Up-regulation of macrophage migration inhibitory factor induced by endotoxin in experimental otitis media with effusion in mice.

Conclusion: Injection of endotoxin into the middle ear causes production of macrophage migration inhibitory factor (MIF) in an experimental mouse model of otitis media with effusion (OME). Down-regulation of MIF may become a new approach for the management of OME.

Objective: To determine the role of MIF in OME.

Materials And Methods: Mice were divided into two groups and their middle ears were injected with either endotoxin or phosphate-buffered saline (PBS). Mice were sacrificed at 6 h, 12 h, or 1, 3, 7, or 14 days after injection and concentrations of MIF, interleukin-1 beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha) in middle ear effusions were measured by enzyme-linked immunosorbent assay.

Results: Concentrations of MIF in the endotoxin group at 1 day and 3 days were significantly higher than in the PBS control group. Concentrations of IL-1beta in the endotoxin group at 6 h, 12 h, 1 day, and 3 days were significantly higher than in controls. Concentrations of TNF-alpha in the endotoxin group at 1 day and 3 days were significantly higher than in controls. Concentration of MIF in the endotoxin group was positively correlated with that of IL-1beta and TNF-alpha.