Daucosterol Protects MC3T3-E1 Cells against H2O2-induced Injury via Regulating IGF-1 Pathway

Daucosterol has been considered as a promising anti-osteoporosis drug due to its capacity of facilitating osteoblast-like cell proliferation. However, its mechanism remains obscure. In this thesis, the protective effects of daucosterol on MC3T3-E1 cells subjected to H2O2 were evaluated by cell viability assay with CCK-8, by cell apoptosis analysis with Annexin V-FITC/PI double staining and flow cytometry, and by caspase-3 activity assay with colorimetry. The mechanism of protection was also studied by IGF-1 protein quantitation with ELISA and picropodophyllin (PPP, IGF-1 receptor chemical inhibitor) inhibition test with CCK-8. Results indicated that daucosterol dose groups of 10,20, and 40 mu M all significantly increased the cell viability, respectively. And 10 mu M was the optimal dose of them. Daucosterol in the dose of 10 mu M reduced caspase-3 activity and apoptotic rate. It was also found that daucosterol (10 mu M) increased the expression level of IGF-1 protein, and the protection of daucosterol was inhibited in the presence of PPP (200 mu M). These results thus suggested that daucosterol might protect MC3T3-E1 cells against H2O2-induced injury via regulating IGF-1 pathway which played an essential role in keeping normal bone metabolism.