• T M Cunha, M M Barsante, A T Guerrero, W A Verri, S H Ferreira, F M Coelho, R Bertini, C Di Giacinto, M Allegretti, F Q Cunha, and M M Teixeira.
• Department of Pharmacology, Faculty of Medicine of Ribeirão Preto University of Sao Paulo, Ribeirão Preto, Sao Paulo, Brazil.
• Br. J. Pharmacol. 2008 May 1;154(2):460-70.

Background And PurposeNeutrophil migration into tissues is involved in the genesis of inflammatory pain. Here, we addressed the hypothesis that the effect of CXC chemokines on CXCR1/2 is important to induce neutrophil migration and inflammatory hypernociception.Experimental ApproachMice were treated with a non-competitive allosteric inhibitor of CXCR1/2, DF 2162, and neutrophil influx and inflammatory hypernociception were assessed by myeloperoxidase assay and electronic pressure meter test, respectively, in various models of inflammation.Key ResultsDF 2162 inhibited neutrophil chemotaxis induced by CXCR1/2 ligands but had no effect on CXCL8 binding to neutrophils. A single mutation of the allosteric site at CXCR1 abrogated the inhibitory effect of DF 2162 on CXCL-8-induced chemotaxis. Treatment with DF 2162 prevented influx of neutrophils and inflammatory hypernociception induced by CXCL1 in a dose-dependent manner. The compound inhibited neutrophil influx and inflammatory hypernociception induced by carrageenan, lipopolysaccharide and zymosan, but not hypernociception induced by dopamine and PGE(2). DF 2162 had a synergistic effect with indomethacin or the absence of TNFR1 to abrogate carrageenan-induced hypernociception. Treatment with DF 2162 diminished neutrophil influx, oedema formation, disease score and hypernociception in collagen-induced arthritis.Conclusions And ImplicationsCXCR1/2 mediates neutrophil migration and is involved in the cascade of events leading to inflammatory hypernociception. In addition to modifying fundamental pathological processes, non-competitive allosteric inhibitors of CXCR1/2 may have the additional benefit of providing partial relief for pain and, hence, may be a valid therapeutic target for further studies aimed at the development of new drugs for the treatment of rheumatoid arthritis.

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