大鼠骨髓间充质干细胞移植治疗心肌梗死的实验研究

Experimental study of bone marrow mesenchymal stem cells transplantation to treat myocardial infarction in Rats

目的研究骨髓间充质干细胞(BMSCs)移植对心肌梗死大鼠左心功能的影响以及在心肌病大鼠体内存活、分化的情况。方法结扎左冠状动脉前降支制备大鼠心肌梗死模型,采用同种异体大鼠BMSCs体外分离、纯化、扩增,胶体金标记。按照对BMSCs的处理方式和心肌内注射的成分不同随机分为3组:A组接受BMSCs移植治疗;B组移植经5-氮胞苷体外诱导的BMSCs;C组列为对照组,注射等量培养基;每组12只。4周后通过血流动力学各项指标评价BMSCs移植对大鼠心功能的改善情况;免疫组织化学法检测移植细胞的存活和分化。结果与对照组C组相比,移植组A,B两组左心功能显著改善(P<0.01)。A,B两组之间无显著性差异。移植组左心室收缩压(LVSP)、左心室等容期压力最大变化速率(±dp/dtmax)明显高于对照组(P<0.01),左心室舒张末期压(LVEDP)明显低于对照组(P<0.01)。移植的BMSCs能在心外膜下、梗死区及与正常心肌的交界处存活并向心肌细胞分化,心肌特异性肌钙蛋白T(cTnT)和α-横纹肌肌动蛋白(α-sarcomeric actin)表达阳性。结论同种异体BMSCs移植入大鼠心肌梗死区后能明显改善心功能并向心肌细胞转化。

Objective To investigate the effects of bone marrow stem cells（BMSCs） transplantation on heart function of acute myocardial infarction（AMI） in rats and to observe their survival and differentiation in damaged host myocardium.Methods AMI was created by occluding the left anterior descending artery（LAD） in SD rats.BMSCs of healthy rats were isolated,purified,amplified and labeled with colloidal gold.The rats were randomly divided into 3 groups according to the means dealing with BMSCs and the components injected into myocardium,with 12 rats for every group.Group A received exogenous transplantation of BMSCs,but group B received exogenous transplantation of BMSCs induced by 5-aza.Group C（control group） was injected 100μl IMDM.At the 4th week after transplantation,index of hemodynamics were tested.Survival and differentiation of the transplanted BMSCs were observed by immunohistochemistry.Results（1） The difference in cardiac function among three groups were remarkably significant（P0.01） at 4th week after intramyocardiac injection.There were no significant difference between group A and B.（2） LVEDP was lower in treatment group than control group（P0.01）,LVSP and ±dp/dtmax were higher in treatment group than control group（P0.01）.Transplanted cells differentiated into cardiomyocytes with positive cTnT and α-sarcomeric actin and survived in area of inferepicardium,myocardial scar and besided normal myocardium.Conclusions The exogenous BMSCs can improve the heart function remarkably when transplanted into infarcted myocardium and can differentiate into viable cardiomyocytes.