Zhong Ze, Hu Jiaqing, Sun Yong, Jiang Jun, Wu Xindong, Xiang Peng, Luo Xiuying
Department of Cardiology, Jiande Branch, Second Affiliated Hospital, Zhejiang University School of Medicine, Jiande 311600, China; Email:
Zhonghua Xin Xue Guan Bing Za Zhi. 2015 Jun;43(6):531-6.
To observe the impact of mesenchymal stem cells (BMSCs) transplantation on myocardial myocardin-related transcription factor-A (MRTF-A) and bcl-2 expression in rats with experimental myocardial infarction (MI).
Thirty rats were randomly divided into sham, MI and MI + BMSCs (1 × 10(6) injected into 4 infarct points immediately post coronary artery ligation) groups (n = 10 each).One week later, TUNEL was used to detect cardiomyocyte apoptosis, the myocardial expression of MRTF-A and bcl-2 was detected by laser scanning confocal microscope and Western blot. In vitro plasmid of MRTF-A and co-transfection with plasmids of MRTF-A and bcl-2 or mutated bcl-2 transfection into cardiomyocyte was applied to evaluate the relationship between MRTF-A and bcl-2.
The number of apoptotic cardiomyocytes in the sham group, MI group and MI + BMSCs group were (4.05 ± 1.56)%, (62.38 ± 8.41)% and (22.36 ± 6.17)%, respectively (P < 0.05). The protein expression of MRTF-A and bcl-2 in the MI group were significantly lower than those in sham group, while significantly upregulated in MI + BMSCs group (P < 0.05 vs. MI). In cultured neonatal rat cardiomyocyte, the expression of bcl-2 protein was significantly upregulated after transfection with MRTF-A plasmid, and bcl-2-luciferase activity significantly increased after co-transfection with plasmids of MRTF-A and bcl-2-luciferase, however, the positive regulatory effect of MRTF-A was abolished after transfection with mutated bcl-2.
Mesenchymal stem cells transplantation can effectively reduce cardiomyocyte apoptosis in this rat MI model, and upregulate the expression of MRTF-A. Consequent up-regulated bcl-2 expression might be involved in the beneficial effects of BMSCs transplantation in this model.
观察间充质干细胞（BMSCs）移植对实验性心肌梗死（MI）大鼠心肌中与心肌素相关转录因子-A（MRTF-A）及bcl-2表达的影响。
将30只大鼠随机分为假手术组、MI组和MI + BMSCs组（冠状动脉结扎后立即于4个梗死部位注射1×10(6)个细胞），每组10只。1周后，采用TUNEL法检测心肌细胞凋亡，通过激光扫描共聚焦显微镜及蛋白质免疫印迹法检测心肌中MRTF-A和bcl-2的表达。体外将MRTF-A质粒转染至心肌细胞，并将MRTF-A质粒与bcl-2或突变型bcl-2质粒共转染至心肌细胞，以评估MRTF-A与bcl-2之间的关系。
假手术组、MI组和MI + BMSCs组心肌细胞凋亡数分别为(4.05 ± 1.56)%、(62.38 ± 8.41)%和(22.36 ± 6.17)%（P < 0.05）。MI组中MRTF-A和bcl-2的蛋白表达显著低于假手术组，而MI + BMSCs组中显著上调（与MI组相比，P < 0.05）。在培养的新生大鼠心肌细胞中，转染MRTF-A质粒后bcl-2蛋白表达显著上调，MRTF-A质粒与bcl-2荧光素酶质粒共转染后bcl-2荧光素酶活性显著增加，然而，转染突变型bcl-2后MRTF-A的正向调节作用被消除。
间充质干细胞移植可有效减少该大鼠MI模型中心肌细胞凋亡，并上调MRTF-A表达。随之上调的bcl-2表达可能参与了该模型中间充质干细胞移植的有益作用。
