PTEN基因沉默骨髓间充质干细胞移植治疗急性心肌梗死

PTEN-silenced bone marrow mesenchymal stem cell transplantation for acute myocardial infarction

背景:骨髓间充质干细胞移植治疗心肌梗死是近年来的研究热点,但是心肌梗死区域的缺血缺氧微环境和早期炎症反应不利于移植细胞的存活,影响治疗效果。目的:探讨PTEN基因沉默骨髓间充质干细胞治疗急性心肌梗死的效果。方法:(1)SD大鼠骨髓间充质干细胞随机分为3组,空白对照组不进行任何处理,阴性对照组用Lipofectamin2000转染无意义的NCsiR NA,RNAi组用Lipofectamin2000转染PTEN基因特异的siR NA。采用MTT法描绘细胞生长曲线,流式细胞仪检测细胞周期;(2)取30只SD大鼠建立心肌梗死模型,随机分为3组,每组10只,分别为空白对照组、阴性对照组、RNAi组。建模6 h后,使用微量注射器和立体定位仪在左心室前壁梗死区中心注射相应的骨髓间充质干细胞,治疗后4周进行超声心功能检测,采用荧光显微镜观察细胞的存活和增殖情况。结果与结论:(1)RNAi组骨髓间充质干细胞在培养各时间点的吸光度值均显著大于空白对照组和阴性对照组;(2)RNAi组S+G2期细胞占总数的比例显著大于空白对照组和阴性对照组(P<0.05);(3)RNAi组大鼠心肌组织中骨髓间充质细胞数量显著多于空白对照组和阴性对照组(P<0.05);(4)治疗4周,RNAi组的左心室射血分数、左心室短轴缩短率显著小于空白对照组和阴性对照组(P<0.05);(5)体外实验表明PTEN基因沉默能有效地促进骨髓间充质干细胞的增殖,抑制细胞凋亡;(6)体内实验表明PTEN基因沉默的骨髓间充质干细胞在心肌梗死区域更易存活和扩增,心功能改善明显。

BACKGROUND： Bone marrow mesenchymal stem cell transplantation for myocardial infarction becomes popularized in recent years, but transplanted cells cannot survive and proliferate under early inflammatory reaction or local ischemia/hypoxia microenvironment, eventually hampering the therapeutic outcomes. OBJECTIVE： To investigate the therapeutic effect of PTEN-silenced bone marrow mesenchymal stem cells on acute myocardial infarction. METHODS：（1） Bone marrow mesenchymal stem cells from Sprague-Dawley rats were randomly assigned to receive no treatment, NCsiR NA transfection using Lipofectamin2000 or PTEN si RNA transfection using Lipofectamin2000. Cell growth curves were described using MTT method to detect cell cycle using flow cytometry.（2） Thirty Sprague-Dawley rats were selected to prepare myocardial infarction models that were randomized into three groups（n=10 per group）： blank control, negative control and RNAi group. Six hours after modeling, bone marrow mesenchymal stem cells transfected with nothing, NCsi RNA and PTEN siR NA were respectively injected into the infarcted center of the left ventricular anterior wall in these three rat groups. After 4 weeks, all rats were subjected to cardiac function detection using echocardiography, and the survival and proliferation of bone marrow mesenchymal stem cells in the rats were observed by fluorescence microscopy. RESULTS AND CONCLUSION： Compared with the other two groups, a significant increase in the absorbance values at different culture time, the proportion of cells in S＋G2 phase, and the number of bone marrow mesenchymal stem cells in the myocardial tissue was found in the RNAi group（all P〈0.05）. Additionally, the left ventricular ejection fraction and left ventricular shortening fraction were significantly reduced in the RNAi group than the blank control and negative control groups at 4 weeks after cell transplantation（P〈0.05）. Both in vivo and in vitro experimental findings showed that PTEN silencing could effectively improve cell survival and proliferation in the infarcted myocardium. Moreover, in the in vivo experiment, an overt improvement in rat＇s cardiac function was achieved.