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Year : 2014  |  Volume : 16  |  Issue : 70  |  Page : 149--156

Protective effect of unilateral and bilateral ear plugs on noise-induced hearing loss: Functional and morphological evaluation in animal model

Department of Otolaryngology-Head and Neck Surgery, The Catholic University of Korea, College of Medicine, Seoul, Korea

Correspondence Address:
Shi-Nae Park
Department of Otolaryngology-Head & Neck Surgery, Seoul St. Mary's Hospital, 505 Banpo-dong, Seocho-gu, Seoul 137-701
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Source of Support: This research was funded by grants from Seoul St. Mary’s Clinical Medicine Research Program year of 2011 through the Catholic University of Korea and from Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (2010-0004744),, Conflict of Interest: None

DOI: 10.4103/1463-1741.134915

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The aim of the following study is to evaluate immediate protective effect of ear plug from noise morphologically and functionally. An 1-month aged 29 male C57BL/6 mice. Subjects were divided into four groups as normal control(G1), bilaterally plugged group (G2), unilaterally plugged group (G3) and noise control group (G4) and later 3 groups were exposed to 110 sound pressure level white noise for 60 min. Immediately after noise exposure, audiologic tests were performed and cochlear morphology and expression levels of a-synuclein in the cochlea were investigated. There were no functional changes in G2 and plugged ears of G3 after noise exposure, whereas unplugged ears of G3 and G4 showed significant hearing loss. In morphological study, there were a significant degeneration of the organ of Corti and mean number and diameter of efferent buttons, in unplugged ears of G3 and G4. Plugged ears of G3 also showed mild changes in morphological study. Reduction of a-synuclein was observed at the efferent terminals or cochlear extracts after noise exposure. The protective effect of ear plug on noise exposure was proven morphologically and functionally in the animal model of noise-induced hearing loss. Further study on cellular or ultrastructural level with ear plug will be needed to reveal more precise mechanism.


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