介导了预缺血抑制脑缺血再灌注诱导增加Bcl-2磷酸化以及海马CA1区锥体细胞凋亡。

Objective： To evaluate the effect of ischemia preconditioning and ischemia preconditioning combination with selective inhibitor of NMDA recepter on the phosphorylation of Bcl-2 and the survival of CA1 subfield. Methods： Transient global brain ischemia was induced by 4-vessel occlusion in adult male Sprague-Dawley rats. The rats were pretreated with 3 min of ischemia preconditioning （IPC） alone or MK801 （selective inhibitor of NMDA） treatment before IPC, after reperfusion for 3 days, 6 min of ischemia was induced followed by different times of reperfusion. As brain ischemia reperfusion models, the rats was given six min of ischemia and followed by different times of reperfusion. We performed this experiment by using SDS-PAGE and Immunoblotting to examine the expression and phosphorylation of Bcl-2 protein. Cresyl violet staining was performed to examine the survival and apoptosis neurons in the pyramidal cell layer of the Hippocampal CA1 subfield. Results： Globle cerebral ischemia/reperfusion induced obvious phosphorylation of Bcl-2 and apoptosis of CA1 pyramidal neuron, which could be depressed by the use of IPC. However, MK801 treatment before IPC antagonized this effect of IPC. At the same time, there was no change in the expression level of Bcl-2. Conclusions： IPC could obviously depress the phosphorylation of Bcl-2 and apoptosis of CA 1 ovramidal neuron induced bv cerebral ischemia/renerfusion through NMDA recenter