Structural efficacy of NSAIDs, COX-2 inhibitor and glucocorticoid compared with TNFα blocker: a study in adjuvant-induced arthritis rats

To evaluate radiographic outcomes after an early treatment for 21 days with etanercept, naproxen, celecoxib, prednisone or methotrexate in adjuvant-induced arthritis in rats.At the onset of arthritis, rats were daily treated with naproxen (10 mg/kg/day i.p.), celecoxib (3 mg/kg/day), prednisolone (10 mg/kg/day), etanercept (10 mg/kg/3 days), methotrexate (2 mg/kg/3 days) or saline solution (vehicle) for 21 days. The arthritis score was daily monitored. At the end of treatment, a hind paw radiographic examination was performed with a BMA high-resolution digital X-ray system (40 mV, 10 mA). A score of 0-20 was determined for each paw. Plasma levels of TNFα were measured.Compared with vehicle, all treatments reduced (P < 0.001) the arthritis score. All treatments, except methotrexate, slowed radiographic destruction (P < 0.001). All treatments, except etanercept, reduced the plasma level of TNFα. Naproxen, glucocorticoid and celecoxib were more effective than etanercept on the radiographic score (P < 0.01). Naproxen was the only treatment to be more effective on all different radiographic subscores than etanercept.Our study demonstrated for the first time that an early treatment with NSAIDs, excluding cyclooxygenase-2 selective inhibitor, is more beneficial than a TNFα blocker in preventing structural damage in adjuvant-induced arthritis.