Abstract:

BACKGROUND: Intramyocardial transplantation of autologous umbilical cord-derived mesenchymal stem cells for repair of myocardial tissue damage is paid increasing attention in the cardiovascular field.  
OBJECTIVE: Human umbilical cord mesenchymal stem cells were isolated and cultured. Passage 2 human umbilical cord mesenchymal stem cells were treated with various concentratins of 5-azacytidine (2.5, 5, 10, 20, 40, 80 μmol/L) for 24 hours . After removal of 5-azacytidine, cells were cultured for another 4 weeks.
RESULTS AND CONCLUSION: Before 5-azacytidine treatment, filament-like structures or particles were not observed in the cells, but the amount of cytoplasm was less and uniform, nuclear/cytoplasm ratio was high, cells exhibited typical fusiform appearance and grew in a swirl-like manner, and nucleolus was obvious. After treatment with 5-azacytidine for 24 hours, some cells died in each group, and typical fusiform appearance turned into stick-like or column-like appearance, especially in the 40 and 80 μmol/L 5-azacytidine groups. Reverse transcription-PCR results showed that atrial natriuretic peptide and α-skeletal actin gene expression levels were detected on human umbilical cord mesenchymal stem cells after treatment with 2.5 or 40 μmol/L 5-azacytidine for 4 weeks or with 5, 10, 20 μmol/L 5-azacytidine for 1, 2, 3 and 4 weeks. These findings suggest that 5-azacytidine-induced human umbilical cord mesenchymal stem cells express the specific gene of myocardiocytes.

Key words: stem cells, umbilical cord/umbilical cord blood stem cells, umbilical cord mesenchymal stem cells, stem cell culture and differentiation, cardiomyocytes, gene expression, 5-azacytidine, reverse transcription-PCR, stem cell photographs-containing paper