title: Effect of Endolymphatic Hydrops on Sound Transmission in Live Guinea Pigs Measured with a Laser Doppler Vibrometer.
abstract: Objective. This study aimed at describing the mechanism of hearing loss in low frequency and the different dynamic behavior of the umbo, the stapes head, and the round window membrane (RWM) between normal guinea pigs and those with endolymphatic hydrops (EH), using a laser Doppler vibrometer (LDV).Methods. Cochlear sections were stained with hematoxylin and eosin (HE) to evaluate the hydropic ratio (HR). Auditory brainstem responses (ABR) and whole-mount immunostaining were measured. Displacement of the umbo, stapes head, and RWM in response to ear-canal sound was evaluated using a LDV.Results. Mean HR values in EH model of all the turns are larger than the control group. The ABR threshold of the EH group was significantly higher than that of the control. Strong positive correlation was found between HR at apical turn and ABR threshold elevation at 1000 Hz and at subapical turn and ABR threshold elevation at 2000 Hz. FITC-phalloidin immunostaining of the cochlear basilar membrane in the apical, subapical, and suprabasal turns showed missing and derangement stereocilia of third-row outer hair cells. The umbo, stapes head, and RWM displacement in ears with EH was generally lower than that of normal ears. The EH-induced differences in stapes head and RWM motion were significant at 0.5 kHz.Conclusion. The LDV results suggested that the higher inner ear impedance in EH affected the dynamic behavior of the two opening windows of the cochlea and then reduced the vibration of the ossicular chain by increasing the afterload, resulting in acoustic dysfunction. The vibration reduction mainly occurred at low frequencies, which has related with the morphology changes of the apical and subapical turns in EH model.
authors.affiliation: Department of Otology and Skull Base Surgery, Eye Ear Nose & Throat Hospital, Fudan University, Shanghai 200031, China; Shanghai Auditory Medical Center, Shanghai, China; Key Laboratory of Hearing Science, Ministry of Health, Shanghai, China.
authors.forename: Chen-Ru
authors.initials: CR
authors.lastname: Ding
authors.affiliation: Department of Otology and Skull Base Surgery, Eye Ear Nose & Throat Hospital, Fudan University, Shanghai 200031, China; Shanghai Auditory Medical Center, Shanghai, China; Key Laboratory of Hearing Science, Ministry of Health, Shanghai, China.
authors.forename: Xin-Da
authors.initials: XD
authors.lastname: Xu
authors.affiliation: Department of Otology and Skull Base Surgery, Eye Ear Nose & Throat Hospital, Fudan University, Shanghai 200031, China; Shanghai Auditory Medical Center, Shanghai, China; Key Laboratory of Hearing Science, Ministry of Health, Shanghai, China.
authors.forename: Xin-Wei
authors.initials: XW
authors.lastname: Wang
authors.affiliation: Department of Otology and Skull Base Surgery, Eye Ear Nose & Throat Hospital, Fudan University, Shanghai 200031, China; Shanghai Auditory Medical Center, Shanghai, China; Key Laboratory of Hearing Science, Ministry of Health, Shanghai, China.
authors.forename: Xian-Hao
authors.initials: XH
authors.lastname: Jia
authors.affiliation: Department of Otology and Skull Base Surgery, Eye Ear Nose & Throat Hospital, Fudan University, Shanghai 200031, China; Shanghai Auditory Medical Center, Shanghai, China; Key Laboratory of Hearing Science, Ministry of Health, Shanghai, China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Cheng
authors.affiliation: Department of Otology and Skull Base Surgery, Eye Ear Nose & Throat Hospital, Fudan University, Shanghai 200031, China; Shanghai Auditory Medical Center, Shanghai, China; Key Laboratory of Hearing Science, Ministry of Health, Shanghai, China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Liu
authors.affiliation: Key Laboratory of Hearing Science, Ministry of Health, Shanghai, China; Research Center, Eye Ear Nose & Throat Hospital, Fudan University, Shanghai 200031, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Yang
authors.affiliation: The First Affiliated Hospital of AnHui Medical University, Hefei, China.
authors.forename: Bu-Sheng
authors.initials: BS
authors.lastname: Tong
authors.affiliation: Department of Otology and Skull Base Surgery, Eye Ear Nose & Throat Hospital, Fudan University, Shanghai 200031, China; Shanghai Auditory Medical Center, Shanghai, China; Key Laboratory of Hearing Science, Ministry of Health, Shanghai, China.
authors.forename: Fang-Lu
authors.identifier: 0000-0002-3243-0393
authors.initials: FL
authors.lastname: Chi
authors.affiliation: Department of Otology and Skull Base Surgery, Eye Ear Nose & Throat Hospital, Fudan University, Shanghai 200031, China; Shanghai Auditory Medical Center, Shanghai, China; Key Laboratory of Hearing Science, Ministry of Health, Shanghai, China.
authors.forename: Dong-Dong
authors.identifier: 0000-0002-2889-9375
authors.initials: DD
authors.lastname: Ren
mesh_terms: D000161:Acoustic Stimulation / Q000295:instrumentation / Q000379:methods*; D000818:Animals; D018159:Endolymphatic Hydrops / Q000473:pathology / Q000503:physiopathology*; D006168:Guinea Pigs; D034381:Hearing Loss / Q000473:pathology / Q000503:physiopathology; D008297:Male; D013016:Sound; D014732:Vibration