Modulation of neutrophil adhesion to vascular endothelial cells in rat experimental otitis media treated with a macrolide

Object: We previously reported that erythromycin (EM) affected the adhesion molecules that interact with neutrophils and inhibited neutrophil infiltration in a rat experimental otitis media model. Purpose: The purpose of the present study was to examine whether EM affects the adhesion of rat neutrophils to endothelial cells. Methods: The adhesion of neutrophils to WK-5 endothelial cells was evaluated. One group of rats was given EM for 2 weeks, while the other group received no treatment. The adhesion of peripheral-blood neutrophils and neutrophils accumulated in the middle ear from these two groups were compared. Results: Two-week EM pretreatment inhibited adhesion of neutrophils to WK-5 cells. The adhesion of neutrophils accumulated in the middle ear cavity to WK-5 cells was significantly higher than that of peripheral-blood neutrophils from control rats. Conclusion: The results suggest that EM affects the adhesion of neutrophils to endothelial cells.