大鼠局灶性脑缺血预处理后IRE1表达的变化

Changes of inositol requiring enzyme 1 expression in rats after focal ischemic preconditioning

目的观察缺血预处理对大鼠脑缺血再灌注后肌醇需求激酶1(IRE1)mRNA及其蛋白表达和神经元凋亡的影响。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),每组按照再缺血后12 h、1 d、2 d、3 d 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,分别用实时荧光定量PCR和Western blot法观察再缺血后各个时间点IRE1 mRNA及其蛋白表达的变化,用流式细胞术检测神经细胞凋亡率。结果 (1)MCAO组12 h IRE1 mRNA及其蛋白表达开始明显升高,24 h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IRE1 mRNA及其蛋白各时间点表达均明显升高(P<0.05,P<0.01)。(2)MCAO组12 h细胞凋亡发生率明显增加,24 h时达到高峰(P<0.01),以后逐渐下降;BIP组各个时间点神经元凋亡发生率较MCAO组明显降低(均P<0.05)。结论脑缺血预处理可能通过诱导内质网应激后IRE1的表达发挥其神经保护作用。

Objective To investigate the effect of focal ischemic preconditioning （ IPC ） on the expression of requiring enzyme 1 （ IRE1 ） mRNA and protein after focal cerebral ischemia/reperfusion （I/R） in rats. Methods 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 12 h,1 d,2 d and 3 d after I/R. The IPC models were made in order to measure the expression of 1RE1 mRNA and protein by Real time PCR and Western blot,and the apoptosis rate of neuron by flow cytometry. Results （ 1 ） The expression both of IRE1 mRNA and its protein all increased and reached the peak at 24 h,then decreased continuously. BIP could increase their expression （P 〈 0.05,P 〈0.01 ）. （2）The rate of apoptosis neuron of rats in MCAO increased markedly at 12 h after reperfusion, and reached the peak at 1 d, then decreased continuously. BIP could decrease the rate of apoptosis neuron （ P 〈 0.05 ）. Conclusion BIP could protect neurons through inducing the expression of IRE1 after endoplasmic reticulum stress in rats.