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

Objective. To evaluate radiographic outcomes after an early treatment for 21 days with etanercept, naproxen, celecoxib, prednisone or methotrexate in adjuvant-induced arthritis in rats. Methods. 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 TNF alpha were measured. Results. 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 TNF alpha. 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. Conclusion. Our study demonstrated for the first time that an early treatment with NSAIDs, excluding cyclooxygenase-2 selective inhibitor, is more beneficial than a TNF alpha blocker in preventing structural damage in adjuvant-induced arthritis