Histology of bone marrow of wild type,

Csf1^op/Csf1^op, and Csf1r⁻/Csf1r⁻mice. (A) Low-power photomicrographs of hematoxylin and eosin–stained midsagittal 5-μm sections of the distal femoral metaphyses of 8-week-old mice (bm, bone marrow; bt, bony trabeculae; ep, epiphyseal plate). Boxes indicate comparable areas of TRAP-stained sections photographed in B. (B) High-power photomicrographs of TRAP staining for osteoclasts in midsagittal 5-μm sections of femurs of 4-week-old mice in areas comparable to those boxed in A. Counterstained with hematoxylin. Arrowheads indicate TRAP⁺ cells. (C) Percentage of trabecular bone in the entire bone marrow cavity determined from the sections used in A. Original magnification A, × 25; B, × 400.A.