Escaping the Research Mousetrap
It’s easy to forget the little guys. While many people are concerned about the abuse of dogs, cats, and chimpanzees in laboratory experiments, rats and mice are not even defined as “animals” in the U.S. Animal Welfare Act. Ditto for birds. And yet these forgotten animals are routinely subjected to miserable conditions in ongoing experiments and are used in far higher numbers than other species.
In many experiments, a large number of animals are bred in attempts to create the right genetic traits in their offspring. The less-than-suitable progeny are all killed along the way. Not only are many scientists asking why they spend their days killing animals by the dozen; more and more researchers are asking the fundamental question—where do these experiments get us? Are we curing diseases or spinning our wheels?
Animal “Models” and Diabetes
Diabetes is an increasingly common condition in which there is too much sugar—or glucose—in the blood, leading to myriad complications. To study diabetes, some experimenters induce it in rodents by forcing them to eat high-fat diets or breeding them to develop obesity, insulin resistance, and high blood sugar.
But mice have very high metabolic rates and are not prone to a sedentary lifestyle, high cholesterol levels, narrowing of the arteries, or many other conditions common to human patients with diabetes.
A common experimental technique is to create “knockout” mice—mice with one or more genes inactivated. For example, a mouse missing a gene involved in insulin signaling—which is essential for shuttling glucose into cells—will develop blood glucose abnormalities, not unlike a person with type 2 diabetes. But unlike humans, these mice often exhibit gene-related disorders starting at birth, including low birth weight and a progressive loss of fat tissue as they age. Many have developmental defects, heart anomalies, reproductive defects, and other health problems.
Experimenters have also tried to recreate late-stage diabetes complications in rodents. About 60-70 percent of people with diabetes eventually develop neuropathy, a condition in which the disease attacks the nerves, leading to pain, numbness, and, in some cases, foot ulcers and amputations. The experiments are rough (and ultimately fatal) on the animals and are frustrating for scientists who have found that diabetes-induced nerve damage does not develop in rodents in the same way it does in humans. Nerve damage in humans occurs in the long nerves running from spinal cords to legs. It initially affects the toes and feet and slowly progresses upward over decades. Because rodents have very short nerve fibers and short lifespans, the disease progression is dramatically different.
Diabetes and the Cost of Mice Experiments
Twelve million people suffered from diabetes in the year 2000. By 2011, that number had more than doubled, and another 79 million had prediabetes. During the same time frame, a conservative estimate of the cost of government-funded diabetes experiments on rodents ballooned from $100 million to more than $600 million.
Diabetes is now the leading cause of kidney failure, lower-limb amputations, and new cases of blindness, and a major contributor to heart disease, stroke, and liver disease. People with diabetes also commonly lose more than a decade of life, and their annual medical expenses are more than double those for other people. It is clear that a focus on developing animal “models” has not turned the tide on the epidemic.
Due to the lack of legal protection, mice and rats in laboratories routinely die from overcrowding, starvation, dehydration, or use in unapproved experiments.
Documents PCRM received through the Freedom of Information Act revealed that, at Yale University, cages were found with many layers of both live and dead mice. On several occasions at Dartmouth College, mice were found still alive in carcass disposal bags after laboratory staff thought they had been euthanized. At Princeton University, mice were injected with a “pseudo rabies virus” and then killed in unapproved experiments.
No federal law protects these small animals from even the cruelest experiments. But mice exhibit easily recognizable winces, grimaces, and other facial expressions showing they feel pain. Despite their small size, mice experience a complex variety of emotions.
A Better Approach to a Human Disease
The most promising diabetes research focuses on people, not animals. Clinical trials, epidemiologic research, gene studies, and basic physiological experiments can be done ethically and effectively in human participants. PCRM’s landmark study funded by the National Institutes of Health and published in Diabetes Care, the American Journal of Clinical Nutrition, and the Journal of the American Dietetic Association found that a low-fat, plant-based diet of fruits, vegetables, and whole grains treats type 2 diabetes more effectively than a conventional “diabetes diet”—and even more effectively than typical oral medications. Many people with diabetes have found they can lose weight, gain control of their blood sugar, and reduce or eliminate their need for medications.