Figure 8: Relative mRNA levels of cytokines and growth factors (IGF-I, IL-6, OPG, RANKL) after 2, 7, and 14 days of culture. Ratios of target genes relative to housekeeping genes (GAPDH, B-actin) were expressed relative to the mean value of the TCP group at day 2, which was set as 100%. Values represent the mean ± SEM. Differences between groups () were assessed by Student’s -test. # versus TiOblast; * versus TCP.