[Differentiation of rabbit bone marrow mesenchymal stem cells into myogenic cells in vitro and expression of vascular endothelial growth factor gene after transfection].

ABSTRACT

OBJECTIVE: To induce the differentiation of rabbit bone marrow mesenchymal stem cells (MSCs) into myogenic cells in vitro, and to investigate the expression of vascular endothelial growth factor (VEGF) gene in AdTrackCMV-hVEGF165- transfected MSCs. METHODS: Twenty rabbits were divided equally into control group and experimental group, and MSCs were isolated and purified from their bone marrow by Percoll (1.073 g/ml) followed by cell culture in low-glucose DMEM supplemented with 10% fetal bovine serum. 5-azacytidine (5-Aza) was added into the cell culture of the experimental group on the third day. The expression of troponin I in MSCs was assayed by immunohistochemistry on the 28th day. AdTrackCMV- hVEGF165 eukaryotic expression vector was constructed and transfected into the MSCs, and subsequent VEGF expression was detected by Northern blotting and Western blotting while enzyme-linked immunosorbent assay (ILISA) was employed to examine the VEGF concentration in the supernatant of the culture medium. RESULTS: Following successful isolation and culture of the MSCs from rabbit bone marrow, 5-Aza-induced differentiation of the cells into myogenic cells was demonstrated by their positive staining for cardiac troponin I (cTnI). Northern blotting showed that the expression of VEGF 165 mRNA was much higher in the VEGF165 gene-transfected cells than in the control cells. Western blotting showed VEGF expression in the transfected cells. The concentration of VEGF in the supernatant mounted to the peak level 3-5 d after VEGF165 gene transfection (1,011-1,027 pg/ml) and decreased gradually thereafter, but still maintaining higher levels than those in the control group and pAdTrackCMV group (349 pg/ml vs 116 pg/ml and 125pg/ml, respectively, P<0.01). CONCLUSION: MSCs can be induced to differentiate into myogenic cells in vitro and express VEGF after VEGF gene transfection, and this success may provided a basis for combining MSC transplantation with gene therapy for regeneration of the damaged myocardial cells.