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
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)