The expression of TGF-βmRNA and its biological function in rat osteoblasts with exposure to raloxifene

Objective:To investigate the effects of raloxifene and estradiol on the proliferation,differentiation and the expression of transforming growth factor-β(TGF-β)of osteoblasts in vitro.Methods:Different doses of raloxifene and estradiol were added into the medium of the second generation osteoblasts obtained from the skull of newborn SD rats.The following parameters including cell proliferation,activity of alkaline phosphatase(ALP),the levels of type Ⅰ collagen(Col-I)mRNA and TGF-β1 mRNA in different groups were measured and analyzed.Results:Raloxifene and 17-βestradiol(17-β E2)showed no significant effect on stimulating the proliferation of osteoblasts(P>0.05 vs the control).However,raloxifene could significantly improve ALP activity and Col-I mRNA expression in high consistency group(P<0.01)in dose-dependent manner.Raloxifene group in 10-8 mol/L increased the expression of TGF-β1 mRNA(vs the control,P<0.05).Estradiol significantly increased ALP activity,Col-I mRNA expression and TGF-β1 mRNA expression(P<0.05 or P<0.01 vs the control).Conclusions:Both of raloxifene and estradiol could stimulate differentiation of osteoblasts and expression of bone matrix,but showed no effect on proliferation of cultured osteoblasts.The expressions of TGF-β1 mRNA were different,which might imply their different mechanisms by means of estrogen receptor.

Objective： To investigate the effects of raloxifene and estradiol on the proliferation, differentiation and the expression of transforming growth factor-β（TGF-β） of osteoblasts in vitro. Methods： Different doses of raloxifene and estradiol were added into the medium of the second generation osteoblasts obtained from the skull of newborn SD rats. The following parameters including cell proliferation, activity of alkaline phosphatase（ALP）, the levels of type I collagen（Col-I） mRNA and TGF-β1 mRNA in different groups were measured and analyzed. Results： Raloxifene and 17-βestradiol（17-β E2） showed no significant effect on stimulating the proliferation of osteoblasts （P〉0.05 vs the control）. However, raloxifene could significantly improve ALP activity and Col-I mRNA expression in high consistency group （P〈0.01） in dose-dependent manner. Raloxifene group in 10^-8 mol/L increased the expression of TGF-β1 mRNA （vs the control, P〈0.05）. Estradiol significantly increased ALP activity, Col-I mRNA expression and TGF-β1 mRNA expression （P〈0. 05 or P〈0.01 vs the control）. Conclusions： Both of raloxifene and estradiol could stimulate differentiation of osteoblasts and expression of bone matrix, but showed no effect on proliferation of cultured osteoblasts. The expressions of TGF-β1 mRNA were different, which might imply their different mechanisms by means of estrogen receptor.