Effects of dietary restriction on presbyacusis in the mouse.

If dietary restriction can extend the human life span, it would be useful to know whether presbyacusis would continue its normal pace. This question was experimentally addressed, using the mouse as a model. Alternate-day feeding and fasting resulted in restricted mice of the AKR and AU/Ss inbred strains weighing less than their continuously fed controls. Restriction did not increase the life span or alter presbyacusis of the AKR mouse, but it improved both functions in the AU/Ss mouse. Their life spans were increased by 40%, and cochlear functions were better than controls at every age at which animals of both groups were still alive. Nonetheless, the oldest remaining restricted AU/Ss mouse had greater cochlear loss than was seen in any AU/Ss control mice. This study demonstrates that dietary restriction can slow the cochlear losses in a mammal which has a presbyacusis condition similar to that of humans.