Reduction in noise-induced functional loss of the cochleae in mice with pre-existing cochlear dysfunction due to genetic interference of prestin

• Published in: PloS one Vol. 9; no. 12; p. e113990
• Main Authors: Cai, Qunfeng, Wang, Bo, Coling, Donald, Zuo, Jian, Fang, Jie, Yang, Shiming, Vera, Krystal, Hu, Bo Hua
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 08.12.2014; Public Library of Science (PLoS)
• Subjects: Acoustic noise; Acoustics; Age; Animals; Auditory Threshold; Biology and Life Sciences; Brain stem; Children & youth; Cochlea; Cochlea - metabolism; Cochlea - physiopathology; Degeneration; Disease Models, Animal; E-cadherin; Emissions control; Female; Gene Expression; Genes; Hair; Hair cells; Hearing loss; Hearing Loss - etiology; Hearing Loss - physiopathology; Hearing protection; Homozygote; Interference; Internal ribosome entry site; Male; Mice; Mice, Transgenic; Molecular Motor Proteins - genetics; Molecular motors; Mutation; Neurobiology; Neurosciences; Noise; Noise - adverse effects; Noise levels; Noise reduction; Organ of Corti - metabolism; Organ of Corti - physiopathology; Otolaryngology; Ototoxicity; Outer hair cells; Proteins; Sound pressure; Stop codon; Surgery; Time Factors; Trauma; Beijing China; New York; United States > US; Tennessee; China
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0113990

Various cochlear pathologies, such as acoustic trauma, ototoxicity and age-related degeneration, cause hearing loss. These pre-existing hearing losses can alter cochlear responses to subsequent acoustic overstimulation. So far, the knowledge on the impacts of pre-existing hearing loss caused by genetic alteration of cochlear genes is limited. Prestin is the motor protein expressed exclusively in outer hair cells in the mammalian cochlea. This motor protein contributes to outer hair cell motility. At present, it is not clear how the interference of prestin function affects cochlear responses to acoustic overstimulation. To address this question, a genetic model of prestin dysfunction in mice was created by inserting an internal ribosome entry site (IRES)-CreERT2-FRT-Neo-FRT cassette into the prestin locus after the stop codon. Homozygous mice exhibit a threshold elevation of auditory brainstem responses with large individual variation. These mice also display a threshold elevation and a shift of the input/output function of the distortion product otoacoustic emission, suggesting a reduction in outer hair cell function. The disruption of prestin function reduces the threshold shifts caused by exposure to a loud noise at 120 dB (sound pressure level) for 1 h. This reduction is positively correlated with the level of pre-noise cochlear dysfunction and is accompanied by a reduced change in Cdh1 expression, suggesting a reduction in molecular responses to the acoustic overstimulation. Together, these results suggest that prestin interference reduces cochlear stress responses to acoustic overstimulation.