Males lose hearing earlier in mouse models of late-onset age-related hearing loss; females lose hearing earlier in mouse models of early-onset hearing loss.

Gender-related differences in human hearing have been attributed to genetic, environmental, and/or genetic x environmental interactive factors. These differences tend to increase with age, with males showing greater high frequency threshold elevations. An appropriate animal model could aid in prediction, treatment, and prevention of some of these losses. This paper examines inbred strains of mice that are widely used as models of late- (CBA/J and CBA/CaJ) and early- (C57BL/6J) onset age-related hearing loss. In the former two genotypes, the thresholds to high frequency stimuli of the auditory brainstem response (ABR) are higher in the male than in the female. This gender difference was less pronounced in thresholds to the cochlear nerve envelope response of the CBA/CaJ, although this response was more sensitive to the influence of age than was the ABR. In contrast, the male C57BL/6J had more sensitive thresholds than the female, with both measures showing massive loss of sensitivity with increasing age. The data are discussed in terms of the applicability of these animals as tools for examining factors that degrade cochlear function.