Objective      To investigate the regulation and mechanism of selective estrogen receptor modulator (SERM) raloxifene on the growth and differentiation in MC3T3-E1 cells in vitro.       Methods      MC3T3-E1 cells cultured in vitro were treated with raloxifene (10

-7

mol/L) and estrogen receptor antagonist ICI-182780 (10

-7

mol/L)

respectively

and the MC3T3-E1 cells without treatment were set as control. The cell proliferation was observed by MTT assay

the activity of alkaline phosphatase (ALP) was measured by trace enzyme labeling method

and the expression of β-catenin

estrogen receptor (ER) α and ERβ were detected by qRT-PCR.       Results      As compared with those of the control group

the cell proliferation

ALP activity and mRNA expression of β-catenin

ERα and ERβ significantly increased in the raloxifene (10

-7

mol/L) group (P0.05) and significantly decreased in the ICI-182780 group (P0.05). The cell proliferation rate was highest （55.93±10.88）% at 24 h

and the ALP activity of increase was highest (30.881±5.614)% at 48 h.       Conclusion      Raloxifene can promote the proliferation and differentiation of MC3T3-E1 cells through up-regulating the mRNA expression of β-catenin

ERα and ERβ

while ICI-182780 can inhibit this process through down-regulating the mRNA expression of β-catenin

ERα and ERβ.