Evaluation of the differentiation process of human bone marrow mesenchymal stem cells to cardiomyocyte-like cells: An in vitro study

Porpose:To evaluate the development of cardiomyocyte-like cells derived from human bone marrow mesenchymal stem cells induced by 5-azacytidine (5-aza) under in vitro condition. Human bone marrow mesenchymal stem cells (BMMSCs) were purified, then the cells were induced by 5µM 5-aza for 5 weeks. To transdifferentiate into cardiomyocyte, the culture medium of human BMMSCs was changed every 24 hours, in the way that the cells were put in the culture medium containing 5-aza for 24 hours and, then were put in a culture medium free of the said material for another 24 hours, and this process continued until sampling. RT-PCR assay was performed to detect the expression of specific myocardium genes including α-actinin, myosin heavy chain (MHC) and connexin-43 each weeks after first induction. Fluocytometry was used to determine the expression of specific myocardium proteins including α-actinin, troponin and connexin-43 at 3rd and 5th weeks after the first induction. The expression of all three myocardium genes was detected 1 to 5 weeks after induction in a time-dependent manner. There was a continuous increase in expression of α-actinin and connexin-43 genes from the 1st to the 5th week, while mRNA of MHC gene was at the highest level in the forth week. The expression of α-actinin and troponin proteins was equal after three and five weeks, whereas that of the connexin-43 was higher after five weeks in comparison to the 3rd week. The current study indicated that stimulating human bone marrow mesenchymal stem cells by 5-aza with the concentration of 5µM under in vitro condition can lead to differentiating cardiomyocyte-like cells. Furthermore prolonged culture duration may lead to more differentiated cells