Cyclooxygenase 2 expression in otitis media with effusion

Objectives: To study whether cyclooxygenase 2 (COX-2) plays a role in the development of otitis media with effusion (OME). Study design/methods: An experimental model of endotoxin-induced OME was used in healthy BALB/c mice. Solutions of Salmonella typhimurium endotoxin were injected into the middle ears of the mice, and COX-2 expression in the middle ears was studied using reverse transcription-polymerase chain reaction (RT-PCR) and in situ hybridization (ISH). Results: Analysis by RT-PCR showed that COX-2 expression in the middle ear increased in a dose-dependent fashion after injection of endotoxin. ISH demonstrated that COX-2 had distinct expression patterns in the epithelium of middle ears with endotoxin-induced OME. Conclusions: COX-2 expression, however, was not detected in normal middle ears. COX-2 expression may be one factor contributing to the development of OME.