关键词: 5-氮杂胞苷, 心肌细胞, 超微结构

Abstract: Abstract:Objective To culture human mesenchymal stem cells (hMSCs) and study the ultrastructure of their myogenic differentiated cells in vitro,and provid the theoretical foundation for hMSCs differentiation into cardiomyocytes (CMs). Methods hMSCs were cultivated and expanded by adhereing peculiarity.The phenotypes of hMSCs were identified by fluorescent - activated cell sorter(FACS).With good growth characteristics and high purity,the fifth passage hMSCs were treated for 24 h with 5-azacytidine (5-Aza,10 μmol•L^-1) to induce cellular differentiation.The expression of desmin,identified by immunohistochemistry,was used to identify cardiac muscle differentiation.The morphology and ultrastructure of treated hMSCs were observed by inverted microscope and transmission electron microscope. Results The cultured cells did not express CD34 and expressed a high level of CD44 by FACS,which indicated that they were hMSCs.The morphology of hMSCs treated with 5-Aza under inverted microscope changed from fusiform to polygon or astrocyte,and the induced hMSCs demonstrated positive staining for desmin.With transmission electron microscope,the ultrastructure of the treated hMSCs was visible.The magnitude of cells was not identical,the surface of some cells had abundance of microvilli.Intracytoplasm had rich organelles,mitochondrium and rough endoplasmic reticulum.In the part of cells,the sedimentary hepatin granules were observed and only the myeloid body could be seen in small part of cells.Myofilaments were found in cytoplasm,and between cells there were cell junctions. Conclusion After treated with 5-Aza,hMSCs cultivated and expanded in vitro could differentiate into cardiomyocyte-like cells with CMs’ ultrastructure characteristics.

Key words: 5-azacytidine, myocardial cells, ultrastructure