Prolonged exposure to an augmented acoustic environment ameliorates age-related auditory changes in C57BL/6J and DBA/2J mice

The effects of exposure to an augmented acoustic environment (AAE) on audit ory function were evaluated in mouse strains that exhibit high-frequency he aring loss beginning during young adulthood (the C57BL/6J strain [C57]) or around the time of weaning/ adolescence (the DBA/2J strain [DBA]). Beginnin g at age 25 days, mice were exposed 12 h every night to a 70 dB SPL broad-b and noise AAE. The AAE was maintained until age 14 months in C57 mice and 9 months in DBA mice. Control mice were age-matched and maintained under nor mal vivarium acoustic conditions. The auditory brainstem response (ABR), ac oustic startle response amplitude, and prepulse inhibition (PPI) were used to assess the auditory system. Exposure to the AAE resulted in improved aud itory performance in both strains (better PPT. lower ABR thresholds, bigger startle amplitudes). (C) 1999 Elsevier Science B.V. All rights reserved.