钙预处理对离体大鼠缺血再灌注心肌细胞的保护作用

Protecctive Effect of Calcuim Preconditioning on Ischemic/Reperfused Myocardium in Isolated Rat Heart

目的 :研究钙预处理是否对缺血再灌注心肌有保护作用 ,其作用是否通过蛋白激酶C(ProteinKinaseC ,PKC)及线粒体ATP依赖性钾通道 (KATP)起作用。方法 :3 2只SD大鼠 ,随机分为 4组 :缺血再灌注组 (I/R组 )、钙预处理组 (CPC组 )、钙预处理加PKC阻滞剂Chelerythine组 (CLT组 )、钙预处理加线粒体KATP通道阻滞剂 5 hy droxydecanoate组 (5 HD组 ) ,分别检测LDH及CK的漏出量、心肌ATP含量、心功能指标 (LVSP及±dp/dtmax)。 结果 :与I/R组比较 ,CPC组CK、LDH漏出量明显减少 (P <0 .0 1) ,心肌ATP含量增加 (P <0 .0 1) ,心功能改善 ;CLT组及 5 HD组上述各指标 (LDH、CK、ATP、LVSP及±dp/dtmax)分别与I/R组相同指标之间无显著性差异 (P >0 .0 5 )。结论 :钙预处理对I/R心肌有保护作用 ,其保护作用可被PKC阻滞剂及KATP阻滞剂所取消 。

Objective: To investigate the protective effects of calcium preconditioning on ischemic/reperfused myocardium and its mechanism in isolated rat heart.Method: 32 rats were randomly divided into 4 groups: Ischemia/Reperfusion group (I/R group), Calcium preconditioning group (CPC group), Chelerythine (a PKC inhibitor) added into CPC group (CLT group) and 5 hydroxydecanoate (5 HD, a mitochondrial K ATP channel inhibitor) added into CPC group (5 HD group). The levels of CK, LDH and ATP, which indicated myocardium injury, and the cardiac function (LVSP and ±dp/dt max) from each group were all observed.Results: Compared with I/R group was that not only were the levels of CK and LDH of CPC group reduced, but also the ATP content was increased and the cardiac function were improved ( P <0.01, respectively). All the corresponding parameters in CLT group and 5 HD group were not obviously different from those in I/R group ( P >0.05, respectively). Conclusion: Calcium preconditioning protects myocardium from reperfused injury through PKC pathway and mitochondrial K ATP channel pathway.