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Investigation of the cochlear effects of intratympanic steroids administered following acoustic trauma
Author(s) -
Ozdogan Fatih,
Ensari Serdar,
Cakir Ozgur,
Ozcan Kursat Murat,
Koseoglu Sabri,
Ozdas Talih,
Gurgen Seren Gulsen,
Dere Huseyin
Publication year - 2012
Publication title -
the laryngoscope
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.181
H-Index - 148
eISSN - 1531-4995
pISSN - 0023-852X
DOI - 10.1002/lary.23185
Subject(s) - otoacoustic emission , acoustic trauma , medicine , saline , audiology , hair cell , cochlea , methylprednisolone , noise induced hearing loss , outer hair cells , anesthesia , hearing loss , noise exposure
Objectives/Hypothesis: To electrophysiologically and histomorphologically demonstrate the effects of intratympanic corticosteroids administered following an acoustic trauma on cochlear hair cells. Methods: The trial was performed on 16 Wistar albino rats. The rats underwent distortion product otoacoustic emissions (DPOAE) measurement before the acoustic trauma, and subsequently rats were exposed to noise. Following acoustic trauma, the otoacoustic emission measurement was repeated. The rats were divided into two groups, a study group and a control group. The study rats were injected with methylprednisolone via the intratympanic route throughout the study. In the control group, the rats were injected daily with saline. After performing repeated otoacoustic emission measurements, one rat in each of the groups was sacrificed and their cochleae isolated. Results: The histological investigation performed after the 1st week revealed a statistically significantly higher rate of apoptotic cells in the inner and particularly the outer hair cells of the rat cochleae in the control group compared to the study group. Early measurement of DPOAE within the 1st week demonstrated significantly better amplitudes in the study group compared to controls. The otoacoustic emission assessment performed on the 14th day demonstrated statistically similar DPOAE values between the two groups. Conclusions: Intratympanic methylprednisolone injection administered following an acoustic trauma appears to reduce cochlear outer hair cell loss. The impact on hearing loss is less certain. Early measurement of DPOAE within the 1st week shows significantly better amplitudes in the study group compared to controls. However at 2 weeks, there is no statistically significant difference in DPOAE amplitudes between the study and control group. Laryngoscope, 2012