FIG. 1.

BMP2 increases RANKL mRNA production in chondrocytes. ATDC5 cells were treated with BMP2 (100 ng/ml) for various times. The expression of (A) RANKL, (B) OPG, and β-actin mRNA was determined by real-time RT-PCR. The relative expression levels of RANKL and OPG were normalized by β-actin in the same samples. The fold induction of RANKL mRNA was calculated as follows: relative RANKL level in a given time/relative RANKL level in day 0. The RANKL/OPG ratio in each time-point was calculated by dividing relative RANKL level with the relative OPG level in the same sample (C). The cells treated with BMP2 at the various times indicated came from the same pool of cells as the control cultures. This is indicated by the broken line from 0 to 2 h. ^a p < 0.05 vs. control value at same time-point.