In vivo and in vitro activity of genistein in osteoporosis

Background : Osteoporosis is conventionally treated with synthetic estrogens. However, the serious side effects of hormone replacement therapy (HRT) hampers the clinical use of estrogens. Hence, alternatives for estrogens are being explored, one of which is the isoflavone, genistein. Many studies show that genistein may exert positive effects on bone. However, there are also studies which report no overall association between genistein intake and bone marrow density (BMD) and fracture rates. The effect of genistein on bone loss is still controversial.
Aims : In this study, we evaluated both in vivo and in vitro pharmacological effects of genistein in osteoporosis.
Materials and Methods : MTT and ALP activity assays were performed to evaluate genistein′s in vitro activity on MC3T3-E1 cells. The OVX rat model was used to test genistein′s in vivo effects by determination of BMD and bone calcium and phosphorus content after treatment for 12 weeks.
Results and Conclusions : The data showed that 10^-6 M genistein both increased the number of MC3T3-E1 cells and elevated ALP activity significantly. In vivo, 9 or 18 mg/kg doses of genistein were found to prevent osteoporosis after 12 weeks treatment. Thus, our results indicated that genistein may be an alternative for HRT in prevention of postmenopausal osteoporosis.