Dynamic expression of Runx2 gene profile during osteogenesis in stem cells from human exfoliated deciduous teeth / 中国组织工程研究

ABSTRACT

BACKGROUND:Runx2 is considered to the main regulatory factor of osteogenic gene expression and be necessary for osteoblast differentiation, it plays an extremely important role in the osteoblast development, differentiation, regulation, bone calcification formation and bone repair. OBJECTIVE:To observe the biological properties of mesenchymal stem cells from human exfoliated deciduous teeth, explore the osteogenic differentiation potential of deciduous teeth stem cells, and observe the dynamic expression of Runx2 gene at varying time points. METHODS:The stem cells from human exfoliated deciduous teeth were isolated and cultured in vitro. The cellsurface antigen was detected with flow cytometry. The third passage cells were cultured in the adipogenic medium for 4 weeks, and oil red O staining was conducted to test lipid droplets formation. The third passage cells were cultured in the osteogenic medium for 21 days, and mineralized nodules were detected by alizarin red staining. Runx2 mRNA dynamic expression was detected with semi-quantitative RT-PCR at different time points. RESULTS AND CONCLUSION:The stem cells from human exfoliated deciduous teeth were obtained by enzyme digestion and limited dilution methods. Flow cytometry results showed that, CD146 and STRO-1 were expressed to varying degrees. Oil red O staining revealed salmon pink positive particles. Alizarin red staining showed positive expression. RT-PCR results showed that, Runx2 expression was found at day 0, up-regulated from day 0 to day 6, and subsequently dropped with an expression bottom at day 12, after that a second expression peak occurred at day 18, fol owed by a stably regulation. The stem cells from human exfoliated deciduous teeth can be isolated and cultured in vitro, express surface antigen of mesenchymal stem cells, and have the potentials of differentiating into adipocytes and ostetoblasts. Runx2 gene profiles are dynamical y expressed during osteoblastic differentiation. Runx2 express throughout every stage of osteoblastic differentiation. The expression is up-regulated during early and later stages, and down-regulated in metaphase.