Expression of endoplasmic reticulum stress mRNAs in otitis media

Background: Endoplasmic reticulum (ER) stress is a cellular defense mechanism that occurs when ER function is impaired. Objective: This study was designed to evaluate the expression of major mRNAs of ER stress in patients with otitis media with effusion (OME), chronic otitis media (COM), and COM with cholesteatoma (CholeOM). Material and methods: Specimens were collected during surgery from patients with OME, COM, and CholeOM, and the levels of ER stress mRNAs measured by real-time polymerase chain reaction. Levels of ER stress mRNAs were compared in the three groups and correlated with clinical findings and pus culture results. Results: The level of CHOP mRNA was higher, and the levels of sXBP1 and ATF6 mRNAs lower, in the OME than in the other two groups (p <.05 each). Evaluation of bacterial pus culture negative patients showed that the level of ATF6 mRNA was higher in the CholeOM than in the other two groups (p <.05), whereas evaluation of bacterial pus culture positive patients showed that the level of CHOP mRNA was higher in the OME than in the other groups (p <.05). Conclusions and significance: ER stress may be involved in the pathophysiology of OM and the levels of ER stress mRNAs were expressed differently in each type of otitis media according to bacterial culture test results.