Pharmacological studies of antigen-induced arthritis in BALB/c mice. I. Characterization of the arthritis and the effects of steroidal and non-steroidal anti-inflammatory agents.

Chronic monoarticular allergic arthritis was induced in BALB/c mice using methylated BSA as antigen and Freund's complete adjuvant, together with Bordetella pertussis as a secondary adjuvant. The optimum conditions for induction of chronic persistent arthritis and the histological characteristics of the arthritic lesion are described. Both the synovitis and erosive progression of the arthritis could be suppressed by daily treatment with prednisolone (1-10 mg/kg) or dexamethasone (0.5-2.5 mg/kg) for 4 weeks commencing 2 weeks after the induction of arthritis. In contrast, daily treatment with the non-steroidal anti-inflammatory agents ibuprofen (50-100 mg/kg), flurbiprofen (1-9 mg/kg) or indomethacin (0.1-3 mg/kg) had no significant effect on either the synovitis or erosions as judged histologically. Synovial fluid differential leukocyte counts were altered by treatment with ibuprofen and indomethacin but not by flurbiprofen or the corticosteroids. The suppressive effect of the corticosteroids was not due to either suppression of antibody synthesis or alteration of the number of leukocytes in the peripheral circulation.