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Aging lengthens TauDD in C57BL/6J, DBA/2J, and outbred SWR male mice (Mus musculus)
A R Mayeda1, J R Hofstetter, B Possidente
1Department of Veterans Affairs, Richard L. Roudebush Medical Center, Indianapolis, Indiana, USA.
Abstract:
The effect of aging on the free-running period (TauDD) of a circadian rhythm for wheel-running activity was observed in two inbred strains (DBA/ 2J and C57BL/6J) and one outbred strain (Tac: (SW)fBR) of laboratory mice (Mus musculus). TauDD in the DBA and C57 mice was monitored at approximately age 100 days and age 300 days. TauDD in the outbred strain was monitored at approximately age 100 days and age 600 days. TauDD increased with age in all three strains. Most studies of age effects in rodent species have shown a shortening of TauDD with age, with th exception of the C57BL inbred mice. These results show that the lengthening of TauDD with age in laboratory mice is not limited to the C57BL strain and may be a general characteristic of this species, in contrast to other rodent species examined.
Insights
Aging lengthens the free-running period (TauDD) of circadian rhythms in laboratory mice. This lengthening effect, observed across multiple strains, contrasts with findings in other rodent species.
Area of Science:
- Chronobiology
- Animal Models
- Gerontology
Background:
- Circadian rhythms regulate physiological processes in mammals.
- The free-running period (TauDD) of circadian rhythms can be affected by aging.
- Previous studies on rodent aging and circadian rhythms have yielded mixed results.
Purpose of the Study:
- To investigate the effect of aging on the free-running period (TauDD) of circadian rhythms in different laboratory mouse strains.
- To compare age-related changes in TauDD across inbred and outbred mouse populations.
- To determine if the lengthening of TauDD with age is specific to certain mouse strains or a general species characteristic.
Main Methods:
- Monitoring wheel-running activity to assess circadian rhythms.
- Measuring the free-running period (TauDD) in laboratory mice (Mus musculus) at different ages.
- Utilizing two inbred strains (DBA/2J, C57BL/6J) and one outbred strain (Tac:(SW)fBR).
Main Results:
- TauDD increased with age in all three mouse strains studied.
- The lengthening of TauDD was observed in DBA/2J and outbred mice, similar to previous findings in C57BL/6J mice.
- Age-related TauDD lengthening was observed at approximately 100 and 300 days for inbred strains, and 100 and 600 days for the outbred strain.
Conclusions:
- The lengthening of the free-running period (TauDD) with age in laboratory mice is not limited to the C57BL strain.
- This age-related lengthening of TauDD may be a general characteristic of Mus musculus.
- Findings contrast with observations in other rodent species, suggesting species-specific aging effects on circadian rhythms.