超速起搏预适应的延迟保护与热休克蛋白27的表达

目的：观察超速心室起搏（VOP）预适应延迟保护阶段热休克蛋白27（HSP27）的表达水平。方法：新西兰兔24只,随机分为3组,缺血再灌注（I/R）空白对照组,起搏组,起搏＋放线菌素D组。制作I/R和超速起搏预适应的动物模型,检测肌酸激酶（CK）和肌酸激酶-同工酶（CK-MB）水平的变化,动态描记再灌注时心电图,以免疫组织化染色法检测HSP27抗原表达水平。结果：I/R后起搏组心肌酶的水平均明显低于I/R空白对照组和起搏＋放线菌素D组（P〈0.01）;I/R空白对照组在再灌注过程中共有5只（62.5%）发生心律失常,起搏＋放线菌素D组有4只（50.0%）,而起搏组无心律失常发生。起搏组心律失常发生率明显低于I/R空白对照组和起搏＋放线菌素D组（P〈0.05）。起搏组HSP27阳性表达＋＋者（37.5%）明显高于I/R空白对照组和起搏＋放线菌素D组（0,12.5%,P〈0.05）。结论：心室超速起搏预适应有心脏保护作用,其机制可能与热休克蛋白27表达增加密切相关。

Delayed cardioprotection effect induced by overdrive pacing preconditioning and expression of heat shock protein 27

Objective:To observe delayed cardioprotection effect induced by preconditioning from ventricular overdrive pacing(VOP) and expression level of heat shock protein 27(HSP27) in phase of ischemia-reperfusion(I/R).Methods:A total of 24 New Zealand rabbits were randomly divided into I/R blank control group,pacing group and pacing + actinomycin D group.Animal models of I/R and VOP preconditioning were established.Changes of levels of creatine kinase(CK) and creatine kinase isoenzyme(CK-MB) were measured,electrocardiogram was recorded during I/R.Immunohistochemical staining was used to detect HSP27.Results:During I/R,levels of CK and CK-MB in I/R pacing group were significantly lower than those of I/R blank control group and pacing + actinomycin D group(P<0.01 all);during I/R,there were 5(62.5%) and 4(50.0%) rabbits occurring arrhythmias in I/R blank control group and pacing + actinomycin D group respectively,and no arrhythmia occurred in pacing group.Incidence rate of arrhythmia in pacing group was significantly lower than those of other two groups(P<0.05).Cases with HSP27 positive expression++in I/R pacing group(37.5%)was significantly higher than those of I/R blank control group and pacing + actinomycin D(0,12.5%,P<0.05 all).Conclusion:Preconditioning from overdrive ventricular pacing possesses cardioprotection effect,and its mechanism may be close correlation with increased expression of heat shock protein 27.