SEARCH

Entries in Mouse (2)

Friday
Mar302012

Keeping Chilly Lab Mice Warm: Key to Better Science?

Comstock/Thinkstock(NEW YORK) -- Joseph Garner imagines how much happier and healthier lab mice would be in a kinder, gentler environment than the stark cages in chilly laboratories -- and how that, in turn, might improve the outcome of research that underlies human medical advances.

In searching for “one thing we could put in every mouse cage in America that would make every mouse better off and would improve the quality of science done with every mouse,” he focused on a simple fact: mice are chronically cold and suffer from thermal stress.

That “one thing” that could be put in every cage is turning out to be shredded paper, which chilly mice use to build toasty, warm nests like the ones that wild mice build, according to a study published Friday in the journal PLoS One.

Given between a fifth and a third of an ounce of crinkly, coarse shredded paper called Enviro-dri, the mice went to work weaving “these beautiful igloos that are just incredible,” said Garner, an associate professor of comparative medicine at Stanford University in California. He conducted the research while at Purdue University in Indiana, with his then-graduate student Brianna Gaskill, now a postdoctoral scientist at Charles River Laboratories in Wilmington, Mass.

Because mice are nocturnal creatures, he said the lab mice were busy during nighttime hours in the lab, “very much like ‘Where the Wild Things Are.’ They’re very naughty at night.”

Garner has devoted much of the last seven years to understanding why 90 percent of compounds that look promising in animals go on to “fail in human trials.” He’s convinced their environment is part of the answer.

A mouse living in captivity is “a little bit like you or I living in a glass house being looked after by Tyrannosaurus rex,” he suggested. And a drafty house at that. That’s pretty close to conditions for mice, whose 98.4 degree body temperature is close to the 98.6 degrees of the lab technicians who tend to them. But air temperatures in research laboratories typically are kept between 68 and 75.2 degrees, putting them in a state of “cold stress.”

Garner is among the few U.S. scientists “really generating good data to support what animals ‘need and want,’ because animals clearly have their own needs,” said Joanne Zurlo, director of science strategy at the Center for Alternatives to Animal Testing at the Johns Hopkins Bloomberg School of Public Health in Baltimore. Without convincing proof that mouse well-being matters to scientific results, she said other scientists likely won’t buy into the idea that they need to make changes after “keeping mice in these conditions for umpteen years.”

The world’s largest breeder of laboratory mice, which has been supplying mice for the research, recognizes the important influence of laboratory conditions.

“The animal’s environment is a crucial factor in research,” said Kathleen Pritchett-Corning, director of research and professional services for Charles River Laboratories. “In research, we can control almost all aspects of an animal’s environment, but we don’t always know what’s best for the animal.”

She said the company has been “testing this material for our own use and have been very pleased with the results thus far.” She also suggested providing lab mice with nesting materials “could be a huge gain in welfare” and that other elements of lab animals’ environment are “ripe for study,” such as light levels, noise, air movement, type of bedding and feed.

“The healthier and more ‘normal’ the animal, the better the science,” said Pritchett-Corning, a veterinarian who has been working with mice for nearly 20 years. “The better the science, the more likely it is to lead to discoveries and advances that affect human health. It doesn’t matter what kind of animal it is, it deserves the best care we can provide.”

Copyright 2012 ABC News Radio

Monday
Nov292010

Aging Reversed in Mice, Say Scientists

Photo Courtesy - Getty Images(BOSTON) -- Scientists have turned back the clock in mice they engineered to age faster than normal, an advance they suggest is the first time aging in mice has been reversed.

Researchers at Harvard-affiliated medical centers genetically manipulated mice to age faster, and then used gene therapy to lengthen telomeres -- compounds found at the ends of strands of DNA -- which reversed age-related problems such as decreased brain function and infertility.

"We at best expected it to be a slowing of the process or perhaps an arresting of the process. We did not anticipate that it would be so dramatic a reversal in all of the problems that the animal was experiencing," said Dr. Ronald DiPinho, professor of medicine at Harvard University Medical School and co-author of the paper published Sunday in the journal Nature. "We were so struck by the findings that we rushed to get the study published."

A human cell holds 23 pairs of chromosomes, each containing protective caps at each end called telomeres. Enzymes called telomerases protect the telomeres and reduce DNA damage thought to contribute to tissue aging. But as we age, our cells produce less telomerase; telomeres are cut shorter and eventually fail to protect DNA from damage.

Researchers boosted telomerase in the mice cells -- which hold 20 pairs of chromosomes -- to prevent telomeres from getting shorter. They found restoring the enzyme not only stopped aging but revived failing organs and even restored dark fur to mice who had turned grey. DePinho said the mice that were equivalent to ages 80 to 90 in human years returned to the equivalent of middle age.

"This [research] indicates there's a point of return for these tissues," said DePinho. "The fact that you can bring a tissue to the brink and then bring it back this dramatically is remarkable."

Previous studies suggest that even in humans, shorter telomeres may be associated with age-related diseases such as heart disease and Alzheimer's disease.

In fact, the brains of the age-modified mice were 75 percent of the size of a normal brain, much as happens in a patient with Alzheimer's disease. But when researchers reactivated the telomerase, the brains returned to a normal size, according to the study.

The aging process is complex and telomeres are just one element that contributes to its course. But DePinho said this is one step in learning more about not only the slowing of aging, but also the reversal.

"Telomere dynamics in mice has taught us the role of telomeres in [diseases like] cancer and helped us better understand how to take advantage of these situations," said DePinho.

Still, DePinho said the research is an early look down the pipeline for subsequent studies. Researchers plan to study the potential benefits in normal aging in mice before understanding whether the process might work in humans.

"We want to understand what contribution this makes to the aging process in conjunction with other factors that are responsible for the aging process," said DePinho. "We need to do a more careful analysis of these tissues and their cells to ascertain whether or not we could further regulate the process."

Copyright 2010 ABC News Radio







ABC News Radio