Regulation of osteoclastic and osteoblastic differentiation marker expressions in osteoblast-like saos-2 cells by Eucommia ulmoides

Bone metabolism characterized by bone resorption by osteoclasts and bone formation by osteoblasts. Imbalances of osteoclast and osteoblast occurred bone diseases, such as osteoporosis. Eucommia ulmoide, which is a medicinal herb, has been used to treat various diseases. Recent studies showed that E. ulmoides has been studied to treat osteoporosis.The osteoblast-like Saos-2 cells were treated with E. ulmoides extract (0.1, 1 and 10 mu g/mL) for 24 h. Bone remodeling-related protein expressions and cell toxicity were examined to confirm the effects of E. ulmoides on regulation of osteoclastic and osteoblastic differentiation.The expression of receptor activator of nuclear factor-kappa B ligand (RANKL) was significantly decreased, while that of osteoprotegerin (OPG) was significantly increased by E. ulmoides treatment. In addition, runt-related transcription factor 2 (Runx2) and Osterix expressions were significantly increased by treatment with E. ulmoides. The cell viability was not changed in E. ulmoides-treated cells.These results demonstrate that E. ulmoides has promoting effects on bone formation as well as inhibitory effects on bone resorption with no toxicity in Saos-2 cells. Therefore, E. ulmoides may be used as an alternative treatment for osteoporosis.