Researcher Calls Out Laboratory ‘Flab Rats’

A medical researcher is calling out laboratory “flab rats” for their obesity and lack of exercise — and he’s not talking about unfit grad students existing on vending-machine candy . He really means the rats (and mice) themselves, the condition of which he says may be leading “to spurious experimental results.”

Writing in New Scientist, Mark Mattson, chief of the laboratory of neurosciences at the U.S. National Institute on Aging Intramural Research Program, argues that rodents used in experiments are overfed and under-exercised, resulting in health problems that may make them poor research subjects. High blood sugar, high blood pressure, cholesterol problems and obesity, among other ailments, all make them more susceptible to certain diseases and may skew results.

How bad is it? “Some strains of lab rat attain a body weight in excess of 1 kilogram, nearly double that of a healthy rat,” he writes. (We think we’ve actually seen one of those on the NYC subway tracks.)

Here’s what Mattson has to say about implications for cancer research:

We know that some carcinogens are more potent in overweight animals and that couch-potato rodents have an elevated risk of developing tumors. In addition, many types of tumor grow more rapidly in animals with unlimited access to food, and certain aspects of metastasis — the process by which tumors spread to new sites in the body — appear to differ between obese and slender mice. Experimental cancer drugs might therefore act differently in couch-potato individuals than in their slender counterparts.

The researcher writes that animal models for neurodegenerative diseases, cardiovascular diseases and renal problems may also be inaccurate if the animals are fat and out of shape. To better mimic the effects of potential treatments in humans who exercise and are at a healthy weight, he suggests withholding food and providing exercise wheels to some of the rodents being used in experiments...