I work in a research laboratory that studies obesity. We use both human and animal models in our experiments, but I work only with the animals. Sometimes I joke that the people with good interpersonal skills get to work with the human volunteers, and the rest of us are kept as far away from them as possible. Seriously though, I do realize that it takes a special person to be able to work with animals each and every day, and I’m proud to have a great group of co-workers that are both compassionate and professional in their chosen careers.
In general, obesity results from either too many calories consumed or too little physical activity, although both factors usually contribute in some degree to the condition in humans. Animals, however, provide a slightly different challenge because they tend to eat only until their calorie needs are met, then they stop. Fortunately, there are some rats and mice that will become obese when fed a high fat diet, so they are the ones we usually use in our research.
When we attempt to introduce physical activity into the experiment, we are presented with another set of issues to consider. Rats don’t like exercise, and will become quite creative in their attempts to avoid it. Mice, on the other hand, absolutely love running, and will spend hours each day on their little wheels. We have been successful using both models in activity experiments, but mice have been the easiest, in my opinion.
Mice love to run so much that we have, on occasion, experienced mice running themselves to death. They get to a point that they can barely even walk, but they continue crawling towards the wheel, obsessed with their desire to run yet a little more. One of our researchers has labeled this behavior “suicide running,” and has introduced a protocol to prevent it from occurring. If an animal runs more than 10 kilometers (6.2 miles) during a 12 hour dark cycle, they will have access to their wheel limited for the next day. Think about it: A 25 gram mouse, about the size of a man’s thumb, covering over six miles in a day! It’s absolutely amazing!
So, it turns out that I’m conducting a “suicide watch” for 60 mice during this Christmas weekend. One of my coworkers is making a list of all animals running more than 10 kilometers, and putting a piece of tape on their wheels, preventing them from turning. I need to go into work each afternoon, and remove the tape, allowing the mice some time to run before their lights come back on, and they go to sleep. This has worked so far, as we haven’t experienced any deaths in this group of animals. It is a little ironic, however, that I’ve been running each day during the time that the “suicide mice” are prevented from doing just that. Well, it’s time for another run. I just hope Sue hasn’t taped my shoes to the wall to keep me home!