Effect of antiinflammatory drugs on human interleukin-1-induced cartilage degradation.

Human monocyte IL-1 stimulated the release of proteoglycans from cartilage in organ culture in a concentration-related manner. This stimulation required protein synthesis as shown by inhibition with cycloheximide. The metal chelator, 1,10-phenanthroline, inhibited breakdown, suggesting the involvement of a metalloproteinase. Various nonsteroidal anti-inflammatory drugs (100 microM), and the corticosteroids, dexamethasone and hydrocortisone (1-10 microM), were not effective in blocking proteoglycan release. Of the disease modifying agents tested, levamisole was ineffective while the antimalarials, chloroquine (100 microM) and hydroxychloroquine (100 microM), inhibited the action of IL-1. The free-radical inhibitor SOD (5000 U/ml but not 1000 U/ml) was effective while catalase (8000 U/ml) was not. The protective effects of SOD and the antimalarials suggest that oxygen reactive species may play a role, while lack of inhibition with NSAIDs and corticosteroids indicate that arachidonic acid metabolites may not be important in this degradative process.