Abstract: Objective: To induce the differentiation of bone marrow mesenchymal stem cells(BMSCs) by three culture methods in vitro, and to explore the best method of inducing the BMSCs to differentiate into the cardiomyocytes in vitro. Methods: The rat BMSCs were separated and cultured with density gradient centrifugation combined with adherence culture method.The rat BMSCs were cultured with 5-azacytidine(5-aza), the myocardial cell cleavage of the dilated cardiomyopathy(DCM) model rats and the serum of DCM model rats+5-aza in vitro,respectively; control group was set up at the same time(The BMSCs were cultured in the L-DMEM medium containing 10% FBS under the same condition).The morphology of BMSCs were observed and the expression of troponin T(cTnT) was detected by RT-PCR, Western blotting method and immunohistochemical staining. Results: The rat BMSCs were obtained by density gradient centrifugation combined with adherence culture method. The BMSCs highly expressed the characteristic surface marker CD44, CD29 and CD105 of mesenchymal stem cells (MSCs), and did not express the characteristic surface marker of hematopoietic stem cells CD34. Under the specific induction conditions, the BMSCs were differentiated into the osteoblasts and the aliphatic cells. In vitro, three culture methods could induce the BMSCs to express cTnT and differentiate into the cardiomyoid cells. In 5-aza group, the cell growth status was poor, and the cells in the other two groups had better growth status. The positive expression rate of cTnT was the highest in DCM model rat serum +5-aza group. Conclusion: The effect of DCM model rat serum combined with 5-aza to induce the BMSCs to differentiation into the myocardial cells is the best.

Key words: bone marrow mesenchymal stem cells, cell differentiation, cardiomyocytes, 5-azacytidine, dilated cardiomyopathy