Vulnerability to noise-induced hearing loss in ‘middle-aged’ and young adult mice: a dose–response approach in CBA, C57BL, and BALB inbred strains

• Published in: Hearing research Vol. 149; no. 1; pp. 239 - 247
• Main Authors: Ohlemiller, Kevin K, Wright, James S, Heidbreder, Arnold F
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.11.2000; Elsevier
• Subjects: Aging; Aging - physiology; Ahl; Ahl2; Animals; Auditory brainstem response; Auditory Threshold; Biological and medical sciences; Cell Death; Cochlea; Disease Susceptibility; Ear, auditive nerve, cochleovestibular tract, facial nerve: diseases, semeiology; Hair cell; Hair Cells, Auditory - physiology; Hearing Loss, Noise-Induced - etiology; Hearing Loss, Noise-Induced - physiopathology; Medical sciences; Mice; Mice, Inbred BALB C - physiology; Mice, Inbred C57BL - physiology; Mice, Inbred CBA - physiology; Mouse; Non tumoral diseases; Otorhinolaryngology. Stomatology; Presbycusis; Species Specificity; Ahl2; Auditory brainstem response; Mouse; Ahl; Cochlea; Aging; Hair cell; Presbycusis; Permanent threshold shift; Noise; Internal ear disease; Rodentia; Auditory disorder; Outer hair cell; Strain; Hearing loss; Acoustic trauma; Vertebrata; Sensitivity; Mammalia; Cell death; Animal; Auditory evoked potential; ENT disease; Genetics; Noise pollution; Age
• ISSN: 0378-5955; 1878-5891
• DOI: 10.1016/S0378-5955(00)00191-X

Vulnerability of the cochlea to noise-induced permanent threshold shifts (NIPTS) was examined in young adult (1–2 months) and ‘middle-aged’ (5–7 months) CBA/CaJ, C57BL/6J, and BALB/cJ inbred mice. For each age and strain, a dose–response paradigm was applied, whereby groups of up to 12 animals were exposed to intense broadband noise (110 dB SPL) for varying durations. Exposure durations reliably associated with <10% and >90% probability of a criterion amount of NIPTS (determined 2 weeks post-exposure) were identified, and the minimum NIPTS exposure and the slope of the dose–response relation were then derived by numerical modeling. For all three strains, young adult mice were more susceptible to NIPTS than older adults; That is, a shorter exposure was able to cause NIPTS in the younger mice. Strain comparisons revealed that C57 mice were more susceptible than CBAs in the older age group only. At both ages examined, however, BALB mice were most susceptible to NIPTS. When animals with a similar amount of NIPTS were compared, outer hair cell loss in the cochlear base was more widespread in the younger animals. BALB mice appear particularly susceptible to noise-induced outer hair cell loss throughout life. Our data suggest that the mechanism or site of noise injury differs between young adults and older adults, and may depend on genetic background. The finding that both BALB and C57 mice, which show pronounced age-related hearing loss, are also especially vulnerable to noise supports the notion that genes associated with age-related hearing loss often act by rendering the cochlea susceptible to insults.