大鼠脑缺血预处理后PERK表达的变化及清热化瘀方的干预

Changes of PKR-like Endoplasmic Reticulum Kinase Expression and Effect of Qingre Huayu Prescription 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PERK mRNA及其蛋白表达和神经元凋亡的影响及清热化瘀方的干预作用。方法 SD大鼠160只,随机分为4组:假手术组、MCAO组、BIP组、QRHY组,每组按照再灌注后12 h、1 d、2 d、3d四个时间点平均分为4个亚组,制备缺血预处理模型,用原位杂交法和Western blot法观察再缺血后各个时间点PERKmRNA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(P<0.01),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显著下降(P<0.05),QRHY组较BIP组进一步降低其表达(P<0.05)。②MCAO组PERK蛋白表达于缺血再灌注后12h开始明显上升,24 h达高峰(P<0.01),2d后表达开始减弱;BIP组较MCAO组PERK表达明显降低(P<0.05或P<0.01),QRHY组较BIP组进一步降低其表达(P<0.05)。③MCAO组12 h细胞凋亡发生率显著增加,1 d时达到高峰(P<0.01),以后时间点逐渐下降(P<0.01);BIP组各个时间点神经元凋亡发生率较MCAO组显著降低(P<0.05或P<0.01);QRHY组较BIP组神经细胞凋亡率进一步降低(P<0.05或P<0.01)。结论脑缺血预处理可能通过抑制内质网应激后PERK表达发挥其神经保护作用,清热化瘀方可促进其作用。

Objective To investigate the effect of focal ischemic preconditioning（IPC） on the expression of PKR -like endoplas- mic reticulum kinase（PERK） mRNA and its protein and the effect of Qingre Huayu Prescription （QRHY） on them after focal cer-ebral ischemia/reperfusion（I/R） in rats. Methods 160 male SD rats were randomly divided into four groups：sham- operation group, middle cerebral artery occlusion （MCAO） group, brain ischemia preconditioning （BIP） group and QRHY group. Each group was further divided into 4 subgroups according to 12 h,1 d,2 d and 3 d after I/R. The BIP models were made in order to measure the expression of PERK mRNA and protein by in situ hybridization and Western blot. Results ①The expression of PERK mRNA increased and reached the peak on the 12 h（ P 〈 0.01 ）, then decreased continuously after 1 d. IPC could decrease its expression （P 〈 0.05 ）. ②The expression of PERK protein increased at 12h and reached the peak at 24h （P 〈 0.01 ） , then decreased continuously after 2d. IPC could decrease its expression（ P 〈 0.05 or P 〈 0.01 ）. QRHYP treatment could further reduce its expression than that of BIP group（P 〈0.05）. ③The rate of apoptosis neuron of rats in MCAO increased markedly at 12h after reperfusion, and reached the peak at 1 d （ P 〈 0. 01 ） , then decreased continuously （ P 〈 0.01 ）. BIP could decrease the rate of ap- optosis neuron （ P 〈 0.05 or P 〈 0.01 ）. QRHYP treatment could further reduce its expression than that of BIP group （ P 〈 0.05 ）. QRHYP treatment could further lower apoptosis neuron than that of BIP group （ P 〈 0.05 or P 〈 0.01 ）. Conclusion IPC can pro- tect neurons through inhabiting the expression of PERK after endoplasmic reticulum stress in rats. QRHYP can augment the neuro- protection induced by IPC.