Deep Phenotyping of a Mouse Model for Hearing Instability Disorders.

Area of Science:

• Otolaryngology
• Genetics
• Immunology

Background:

• Hearing instability (HI) disorders, characterized by fluctuating or sudden hearing loss, are not fully understood.
• The Slc26a4 (pendrin)-insufficiency mouse model (DE17.5) offers a genetic model for HI, but requires detailed audiometric and immunohistologic characterization.

Purpose of the Study:

• To deeply phenotype the Slc26a4-insufficiency mouse model (DE17.5) to understand the mechanisms of hearing instability.
• To investigate the roles of ion homeostasis and macrophage activation in the pathogenesis of hearing instability.

Main Methods:

• Serial auditory brainstem responses (ABR) were used to identify hearing instability (F) in DE17.5 mice.
• Gene expression analysis of stria vascularis (SV) cell types, endolymphatic hydrops (EH), endocochlear potential (EP), and macrophage activation were compared between HI and non-HI mice.

Main Results:

• Mice with hearing instability showed reduced expression of ion homeostasis genes and increased macrophage activation in the SV.
• Both HI and non-HI DE17.5 mice exhibited reduced EP and increased EH compared to controls.

Conclusions:

• Hearing instability in DE17.5 mice is associated with differential ion homeostasis gene expression and enhanced macrophage activation in the SV.
• These findings suggest potential immunologic contributions to hearing instability and offer insights into its pathogenesis.