Abstract: Abstract Objective:To study the functional roles of 1,25 (OH) 2D3 inducing osteogenic differentiation of the dental papilla stem cells.Methods:The dental papilla stem cells were isolated and cultured in medium supplemented with different concentrations of 1,25 (OH) 2D3. MTT assay was used to detect cell growth, and flow cytometry to detect cell cycle. Western blot was used to detect protein expression levels of receptor activator of nuclear factor-k B ligand (RANKL), osteoprotegerin (OPG) and vitamin D receptor (VDR). After siRNA silencing VDR expression, RANKL and OPG protein level were detected. Results:MTT and flow cytometry results showed that 1,25 (OH) 2D3 have no obvious effect on dental papilla stem cell proliferation. Western blot results showed that RANKL, OPG and VDR protein expression level were in a dose correlation with 1,25 (OH) 2D3 concentration. When VDR expression was silenced by siRNA, the protein expression levels of RANKL and OPG were decreased as vary degrees. Conclusion:1,25 (OH) 2D3 affects the osteoblast differentiation process of the dental papilla stem cell by adjusting the VDR expression.

Key words: Dental papilla stem cells, 25(OH)2D3, OPG, Vitamin D receptor