Osteogenic potential of icariin compared with recombinant human bone morphogenetic protein 2 in vitro: a preliminary study

Icariin, the primary active ingredient of Herba Epimedii which has been used for decades to treat bone related maladies in China, has the ability to support bone regeneration. In this study, we investigated icariin's potential to stimulate osteogenesis using an in vitro studies to compare icariin's ability as a function of time and dose to induce osteoblastogenesis in MC3T3-E1 cells with that of recombinant human bone morphogenetic protein 2 (rhBMP2). The optimal concentration of icariin in stimulating the proliferation of MC3T3-E1 was 10-5 M. There is no significant difference between icariin and rhBMP2 relative to cell proliferation, alkaline phosphatase (ALP) activity, and osteocalcin (OCN) expression. Icariin had better ALP activity after a 7 day culture and OCN expression after 4 and 10 day cultures compared with rhBMP2. Moreover, icariin produced more mineralized nodules of a larger area than rhBMP2. However, compared with rhBMP2, icariin only showed a significantly higher ALP gene expression on day 4, a 3 fold BMP2 expression on day 7, and Col 1 expression on day 4. In conclusion, compared with rhBMP2, the results indicate that icariin could be a good option for bone regeneration clinically, since it is an inexpensive and safe drug with an excellent osteogenesis potential.