Effects of Moderate Noise Exposure on Hearing Function in C57BL/6J Mice

ObjectiveTo study characteristics of hearing loss after exposure to moderate noise exposure in C57BL/6J mice.MethodsMale C57BL/6J mice with normal hearing at age of 5-6 weeks were chosen for this study. The mice were randomly selected to be studied immediately after exposure (Group P0), or 1 day (Group P1), 3 days (Group P3), 7 days (Group P7) or 14 days (P14) after exposure. Their before exposure condition served as the normal control. All mice were exposed to a broad-band white noise at 100 dB SPL for 2 hours, ABR thresholds were used to estimate hearing status at each time point.ResultsABR threshold elevation was seen at every tested frequency at P0 (P<0.01). Elevation at high-frequencies (16 kHz and 32 kHz) was greater than at lower frequencies (4 kHz and 8 kHz, P<0.05). From P1 to P14, ABR thresholds continuously improved, and there was no significant difference between P14 and before exposure (P>0.05).ConclusionThere is a frequency specific response to 100 dB SPL broad-band white noise in C57BL/6J mice, with the high-frequency being more susceptible. Hearing loss induced by moderate noise exposure appears reversible in C57BL/6J mice.