Abstract: Objective To investigate the effects of Rap1b on the early osteogenic differentiation of mouse preosteoblasts(Mc3T3-E1). Methods Mc3T3-E1 osteoblast differentiation was induced by osteogenic induction. The relative expression of mRNA Rap1b was detected by real-time quantitative PCR, at 0, 3 and 7 d respectively. At the same time, Rap1b-mus-462 and Rap1b-mus-703 were transfected to the experimental group cells respectively, and stained by ALP at 4 d. Then the mRNA relative expression of Rap1b was determined, and the mRNA expressions of ALP, Runx2 and Osterix at 0, 3, 7 d were also measured. And the effect of siRNA transfection on the migration of Mc3T3-E1 cells was observed by scratch test. Results The expression of Rap1b increased with the induction time in the early stage of osteogenic induction. The expression of Rap1b decreased after siRNA transfection, and the expression of Osterix, Runx2 and ALP decreased. The migration ability of Mc3T3-E1 cells decreased. Conclusion Rap1b can promote the osteogenic differentiation of Mc3T3-E1 cells and cell migration in the early stage.

Key words: Rap1b, rat osteoblast, mRNA relative expression, RT-q PCR