Susceptibility to noise-induced hearing loss in two congenic mouse strains.
Davis-R; Joohnson-KR; Custer-DA; Krieg-E Jr.
Abstr 33rd Midwinter Res Meet 2010 Feb; 33:235
In 1993 Erway et al. identified a single genetic locus (Ahl) that could explain the early presbycusis observed in the inbred C57BL/6J mouse strain. This locus was later shown to make this strain more vulnerable to noise-induced hearing loss (Davis et al., 2001). This locus is believed to code for cadherin 23. Recently, Johnson has developed two relevant congenic mouse strains. In the congenic C57BL/6J strain, the Ahl locus has been replaced by the wild-type locus from the inbred CBA/CaJ strain (strain B6.CBA). In the congenic CBA/CaJ strain the wild-type locus has been replaced by the mutant Ahl locus (strain CBA.B6). The present study was designed to test these congenic strains for their vulnerability to noise-induced hearing loss. Mouse hearing was tested pre-exposure by ABR at 8, 16 and 32 kHz. Groups of both strains were exposed to various levels of broadband noise between 98 and 118 dB for one hour. Seven to nine days later their hearing was again tested by ABR. Generally, pre-exposure the B6.CBA congenics started out with more sensitive ABR thresholds than the CBA.B6s (strain differences were statistically significant at all frequencies pre-exposure.) This would be expected based on the fact that the congenic CBA.B6 mice genotypes included the mutant Ahl locus. This presentation will compare ABR results in the two congenic strains as well as compare the present data with the previous inbred C57BL/6J and CBA/CaJ data.
Noise-exposure; Exposure-levels; Noise-induced-hearing-loss; Noise-exposure; Noise; Hearing; Hearing-disorders; Hearing-loss; Laboratory-animals; Animals; Molecular-structure; Genetics; Genetic-factors
Abstracts of the 33rd Midwinter Research Meeting