远隔缺血后处理对兔心肌缺血/再灌注损伤保护作用的时效关系

目的探讨远隔缺血后处理时间长短对大白兔心肌缺血/再灌注损伤保护作用的影响。方法将54只大白兔随机分为6组,假手术组和A组、2次缺血5min/灌注5min组(B组)、3次缺血10min/灌注5min组(C组)、4次缺血5min/灌注5min组(D组)、4次缺血10min/灌注5min组(E组)。假手术组只穿线,其他5组均接受冠状动脉左前降支闭塞30min后再灌注6h的处理。B、C组分别同时双侧股动脉实施2次缺血5min再灌注5min、3次缺血10min再灌注5min远端缺血后处理,D、E组分别同时双侧股动脉实施4次缺血5min再灌注5min、缺血10min再灌注5min远端缺血后处理,并全程记录心电图(室性心律失常),分别在缺血前后和再灌注后3、6h获取血浆标本检测肌钙蛋白(cTnT),利用cTnT总释放量曲线下面积量化评估心肌梗死面积。结果 6组0～30min室性心律失常评分差值组间比较:假手术组实验前后无变化;B、D组与A组比较差异无统计学意义(P>0.05),C、E组与A、B、D组比较差异有统计学意义(P<0.01);且与缺血后处理时间长短呈负相关(r=-0.892)。cT-nT水平:假手术组实验前后无变化;B、C、D、E组较A组下降显著(P<0.05),E组较B、C、D组下降显著(P<0.05)。且与缺血后处理时间长短呈负相关(r=-0.833);心肌梗死面积:假手术组无心肌梗死。与A组比较,B组下降32.3%,C组下降32.8%,D组下降31.0%,E组下降35.8%;且与缺血后处理时间长短呈负相关(r=-0.782)。结论远隔缺血后处理可减少心肌缺血/再灌注损伤,且其作用与后处理时间明显相关。

Time-effect relationships of remote ischemia postconditioning on protection of myocardial ischemia/reperfusion injury of rabbit

Objective To investigate the effect of the time length of remote ischemia postconditioning on the protection role of ischemia/reperfusion injury of rabbit.Methods 54 rabbits were randomly divided into 6 groups.Sham group,the control group(group A),2 episodes of postconditioning 5 min/ 5 min reperfusion group(group B),3 episodes of postconditioning 10 min/5 min reperfusion group(group C),4 episodes of postconditioning 5 min/5 min reperfusion group(group D),4 episodes of postconditioning 10 min/ 5 min reperfusion groups(group E).The sham group only were threaded a silk,the other five groups underwent 30 min coronary artery anterior descending branch occultation and then with 6 h perfusion treatment.The group B and C underwent simultaneously 2 circulation ischemia with 5 min in bilateral femoral artery,3 circulation ischemia with 10 min in bilateral femoral artery,and then with 5 min post treatment of remote ischemia.The group D and E underwent simultaneously 4 circulation ischemia of 5 and 10 min in bilateral femoral artery and with 5 min post treatment of remote ischemia.Full record of ECG(ventricular arrhythmias) was performed during the whole process.To collect the plasma samples for detecting troponin(cTnT) before and after ischemic conditioning,and at 3,6 h after reperfusion respectively,and to assess the size of myocardial infarct.Results Comparing differences in scores of ventricular arrhythmias at 0-30 min among 6 groups:no change in the sham proup was found before and after experiment,there was no difference in thecomparisun between the group B,D with the group A(P>0.05);and significant differences existed between group C,E with A,B,D(P<0.01).And its action was negatively correlated with the time of postconditioning(relevant coefficient=-0.892).In the cTnT level:there was a significant decrease in the group B,C,D and E in comparison with the group A(P<0.01),and in comparison with group B,C and D,there was significant decrease in the group E(P<0.05).And its action was negatively correlated with the time of postconditioning(relevant coefficient=-0.833).In myocardial infarct size:in comparison with the group A,the group B dropped by 32.3%,the group C dropped by 32.8%,the group D dropped by 31.0% and the group E by 35.8%.And its action was negatively relevant with the time of postconditioning(relevant coefficient=-0.782).Conclusion Remote ischemia postconditioning can reduce myocardial ischemia and ischemia/reperfusion injury,and its action is relevant with the time of postconditioning.