Effect Of 5-azacytidine And Dexamethasone On Differentiation Of Rat Bone Marrow Mesenchymal Stem Cells

Objective: The aim of this study was to investigate the effect of 5-azacytidine and dexamethasone on osteogenic differentiation of rat mesenchymal stem cells, in vitro.Methods: MSCs were isolated from SD rat bone marrow using different adherent time method. The presence of cell surface markers CD90, CD34 and CD45 on the MSCs was analyzed by flow cytometry. Cells were cultured in medium containing dexamethasone and 5-azacytidine in various concentrations. Cell proliferation was detected by CCK8 assay. The cells from passage 3 were divided into three groups: control, dexamethasone and 5-azacytidine+dexamethasone. The dexamethasone group were treated with 10-5M dexamethasone for 72 hours while the latter were treated with 10-5M dexamethasone and 10μM 5-azacytidine. After that, all groups were induced to osteogenic differentiation. Western blot and real time RT-PCR were performed to detect the expression of the Runx2 and PPARγ gene after 2 weeks osteoinductive differentiation.Results: On average, 99.84% of the cells stained positive for CD90. Meanwhile, 99.50% and 97.60% were negative for CD34 and CD45. Cells treated with 10μM 5-azacytidine were highly proliferative. After drug intervention and osteogenic differentiation, the expression of Runx2 in dexamethasone group decreased and PPARγ increased. The situation in 5-azacytidine group was contrary.Conlusion :Osteogenic differentiation of MSCs treated with dexamethasone was decreased and adipogenic differentiation was decreased. Nevertheless, the effect of 5-azacytidine is antagonistic to that of dexamethasone.