Noise beyond hearing: metabolic and vascular changes in the mouse amygdala following acute acoustic trauma

Acute exposure to noise, at a high intensity of 100 dB SPL for a duration of 2 hours, triggers immediate alterations in the amygdala of mice. These changes encompass metabolic and vascular modifications, though the full extent of these effects remains incompletely understood. To investigate these effects, researchers utilized advanced techniques such as untargeted metabolomics and ultrasound localization microscopy to analyze the amygdala tissues before exposure and at 1 and 7 days post-exposure.

The findings revealed a notable increase in auditory thresholds across all frequencies at day 1, with a partial recovery of normal hearing ability at select frequencies by day 7. Additionally, metabolomic analysis unveiled a consistent rise in glutamate levels over the seven-day period, whereas GABA levels exhibited a decrease at day 1, which normalized by day 7, indicating a disruption in the excitation-inhibition balance within the amygdala.

Concurrently, the blood flow velocity within the amygdala significantly increased by day 1 and persisted at elevated levels by day 7. Furthermore, a marked rise in vascular density was observed by day 7, suggesting a lasting impact on the vascular structure of the amygdala following acute noise exposure. This study provides compelling evidence that acute noise exposure induces both metabolic disturbances and hemodynamic changes in the amygdala, alongside vascular alterations, thereby offering fresh insights into the direct impact of noise on non-auditory brain regions.

The research was supported by the Shanghai Key Clinical Specialty Fund, and the findings are published under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.