PATHOLOGICAL EVALUATION OF EFFECT OF ANTIRHEUMATIC DRUGS ON TYPE-II COLLAGEN-INDUCED ARTHRITIS IN LEWIS RATS

The effects of anti-rheumatic drugs (dexamethasone 0.1 mg/kg and napro xen 5 mg/kg) were evaluated immunologically and histopathologically on type II collagen-induced arthritis in Lewis rats. Increased paw volum e in the hind limbs was significantly suppressed in the groups treated with dexamethasone or naproxen, but noticeable retardation of body we ight gain was observed in the group treated with dexamethasone. Serum anti-type II collagen IgG was significantly suppressed in the group tr eated with dexamethasone but not naproxen. Histopathological evaluatio n by our grading system, classification of the stages in arthritic les ion development, revealed suppression of the inflammatory changes in t he tarsal joints of the animals treated with dexamethasone or naproxen . From our results, histopathological evaluation is considered to be m ore suitable for assessment of the efficacy of anti-rheumatic drugs on type II collagen-induced arthritis, an animal model for human rheumat oid arthritis.