A cell-based model of bone remodeling for identifying activity of icarrin in the treatment of osteoporosis.

The activity of icarrin (a flavonoid from Herba epimedii) was investigated in the regulation of bone remodeling, a process coupled by osteoblast-mediated bone forming and osteoclast-mediated bone resorption. By directly co-culturing mouse bone marrow stromal cells and mouse preosteoclastic RAW264.7, and transwell co-culturing rat ovarian follicular granulosa cells (FGC), a 30 % increase in alkaline phosphatase (ALP) activity and 25 % increase in estradiol level occurred. Compared with the antiresorptive drug, alendronate, and an anabolic drug, PTH1-34, icarrin possessed all of the positive effects on the co-culture by increasing ALP activity, estradiol production and decreasing tartrate-resistant acid phosphatase activity. A similar action of icarrin occurred on co-culture of mesenchymal stem cells, mouse peripheral blood mononuclear cells, and FGC. Overall, by using a co-cultured cell-based in vitro screening assay, icarrin is suggested as a new class of dual-action therapeutic agent for osteoporosis.