EFFECTS OF MODERATE NOISE EXPOSURE ON HEARING FUNCTION IN C57BL/6J MICE

Objective To study characteristics of hearing loss after exposure to moderate noise exposure in C57BL/6J mice.Methods Male 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.Results ABR 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).Conclusion There 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.