ABSTRACT
BACKGROUND:Bone marrow mesenchymal stem cells (BMSCs) have been induced to differentiate into cardiomyocyte-like cells in vitro.OBJECTIVE:To explore the association between GATA-4, Nkx-2.5 and α-myosin heavy chain (α-MHC) expression and cell morphological changes and structure formation in the process of BMSCs differentiation into cardiomyocyte-like cells.METHODS:By using myocardial lysate, BMSCs were induced to differentiate into cardiomyocytes.Immunocytochemistry staining was used to detect cardiac troponin T (cTnT) and connexin43, for the identification of cardiomyocytes. In the process of directional differentiation, RT-PCR was used to detect the expression of GATA-4,Nkx2.5 and α-MHC.RESULTS AND CONCLUSION:During the directional differentiation of BMSCs, the cells were changed from long fusiform to short rod, forming protrusions that were interconnected to form mesh-like, bamboo-like or myotube-like structure. When the cells were interconnected like a bamboo, cTNT and connexin43 positive cells were visible, and then the number of positive cells increased with the presence of myotube-like structure. RT-PCR results showed that during the induced directional differentiation of BMSCs, GATA-4, Nkx2.5 and α-MHC mRNA levels increased continuously. When interconnected cells formed a mesh-like structure, GATA-4 expression reached the peak and then kept a high level. When adjacent cells were fused into a myotube-like structure, α-MHC reached the peak. Additionally, the expression of Nkx2.5presented a time-dependent increase trend. Overall, during the induced differentiation of BMSCs into cardiomyocyte-like cells, the expression of cardiomyocyte specific genes, characterized by temporality and spatiality, is related to the changes of cell morphology and special structure formation.