Interleukin‐10 inhibition of the progression of established collagen‐induced arthritis

Abstract Objective . Interleukin‐10 (IL‐10) is a potent inhibitor of the proinflammatory cytokines, including tumor necrosis factor α and IL‐1, which are considered important in the pathogenesis of rheumatoid arthritis (RA). The study was undertaken to establish whether IL‐10 can ameliorate arthritis in the collagen‐induced arthritis (CIA) model of RA. Methods . DBA/1 mice were immunized with bovine type II collagen in adjuvant, and treated daily after disease onset with recombinant murine IL‐10 or with saline as a control. Mice were monitored for paw swelling and clinical score. Histologic analysis was also performed. Results . IL‐10 treatment of established CIA inhibited paw swelling ( P < 0.0001), as well as disease progression as defined by clinical score ( P < 0.0002). Cartilage destruction, as assessed histologically, was reduced in IL‐10–treated mice compared with controls ( P < 0.01). Conclusion . IL‐10 suppresses established CIA, probably by inhibiting proinflammatory cytokine production. Our results, taken together with previously reported findings, indicate a potential therapeutic role for IL‐10 in RA.