Figure 1.

Representative immunohistochemical staining section for (a) metalloprotease-13 (MMP-13) and (b) cathepsin K in human osteoarthritis subchondral bone. MMP-13 was detected in the osteoblasts (Ob) as well as in the osteoclasts (Oc). Cathepsin K was detected only in osteoclasts. Original magnification, ×100.