The Effects of BMP-2 and Dexamethasone on Different Kinds of Osteoblasts

Objective:To observe the effects of different concentrations of bone morphogenetic protein_2(BMP_2)and dexamethasone(DEX)on three kinds of osteoblasts and compare their characters.Methods:Three kinds of osteoblasts were cultured in vitro which included human adult osteoblasts isolated from trabecular bone with trypsin digestion, osteoblast_like cell line,and osteoblasts induced by bone marrow monocytes by DEX for 7 days.Osteoblasts were treated with different concentrations of BMP_2 and DEX.Morphological changes were investigated.Proliferations were measured with methylthiazol tetrazlium(MTT)method,and alkaline activity(ALP)in the lysate was determined.Results:For the normal adult osteoblasts,BMP_2 had no significant effects on the proliferation and differentiation of the fourth and eighth passage cells after 48 and 72 h.DEX could improve the fourth cell's growth,and significantly increased the expression of ALP after 48 and 72 h.DEX had a significant effect under the condition of 10-8 mol/L.For osteoblast_like cell line,BMP_2 had no significant effect on its proliferation and the effect of proliferation was significant with the use of DEX after 48,72 h.BMP_2 and DEX could enhance ALP activity after 72 h.For the bone marrow_derived osteoblasts,BMP_2 and DEX significantly increased the proliferation and differentiation after 48 h and 72 h.Conclusion: The effects of BMP-2 and DEX on different osteoblasts varied because of the different sources and exposure duration.