超速起搏预适应的延迟保护作用与环氧化酶2表达的关系

目的观察在超速心室起搏(VOP)预适应延迟保护阶段环氧化酶2(COX-2)的表达水平,从而探讨预适应延迟保护作用机制与COX-2的关系。方法健康的新西兰雄兔24只,随机分为3组,单纯结扎组、起搏组、起搏+放线菌素D组,每组8只,制作超速起搏预适应和缺血/再灌注动物模型,检测肌酸激酶(CK)、CK同工酶(CK-MB)的变化,动态描记再灌注时心电图变化,免疫组化染色检测COX-2抗原。结果缺血后起搏组CK、CK-MB的水平[(1492±474)IU/L和(614±182)IU/L]在再灌注时低于单纯结扎组[(2625±423)IU/L和(1332±178)IU/L]及起搏+放线菌素D组[(2071±390)IU/L和(1095±183)IU/L](P<0.01);单纯结扎组再灌注过程中共有5只(62.5%)发生心律失常,起搏+放线菌素D组也有4只(50%),而起搏组中无心律失常发生,起搏组和单纯结扎组中之间差异具有统计学意义(P<0.05),起搏组中COX-2的阳性表达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COX-2的表达增加密切相关。

Relationship between delayed cardioprotection induced by ventricular overdrive pacing preconditioning and COX-2

Objective To observe the expression of COX-2 in late phase of cardioprotection induced by ventricular overdrive pacing preconditioning and to explore the relationship between delayed cardioprotection of preconditioning and COX-2. Methods A total of 24 Newzealand rabbits were randomly divided into 3 groups: the control group,the pacing group and the Pacing + Actinomycin group.The animal models of ventricular overdrive pacing preconditioning and ischemia and reperfusion were made.Serum creatine kinase(CK) and creatinine kinase isoenzyme(CK-MB)were measured and electrocardiogram was recorded during the phase of reperfusion.COX-2 was detected by immunohistochemistry method. Results Serum level of CK was significantly lower in pacing group [(1492±474)IU/L] than in control group[(2625±423)IU/L] or pacing+actinomycin group[(2071±390)IU/L] after ischemia(both P<0.01).No Arrhythmia occurred in pacing group.Expression of COX-2 was significantly increased in pacing group than in control or pacing+actinomycin group. Conclusions Overdrive pacing preconditioning can mimic ischemic preconditioning and the delayed cardioprotection may closely correlated with the overexpression of COX-2.