Effects of interleukin-1β on chondroblast viability and extracellular matrix changes in bovine articular cartilage explants

Osteoarthritis is a degenerative disease of joint cartilage, characterized by the progressive and permanent degeneration of cartilage due to an imbalance in normal extracellular matrix turnover. Interleukin-1beta is a proinflammatory agent, which is present in an elevated amount in osteoarthritic cartilage; and is thought to play a decisive role in osteoarthritis. Interleukin-1beta acts as an important mediator of extracellular matrix changes where its activity is regulated by glycosaminoglycan composition. The aim of this study was to investigate the extracellular matrix changes in bovine cartilage explants following interleukin-1beta treatment by morphological, histochemical and biochemical methods. Interleukin-1beta stimulated the release of matrix sulfated proteoglycans in the culture medium, and significantly inhibited sulfated proteoglycan synthesis. These events were associated to a strong stimulation of nitric oxide production. Interleukin-1beta treated cartilage showed evident Collagen fibers around the chondrocytes, together with diminished glycosaminoglycan sulfate content in the extracellular matrix of the explants. Moreover, the ultrastructure and viability of cells did not change in treated cartilage. Our data show that interleukin-1beta modifies the ECM turnover without toxic effect on chondrocytes. (C) 2003 Editions scientifiques et medicales Elsevier SAS. All rights reserved.