Effects of Ipriflavone on Bone Regeneration in Rats

Kim, H J; Kim, O J; Kim, D Y; Jung, J Y; Kim, M S; Kim, W J; Choi, H R; Lee, E J; Kim, S H

Abstract

Ipriflavone (isopropoxyisoflavone) is a synthetic derivative from soy isoflavone daidzein. There are compelling evidences that it has an inhibitory effect on bone resorption in vitro and in vivo. It is not clarified however, whether its anti-osteopenic effect derives from inhibition of bone resorption or stimulation of bone formation. The present study aims to elucidate effects of ipriflavone on osteoblasts gene expression and possible clinical application on bone regeneration. Three days' continuous treatment of ipriflavone had no effects on MC3T3-E1 osteoblastic cell proliferation at 10(-8) M to 10(-4) M concentration from MTS assay. Gene expression of collagen alpha1(I), which is a bone formation marker, was markedly increased by ipriflavone treatment at 10(-9) M to 10(-5) M, but decreased to control level at 10(-6) M concentration. Alkaline phosphatase, another bone formation marker, was also increased at its gene expression at 10(-5) M concentration. Artificial bone defects on the rat calvaria were healed with hematoma and much more profuse and delicate fibrin at 3 days treatment of ipriflavone. Primary spongy bone was noted in bony defect center after 7 days treatment of ipriflavone, in contrast to woven bone in control group. Newly formed trabecular bone could be attained by the treatment after 14 days. These results suggested that ipriflavone can affect on osteoblasts at molecular level, and be clinically applied for local bone regeneration.