Long-lived mice exhibit 24 h locomotor circadian rhythms at young and old age

Abstract

αMUPA transgenic mice exhibit spontaneously reduced eating and increased life span compared with their wild type (WT) control FVB/N mice. αMUPA mice also show high-amplitude circadian rhythms in food intake, body temperature, and hepatic clock gene expression. Here we examined young and aged WT and αMUPA mice for the period of locomotor activity ( tau) under total darkness (DD). We show that tau changed in WT mice from a period < 24 h at 8 months to a period > 24 h at 18 months. However, the period of αMUPA mice was ~ 24 h at both 8 and 18 months. As deviation of tau from 24 h has been found to be inversely related to life span in a large number of rodents, our results suggest that the sustainable endogenous period of ~ 24 h in αMUPA mice may contribute to their prolonged life span.