Inhibition of interleukin 1 induced chondrocyte protease activity by a corticosteroid and a nonsteroidal antiinflammatory drug

We report that administration of the corticosteroid, methylprednisolone (PRED) inhibited interleukin 1 (IL-1) induction of chondrocyte caseinolytic activity (25-55%) and collagenolytic activity (15-24%). The nonsteroidal antiinflammatory drug (NSAID), naproxen (NAP) had no effect on either enzyme activity over a therapeutic range (7-30 μg/ml) but at 120 μg/ml inhibited IL-1 induced caseinolytic and collagenolytic activity by 17 and 19%, respectively. However, PRED (2 μg/ml) in combination with NAP (30 μg/ml) significantly increased the inhibition of caseinolytic activity (p < 0.001) compared to that observed with PRED (2 μg/ml) alone. The suppression of IL-1 induced collagenolytic activity noted with PRED in combination with NAP did not exceed that observed with PRED alone.