Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Chronic jet-lag conditions hasten death in aged mice

07.11.2006
Researchers have found that aged mice undergoing weekly light-cycle shifts--similar to those that humans experience with jet lag or rotating shift work--experienced significantly higher death rates than did old mice kept on a normal daylight schedule over the same eight-week period.

The findings may not come as a great surprise to exhausted globe-trotting business travelers, but the research nonetheless provides, in rather stark terms, new insight into how the disruption of circadian rhythms can impact well-being and physiology, and how those impacts might change with age. The mouse study is reported by a group led by Gene Block and Alec Davidson of the University of Virginia and appears in the November 7th issue of the journal Current Biology, published by Cell Press.

The researchers were led to examine a possible link between jet lag and mortality by something they had noticed in an earlier, unrelated study: A surprising fraction of old (but genetically altered) rats exposed to a six-hour advance in their light cycle died after the shift in schedule.

In the new work, the researchers examined the mortality link in earnest by looking at how young mice and old mice fared when subjected to two different types of light-cycle shifts. In one regimen, mice experienced a six-hour forward shift once a week, while in the other, mice experienced a six-hour backward shift. A "control" group of young and old mice did not experience any schedule shifts.

The researchers found that the young mice generally survived well under the various conditions. In contrast, the light-cycle shifts had a marked effect on the survivorship of the old mice. While 83% of old mice survived under the normal schedule, 68% survived under the backward-shift regimen and 47% survived under the forward-shift regimen.

Past work has also linked changes in light schedule with death in other animals and under different experimental circumstances, but the findings here indicate that there may be a differential effect of mortality depending on the direction of the schedule shift--forward or backward. Schedule "advancers" did more poorly in the present experiment than did "delayers."

Notably, the researchers found that chronic stress--as measured by daily corticosterone levels--did not increase in the old mice experiencing the light-cycle shifts. The underlying cause of the increased mortality is not yet clear, but could involve sleep deprivation or immune-system disruption.

The body's physiological reaction to time change may be complex. Past research has indicated that circadian clocks govern physiological rhythms in a great variety of tissues in the body, and that different aspects of the physiological clock can adjust to schedule changes at different rates. The researchers speculate that the internal lack of synchrony among different physiological oscillations may have serious health consequences that are exacerbated in aged animals.

Heidi Hardman | EurekAlert!
Further information:
http://www.current-biology.com

Further reports about: Researchers light-cycle mortality physiological survived

More articles from Life Sciences:

nachricht Fine organic particles in the atmosphere are more often solid glass beads than liquid oil droplets
21.04.2017 | Max-Planck-Institut für Chemie

nachricht Study overturns seminal research about the developing nervous system
21.04.2017 | University of California - Los Angeles Health Sciences

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

Im Focus: Quantum-physical Model System

Computer-assisted methods aid Heidelberg physicists in reproducing experiment with ultracold atoms

Two researchers at Heidelberg University have developed a model system that enables a better understanding of the processes in a quantum-physical experiment...

Im Focus: Glacier bacteria’s contribution to carbon cycling

Glaciers might seem rather inhospitable environments. However, they are home to a diverse and vibrant microbial community. It’s becoming increasingly clear that they play a bigger role in the carbon cycle than previously thought.

A new study, now published in the journal Nature Geoscience, shows how microbial communities in melting glaciers contribute to the Earth’s carbon cycle, a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

New quantum liquid crystals may play role in future of computers

21.04.2017 | Physics and Astronomy

A promising target for kidney fibrosis

21.04.2017 | Health and Medicine

Light rays from a supernova bent by the curvature of space-time around a galaxy

21.04.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>