Enhancing effect of daidzein on the differentiation and mineralization in mouse osteoblast-like MC3T3-E1 cells

The effect of daidzein, an important isoflavone, on the differentiation and mineralization in MC3T3-E1 cells, a mouse calvaria osteoblast-like cell line, was investigated. The MTT assay, the alizarin red S and von Kossa staining, the measurement of calcium (Ca) and phosphorus (P) concentrations by inductively coupled plasma-atomic emission spectrometry and the nitrophenol liberation method were used to determine the cell proliferation, mineralization and intracellular alkaline phosphatase (ALP) activity, respectively. Daidzein enhanced the cell proliferation after the culture for 2 days and the effect reached maximum on day 6. ALP activity and cellular Ca and P contents were increased time- and dose-dependently when the cells were treated with daidzein in the presence of disodium beta-glycerophosphate and L-ascorbic acid. Differentiation of the cells to the mature osteoblasts was prompted under incubation in the presence of daidzein for 21 days, by the time the mineralized nodules formed. The calcium depositions of the cells by alizarin red S staining were increased significantly after the culture with daidzein as long as 28 days. It has been demonstrated that daidzein may be able to enhance the bone differentiation and mineralization and prompt the bone formation in the early growing stage and the late growing stage of osteoblasts.