| Objective Curculigoside (CCG) is reported to prevent bone loss in ovariectomized rats. However, the underlying molecular mechanisms are largely unknown. Therefore, we investigated the effects of CCG on the proliferation and differentiation of osteoblasts and discussed the related mechanisms. Methods Osteoblasts were incubated with dexamethasone (DEX) in the absence or presence of different concentrations of CCG for 24-72 h. Cell proliferation was evaluated with Cell Counting Kit-8 assay. Mitochondria membrane potential (MMP) and reactive oxygen species (ROS) were assessed with flow cytometry. We assessed expression of cytokines such as TNF-?, IL-1?, IL-6, COX-2, IGF-1and M-CSF with enzyme-linked immunosorbent assays. Relative protein expression of BMP-2, β-catenin, RANKL, OPG and RANK was measured using Western blotting. Results The proliferation of osteoblasts decreased significantly after treated with 1μM of dexamethasone (DEX), compared with untreated osteoblasts. The cytotoxic effect of DEX was reversed remarkably after pretreatment with 25-100 μg/mL of CCG. Pretreatment with 25-100 μg/mL of CCG increased MMP level and decreased ROS production in osteoblasts induced by DEX. In addition, DEX-induced inhibition of differentiation markers such as alkaline phosphatase (ALP), OPG, BMP-2, β-catenin, IGF-1 and M-CSF level, and promotion of differentiation markers such as RANKL and RANK was significantly reversed in the presence of CCG. CCG also reversed DEX-induced production of pro-inflammatory cytokines. Conclusion These results provide new insights into the osteoblast-protective mechanisms of CCG through inducing proliferation and differentiation and reducing the inflammatory responses, indicating that CCG may be developed as an agent for the prevention and treatment of osteoporosis. |