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Updated: Jul 23, 2026

The Mouse Round-window Approach for Ototoxic Agent Delivery: A Rapid and Reliable Technique for Inducing Cochlear Cell Degeneration
12:21

The Mouse Round-window Approach for Ototoxic Agent Delivery: A Rapid and Reliable Technique for Inducing Cochlear Cell Degeneration

Published on: November 26, 2015

Hearing loss in relation to round window membrane morphology in experimental chronic otitis media

L Nordang1, M Anniko

  • 1Department of Otorhinolaryngology and Head and Neck Surgery, University Hospital (Akademiska sjukhuset), S-751 85 Uppsala, Sweden. leif.nordang@ent.uas.lul.se

ORL; Journal for Oto-Rhino-Laryngology and Its Related Specialties
|November 20, 2001
PubMed

Insights

Pseudomonas aeruginosa exotoxin A causes hearing loss in rats. Single doses lead to reversible hearing loss and thickened round window membranes, while repeated doses show diminished effects.

Area of Science:

  • Ototoxicity research
  • Auditory system pathology
  • Bacterial toxin effects

Background:

  • Pseudomonas aeruginosa exotoxin A (PaExoA) is a potent bacterial toxin.
  • Middle ear infections can lead to hearing impairment.
  • Understanding toxin-induced ototoxicity is crucial for developing treatments.

Purpose of the Study:

  • To investigate the ototoxic effects of single and repeated PaExoA instillations in the rat middle ear.
  • To assess the impact on hearing levels, round window membrane (RWM) thickness, and morphology.

Main Methods:

  • PaExoA was instilled into the middle ear of rats.
  • Auditory Brainstem Response (ABR) technique was used to measure hearing levels.
  • Round window membrane (RWM) thickness was measured, and morphology was examined via light microscopy.

Main Results:

  • Both reversible and permanent hearing loss (HL) were observed.
  • Single PaExoA dose caused initial RWM thickening, which persisted.
  • Repeated PaExoA doses led to initial RWM thickening followed by a decrease to near-control levels.

Conclusions:

  • PaExoA is confirmed as an ototoxic agent.
  • Partially reversible hearing loss occurs after single PaExoA application.
  • The diminished ototoxic effect of repeated PaExoA instillations, despite RWM changes, warrants further investigation.

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