中文摘要：

目的观察全脑缺血再灌注时Bad蛋白的表达和细胞凋亡及ERK信号转导通路对其的影响。方法 90只健康雄性SD大鼠随机分为三组（n=30）：假手术组（sham组）、全脑缺血再灌注组（IR组）、抑制剂PD98059干预组＋全脑缺血再灌注组（PD组）。采用四血管法建立大鼠全脑缺血再灌注模型,在2,6,12,24,48,72 h各个时间点分别用免疫组化法检测磷酸化ERK和磷酸化Bad蛋白在大鼠海马区的表达,TUNEL染色观察不同时点海马神经元存活和凋亡的变化。结果 TUNEL阳性细胞于IR组再灌注6 h后开始出现,24-48 h达高峰。PD组TUNEL阳性细胞表达各时点均强于IR组,随再灌注时间延长而表达增强,24 h达高峰。sham组各时点未见TUNEL阳性细胞。磷酸化ERK于IR组再灌注2 h后在CA3区可见表达,再灌注6 h后逐渐下降,至再灌注后48 h未见表达。IR组磷酸化ERK表达强于sham组,sham组随再灌注时间延长而表达减弱;PD组各时点磷酸化ERK未见表达。磷酸化Bad蛋白于IR组再灌注后2 h在CA3区可见表达,之后逐渐减弱,再灌注后24 h后未见;PD组各时点磷酸化Bad表达弱于IR组,变化趋势与IR组相同。sham组各时点磷酸化Bad表达明显,无时点变化;二者在CA1区的表达均弱于CA3区。二者的表达下降变化与凋亡发生的高峰时间一致。结论磷酸化ERK和磷酸化Bad在脑缺血再灌注时表达下降且变化一致,提示ERK信号通路可通过抑制Bad的磷酸化抗凋亡形式向去磷酸化促凋亡形式的转变,发挥抗调亡机制,参与脑缺血再灌注时神经细胞的保护。

英文摘要：

Objective To investigate the relationship between expression of Bad and apoptosis and the effect of ERK signal transdue- tion pathway on the expression in hippocampus of SD rats after global cerebral ischemia reperfusion. Methods Ninety healthy male SD rats were divided into three groups randomly： sham group （n = 30）, ischemia/reperfusion group （IR group, n = 30） and PD98059 ＋ IR group（PD group, n = 30）. Global cerebral ischemia reperfusion model was induced by 4-VO method. The rats were executed at 2, 6,12,24,48,72 h . The expression of phosphorylated ERK and p-Bad protein was detected in hippocampus by HE staining, immuno- histochemical staining, and the apoptosis of neuron was observed by TUNEL staining. Results The TUNEL positive cells were not found in sham group, while the positive cells began to appear at 6 h after reperfusion and peaked in 24 -48 h in IR group. In PD group, the TUNEL positive cells increased with the increasing of reperfusion time and reached the peak at 24 h, and they were stronger than those in IR group. In IR group, the expression of phosphorylated ERK was observed in CA3 at 2 h after reperfusion, decreased at 6 h after reperfusion and disappeared at 48 h after reperfusion. The expression was stronger in IR group than that in sham group, and it decreased with the increasing of reperfusion time in sham group, while in PD group the expression of phosphorylated ERK was not found. In IR group, the expression of p-Bad was seen in CA3 at 2 h after reperfusion, then decreased gradually and disappeared at 24 h after reperfusion. In PD group the expression of p-Bad was weaker than that in IR group at each time point, and the change trend was the same as that in IR group. In sham group, the p-Bad was expressed at each time point, and showed no change at different time points. The expression of p-ERK and p-Bad in CA1 was weaker than that in CA3. The time of decrease of p-ERK and p-Bad was the same as the time of peak apoptosis. Conclusion The expression of p-ERK and p-Bad decrease