FO upregulates the specific marker gene expression responsible for osteoblast differentiation in MC3T3-E1 cells. (A) MC3T3-E1 cells were treated with 100 µg/mL of FO and 100 nM DEX for 7 days. The expression of mRUNX2, mALP, mCol1a1, mOCN, mOSX, mBMP2, and mBMP4 was measured on day 1 (D1), day 3 (D3), day 5 (D5), and day 7 (D7). (B) The cells were also treated with 50 µg/mL and 100 µg/mL of FO or 100 nM DEX for 5 days. The expression of mRUNX2, mALP, mCol1a1, mOCN, mOSX, mBMP2, and mBMP4, was observed. mGAPDH was used as a house keeping gene. Significant differences among the groups were determined using the one-way ANOVA followed by Bonferroni correction. All data are presented as mean ± SEM (*** p < 0.001, ** p < 0.01, and * p < 0.05 versus untreated group). FO; fermented extract of C. gigas and DEX; dexamethasone.