Figure 5. Osteoblastogenic induction selectively alters OPG and RANKL expression, while BMP2 sustains the osteoclastogenic phenotype in long-term culture.

(A) Freshly isolated stromal cells were cultured for 12 days in MEM-α alone, in osteogenic media, or in medium supplemented with SB415286 or BMP2. The ratio of OPG/RANKL mRNA levels are presented relative to the ratio obtained by culture in MEM-α. While BMP2 suppresses the ratio, SB415286 increases it and osteogenic conditions fail to alter the values. The results for BMP2 treatment differs from that of cells grown in osteogenic media. (B) GCT stromal cells were cultured in the presence or absence of rhBMP-2 in MEM-α media over 21 days. Normalized OPG/RANKL ratios are presented relative to the ratio in untreated, freshly-isolated cells.