外源性一氧化碳分子释放剂CORM-2对抗大鼠离体心脏缺血复灌损伤及其作用机制

Cardioprotection and mechanisms of exogenous carbon monoxide releaser CORM-2 against ischemia/reperfusion injury in isolated rat hearts

目的:研究外源性一氧化碳(carbon monoxide,CO)对大鼠离体心脏缺血复灌的作用及其机制。方法:采用Langendoff离体心脏灌流模型,用结扎心脏冠脉前降支30min造成心肌缺血,松开结扎120min作为再灌。观察心脏收缩功能、心肌酶学和心肌梗死面积等指标。结果:25μmol/LCORM-2(外源性CO释放剂)显著改善了离体心脏缺血复灌时心功能的损伤,降低了乳酸脱氢酶(LDH)、磷酸肌酸激酶(CK)的释放,减少了梗死面积,但对冠脉流量的影响不大。10μmol/LCORM-2可减少LDH、CK和心肌梗死面积,但对心功能的影响不明显;而100μmol/L CORM-2却可增加缺血复灌心肌LDH的释放,加重心功能的损害。可溶性鸟苷酸环化酶抑制剂亚甲蓝、一氧化氮合酶(NOS)抑制剂L-NAME、线粒体ATP依赖性钾离子通道阻断剂(mitoKATP)5-HD和血红素氧化酶-1(HO-1)抑制剂Znpp均可不同程度地阻断25μmol/L CORM-2缩小缺血心肌梗死面积的作用。L-NAME和Znpp可阻断CORM-2降低LVEDP的作用,但是CORM-2增高LVDP和+dp/dt的作用仅被亚甲蓝和L-NAME所取消。结论:外源性一氧化碳对大鼠缺血复灌心脏有保护作用,其作用机制可能是通过NOS-cGMP和HO-1途径,激活线粒体ATP依赖性钾离子通道起作用的。

Objective. To investigate the role of exogenous carbon monoxide （CO） in protection of rat hearts from ischemia/reperfusion injury and its underlying mechanisms. Methods. Cardiac contractility,lactate dehydrogenase （LDH）,creatine kinase （CK） and infarct area were analyzed by the Langendorff isolated rat hearts. All isolated hearts were subjected to 30 min of ischemia followed by 120 min of reperfusion. Results. Perfusion with 25 μmol/L of CORM-2 （an exogenous CO releaser）during the first 10 min of reperfusion prevented the increase in LVEDP and decrease in LVDP, ＋dp/dtmax in isolated ischemia/reperfusion hearts. CORM-2（25 μmol/L） had no effect on the changes of coronary flow,but it really inhibited the release of LDH and CK, and also reduced the infarct size. Perfusion with 10 μmol/L of CORM-2 decreased the LDH,CK and infarct size,but it did not improve the contractility of ischemia/reperfusion hearts. However, perfusion with 100 μmol/L of CORM-2 exacerbated the injury induced by ischemia/reperfusion. Pretreatment of a NOS inhibitor L-NAME and a HO-1 inhibitor ZnPP partly abolished the protection effect of CORM-2 （25 μmol/L） on LVEDP, and L-NAME and a GC inhibitor methylene blue could also cancel the enhance of LVDP and ＋dp/dtmaxincuced by CORM-2. All of the inhibitor（methylene blue,L-NAME,a mitoKATpchannel blocker 5-HD and ZnPP） could partly enlarge infarct area compared with CORM-2 treatment. Conclusions： Exogenous CO could protect heart from ischemia/reperfusion injury. The cardiac protection of CO might be through NOS-cGMP and HO-1 pathway,and the activation of mitOKATp channel might be also involved in.