Figure 4

Immunogold histochemistry for cartilage oligomeric protein (COMP) of healthy and osteoarthritic (OA) tissue taken from the area adjacent to the main defect. (a) Healthy cartilage tissue with staining for COMP in the pericellular space (arrow) and in the territorial matrix (asterisk). (b) The pericellular space of a type 2 cell of OA tissue taken from the area adjacent to the main defect; note the stronger staining compared with the healthy tissue (arrows). (c) Higher magnification of the interterritorial matrix from healthy cartilage tissue; note the sparse COMP staining on fibers (arrow). Inset shows higher magnification of the interterritorial matrix taken from the area adjacent to the main defect; note the stronger staining for COMP on fibers (arrows). Bars, 0.4 μm in (a) and (b) and 0.2 μm in (c) and inset.