Role of interleukin-1beta in a murine model of otitis media with effusion

To clarify the role of interleukin-1beta (IL-1beta) in the pathogenesis of otitis media with effusion (OME), we developed and investigated a murine model of this disease. Specific pathogen-free male BALB/c mice received intratympanic injections of 20 microg of endotoxin derived from nontypeable Haemophilus influenzae. Three days after injection, middle ear effusions were observed through the eardrum. Similar pathological changes were observed after inoculation with 100 ng of recombinant IL-1beta. Anti-IL-1 receptor antibodies inhibited the pathological changes induced by the endotoxin. In situ hybridization showed expression of IL-1beta messenger RNA in the epithelium of the middle ear mucosa. These results suggest that IL-1beta might be associated with endotoxin-induced inflammation in the middle ear and might play an important role in the induction of otitis media with effusion.