Related Experiment Video
Updated: Jul 2, 2026
Modified Experimental Conditions for Noise-Induced Hearing Loss in Mice and Assessment of Hearing Function and Outer Hair Cell Damage
Published on: February 10, 2023
Detection of cochlear microphonic for differential diagnosis between auditory neuropathy mice and noise-induced
Yuhan Chen1, Jin Li1, Ziyi Chen1
1Department of Audiology and Vestibular Medicine, Senior Department of Otolaryngology Head and Neck Surgery, the 6th Medical Center of Chinese PLA General Hospital, Chinese PLA Medical School, Beijing 100048, China; State Key Laboratory of Hearing and Balance Science, Beijing 100853, China.
Background:
The cochlear microphonic (CM) primarily reflects the composite receptor potential of outer hair cells (OHCs), providing an objective assessment of OHC mechanoelectrical transduction (MET) capacity. However, systematic studies on CM in basic research remain scarce, and baseline CM values for CBA/CaJ mice have not yet been established. Moreover, whether CM can functionally differentiate between auditory neuropathy (AN) and noise-induced hearing loss (NIHL) has not been systematically addressed. This study aimed to establish normative CM reference values for CBA/CaJ mice and to explore the utility of CM as an objective electrophysiological tool for assessing OHC function across different pathophysiological conditions.
New Method:
CM was recorded from the round window in three mouse models: wild-type (WT) CBA/CaJ mice (1, 2, and 7 months), Aifm1 p.R450Q knock-in AN mice, and NIHL models of permanent threshold shift (PTS) and temporary threshold shift (TTS). Input-output (I/O) nonlinearity and frequency-specific were analyzed.
Results:
In WT mice, CM amplitude exhibited an approximately linear relationship with stimulus intensity at levels ≤ 90 dB SPL. When the intensity exceeded 90 dB SPL, the amplitude saturated and subsequently declined, demonstrating nonlinear characteristics under high-intensity stimulation. Compared to 1- and 2-month-old WT mice, CM amplitude was reduced at 7 months of age. In AN mouse models, CM waveforms remained generally normal, but amplitude increased at 1 month and declined by 7 months. In noise-exposed mice, CM amplitude significantly decreased in the PTS group, while only a slight reduction was observed in the TTS group.
Conclusion:
This study establishes normative CM values for CBA/CaJ mice and demonstrates that CM profiling provides a functional differentiation between AN and two types of NIHL. These findings support CM as a robust, objective tool for assessing OHC function in murine models and encourage broader implementation of CM testing in both preclinical research and clinical diagnostics.
