Figure 4.

MC3T3-E1 cells were seeded, cultured for 72 h (in the presence of FBS) to reach subconfluency (no Ki-exposure). The medium was exchanged (no FBS), and cells were exposed to 10-min Ki-energy once, and cells were cultured in the absence of FBS for another 48 h. Then, RT–PCR was performed. The open columns are without Ki-exposure and the filled columns are with Ki-exposure. The increases in mRNA expressions for RUnx2, a1(I) collagen, alkaline phosphatase and osteocalcin were all statistically significant as indicated by * symbols (P < 0.05; n = 4 for each).