Figure 2. Gene expression at day 10 of the bone markers, RUNX2 (A), OSX (B), ALP (C), BSP (D), OPN (E), and OC (F) of cells from 1-month and 21-month rats grown on Ti discs. Data are presented as the mean±standard deviation (n=4). * indicates statistically significant differences between cells from 1-month and 21-month rats (p≤0.05).