Fig. 3. Immunolocalization of MMP-13 in bone. (A-E) Bone sections from 30- and 40-day-old wild-type mice stained with antibody specific for MMP-13. (A) Section of cortical bone from 30-day-old wild-type mouse demonstrating staining of the periosteal surface (p) as well as of osteocyte lacunae and cell processes radiating into the bone matrix. e, endosteal surface. (B) Bone section from 40-day-old wild-type mouse demonstrating intense staining for MMP-13 associated with both osteocytes and their processes. e, endosteal surface. (D,E) High-power magnification of bone from 40-day-old wild-type mouse demonstrating osteocytes and associated processes staining intensely for MMP-13. Notice the punctate staining pattern in E, which indicates cross-sectioned cell processes. (C) Negative control. Bars, 30 µm (A-C), 10 µm (D,E).