RESUMO
BACKGROUND AND OBJECTIVES: Interleukin (IL)-10 is a major regulator of innate immunity. It interferes with the production of inflammatory mediators by reacting with polymorphonuclear neutrophils, monocytes and macrophages. In addition, it also up-regulates the ex-pression of molecules that amplify the anti-inflammatory effect of IL-10. This study tested the hypothesis that injection of various concentrations of exogenous IL-10 in the middle ear cleft can inhibit the acute stage of otitis media induced by lipopolysaccharide (LPS). And if so, the level of concentration for inhibition can be determined. MATERIALS AND METHOD: IL-10 and/or LPS were injected transtympanically into the middle ear cavity of normal mice. Histopathological measurement of submucosal thickness and num-ber of inflammatory cell infiltration was performed at 24 hours after inoculation of IL-10 and/or LPS. RESULTS: At 24 hours after inoculation, every group of IL-10 inoculation reduced both thickening of the mucous and submucosal infiltration of inflammatory cells in a dose-dependent manner. As the concentrations of IL-10 inoculated increased, mucosal thickness and submucosal infiltration of inflammatory cells were more reduced. CONCLUSION: This study demonstrated that exogenous IL-10 injection into the middle ear can directly reduce LPS-induced otitis media in acute stage in a dose-dependent manner. These findings also indicate that IL-10 may be a candidate for local modulator of acute otitis media.