Cool Mice Live Longer
Extended Life Span in Mice Genetically Engineered for Low Body Temperature
Nov. 2, 2006 -- Cool mice live longer, find scientists at Scripps Research
No, the mice aren't more hip than other mice. They've been genetically
engineered to have a slightly lower body temperature than normal mice.
The low body temperature -- about one-half to one degree Fahrenheit lower
than normal -- doesn't seem to hurt the mice. During infections, they get
fevers that spike as high and last as long as those of normal mice. And they
have normal appetites -- especially male cool mice, which gain a bit of extra
weight as they age.
But the cool mice live significantly longer than normal mice. Females lived
about 20% longer than normal. Males lived about 12% longer.
It's already known that animals live longer if put on a very low-calorie
diet. One explanation for this is that burning fewer calories lowers body
temperature. So Bruno Conti, PhD, Tamas Bartfai, PhD, and colleagues came up
with a plan to lower the body temperature of mice.
They genetically engineered a strain of mice that make excessive amounts of
a heat-generating protein in a specific brain region -- the brain's internal
thermostat. If you heat the thermostat in your home, the thermostat will be
tricked into thinking it's hot and will turn down the heat. The same thing
happens in the brains of cool mice.
Of course, the point isn't simply to make mice that live longer. The
researchers -- who have spent five years on this project -- hope that future
drugs or devices could be used to extend human lives.
"This mechanism, we believe, will be a good target for pharmacological
manipulation or heating," Bartfai said in a news release.
The findings appear in the Nov. 3 issue of the journal Science.