左旋卡尼汀后处理联合预处理对离体大鼠心肌缺血再灌注损伤作用的研究

目的评价左旋卡尼汀（L-CN）对离体大鼠急性心肌缺血再灌注损伤的保护作用并比较预处理与后处理及预处理联合后处理保护作用的区别。方法动物心脏随机分为对照组、缺血后处理组、L-CN后处理组、L-CN预处理组和联合处理组。左旋卡尼汀分别于缺血后、缺血前或缺血前后给予10 min。检测心率（HR）、冠脉流量（CF）和不同时间点冠脉收集液中肌酸激酶（CK）、乳酸脱氢酶（LDH）含量,并测定心肌梗死区与风险区的比例。结果各组CK,LDH,CF,HR及心肌风险区在灌注前均无明显差异（P〉0.05）,复灌60 min时,各项指标在各处理组与对照组之间有明显差异,各处理组之间无显著差异,而CF在复灌120 min时,、L-CN后处理组与其他处理组相比P〈0.05。各组心肌梗死范围在心肌风险区无明显差别。结论左旋卡尼汀预处理、后处理及二者联合对离体大鼠心肌均有保护作用,预处理及后处理与二者联合的保护作用无显著差异。

Effects of ischemic-postconditioning and preconditioning induced by L-Carnitine on myocardial ischemia-reperfusion injury in isolated rat hearts

Objective: To evaluate protective effects of L-carnitine on acute myocardial ischemia reperfusion injury in isolated rat hearts and compare difference in synergistic effect of both on myocardial I /R injury between L-Carnitine(L-CN) postconditioning and preconditioning in isolated rat hearts.Methods: All hearts were randomly divided into 5 groups: the Control group,the postconditioning group(IPo),the L-CN postconditioning group(LIPo),the L-CN preconditioning group(LIPc) and the L-CN preconditioning combined with L-CN postconditioning group(LIPP).L-Cn was given for 10 minutes.Coronary flow(CF,ml/min),heart rate(HR) and contents of CK,LDH in the effluent at different times from the coronary were detected.Myocardial infarction area was also detected.Results: There are no difference in HR,CF,CK,LDH and myocardial risk area before reperfusion.At 60min after reperfusion,all parameters were found significantly different in experimental groups compared with control group.At 120min after reperfusion,there was difference in CF in LIPo compared to other experimental groups.There was no difference in myocardial infarct area between the groups.Conclusion: L-Carnitine(L-CN) postconditioning,preconditioning and their synergistic effects can protect myocardial I /R injury in isolated rat hearts,and there is no difference among these three methods.