Effects of low doses of estrone on the proliferation, differentiation and mineralization of osteoprecursor cells

The purpose of this study was to evaluate the effects of low doses of estrone on the proliferation, differentiation and mineralization of osteoprecursor cells. The effect on cell viability was determined using a 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay, whereas differentiation and mineralization were examined using an alkaline phosphatase activity test and alizarin red S staining, respectively. The protein expression of estrogen receptor-α (ER-α), estrogen receptor-β (ER-β) and osteopontin (OPN) is assosciated with bone formation. Cell cultures grown in the presence of estrone at concentrations of 0.1 and 1 nM demonstrated an increase in relative values in the MTT assay and cells grown in the presence of estrone at the 10 nM concentration demonstrated an increase in mineralization. The results of the western blot analysis indicated that the addition of estrone upregulated ER-α and ER-β expression, but downregulated the expression of OPN. Based on these findings, it was hypothesized that a low dose of estrone produces positive effects on the mineralization of osteoprecursor cells. Moreover, these results also suggested that higher doses of estrone may be required to significantly enhance the differentiation and mineralization.