A TACE inhibitor restores OC formation and activation in the presence of GM-CSF and IL-4. (A-D) Monocytes were cultured in 24-well culture plates (A,D) as well as on dentine slices in 96-well culture plates (B-C) in quadruplicate for 21 days in the presence of M-CSF and sRANKL. GM-CSF and IL-4 in combination were added to the monocytic cultures together with M-CSF and sRANKL in the indicated wells. TAPI-0 and a soluble M-CSF receptor-Fc fusion protein were further added to the indicated wells at 10μM and 10 μg/mL, respectively. After culturing for 21 days, the cells were stained for TRAP. Representative results in 24-well culture plates are shown panel A. The numbers of TRAP-positive adherent cells with more than 5 nuclei (B) and pits (C) formed on dentine slices in 96-well culture plates were counted. Data are expressed as means ± SD; *P < .05. (D) Actin and nuclei in the cells in 24-well culture plates were stained with rhodamine-labeled phalloidin and DAPI, respectively. Samples were visualized with a confocal microscope (Axiovert 200M) using Plan Apochromat 10× objective.