Depletion of osteoblasts affects cellularity in the bone marrow. (A) Control wild-type littermates and Col2.3ΔTK mice were injected with GCV; at defined times they were killed, and their bones were subjected to histologic analysis. Tissue was placed in paraffin and stained with hematoxylin and eosin. Microphotographs were taken at 10 × magnification. (B) Absolute number of cells recovered from bone marrow of 4 long bones in control and Col2.3ΔTK mice after GCV treatment.