Effects of media condition and mixed co-culture on gene expression. Cartilage-specific gene expression of (A) Agg, (B) COL2, (C) COL1, and (D) COLX after 21 days in mixed co-culture at various cell ratios (OAC:ADSC: 50C:50A, 25C:75A, and 10C:90A) with or without TGF-β supplementation. Fold changes relative to OAC control without TGF-β supplementation at day 21. Data presented as mean±(n=3 samples/group). * and ^ represent significance versus OAC and ADSC control under the same media condition, respectively; *p<0.05, **p<0.01, and ***p<0.001.