Phenotype and functionality of MODP- and MOP-derived OCs. Sorted MODPs and MOPs were plated at 3000 cells/well with or without bovine bone chips and cultured in the presence of RANKL and M-CSF for 6 days. (A) CCD microscopic images (bottom row: digital zoom in) of TRAP- and DAPI-stained OC cultures. (B-C) Quantitative analysis of MODP- and MOP-derived OCs. Fused cells with multiple nuclei were counted as 1 cell. (B) OC diameter presented as the mean value of 80 (MODP derived) or 100 (MOP derived) TRAP⁺ OCs. (C) Total TRAP⁺ OC yield per well in absolute number (#), with OCs subdivided according to nuclei count. Small: 3-10 nuclei; big: 10-20 nuclei; giant: >20 nuclei. Data represent pooled data from 2 experiments (n = 4). Error bars indicate standard error of the mean. (D) CCD microscopic images of CBB-stained OCs on bovine bone chips. (E-F) Quantification by ImageJ capture and manual counting of CBB-stained pits on bone chips from MODP- derived OC cultures (n = 6) and MOP-derived OC cultures (n = 5). In each graph, all pits were counted and measured. Resorption area was calculated as total pit size divided by the number of pits.²⁹  Error bars indicate standard error of the mean. *P < .05; **P < .01; ****P < .0001. ns, not significant.