钙调节蛋白在七氟烷后处理心脏保护中的机制探讨

摘要

Objective To discuss the mechanism of calcium regulatory proteins in cardiac protection after sevoflurane postconditioning (SevoPoC).Methods Isolated hearts were separated from 30 SD rats to make ischemia-reperfusion injury(I/RI) models and they were randomly divided into 3 groups(n =10):①Time control (TC) group had continuous perfusion of oxygenated KH solution for 120 min;②I/RI group had continuous perfusion of oxygenated KH solution for 30 min,stopped 30 min,and then reperfused for 60 min;③SevoPoC group had continuous perfusion of oxygenated KH solution for 30 min,stopped 30 min,and then had 3％ sevoflurane perfusion for 10 min and KH solution perfusion for 50 min.Left ventricular end-diastolic pressure(LVEDP),heart rate(HR),left ventricular developed pressure(LVDP),the maximum LVDP increase rate(+ dp/dt) and the maximum LVDP decrease rate were observed.Myocardial infarct size was measured.Cardiac troponin (cTnI) in coronary outflow fluid was tested.Expressions of L-type Ca2+ channels (LTCCs),ryanodine receptor 2 (RyR2) and Na +-Ca2+ exchanger isoform 1 (NCX1) were determined.Results LVEDP in SevoPoC group was significantly lower,RPP(HR × LVDP) and + dp/dt were significantly higher than those in I/RI group (P ＜ 0.05).Level of cTnI in SevoPoC group was significantly lower than that in I/RI group[(0.060 ±0.003)mg/L vs (0.110 ±0.004)mg/L](P ＜0.01).NCX1 expression level in I/RI group was significantly higher than that in TC group[(0.59 ±0.09) vs (0.35 ± 0.05)];NCX1 expression level in SevoPoC group (0.32 ± 0.06) was significantly lower than that in I/RI group(P ＜ 0.01).Expressions of LTCCs and RyR2 showed no significant differences among groups(P ＞ 0.05).Conclusion SevoPoC can promote cardiac function recovery,increase cTnI release in coronary outflow fluid and reduce infarction size;the cardioprotection effect may be associated with NCX1 deactivation.%目的 探讨钙调节蛋白在七氟烷后处理(SevoPoC)心脏保护中的机制.方法 选取30只SD大鼠建立离体心脏模型,血流动力学稳定30 min后,缺血30 min复灌60 min建立缺血再灌注损伤模型,完全随机分入以下3组,每组10只:①时间对照组(TC组):将离体心脏在恒流下灌注充分氧合的KH液120 min;②缺血再灌注组(I/RI组):将离体心脏在恒流下灌注充分氧合的KH液30 min后,停止灌注30 min,随后恢复灌注60 min;③七氟烷后处理组(SevoPoC组):将离体心脏在恒流下灌注充分氧合的KH液30 min后,停止灌注30 min,在复灌即刻使用含3％的七氟烷持续灌注10 min,然后使用氧合的KH液灌注50 min.各实验组均持续监测左心室舒张末期压力(LVEDP)、心率、左心室发展压(LVDP)、最大LVDP上升速率(+ dp/dt)及最大LVDP下降速率.检测心肌梗死面积和冠状动脉流出液中心肌肌钙蛋白I(cTnI)水平.分别用蛋白印迹法和荧光实时定量聚合酶链反应(RT-PCR)方法检测L型钙通道(LTCCs)、兰尼碱受体2(RyR2)以及钠钙交换体1(NCX1)的蛋白和基因转录水平.结果 SevoPoC能明显加快LVEDP、RPP(心率与LVDP的乘积)和+dp/dt向基线水平恢复,SevoPoC组LVEDP水平低于,RPP及+dp/dt高于I/RI组(均P＜0.05).同时,SevoPoC可以降低心肌缺血再灌注损伤后cTnI的释放,SevoPoC组cTnI水平低于I/RI组[(0.060 ±0.003) mg/L比(0.110±0.004) mg/L](P＜0.01).NCX1相对表达水平I/RI组高于TC组[(0.59±0.09)比(0.35±0.05)],SevoPoC组(0.32 ±0.06)低于I/RI组(均P＜0.01).LTCCs和RyR2的表达各组间差异无统计学意义(P＞0.05).结论 SevoPoC可以提供心肌保护作用,表现在心功能恢复的增强、冠状动脉流出液cTnI释放以及心肌梗死面积的减少.其作用可能与其对NCX1的抑制有关.