BML-111, a lipoxin receptor agonist, modulates the immune response and reduces the severity of collagen-induced arthritis

Objective: Lipoxins (LXs) are endogenous antiinflammatory and pro-resolving eicosanoids generated during various inflammatory conditions. Recent research has revealed the novel immunomodulatory function of LXs. The aim of this study is to investigate whether LXs modulate the pathogenesis of collagen-induced arthritis (CIA), a typical chronic immune-mediated inflammatory disease. Methods and results: CIA was induced in DBA/1 mice and BML-111, a lipoxin A ₄ receptor agonist, was administrated. Results indicated that compared with untreated CIA mice, both clinical disease activity scores and histological destruction of joint were significantly reduced in BML-111-treated CIA mice. The dampened joint injury was accompanied by decreased concentrations of serum pro-inflammatory cytokines tumor necrosis factor α and interleukin-6 in BML-111-treated CIA mice. In addition, proliferation of isolated spleen cells, as well as circulating levels of antibody to type II collagen, were reduced significantly in BML-111-treated CIA mice. Conclusion: BML-111 attenuated CIA in part by negatively regulating the immune response, which implicates the potential pharmacological value of LXs in the treatment of chronic immune-mediated inflammatory diseases such as RA. Received 30 July 2007; returned for revision 24 August 2007; received from final revision 14 September 2007; accepted by J. Di Battista 25 October 2007