View article

To determine the sites of cleavage and denaturation of type II collagen (CII) by collagenase(s) in healthy and osteoarthritic (OA) human articular cartilage and their relationship to the distribution of matrix metalloproteinase 1 (MMP‐1) and MMP‐13.

Single (per subject) full‐depth specimens from femoral condylar cartilage were isolated from articulating surfaces at autopsy from 8 subjects without arthritis and during arthroplasty from 10 patients with OA. Fixed frozen sections of cartilage were examined by immunoperoxidase localization, using antibodies to the collagenase‐generated cleavage site in CII, to an intrachain epitope recognized only in denatured CII, and to MMP‐1 and MMP‐13 (proenzyme, activated enzyme, or enzyme/inhibitor complex).

Staining for collagen cleavage, denaturation, and both MMPs was weak to moderate and was frequently observed in pericellular sites in …