缺血后适应对急性缺血-再灌注犬心脏保护作用

The protective effects of ischemic postconditioning on acute ischemia-reperfused canine heart

目的:探讨缺血后适应对急性缺血-再灌注犬心脏保护作用及其与氧自由基关系。方法:21只杂种犬随机平均分为三组:对照组(Con组),结扎左前降支(LAD)1h,再灌注3h;缺血预适应组(Pre-C组),结扎LAD1h前行缺血预适应(5min结扎/5min再灌注,4次循环);缺血后适应组(Post-C组),结扎LAD1h后,再灌注前行缺血后适应(30s再灌注/30s再关闭,3次循环)。实验犬分别于缺血前、缺血1h、再灌注1、2、3h抽血检测丙二醛(MDA)及超氧化物歧化酶(SOD)。实验前、结束时抽血测定血清肌酸激酶(CK);结束时测定心肌梗死范围。结果:再灌注3h后,Pre-C组及Post-C组血清MDA含量低于Con组,P<0.05,而SOD活性高于Con组,P<0.05。再灌注3h后各组血清CK水平均升高,Pre-C及Post-C组低于Con组,P<0.05。心肌梗死范围在Pre-C和Post-C组小于Con组,P<0.05。结论:缺血后适应与缺血预适应相似,对缺血-再灌注心脏有保护作用;氧自由基的减少在其保护机制中可能发挥部分作用。

Objective：To assess the protective effects of ischemic-postconditioning on acute ischemia-reperfused canine heart and the relation between oxygen free radical and ischemic-postconditioning. Methods：In anesthetized canines, the left anterior descending artery （LAD） was reversibly occluded for 60 min followed by 3h of reperfusion. In the ischemie-preconditioning group （Pre-C, n = 7） ,the LAD was occluded for 5 min followed by 5 rnin of reperfusion before the prolonged occlusion. In the ischernicpostconditioning group（Post-C, n = 7）, three cycles of 30s＇ reperfusion and 30s＇ reocclusion were performed before three hours of reperfusion. All indexes were examinated at baseline, at the end of ischemia, and at 1, 2, 3h of reperfusion. Results：In all canines, compared to the Con group, plasma CK and MDA were significantly lower （P〈0.05）, whereas SOD was significantly higher （P〈0.05） ;the infarct size measured by TTC was significantly smaller（P〈0.05）. Conclusion：Postconditioning exerts protective effects on acute ischemia-reperfused canine heart, which may be partly mediated by oxygen free radical redaction.