Figure 1. Expression levels of osteoblast-related genes by real-time polymerase chain-reaction and alkaline phosphatase activity in MC 3T3-E1 cells. Cells were cultured in differentiation medium with 1 mM Poly(P) or without 1 mM Poly(P) (Control) for 35 days. Relative mRNA levels of OPN (A), OCN (B), Col I(C), OPG (D), and ALP activity (E)—without treatment (open circles) and following treatment with 1 mM Poly(P) (closed circles)—are shown. Error bars represent the mean ± SD of three independent analyses.