大鼠局灶性脑缺血预处理后蛋白激酶样内质网激酶及葡萄糖调节蛋白78表达的变化
Changes of protein kinase-like endoplasmic reficulum kinase and glucose-regulated protein 78 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蛋白激酶样内质网激酶(PERK)和葡萄糖调节蛋白( GRP78) 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、脑缺血再灌注组(MCAO)、腩缺血预处理组(BIP),每组按照再缺血后12h,1、2、3d4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,分别用原位杂交法和Western blot法观察再缺血后各个时间点PERK和GRP78 mRNA及其蛋白的表达变化,用流式细胞术检测神经细胞凋亡率.结果 ①MCAO组12 h PERK mRNA表达达高峰,随再灌注时间延长其表达逐渐下降;BIP组缺血各时间点其表达水平均明显下降.MCAO组PERK蛋白表达于缺血再灌注后12 h开始明显上升,24 h达高峰,2d后表达开始减弱;BIP组较MCAO组PERK表达明显降低.②MCAO组12 h GRP78 mRNA及其蛋白表达均达高峰,随再灌注时间延长其表达逐渐下降;BIP组较MCA0组GRP78 mRNA及其蛋白各时间点表达均明显升高(mRNA:12 h:136.70±9.53,F=32.265;24h:147.54±9.97,F=54.920;2 d:158.16±9.44,F=45.374;3 d:165.85±10.26,F=16.493,均P<0.05;蛋白:12 h:1.319±0.116,F=5.619,P<0.05;24 h:1.226±0.108,F=33.742,P<0.01;2 d:1.183±0.112,F=46.556,P<0.01;3 d:1.115±0.098,F=11.730,P<0.05).③MCAO组12 h细胞凋亡发牛率明显增加,24h时达到高峰,以后逐渐下降;BIP组各个时间点神经元凋亡发牛率较MCAO组明显降低.结论 脑缺血预处理可能通过抑制内质网应激后PERK表达和诱导GRP78表达发挥其神经保护作用.
更多Objective To investigate the effect of focal ischemic preconditioning (IPC) on the expression of protein kinase-like endoplasmic reticulum kinase ( PERK ) and glucose-regulated protein 78 (GRP78) mRNA and protein after focal cerebral ischemia/reperfusion (I/R) in rats.Methods All 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,1,2 and 3 d after I/R.The IPC models were made in order to measure the expression of PERK,GRP78 mRNA and protein by in situ hybridization and Western blot,and the apoptosis rate of neuron by flow cytometry. Results ①The expression of PERK mRNA increased and reached the peak at 12 h,then decreased continuously after 1 d.BIP could decrease its expression.The expression of PERK protein increased at 12 h and reached the peak at 24 h,then decreased continuously after 2 d.BIP could decrease its expression.②The expression both of GRP78 mRNA and its protein all increased and reached the peak at 12 h,then decreased continuously.BIP could increase their expression (mRNA:12 h: 136.70±9.53,F=32.265; 24 h:147.54 ±9.97,F=54.920; 2 d:158.16 ±9.44,F=45.374; 3d: 165.85±10.26,F=16.493,P<0.05; protein:12 h: 1.319±0.116,F=5.619,P<0.05; 24 h: 1.226±0.108,F=33.742,P<0.01; 2 d:1.183 ±0.112,F =46.556,P <0.01; 3 d:1.115± 0.098,F =11.730,P<0.05).③The 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. Conclusion BIP can protect neurons through inhibiting the expression of PERK and inducing the expression of GRP78 after endoplasmic reticulum stress in rats.
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