反向钠钙交换体在大鼠心脏钙预处理中的作用

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1、反向钠钙交换体在大鼠心脏钙预处理中的作用作者：毕生辉，金振晓，王喜明，周京军，彭道荣，魏旭峰，段维勋，易定华【摘要】目的探讨钙预处理时反向钠钙交换体对抗钙矛盾损伤的作用及机制。方法25只SD大鼠随机等分为5组：正常对照(Control)组、钙矛盾(CaPD)组、钙预处理(CPC)组、反向钠钙交换体抑制剂（KB-R7943）+CPC组和KB-R7943+CaPD组。采用离体大鼠心脏Langendorff逆行灌注模型，观察各组心脏冠状动脉流量(CF)、左心室发展压(LVDP)、左心室内压变化速率(dp/dt)及冠状动脉循环流出液心肌肌

2、钙蛋白I(cTnI)浓度的变化，HE染色观察各组心脏组织形态。结果与CaPD组相比，CPC组CF、LVDP、dp/dt均显著提高(P<0.001)，冠状动脉循环流出液中cTnI水平显著降低(P<0.001)。而钙预处理过程中加入反向钠钙交换体抑制剂KB-R7943，其心肌保护作用均被明显减弱(P<0.05)。结论钙预处理能够有效对抗钙矛盾对心肌造成的损伤，其机制涉及钙预处理时钠钙交换体反向交换活性的上调。【关键词】心脏；大鼠；钠钙交换体；钙预处理；钙矛盾11Abstract:OBJECTIVEToinvestig

3、atetheroleofreversemodeNa+/Ca2+exchangeronthecardioprotectionofcalciumpreconditioning(CPC).METHODSTheheartsoftwenty-fiveSDratswereisolated,underwentLangendroffperfusion,andwererandomizedinto5groups:(1)controlgroup(65minperfusionwithKHbuffer),(2)calciumparadoxgroup(5mi

4、nperfusionwithKHbufferlackingCa2+followedby30minKHbuffercontainingCa2+,CaPD),(3)calciumpreconditioninggroup(5cyclesperfusionof1minCa2+depletion/5minCa2+repletion+Ca2+PD,CPC),(4)reversemodeNa+/Ca2+exchangerinhibitorKB-R7943(3μmol/L)+CPCgroup(additionofKB-R7943duringcal

5、ciumpreconditioning).(5)reversemodeNa+/Ca2+exchangerinhibitorKB-R7943(3μmol/L)+CaPDgroup(30minperfusionwithKHbuffercontainingKB-R7943+CaPD).Leftventriculardevelopedpressure(LVDP),rateofriseofleftventricularpressure(dp/dt),coronaryflow(CF),andcardiactroponinI(cTnI)rele

6、aseweremeasured.SectionswithHEstainingwereanalyzedtodisplaythemorphologicstructuresofthehearts.RESULTSThelevelsofLVDP,dp/dt,andCFoftheCPCgroupweresignificantlyhigherthanthoseoftheCaPDgroup(allP<0.001).ThereleaseofcTnIwasreducedsignificantlyintheCPCgroupascomparedto

7、theCaPDgroup(P<0.001).However,theimprovementofthe11hemodynamicsandthedecreaseinthecTnIreleaseelicitedbycalciumpreconditioningweresignificantlyattenuatedbythereversemodeNa+/Ca2+exchangerinhibitorKB-R7943employedduringthewholeprocessofthecalciumpreconditioning(allP&l

8、t;0.05).CONCLUSIONTheenhancementofreversemodeNa+exchangerwasinvolvedinthecardioprotectioninducedbycalciumpreconditioninginth