超速起搏预适应的延迟保护与热休克蛋白70的表达

Delayed cardioprotection induced by ventricular overdrive pacing preconditioning and expression of heat shock protein 70

目的观察在超速心室起搏(ventricular overdrive pacing,VOP)预适应延迟保护阶段热休克蛋白70(HSP70)的表达水平。方法新西兰兔24只,随机分为3组,单纯结扎组,起搏组,起搏+放线菌素D组。制作超速起搏预适应和缺血/再灌注的动物模型,检测CK和CK-MB的变化,动态描记再灌注时心电图,免疫组织化染色检测HSP70抗原。结果缺血后起搏组心肌酶的水平在再灌注时均低于单纯结扎组和起搏+放线菌素D组(P<0.01);单纯结扎组中在再灌注过程中共有5只发生心律失常,起搏+放线菌素组也有4只,而起搏组无心律失常发生。起搏组和单纯结扎组之间有显著性差别(P<0.05)。起搏组HSP70的阳性表达的程度明显高于其他两组。结论超速起搏预适应可以模拟缺血预适应,其延迟保护作用可能与HSP70表达增加密切相关。

AIM To observe the expression of heat shock protein 70 （HSP70） in late phase of cardioprotection induced by ventricular overdrive pacing preconditioning. METHODS Twenty-four New Zealand rabbits were randomly divided into 3 groups： the simple ligation group, the pacing group and the pacing ＋ actinomycin group. The animal models of ventricular overdrive pacing preconditioning and ischemia and reperfusion were made. The levels of creatine kinase （CK） and creatinine kinase isoenzyme （CK-MB） were monitored and the electrocardiogram was recorded during the phase of reperfusion. HSP70 was tested by immunohistochemistry. RESULTS The levels of CK and CK-MB were significantly lower in the pacing group when compared with those in the simple ligation group and the pacing ＋ actinomycin group at the different phases after ischemia（P 〈 0. 01 ）. Arrhythmia was found in 5 cases in the simple ligation group and 4 cases in the pacing ＋ actinomycin group, but no one in the pacing group. The occurrence rate of arrhythmia was significantly different between the simple ligation group and the pacing group （P 〈 0. 05）. The levels of HSP70 expression in the pacing group were significantly higher than those in the other two groups. CONCLUSION The overdrive pacing preconditioning can mimic the ischemic preconditioning and the delayed cardioprotection may closely correlated with the overexpression of HSP70.