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Cochlear Implant Surgery and Electrically-evoked Auditory Brainstem Response Recordings in C57BL/6 Mice
Published on: January 9, 2019
Early cochlear response and ICAM-1 expression to cochlear implantation
Gordana Elizabeth Kel1, Justin Tan, Hayden Timothy Eastwood
1*Department of Otolaryngology, University of Melbourne; and †Department of Surgery, Monash University, Clayton, Melbourne, Victoria, Australia.
Summary
Cochlear implantation triggers an early inflammatory response, with peak cell recruitment occurring 24 hours post-surgery. This suggests anti-inflammatory drugs should target the initial days after electrode insertion to protect hearing.
Area of Science:
- Otoacoustic emissions and inner ear physiology
- Biomaterials and tissue engineering
- Surgical innovation in otology
Background:
- Understanding the cochlea's early response to electrode implantation is crucial for optimizing drug delivery durations.
- Protecting residual hearing during cochlear implantation is a key clinical challenge.
Purpose of the Study:
- To investigate the early cochlear response to electrode insertion.
- To analyze intercellular cell adhesion molecule-1 (ICAM-1) expression following cochlear electrode implantation.
Main Methods:
- Guinea pigs underwent cochlear electrode implantation.
- Cochleae were harvested at 1, 2, and 7 days post-surgery for analysis.
- Immunohistochemistry was used to assess ICAM-1 expression.
Main Results:
- Early post-implantation (1-2 days) showed fibrin, blood clot, and leukocytic infiltrate in the scala tympani.
- By 7 days, fibroblasts infiltrated the clot, and red blood cells and neutrophils decreased.
- Intercellular cell adhesion molecule-1 (ICAM-1) expression peaked in the basal turn near the electrode at 24 hours.
Conclusions:
- Cochlear vasculature maximally recruits circulating cells at 24 hours post-implantation, indicated by ICAM-1 expression.
- The cochlear response involves early fibrin/clot formation followed by fibroblast infiltration.
- Anti-inflammatory therapies should focus on the first few days after surgery to reduce immune cell extravasation.
