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Objectives: Experimentally test the effect of vestibular nerve neurectomy on the function and histopathology of the cochlea.
Methods: The study was conducted on 20 normal male adult pigmented guinea pigs (Cavia porcellus). First, each animal was tested with Distortion Product Otoacoustic Emissions (DPOAEs) preoperatively then vestibular neurectomy (V.N) was performed on the right side through suboccipital modified retrosigmoid approach. We tested the DPOAEs postoperatively; After 8 weeks, Guinea pigs were euthanized the cochlea of guinea pig was processed for light microscope and transmission electron microscope examination to observe the outer hair cell count, and spiral ganglion cell density in the operated ear compared to contralateral non operated cochlea of the same guinea pig.
Results: There was a significant decrease in spiral ganglion cell density in the operated side compared to the non-operated side. However, there was no significant difference in outer hair cell count or DPOAEs between the two sides, except for a significant increase in DPOAEs at 2 KHz in the operated side.
Conclusion: The results suggest that vestibular neurectomy may affect spiral ganglion cell density but not necessarily outer hair cell count or DPOAEs, and the relationship between these variables is complex and could be frequency-dependent.
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http://dx.doi.org/10.1016/j.anl.2025.01.010 | DOI Listing |
Front Immunol
July 2025
Department of Otorhinolaryngology, Hannover Medical School, Hannover, Germany.
Purpose: After cochlear implantation, molecular processes at the electrode-nerve interface significantly influence the variability in clinical outcomes. The present study investigates molecular processes in a guinea pig model of cochlear implant (CI) using positron emission tomography/computed tomography (PET/CT) and correlates the imaging findings with histological analyses.
Methods: Animals were examined with PET in the 3 weeks and 9-12 months post-implantation using the inflammation marker [F]FDG and, at the later time points, [Ga]FAPI-46 as a marker for fibrosis.
Hear Res
September 2025
ENT Institute and Department of Otolaryngology, Eye & ENT Hospital, Fudan University, Shanghai 20031, China; NHC Key Laboratory of Hearing Medicine Research, Fudan University, Shanghai 20031, China. Electronic address:
Objectives: Tinnitus affects millions globally, yet its clinical assessment relies on subjective reports, limiting diagnostic accuracy and treatment development. This study aimed to identify objective, tinnitus-related features within ensemble spontaneous activity (ESA) recorded from the cochlear surface in a guinea pig model and to evaluate their reversibility using extracochlear electrical stimulation (EES) and machine learning.
Design: ESA was recorded from four groups: normal controls, noise-exposed animals with tinnitus, noise-exposed animals without tinnitus, and tinnitus animals after EES.
Hear Res
September 2025
Department of Experimental Otology, Hannover Medical School, Stadtfelddamm 34, 30625 Hannover, Germany; Lower Saxony Center for Biomedical Engineering, Implant Research and Development (NIFE), Germany.
While cochlear implants (CIs) historically use cathodic-leading pulses for stimulation, studies in humans found that anodic-leading pulses are perceived louder than cathodic-leading ones. Modeling studies proposed that cathodic pulses excite the spiral ganglion neurons (SGNs) more peripherally than anodic pulses. Thus, the anodic-benefit in human CI listeners is thought to reflect degenerated peripheral processes.
View Article and Find Full Text PDFJ Otolaryngol Head Neck Surg
June 2025
Department of Otolaryngology-Head & Neck Surgery, University of Manitoba, Winnipeg, MB, Canada.
ImportanceThis study investigates the potential of brain-derived neurotrophic factor (BDNF) as treatment for sensorineural hearing loss (SNHL) in a guinea pig model to potentially advance hearing restoration strategies. The correlation between oxidation-reduction (REDOX) potential in blood and perilymph is evaluated to confirm using blood as a proxy for perilymph in further study.ObjectivesTo evaluate hearing following 2 intracochlear applications of BDNF as a therapy for hearing loss.
View Article and Find Full Text PDFLaryngoscope Investig Otolaryngol
June 2025
Université Paris Cité, Institut Pasteur, AP-HP, Inserm, Fondation Pour l'audition, Institut de l'audition, IHU Re-Connect F-75012, Technologies and Gene Therapy for Deafness Paris France.
Objectives: Rodents are used in most otological research studies and the choice of the most appropriate animal model may be crucial in studies of ear diseases and in the development of effective treatments. Here, we used micro-CT to compare temporal bone anatomy between four rodent model animals (guinea pigs, gerbils, rats, and mice) and humans, aiming to better characterize the anatomy of the inner and middle ear, and facial nerve to support informed animal model selection in otologic research.
Methods: We generated three-dimensional reconstructions and measured the various middle (tympanic membrane, ossicular chain, and facial nerve) and inner (cochlea, vestibular labyrinth) ear structures.