A Comparative Study On The Differentiation Ability Of Mouse Bone Marrow Derived Progenitor Cells And Reparative Abilities In Myocardial Infarction

Objective: To study the differentiation ability of mouse bone marrow derived Sca-1~+/CD31~+ subsets and Sca-1~+/CD31~- subsets into cardiac muscle cells and vascular endothelial cells, and to study their difference in myocardial infarction reparative ability.Methods: Bone marrow mononuclear cells(Bone Mononuclear Cells, BMNCs) were isolated from the bone marrow of mice, and were divided into Sca-1~+/CD31~+ subgroup and Sca-1~+/CD31~- subgroup by flow cytometry. Cells were cultured in 5% FBS/EBM-2 with the addition of vascular endothelial cell growth factor(VEGF), fibroblast growth factor(hFGF-B), epidermal growth factor(EGF), insulin-like growth factor(R3-IGF-1) and ascorbic acid(Ascorbi cacid) for 14 days, and then endothelial cell markers vWF and vecadherin and CD31 expressionby were detected by immunofluorescence staining and RT-PCR. In order to compare the differences in the differentiation ability of bone marrow derived progenitor cells into vascular endothelial cells. Cells were also cultured in culture medium supplied with antagonists of Wnt agent DKK-1 and dimethyl sulfoxide(DMSO), bone morphogenetic occurred protein(BMP), fibroblast growth factor(FGF-4 and FGF-8), and 5-azacytidine(the first to the third day for 14 days, and then myocardial cells markers Nkx2.5 and GATA-4 and cTnT expression were detected by immunofluorescence staining and RT-PCR. To compare the differences in the ability of differentiation of mouse bone marrow derived from different progenitor cells into cardiac muscle. The model of myocardial infarction was established by ligation of the anterior descending branch of the coronary artery(LAD) in mice under open chest. The Sca-1~+/CD31~+ subsets, Sca-1~+/CD31~-subsets and mononuclear cells(MNCs) were injected into the peri-infarcted myocardium and echocardiography were detected 7 days and 28 days later.And then heart tissue were collected at 28 days to detect cell survival, angiogenesis, and the degree of myocardial fibrosis.Results: In vascular endothelial cells- inducing medium,Sca-1~+/CD31~+ subsets are more easy to differentiate into vascular endothelial cells, and Sca-1~+/CD31~- subsets proliferation slowly, the endothelial cell marker expression is very low; in myocardial cells inducing culture medium, Sca-1~+/CD31~- subsets are more easy to differentiate into myocardial cells and cTnT positive expression rate is higher than that of Sca-1~+/CD31~+ subsets and MNCs as the immunofluorescence staining and RT-PCR results show. In vivo injection of bone marrow progenitor cell subsets, cardiac color Doppler ultrasound: 7 days and 28 days Sca-1~+/CD31~+ subsets of cardiac function improved significantly better than the Sca-1~+/CD31~- subgroup and MNCs. And the number of Sca-1~+/CD31~+ subsets in the peripheral area of myocardial infarction was significantly increased, the capillary density in the peri-inforrct zone was significantly increased, and the degree of myocardial fibrosis was significantly decreased.Conclusion: Bone marrow derived Sca-1~+/CD31~+ subsets were more easily differentiated into vascular endothelial cells in vitro. The improvement of cardiac function after myocardial infarction in vivo was significantly better than that of Sca-1~+/CD31~-subgroup and MNCs.