Degradation of the cartilage collagen matrix associated with changes in chondrocytes in osteoarthrosis. Assessment by loss of background fluorescenceand immunodetection of matrix components

Articular cartilage damage and eventual loss is the primary pathological ch ange seen in osteoarthrosis (OA). In this study we have investigated the li nk between turnover of the collagen matrix and changes in chondrocytes. The background fluorescence of articular cartilage, as indicated by its emissi on spectrum and resistance to extraction was generated by the slow non-enzy mic modification of the collagen matrix by advanced glycation end products (AGEs). Assessment of changes in background fluorescence in sections of art icular cartilage provided a narrative of collagen degradation. Patients wit hout OA pathology typically had a uniform strong background fluorescence th roughout the depth of the cartilage. Cartilage from OA patients showed a ra nge of changes in background fluorescence dependent on depth from the artic ular surface and proximity to overt lesions. Loss of background fluorescenc e was centered on chondrocytes, more extensive near the surface and associa ted with detection of the proteo-glycan epitope 7D4. Expression of type X c ollagen was seen in articular cartilage in the region of the interface of w ith subchondral bone in most OA patients but was not associated with promin ent, pericellular; loss of background fluorescence. These observations are consistent with progressive cartilage damage in OA, whereby collagen turnov er and loss of surface integrity is associated with chondrocyte activity si milar to that seen in immature articular cartilage. (C) 2001 Orthopaedic Re search Society. Published by Elsevier Science Ltd. Al rights reserved.