Figure 4: Temporal analysis of callus gene expression. Temporal changes in RUNX2, OPN, OSX, and PPARγ2 mRNA expression levels in callus samples after drill-hole surgery were determined by quantitative real-time PCR. Expression levels were normalized to that of GAPDH, and levels were calculated as fold-change values relative to that of the Ovx group. Data are reported as means ± SD, .