热休克蛋白A12B对心肌缺血/再灌注损伤的保护作用

Protective effects of heat shock protein A12B on myocardial ischemia/reperfusion injury in mice

目的探讨热休克蛋白A12B(heat shock protein A12B,HSPA12B)在心肌缺血/再灌注(ischemia/reperfusion,I/R)损伤中的作用。方法本实验采用8~10周龄、雄性高表达HSPA12B转基因鼠(HSPA12B transgenic mice,Tg鼠),一窝所生的雄性野生型(wild type,WT)鼠作为对照,随机分配后行假手术或I/R手术,结扎冠状动脉左前降支45 min(缺血)、松开结扎线4 h(再灌注)。通过聚合酶链式反应(PCR)检测WT鼠I/R手术与假手术后4 h,心肌HSPA12B mRNA的表达水平;通过2,3,5-氯化三苯基四氮唑(TTC)染色法测定I/R手术后4 h,WT鼠与Tg鼠的心肌梗死面积;通过免疫印迹法检测WT鼠与Tg鼠分别行I/R手术与假手术的4组心肌中Bcl-2和Bax蛋白水平。结果 I/R损伤引起WT鼠心肌HSPA12B mRNA表达水平增高。在共同经历I/R损伤后,Tg鼠较WT鼠的心肌梗死面积缩小,并且Tg鼠心肌组织抗凋亡能力(Bcl-2/Bax比值)明显高于WT鼠。结论高表达HSPA12B可能通过减少细胞凋亡,减轻心肌I/R损伤,发挥心肌保护的功能,提示HSPA12B可能是干预心肌I/R损伤的潜在靶点。

Objective To investigate the effect of heat shock protein A12B （HSPA12B） on myocardial ischemia/reperfusion injury in mice. Methods Male littermates of transgenic mice （Tg） with over expression of HSPA12B and wild type （WT） mice as the control aged 8-10 weeks were enrolled in the experiments. The mice were randomly devided into sham operation group and myocardial ischemia/ reperfusion （I/R） injury group. The mice in I/R group received the intervention that left anterior descending （LAD） coronary artery was legated for 45 min （iscbemia） and then the blood flow was restored for 4 h （reperfusion）. The mRNA level of HSPA12B was measured by real time-PCR; the myocardial infarction size was determined by TTC staining; And the expression of Bcl-2 and Bax were detected by immunoblot. Results I/R injury could induce the increase of the mRNA level of HSPA12B in WT mice. After I/R injury, the infarction area of Tg mice was smaller than that of WT mice, and the myocardial anti-apoptosis ability （the ratio of Bel-2/Bax） of Tg mice was better than thatof WT mice. Conclusions The over expression of HSPA12B can protect heart from I/R injury in mice through reducing the cell apoptosis and might be the potential target to the intervention of myocardial I/R injury.