Fig. 6.

HC and IHC. TRAP positive cells (red staining) and osteopontin (brown staining). A1, A2 Longitudinal sections through the POC (poc). At P 7, a distinct layer of osteopontin lines the trabeculae of the POC, and numerous chondro/osteoclasts are visible in the Wt mice. B1–C2 Longitudinal sections through the developing epiphysis show the cartilage canals (cc), the marrow cavity (mc) and the SOC (soc). B1–C2 Localization of osteopontin is coupled with the onset of the marrow space formation. In TRAP^−/− mice labeling for the protein is detected in the branched segment of the cartilage canal (cc) at P 7 whereas in the Wt mice it is observed at P 8. Inset in B2 shows a higher magnification of the area indicated by the arrowhead; bar = 20 μm. All sections have the same magnification and are counterstained with hematoxylin; bar = 50 μm.