骨髓间充质干细胞移植对心肌梗死后心室肌细胞钾离子通道Ito Kv4.2的影响

目的 研究心肌梗死后移植骨髓间充质干细胞(bone marrow mesenchymal stem cells,BMMSCs)对心室肌细胞钾离子通道Ito亚单位Kv4.2基因表达的影响方法 40只SD(Sprague-Dawley)大鼠随机分成4组(10只/组):假手术组、心肌梗死组、心肌梗死+干细胞组和心肌梗死+细胞培养基组.开胸结扎冠状动脉前降支建立心肌梗死模型,建模成功后,在梗死周围分别注入BMMSCs和细胞培养基,心肌梗死组仅建立心肌梗死模型,假手术组仅开胸子以前降支穿线但不结扎.2周后行心肌组织HE染色和荧光显微镜观察移植细胞,逆转录聚合酶链反应(RT-PCR)和Western blot分别检测钾离子通道Ito亚单位Kv4.2基因mRNA和蛋白水平.结果 (1)心肌组织免疫荧光检测发现,BMMSCs集中分布于梗死区和梗死心肌周围;(2)心肌梗死组和心肌梗死+细胞培养基组Kv4.2 mRNA量(0.39±0.02,0.41±0.04)和蛋白量(0.47±0.02,0.50±0.05)明显下降,与假手术组(0.76±0.05,0.74±0.06)相比差异有统计学意义(P＜0.01);心肌梗死+干细胞组Kv4.2 mRNA量和蛋白表达量(0.57±0.05,0.64±0.03)较心肌梗死组(0.39±0.02,0.47±0.02)明显升高(P＜0.01).结论 骨髓间充质干细胞移植后心肌梗死大鼠钾离子通道Ito亚单位Kv4.2基因表达上升,可能减少心律失常发生.

Effects of bone marrow mesenchymal stem cells transplantation on transient outward potassium Kv4. 2 of ventricular cardiomyocytes in postinfarcted rat myocardium

Objective To investigate the effects of bone marrow mesenchymal stem cells (BMMSCs) implantation on transient outward potassium Kv4. 2 of cardiomyocytes in postinfarcted rat left ventricle myocardium. Methods Total 40 Sprague-Dawley(SD) rats were divided into four groups at random:sham-operating group,myocardial infarction (MI) group, BMMSCs transplantation (MI-BMMSCs) group and cell medium(MI-CM) group,10 rats in the each group. MI was induced by ligation of left anterior descending artery. About 1h after the ligation BMMSCs cells suspension labeled by DAPI,were injected into different acute myocardial ischemia regions. While,in MI-CM group,DMEM medium was injected into similar regions as the MI-BMMSCs group. The rats were sacrificed at the end of the second week. Left ventricular histopathologic myocardial changes were evaluated through H&E. Transplanted cells were observed by fluorescent microscope. RT-PCR and Western blot were used to identify expression of Ito Kv4. 2. Results( 1 ) Fluorescent microscope showed that MSC-derived cells survived. (2) The expression of Kv4. 2 in the MI group and MI-CM group was significantly lower than that in the sham-operating group (P ＜0. 01 ). Compared to MI-CM group and MI group, the expression of Kv4. 2 was significantly increased( P ＜0. 01 ). Conclusion The MSCs transplantation treatment can promote the expression of Kv4. 2 in AMI rats,which may contribute to decrease of arrhythmias after MSCs transplantation.