Cages Cause Brain Damage in Lab Mice

There are a lot of reasons why animal testing doesn't make sense: it's inhumane, it's costly and animal models don't work for predicting human outcomes. Now, there's one more reason to add to the list — the cages where lab mice are kept actually alter their brains.

It's long been argued that one of the many reasons why animal testing doesn't work — other than the fact that humans have different physiology than mice, or even chimpanzees — is that the stressful condition of a laboratory can alter the outcome of an experiment. Stress causes a series of physical reactions that change the way the body reacts to drugs and other stimuli. In other words, the contrived environment of a lab says nothing about how that animal would respond to various factors out in the real world; it's even farther from shedding light on what it means for an actual human in society.

Scientists around the world have created well-funded experiments that revolve around mice. Turns out it could be an even bigger waste of money than we thought. A new study from the University of Colorado's Anschutz Medical Campus shows that the effects of the research environment on mice aren't just psychological or stress-based — the cages actually physically alter the rodents' brains.

Mouse brains are extremely sensitive to their surroundings. Different types of cages can change factors ranging from sense of smell to level of aggression. Diego Restrepo, who recently published a paper on this topic, says, "This could explain some of the failures to replicate findings in different laboratories and why contradictory data are published by different laboratories even when genetically identical mice are used as subjects."

Restrepo went on to say: "We need to ensure that laboratory findings are truly indicative of natural processes and not simply the result of environmental factors within each lab."

And that's where he lost my vote of confidence. Anything that happens in a lab, by definition, is not a "natural process."

This research could be used for good or evil. In an ideal world, scientists would recognize the implications of this study: Animal models don't work and, on the whole, are unscientific. However, in reality, when Restrepo says he hopes his findings inspire scientists to "overcome" the problem, it's more likely to result in more tests that mess with mouse brains and a company that ends up with a monopoly on producing identical laboratory cages.

Photo credit: Aaron Logan