RESUMEN
[Objective]To explore the intervention effect of β-sitosterol,an effective monomer component of Eucommia ulmoides,on postmenopausal osteoporosis in mice and its potential mechanism.[Methods]Twenty-four female C57BL/6J mice of 12 weeks old were randomly divided into sham operation group,model group and β-sitosterol intervention group,with 8 mice in each group.The model of postmenopausal osteoporosis was established by bilateral ovariectomy.Mice in sham group and model group were given 0.9％sodium chloride solution and β-sitosterol intervention group was given β-sitosterol.Eight weeks after operation,all the mice were sacrificed and samples were collected.Micro-computed tomography(Micro-CT)was used to observe the protective effect of the β-sitosterol intervention on postmenopausal bone loss and trabecular bone breakage.Hematoxylin-eosin(HE)staining was used to analyze the bone histomorphology of the distal femur.The tartrate-resistant acid phosphatase(TRAP)staining and the alkaline phosphatase(ALP)staining were used to evaluate bone resorption and bone formation respectively.Then the expression level of β-catenin in each group was detected by immunohistochemistry.[Results]Micro-CT scanning showed that β-sitosterol could reduce bone loss and bone microstructure destruction in postmenopausal mice.HE staining also confirmed that β-sitosterol could effectively maintain the number and morphology of trabecular bone and inhibit abnormal fat accumulation caused by estrogen deficiency.TRAP staining also showed that β-sitosterol treatment did not affect osteoclast formation,while immunohistochemical results showed that β-sitosterol could significantly promote the expression of osteogenic marker ALP.Moreover,β-sitosterol can increase the expression of β-catenin in the distal femur to promote bone formation.[Conclusion]β-sitosterol treatment could enhance osteogenic differentiation and promote bone formation to relieve postmenopausal osteoporosis by upregulating β-catenin expression in vivo.