Effects of human recombinant interleukin-1beta on canine articular chondrocytes in three-dimensional culture

Objective—To determine the effects of interleukin (IL)-1β on matrix synthesis and degradation by chondrocytes cultured in a 3-dimensional (3-D) gel medium. Sample Population—Chondrocytes from 7 dogs. Procedure—Articular chondrocytes were harvested and cultured in 3-D gel medium alone or with 10 or 20 ng IL-1βml that was added beginning on day 0, 3, 6, or 9. On days 3, 6, 12, and 20 of 3-D culture, samples of the liquid medium were evaluated for glycosaminoglycan (GAG), prostaglandin E2 (PGE2), and matrix metalloprotease (MMP)-3 content. The 3-D plug in each well was evaluated for histologic characteristics of viability, cell morphology, and proteoglycan staining, immunohistochemically stained for collagen type II, and spectrophotometrically analyzed for GAG content. Results—Significant differences for all variables were detected between controls and each IL-1β group, among groups with different IL-1β concentrations, and among groups with IL-1β added at various time points. Chondrocytes exposed to IL-1β had loss of GAG, increased PGE2 and MMP-3 concentrations, and lack of collagen type-II synthesis. These IL-1β effects appeared to be time and concentration dependent. Conclusions—Addition of IL-1β to chondrocytes in 3- D gel medium results in time- and concentrationdependent effects on matrix synthesis and degradation and provides an appropriate in vitro model for many of the pathophysiologic events associated with osteoarthritis. (Am J Vet Res 2000;61:766–770)