The real mechanism of bone loss leading to osteopenia or osteoporosis in postmenopausal women is yet to be studied further, but both increased bone destruction and/or decreased bone formation, in other words, either increased activity of
osteoclasts or
decreased activity of osteoblasts, or both must be responsible. Various kinds of substances administered in vitro have shown activation or suppression in differentiation of osteoblasts. Recently,phytoestrogen, especially isoflavone derived from
soy, has
been under attention by various authors.
Human osteoblasts(RCB0454)supplied by Riken Cell Bank of Tsukuba, Japan were grown in DMEM media with 10% fetal bovine serum. The cells were treated with isoflavone 10㎕ and 50㎕, for 2 and 4 days respectively, and then, alkaline phosphotase
activities
were analyzed by means of Mouse Monoclonal Antibody Reagent(Zymed, U.S.A.).
Followings are brief summary of this study.
1.The osteoblasts after treatment with isoflavone 10㎕ for 2 days had increased to 80×104/㎖ of cells, 46.5 percent of that were stained indicating alkaline phosphatase activities. Those after treatment for 4 days had increased to
220×104/㎖ of cells and 52.9% were alkaline phosphatase positive.
2. Osteoblastic cells treated with 10 ㎕ of isoflavone increased to 200×104/㎖ and 56.9 percent of activity after 2 days while those went up to 280×104/㎖ and 71.9 percent after 4 days.
3. Osteoblastic growth as well as its alkaline phosphatase activity were positively correlated with dosage and duration of its treatment with isoflavone.
4. Alkaline phosphatase mostly were found in the cytoplasm on 2nd day but on the 4th day, they were mainly present extracellularly and in their periphery of the osteoblast.
In conclusion, this study showed that isoflavone, one of the phytoestrogens, may stimulates matrix development and induces the primary step of mineralization in human osteoblast(RCB0454) cell line to ultimately stimulate to form new bones as it
provokes
increased alkaline phosphotase activities of the cells.
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