Effects of anti-arthritic drugs on IL-1 induced inflammation in rats.

Intra-articular injection of IL-1 in rats results in profound changes in the synovial joints including edema, synovitis, cartilage degeneration and fibroblast proliferation. We have tested the efficacy of several anti-arthritic drugs in this model to characterize the mechanism of IL-1 induced inflammatory lesions. The response to IL-1 was evaluated by measurement of soft-tissue swelling and by histological scoring. Dexamethasone, and several NSAIDS were effective in reducing the soft tissue swelling but only some were effective in improving the histological lesions. The slow-acting antirheumatic D-penicillamine and immunosuppressive agents such as cyclosporine A were ineffective. These observations provide further evidence that in vivo, at least some aspects of IL-1 induced changes in rat knee joints are likely to be prostaglandin mediated.