Effects Of Different Myocardial Lysates On BMSCs Directional Differentiation

Objective: To improve the identification of tissue like structure of myocardium,explore the effect of different myocardial tissue lysates on the directional differentiation of bone marrow mesenchymal stem cells(BMSCs),and explore the construction of tissue engineered myocardium.Methods: The differentiation of BMSCs into the tissue like structure of myocardial tissue was taken as the experimental control,and the BMSCs directed differentiation was induced by the lysate of the atrial muscle tissue and the lysate of the ventricular muscle tissue.The morphological changes of cells during induction were observed under inverted phase contrast microscope.The ultrastructure of the cells was observed by transmission electron microscopy.Immunofluorescence cytochemical staining was applied to detect any group of cell-related proteins(α-actin and c TnI).The expression of ANP,HCN4 and MLC-2v genes in each group of cells was detected by qRT-PCR.Immunofluorescence histochemical staining was used to detect correlative proteins(Collagen I,collagen III,VEGF,vWF,CD31 and cTnI)in myocardial tissue,The aim is to explore the structure of myocardial tissue.Results:(1)the whole heart tissue lysate could induce BMSC to differentiate into a more complex tissue like structure.Immunofluorescence staining showed that there were cTn I,VEGF,vWF and CD31 positive cells in the structure,and collagen I and collagen III were detected between the cells,and collagen I was the main type.(2)the whole heart tissue lysate can induce BMSCs to differentiate into a complex myocardial tissue like structure.Under the same condition,the myocardial tissue like structure can not be induced by the lysate of the atrial tissue and the lysate of the ventricular muscle tissue.(3)a large number of secretory granules were observed during the induction of differentiation in the atrial myocyte lysate group.(4)high expression of ANP and HCN4 could be detected in the induction group of atrial myocyte lysate,and MLC-2v was not expressed.High expression of MLC-2v was detected in the ventricular myocyte lysate induced group,and ANP and HCN4 were not expressed.Conclusion: The cardiac tissue like structure induced by lysate is not only in the cardiac muscle like cells,but also in the early differentiated endothelia cells.The connective tissue encapsulates the myocardial like cells to form a fascicular structure and contains a large number of collagen fibrils mainly composed of type I collagen.Atrial myocytes lysate can induce BMSCs to differentiate into atrial myocytes,atrial natriuretic peptide ANP is highly expressed,and sinus node cell marker HCN4 is highly expressed.The lysate of ventricular myocytes can induce BMSCs to differentiate into ventricular myocytes.The specific myosin light chain MLC-2v of ventricular myocytes is highly expressed.Functional activities play an important role in promoting the occurrence and development of morphology and structure,which is a necessary condition for the maturation of morphology and structure.