title: Disparities in auditory physiology and pathology between C57BL/6J and C57BL/6N substrains.
abstract: C57BL/6 inbred mice are frequently used as models in auditory research, mostly the C57BL/6J and C57BL/6N substrains. Genetic variation and phenotypic disparities between these two substrains have been extensively investigated, but conflicting information exists about differences in their auditory and vestibular phenotypes. Literature-based comparisons are rendered difficult or impossible because most auditory publications do not designate the substrain used. We therefore evaluated commercial C57BL/6N and C57BL/6J mice for their baseline auditory brainstem response (ABR) thresholds at 3 months of age as well as their susceptibility to noise exposure and aminoglycoside antibiotics. Both substrains have similar thresholds at 4 and 12 kHz, but C57BL/6N show significantly higher baseline thresholds at 24 and 32 kHz. Because of these elevated thresholds, the N substrain is unsuitable as a model for drug ototoxicity, which primarily affects high frequencies. Exposure to 2-20 kHz broadband noise for 2 h at 110 dB produced significantly higher threshold shifts in the J substrain. These results suggest caution in the selection of C57BL/6 substrains for auditory research and indicate the need to specify substrains, age and the breeding source in all publications.
authors.affiliation: Kresge Hearing Research Institute, Department of Otolaryngology, University of Michigan, Ann Arbor, MI 48109-5616, USA. Electronic address: akendall@umich.edu.
authors.forename: Ann
authors.initials: A
authors.lastname: Kendall
authors.affiliation: Kresge Hearing Research Institute, Department of Otolaryngology, University of Michigan, Ann Arbor, MI 48109-5616, USA. Electronic address: schacht@umich.edu.
authors.forename: Jochen
authors.initials: J
authors.lastname: Schacht
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001306:Auditory Pathways / Q000473:pathology* / Q000502:physiology*; D001309:Auditory Threshold / Q000187:drug effects; D007612:Kanamycin / Q000494:pharmacology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL / Q000235:genetics*; D009622:Noise; D010641:Phenotype; D014722:Vestibule, Labyrinth / Q000473:pathology / Q000502:physiology
chemical_list: D000900:Anti-Bacterial Agents; D007612:Kanamycin