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DOI: 10.1055/s-0039-1686517
Cochlear expression patterns of endothelial nitric oxide synthase in guinea pigs after loud noise
Deutsche Forschungsgemeinschaft (DFG grant STR 1014); Impulsfonds des Landes Rheinland-Pfalz 2017 – 2018 (Research Initiative of the Government of Rhineland-Palatia); BiomaTiCS-Programm der Universitätsmedizin Mainz, ('Biomaterials, Tissues and Cells'-program, University Medical Center Mainz)Introduction:
Intense noise exposure results in increased nitric oxide (NO)-production by inducible NO-Synthase (iNOS) overexpression. It is unclear, whether the constitutively expressed endothelial nitric oxide synthase (eNOS) may act in an otoprotective manner after noise exposure of the cochlea.
Methods:
Eleven male guinea pigs were exposed to 90 dB SPL for 1 hour (h) and 2 animals for 2h, with 5 or 6 animals serving as controls, respectively. On paraffin sections eNOS immunostaining was analyzed and quantified after noise (1h) in 4 cochlear regions by light microscopy. After 2h noise exposure, an eNOS-specific gold-labeling was quantified on sections of the Organ of Corti at the electron microscopic level.
Results:
The expression of the eNOS isoform in the guinea pig cochlea was found to be already up-regulated 1h after noise exposure in all 4 cochlear regions. At the ultrastructural level, a clear increase of the eNOS expression was located in actin-containing cells linked to the reticular lamina of the Organ of Corti 2h after noise exposure.
Conclusion:
Distinct alterations in of eNOS expression patterns may indicate an early intrinsic otoprotective mechanism of the inner ear after noise exposure.
Publication History
Publication Date:
23 April 2019 (online)
© 2019. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial-License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/).
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