Effect of erythromycin on otitis media with effusion in experimental rat model

To understand the mechanism of erythromycin (EM) on otitis media with effus ion, we examined its effects on leukocyte accumulation and expression of ad hesion molecules L-selectin and Mac-1, using a rat experimental model. Admi nistration of EM inhibited leukocyte (neutrophil) accumulation in the middl e ear cavity after LPS stimulation. Moreover, EM downregulated L-selectin e xpression and inhibited interleukin (IL)-8-induced upregulation of Mac-1 on peripheral blood neutrophils. These finding suggests that EM may improve o titis media with effusion by inhibiting neutrophil accumulation in the midd le ear cavity through modulating the expression of adhesion molecules L-sel ectin and Mac-1 on peripheral blood neutrophils.