Effect of monocyte/macrophage depletion on osteoblast thickness. (A) Flow analysis of BM after DT or clodronate depletion at 48 hours after TBI showing depletion of F4/80 and CD11b cell populations. (B) BM sections (40×) of DT depleted, clodronate depleted, and WT control 48 hours after TBI stained for F4/80 showing histologic depletion of osteomacrophages in all groups (top). H&E-stained sections (40×) of metaphyseal BM showing consistent thickness of osteoblasts despite depletion (middle.) IF-stained section of metaphyseal BM (40× objective) showing depletion of F4/80 population (red) with reservation of osteoblast thickening (green) in all groups (bottom). (C) Histologic analysis of osteoblast thickness in LYZ/iDTR and clodronate depletion show no significant change from TBI only group (LYZ/iDTR cohort cell thickness, 7.35 ± 0.76 μm vs 7.16 ± 0.43 μm; P = not significant [ns]; clodronate cohort cell thickness, 6.44 ± 0.85 μm vs 6.44 ± 0.85 μm; P = ns). SSC, side scatter channel.