Abstract:

BACKGROUND: Studies addressing the induced effect of different-concentration 5-azacytidine on the in vitro differentiation of human umbilical cord mesenchymal stem cells (hUC-MSCs) into cardiomyocytes are fewer.
OBJECTIVE: To select a suitable concentration of 5-azacytidine to induce differentiatiown of hUC-MSCs into cardiomyocytes in vitro.
METHODS: Second passage hUC-MSCs were cultured in culture medium containing different -concentration 5-azacytidine (2.5, 5, 10, 20, 40, 80 μmol/L, respectively). After incubating for 24 hours, the medium was changed to complete medium without 5-azacytidine. Thereafter, the cells were cultivated for 4 weeks. Two weeks after the cells were treated with 5-azacytidine, cardiac troponin Ⅰ was assayed by immunohistochemical methods and the ratio of positive cells for cardiac troponin Ⅰ was counted.
RESULTS AND CONCLUSION: Seven days after hUC-MSCs were treated with 5-azacytidine, the cellular morphology began to change. The cells arranged closely and in parallel. The cellular morphology of 40 and 80 μmol/L groups changed obviously. At 4 weeks, the refraction and activity of cultured cells declined in the 40 and 80 μmol/L groups, and some of the cells died. At 2 weeks, cardiac troponin Ⅰ was positive for hUC-MSCs in 5, 10, 20, 40 and 80 μmol/L groups and negative in 2.5 μmol/L and control groups. The ratio of positive cells for cardiac troponin Ⅰ in 10, 20, 40 and 80 μmol/L groups was significantly higher than that of
5 μmol/L group (P < 0.05). l0 μmol/L 5-azacytidine is the optimal concentration for hUC-MSCs differentiation into cardiomyoctyes.