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

Objective. Interleukin-10 (IL-10) is a potent inhibitor of the proinflammatory cytokines, including tumor necrosis factor alpha 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.