Cardioprotective Effects of Legs and Myocardial Ischemia Postconditioning on Myocardial Ischemia/Reperfusion Injury in Rabbits

Objective To study the cardioprotective effects of legs and myocardial ischemia postconditioning against ischemia and reperfusion injury in rabbit heart.Methods In anesthetized open-chest rabbits,the left anterior descending artery(LAD)was occluded for 30min,and reperfused for 3hrs.Thirty-two rabbits were randomly divided into 4 groups(n=8 in each group):(1)sham group,(2)I/R group,(3)myocardial ischemia postconditioniong group,and(4)remote double limbs postconditioning group.Myocardial infarct size(IS)and area at risk(AAR)were defined by Evans blue and TTC staining.Blood samples were taken from artery line before occlusion,30min after occlusion,1h and 3hrs after reperfusion for determination of plasma CK and cTnI.Result Legs and myocardial ischemia postconditioning significantly(P0.05)reduced infarct size(19.0±5.2 in group 3,20.4±5.1 in group 4)as compared with the I/R group(28.5±4.4).The cTnI and CK levels of group 3 and group 4 were significantly lower than those of group 2(P0.05).The injury of group 2 was worse than that of the group 3 and group 4 from the change of the cellular structure under electron microscope.Conclusion Legs and myocardial ischemia postconditioning can induce cardioprotection against myocardial ischemia/reperfusion injury in rabbits.