Published: May 05, 2009 10:27 pm         

Stephanie Salter: When a mouse is cold but can’t put on a sweater

The kind of work Joseph Garner does with animals might strike a lot of us as proving the obvious. But those of us who might think that are not scientists.

We would base our ideas about what hurts or pleases little critters like lab mice or goldfish on projections of our own pleasure and pain triggers. That attitude makes for good children’s books, but bad science.

Humans and mice have a lot in common (DNA-wise), but broadly attributing human characteristics to mice or fish is an unwise stretch. Lucky for the critters that Garner, an assistant professor of animal sciences at Purdue University, is using scientific methods to demonstrate significant shared traits among all creatures great and small.

I became a fan of Garner’s work last year when Purdue News Service released a fascinating story about his research with the lowly lab mouse and its environment. I called to ask him a couple follow-up questions, and we were on the phone for nearly an hour talking about amazing animal behaviors such as the way male mice will “sing” in ultra-sound to a Q-tip dipped in female mouse urine.

That story was titled, “Stress relief: Lab mice that exercise control may be more normal.”

As any first-year psych student can tell you, people get anxious and depressed (and often physically ill) when they perceive they have lost control of their life. So, too, with mice who are born in cages, live a life of experiments in cages, and die in cages.

Garner and fellow researchers have found that if the mice perceive they have some control over their being, they are less stressed, therefore healthier, and make better experimental subjects.

Until scientists started studying “the animalness of animals,” the common scientific view of laboratory animals’ “health” was pretty narrow. Animals were considered healthy if they had energy, an appetite and were disease-free. The preferred environment for them was sterile and impeccably controlled — by humans.

As researchers began looking more closely at lab animal life, however, “health” took on new dimensions, including psychological well-being (you can tell when a mouse is bummed out, not to mention psycho) and lack of pain or suffering.

The most interesting dimension, though, is the animalness element, or the essence of being an animal. Garner’s experiments with mice and control showed a couple significant things in that realm.

For one, when given choices of various cage temperatures, lab mice primarily chose the warmest (86 degrees) for most of their activities, but they moved to other temperatures for other functions during the day and night. This told Garner that the typical lab tendency to try to regulate one temperature for all mice all the time is not optimum.

When people get too cold or too hot, they can put on or remove clothes. If for some reason that isn’t possible, people get stressed. Mice, who don’t wear clothes, react the same way. Garner theorized that perhaps the least labor-intensive way to let mice do their own temperature regulating is to allow them to build nests, as wild mice do.

Again, a widely-held attitude about lab mice and nests has been that the building instinct was long ago bred out of them. Researchers who share Garner’s view tested to see if maybe the material given to lab mice for nest building was simply the wrong stuff.

Sure enough, when provided in-the-wild-like materials — facial tissues, cotton squares and shredded paper strips — even mice who had never nested before built nests. The nests that most approximated the complex nests of wild mice, Garner found, were made of paper strips.

Increasing research literature, he said, indicates “this behavior hasn’t been bred out of them. Now, we’re seeing this behavior described in mice that are hundreds of generations in captivity.”

Rather than worry about controlled lab temperatures, just give the mice the materials they need for house building.

“Mice can live in deep freezers if they can build nests,” he said. “… Control is the animalness of animals.”

Most recently, Garner and a colleague at the Norwegian School of Veterinary Science, Janicke Nordgreen, have turned to fish and their supposed imperviousness to pain.

Because fish don’t scream or make faces when they’re cut or punctured or stabbed, humans long have told themselves that fish don’t feel pain as we do. Garner’s and Nordgreen’s findings cast major doubt on that.

Using tiny foil heaters attached to two groups of goldfish — one group injected with morphine, the other with only saline — the two scientists discovered fish responded “reflexively and cognitively” to hurtful stimuli. (The heaters had sensors that shut them down before a fish’s tissue could be physically damaged.)

Both the morphine and saline fish “wriggled” at about the same temperatures when the heaters were turned up. Thus the reflexive response. The cognitive response came later when the goldfish were back in their usual tanks.

The fish who’d had pain-killing morphine “acted like they always had; swimming and being fish,” Garner reported. “The fish that had gotten saline — even though they had responded the same way in the [heater] test — later acted different, though. They acted with defensive behaviors, indicating wariness, or fear and anxiety.”

They remembered being hurt.

Before anyone labels Garner as some sentimental, bleeding heart who would sacrifice human health to keep lab rats from suffering, don’t. What Garner and his like-minded scientists are saying is, those two goals don’t have to be mutually exclusive.

Myriad adjustments, most of them easy and cheap, can be made to give lab animals as ordinary and stress-free a life as possible. The key is to acknowledge that they, like humans, are multi-dimensional beings who need a lot more than regular food and water to be normal, healthy and authentically themselves.

And Garner’s got good science to prove it.

Stephanie Salter can be reached at (812) 231-4229 or stephanie.salter@tribstar.com.