ABSTRACT
Objective: To investigate the effect of all trans retinoid acid (ATRA) on bone cell proliferation and differentiation. Methods: Newborn rat calvarial osteoblastic cells were isolated and the metabolism of the osteoblastic cells were determined by MTT, Goldens method and immunocytohistologic method. Results: 10 -5 , 10 -6 , 10 -7 , 10 -8 , 10 -9 mol/L ATRA could increase osteoblastic cells proliferation after 72 h culture; 10 -5 , 10 -6 , 10 -7 mol/L ATRA could increase ALP activity. The expression of cyclin D 1 was decreased. Conclusion: ATRA stimulates the proliferation and differentiation of rat calvarial osteoblastic cells in vitro. Cell cycle relative proteins may play an important role in control of cell proliferation and differentiation induced by retinoic acid and derivatives.