Effect of combined use of daidzein and raloxifene on osteoblast-like cells

抄録

Osteoporosis is caused by a decrease in bone mass resulting from estrogen deficiency. We hypothesized that taking selective estrogen receptor modulator (SERM) with dietary intake of isoflavones could have a mutually potentiating effect in postmenopausal women with osteoporosis. The purpose of this study was to investigate the effect on osteoblasts of the combined use of daidzein (Dz), which is a phytoestrogen derived from soy isoflavone, and raloxifene (Ral), which acts on different antiresorptive agents. Osteoblastic KUSA-A1 cells were grown in culture medium with Dz and/or Ral. The differentiation and mineralization of osteoblasts were determined using alkaline phosphatase (ALP) activity and von Kossa staining. Production in culture supernatant of osteocalcin, receptor activator for nuclear factor κB ligand (RANKL), interleukin-6 (IL-6) and osteoprotegerin (OPG) was evaluated by enzyme-linked immuno sorbent assay (ELISA). The ALP activity was expressed significantly in the presence of Dz (10^-6M) and Ral (10^-7M) at 14 days. RANKL expression decreased significantly in the presence of Dz and Ral at 14 days. There were no significant differences in the production of IL-6 in the presence of the various conditioned media. These findings indicate that concomitant treatment of osteoporosis with daidzein and raloxifene may inhibit bone loss.