不同浓度左旋卡尼汀对离体兔缺血／再灌注心脏功能的保护作用

Protective effects of different concentration of L-carnitine on rabbit myocardium against ischemia/reperfusion injury

目的观察不同浓度左旋卡尼汀（L-carnitine，L-CN）预处理对高钾停跳离体兔缺血，再灌注心脏功能的保护作用。方法采用离体兔心Langendorff灌注实验模型，离体兔心24只随机等分成缺血／再灌注组、L-CN2．5mmol／L、L-CN5．0mmol／L、L-CN10mmol/L 4组（n=6）。缺血／再灌注损伤组：灌注K-H液25min，（兔心）4℃标准St．Thomas停搏液（K^＋16mmol／L）至心脏停跳，45min后恢复K-H液灌注20min；不同浓度L-CN组：灌注K-H液10min，再予不同浓度的L-CN续灌15min，余步骤同缺血厢獾注组。观察灌注过程中各组的血流动力学指标，心肌TTC染色测定缺血面积和梗死面积百分比。结果再灌注后浓度5．0mmol／L和10．0mmol／L的L-CN预处理的离体兔心心功能的恢复率均明显高于对照组（P〈0．05）；其心肌存活面积百分比高于对照组（P〈0．05）。结论L-CN预处理对高钾停跳离体兔缺血／再灌注心脏具有较好的心功能保护作用。

Objective To investigate the protective effect of L-carnitine （L-CN） against the myocardial ischemia/reperfusion injury in isolated rabbit hearts. Methods The experiment was performed on isolated rabbit hearts perfused with Langendorff apparatus. Twenty four rabbit hearts were randomly divided into ischemia/reperfusion （I/R） group, L-CN 2.5 group, L-CN 5.0 group and L-CN 10.0 group （n=6）. The I/R group was firstly perfused with Krebs-Henseleit buffer （K-H） solution for 25 min, followed with St. Thomas Ⅱ solutions until cardiac arrest for 45 min and then reperfused with K-H solution for 20 min. Different concentration of L-CN groups were similarly treated to that of the I/R group, except that every group was firstly perfused with K-H solution for 10 min and then perfused with different concentration of L-CN. The hemodynamic indexes were determined in the course of perfusion. The heart was stained with TTC and photograph was taken to measure the ischemic area. Results In contrast to the findings in the control group, the recovery of myocardial contractility and heart rate was earlier in the L-CN 5.0 groups and the L-CN 10.0 groups （P〈0.05）, the percentages of survival myocardium areas in the L-CN 5.0 groups and the L-CN 10.0 groups were higher （P〈0.05）. Conclusion L-CN pretreatment can increase the survival myocardium areas after reperfusion and make cardiac function recover as soon as early after ischemia-reperfusion injury. L-CN has protection on isolated rabbit ischemia reperfusion myocardium.