Figure 7.

Effect of disruption of the PGHS-2 gene on TRAP⁺ MNC formation and GM-CSF mRNA expression in spleen cells cultured without osteoblasts. Cultures were treated with M-CSF (10 ng/mL) and RANKL (10 ng/mL), and then with either vehicle (Control; white bars) or PGE₂ (1 μM; black bars). (a) TRAP⁺ MNC formed after 6 days of culture. Data are expressed as mean ± SE for quadruplicate cultures. (No TRAP⁺ MNC were formed in cultures without RANKL and M-CSF; data not shown.) ^ASignificant difference from vehicle treatment; P < 0.01. ^BSignificant effect of PGHS-2^–/– genotype; P < 0.01. (b) RT-PCR analysis of GM-CSF mRNA levels at the end of the culture period for the experiment shown in a. Ethidium bromide–stained RT-PCR products are shown in the top panel. The optical density ratios of GM-CSF mRNA to GAPDH mRNA are shown in the bottom panel.