中文摘要：

目的观察缺血预处理对大鼠脑缺血再灌注后激活转录因子4（ATF4）mRNA及其蛋白表达的影响。方法 SD大鼠120只,随机分为假手术组（SO）、脑缺血再灌注组（MCAO）、脑缺血预处理组（BIP）3组,每组按照再缺血后12h、1d、2d、3d 4个时间点分为4个亚组。采用二次线栓法制备大鼠局灶性脑缺血预处理模型,用原位杂交法和Western blot法观察再缺血后各个时间点ATF4 mRNA及其蛋白表达的变化。结果 MCAO组12hATF4 mRNA及其蛋白表达均达高峰（P〈0.01）,随再灌注时间延长其表达逐渐下降;BIP组较MCAO组ATF4 mR-NA及其蛋白表达均明显降低（P〈0.05,P〈0.01）。结论脑缺血预处理可能通过抑制ATF4表达发挥其神经保护作用。

英文摘要：

Objective To investigate the effect of focal ischemic preconditioning（IPC） on the expression of activating transcription factor 4（ATF4） mRNA and protein after focal cerebral ischemia/reperfusion（I/R） in rats.Method 120 male SD rats were randomly divided into three groups：sham-operation group,middle cerebral artery occlusion（MCAO） group and brain ischemia preconditioning（BIP） group.Each group was further divided into 4 subgroups according to 12h,1d,2d and 3d after I/R.The BIP models were made in order to measure the expression of ATF4 mRNA and protein by in situ hybridization and Western blot.Results The expression both of ATF4 mRNA and its protein all increased and reached the peak at 12h（P0.01）,then decreased continuously after 1d.IPC could decrease their expression（P0.05,P0.01）.Conclusion IPC could protect neurons through inhabiting the expression of ATF4 after I/R in rats.