Expression of beta-defensins in the tubotympanum of experimental otitis media

Abstract

Conclusion: Since the expression levels of beta-defensins 2-4 were up-regulated in experimental otitis media, they may play a protective role in the pathogenesis of otitis media.

Objectives: Defensins are antimicrobial peptides that play a major role in innate immunity. The goal of this study was to identify the expression of defensins in experimental otitis media of the mouse.

Materials and methods: The expression of three alpha-defensins (cryptdins, cryptdin-related sequences 1-C (CRS1-C), and CRS4-C) and four beta-defensins (mBD1, mBD2, mBD3, and mBD4) was investigated in the tubotympanum of experimental otitis media in mice by a semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR), and the expression levels of three beta-defensins (mBD2, mBD3, mBD4) were evaluated by Western blotting.

Results: The alpha-defensins were not expressed in the tubotympanum. mBD1 was expressed constitutively in normal middle ear mucosa and Eustachian tube mucosa, but up-regulated expression of mBD2, mBD3, and mBD4 was observed with RT-PCR and Western blotting in the tubotympanums in experimental otitis media, while the normal tubotympanums did not express them.