Expression of endoplasmic reticulum stress-related mRNA in otitis media with effusion

Objectives: The endoplasmic reticulum (ER) is an intracellular organelle involved in the synthesis and secretion of proteins. The ER stress response, which protects cells from cytotoxic proteins such as unfolded proteins, is related to several diseases including inflammation. In this study, we investigated the effect of ER stress on the pathophysiology of otitis media with effusion (OME). Methods: Thirty-nine pediatric patients who were diagnosed with OME and underwent ventilation tube insertion were enrolled in this study. Exudate from the middle ear cavity was collected through ventilation insertion, and ER stress gene expression was analyzed via real-time polymerase chain reactions(PCR). Results: There were no significant differences in ER stress-related mRNA expression between effusion culture-positive and culture-negative groups (p > 0.05). Expression of the C/EBP-homologous protein (CHOP) was higher in the otitis-prone group than in the non-otitis-prone group (p < 0.05). The most common type of fluid was mucoid, and inositol-requiring enzyme 1α expression was higher in serous fluid than in mucoid, mucopurulent, or purulent fluid (p < 0.05). Conclusions: Endoplasmic reticulum stress-related responses are activated in pediatric OME patients, and specific ER-stress related pathways are related to both the characteristics of fluid and the frequency of OME. Thus, ER stress-related responses affect the pathophysiology of OME in pediatric OME patients.