Abstract: AIM: To study the mechanisms of the human mesenchymal stem cells differentiating into cardiomyocytes induced by 5-azacyditine. METHODS: The mesenchymal stem cells were separated and purified in vitro, then given 5-azacyditine at three concentrations and at different incubation time.The vitality of the mesenchymal stem cells were assayed with the methylthiazolyl tetrazolium method in order to estimate the best concentration and incubation time.The induced cells were checked by transmission electron microscope, immunohistochemistry and RT-PCR. RESULTS: The induced cells changed their morphology to that of cardiomyocyte type. Transmission electron microscope revealed striation.Some cells were positive expression of α-sarcomeric actin, troponin-T and cardiac specific transcript factors GATA-4, Nkx2.5. CONCLUSION: The huaman bone marrow-derived mesenchymal stem cells possesses the multiple differentiation potential and can be induced to cardiomyocytes by 5-azacyditine in vitro.

Key words: human mesenchymal stem cells, differentiation, cardiomyocyte, in vitro