Abstract: Objective The study shows that puerarin regulates pathway of metabolism in osteoblasts and provides the theoretical foundation for treating methods of postmenopausal osteoporosis.Methods Culture of primary calvarial osteoblasts in rats were digested,and used in experiments.Then,the cells were treated with different concentrations of puerarin(5,10,25,50, 100 μmol/L)in different groups,respectively.The methylation status of CpG islands in estrogen receptor α(ERα)gene promoter region of genome DNA was analyzed by nested-methylation-specific PCR;ER-α gene mRNA expression was examined by semiquantitative reverse transcription PCR analysis.The proliferation and viability of osteoblasts were assayed by MTT assay using the spectrophotometric method.Furthermore,the differentiation of osteoblast-like cells by p-nitrophenyl phosphate were identified.Results The cultured osteoblasts treated by puerarin with different concentrations reduced in de novo methylation in promoter region of ERαgene with a concentration-treating manner,and a dose-dependent raising effect on osteoblasts proliferation and differentiation (P < 0.01 ).Meanwhile,ER-α gene mRNA expressions in osteoblasts treated by puerarin with different concentrations became stronger and stronger,until in the 25 μmol/L treating group,their expressions were the stongest(P < 0.01 ).Conclusion Puerarin reduces DNA methylation in promoter region of ERα in osteoblasts and enhences ERαgene mRNA expressions in osteoblasts.Above results possible influence its proliferation and osteoblastic differentiation.

Key words: osteoblasts, puerarin, dna methylation, estrogen receptorα