中文摘要：

目的调查心肌梗死后植入骨髓间充质干细胞（mesenchymal stem cells，MSCs）对心室肌细胞复极活动的影响。方法10只健康幼猪作为正常对照组，23只幼猪通过球囊导管堵闭左冠状动脉前降支法建立心肌梗死模型并分别移植MSCs悬液（干细胞组，n=13）或等量生理盐水（梗死组，n=10），6周后行心肌组织免疫组化双染色、左心室血流动力学及左心室肌细胞复极活动的检查。结果（1）心肌组织免疫组化双染色示，MSCs源性细胞集中分布于梗死区，胞浆中出现了肌钙蛋白T（troponinT）；（2）干细胞组左心室射血分数、左心室收缩压和舒张末压虽未恢复正常（与对照组相比，P均〈0．01），但较梗死组均改善（P均〈0．05）；（3）梗死组和干细胞组动作电位复极90％的时间（APD90）、复极时间（RT）、APD和RT离散度值较对照组均延长（P均〈0．01），但干细胞组较梗死组显著缩短（P〈0．05—0．01）；（4）对照组APD重建曲线斜率〈1（正常），而干细胞组和梗死组APD重建曲线斜率均〉1（异常），但前者斜率明显小于后者；（5）干细胞组诱发APD交替的阈值周长虽高于对照组（P〈0．01），却低于梗死组（P〈0．05）。结论MSCs移植可减轻梗死心室复极紊乱，其机制可能与MSCs参与心肌组织修复、改善血流动力学水平有关。

英文摘要：

Objective To investigate the effects of mesenchymal stem cell implantation in postinfarcted swine myocardium on repolarization of cardiomyocytes in left ventricle. Methods Ten swine were used as normal controls（ Control group） ,23 swine with acute myocardial infarction （AMI） received intracoronary infusion of either MSC solution （ MSC group,n = 13） or 0. 9% sodium chloride solution （ MI group,n = 10）. Six weeks later, immunocytochemical double-staining, hemodynamic study and analyses of the repolarization parameters were performed. Results （1） Immunocytochemical double-staining showed that MSC-derived cells survived and appeared troponin T-positive in the infarct area. （2） MSC implantation significantly improved abnormal hemodynamics （LVEF,LVSP and LVEDP） resulted from MI （MSC group vs MI group,P 〈0. 01）. （3）The values of action potential duration of 90% repolarization （APDgo）, repolarization time （RT）, and dispersion of APD and RT（APDd and RTd ） in the MI and MSC group markedly increased compared with the Control group（all P 〈0. 01 ）,however,those in the MSC group were significantly lower than MI group（all P 〈0. 05）. （4） Only the slope of reconstitution curve in the Control group was normal （ 〈 1 ）, but that in the MSC group was apparently less than MI group. （5） The critical cycle length of APD alternan in the MSC group was remarkably higher than that in the Control group（ P 〈 0. 01 ）and lower than that in the MI group（ P 〈 0. 05 ）. Conclusion Abnormal repolarization activities in infarcted ventricle can be improved by MSC implantation,it may be attributed to the contribution of MSCs on tissue repair and hemodynamics.