['To assess the effects of celecoxib, a cyclooxygenase (COX-2) selective inhibitor, on the metabolism of hyaluronan (HA) and proteoglycans (PG) in human cartilage explants with midrange severity of osteoarthritis (OA). Results were compared with those of diclofenac, a non-selective COX inhibitor.', "Cartilage specimens (OA grade 4-8 on Mankin's scale) were pulsed with 3H -glucosamine and chased in the absence or presence of 1-10 micro g/ml of celecoxib or diclofenac. After papain digestion, the labeled chondroitin sulfate and HA molecules were purified by anion-exchange chromatography.", 'Diclofenac did not affect the metabolic balance of PG and HA whereas, in a relatively dose-dependent manner, celecoxib increased the synthesis of HA and PG; celecoxib also reduced the net loss of labeled HA and PG molecules from cartilage explants.'] Does celecoxib have a positive effect on the overall metabolism of hyaluronan and proteoglycans in human osteoarthritic cartilage?