Figure 5.
Loss of Runx1 function accelerated osteoclastogenesis in vitro. Bone marrow cells were isolated from the long bones of either 8-week-old Runx1F/F or CD11b-Cre;Runx1F/F mice. Cells were seeded in 96-well plates at a density of 5000 cells per well and cultured in the presence of 30 ng/mL M-CSF and 30 ng/mL RANKL to induce osteoclast formation. A, Image of multinuclear osteoclasts stained with TRAP at culture day 5 (magnification, ×4). B, TRAP+ multinuclear osteoclasts with greater than 3 nuclei were counted as osteoclasts in bone marrow cells from Runx1F/F and CD11b-Cre;Runx1F/F mice that were cultured for 4, 5, and 6 days. C, Micrographs show osteoclast-mediated resorbing surfaces (pits) formed on bovine bone chips after bone marrow cells from either Runx1F/F or CD11b-Cre;Runx1F/F mice were cultured on bovine cortical bone chips with M-CSF and RANKL (30 ng/mL for each) for 14 days. D, Total pit area per slice was measured in both Runx1F/F and CD11b-Cre;Runx1F/F groups. Data obtained were means ± SE (n = 3) and were representative of 3 replicate experiments. *, P < .05 vs Runx1F/F mice