The effect of salicylate on prostaglandin levels in rabbit knees following inducement of osteoarthritic changes.

Surgical inducement of medial instability in the right knee of rabbits was used to produce joint changes which resemble those observed in human osteoarthritis. Ordinary tap water was supplied to half of the rabbits and tap water plus sodium salicylate to the others. Determinations of prostaglandin were made on the synovial fluid and cartilage from all rabbits five months after surgery. In both groups, the concentration of prostaglandin in synovial fluid was lower in the operated knees, but the total amount of prostaglandin was found to be approximately equal to that in the unoperated knees. The development of degenerative joint changes therefore was not accompanied by increases in prostaglandin content. Salicylate treatment did not alter this observation, however, it did reduce overall prostaglandin levels. These results suggest that prostaglandin interaction is not involved in osteoarthritic joint degeneration.