蛋白激酶C对缺血预处理家兔心肌热休克蛋白70 mRNA的影响

Effect of protein kinase C on the expression of myocardial HSP70 mRNA during myocardic ischemic preconditioning in rabbits

目的 :探讨心肌缺血预处理 (IPC)过程中蛋白激酶 (PKC)对热休克蛋白 (HSP) 70mRNA表达的影响。方法 :在原位及离体家兔心脏缺血再灌注 (I/R)、缺血预处理模型上分别应用PKC抑制剂和激动剂 ,观察对心肌的作用和对心肌HSP70mRNA的表达的影响。结果 :缺血预处理和使用佛波酯 (PMA)使心肌HSP70mRNA的表达、左心功能明显高于I/R组 ,磷脂酶A2 (PLA2 )活性及心律失常发生率明显低于该组 ;而使用多粘菌素B(PMB)则阻断了缺血预处理对心脏的保护作用 ,同时HSP70mRNA表达也明显低于IPC及PMA组。结论 :PKC参与了缺血预处理过程中HSP70表达的调控。

AIM: To study the relationship between myocardial HSP70 and PKC during myocardial ischemic preconditioning(IPC). METHODS: PKC inhibitor, polymyxin B(PMB) and PKC activator, phorbol 12-myristate 13-acetate(PMA) were applied to the models of myocardial ischemia/reperfusion in vivo and in vitro in rabbits, respectively, and the ventricular functions, PLA 2 in the serum, and the expression of mycardial HSP70 mRNA were examined.RESULTS: IPC decreased PLA 2 activity, improved the left ventricular function and increased the expression of myocardial HSP70 mRNA. Howerer, all these effects of IPC could be blocked by PMB. Interestingly, PMA mimicked IPC with attenuating the injuries of cardial myocytes and increasing myocardial HSP70 mRNA expression. CONCLUSION: PKC is involved in the myocardial HSP70 expression in case of ischemic preconditioning.