While laboratory tests involving any animal can be fraught with controversy, the scientific community has been using mice experimentally for decades without much vocal objection. Perhaps the reputation of these animals as nasty, disease-infected worms did them no good. Researchers and scientists rarely use these animals of unknown origin in laboratory tests, however. Carefully bred mice with documented genetic histories are used in animal testing for a number of reasons, including their frequent breeding, genetic purity, and similarities to human biology.
Genetic consistency is one of the reasons mice are used for testing.
Several laboratory tests performed on mice involve the safety of chemicals, whether they are used in medicines, food products, or cosmetics. Because they are mammals, their systems must react to these chemicals in a similar way to a human test subject. To be considered safe enough for human consumption or exposure, a new chemical must first be tested in other mammals. Laboratory rats are often fed extremely high amounts of a new food additive or injected with large doses of a new chemical. Theoretically, if the product under test is completely safe for humans, it shouldn’t matter if they ingest two hundred times the recommended levels.
Some cosmetic companies are formulating an increasing number of cruelty-free products.
Another reason labs use mice is genetic consistency. Those bred for animal testing are tested for any genetic defects that could affect the results of the experiments. Only animals with a known genetic history are candidates for testing. Since mice tend to breed frequently, their offspring can also be tested for any genetic abnormalities possibly caused by exposure to the test product. Once researchers know of any genetic predisposition to weight gain or cancer formation, for example, they can safely eliminate these test-product-related factors.
Drugs and vaccines are often tested on rats and mice.
Because mice reproduce quickly and tend to have large litters, researchers don’t have to wait long to evaluate test results across generations. The grandchildren and granddaughters of the original test animals could show up in a few months, not the years it would take in humans. When looking for potential health hazards, examining multiple generations of a test subject at once can provide more definitive proof of a product’s safety or potential threat. Supervisors such as the Federal Food and Drug Administration (FDA) require this level of proof before even considering human clinical trials. While the issue of animal testing remains controversial, there can be no doubt that the use of mice in laboratory studies has provided a number of breakthroughs in the medical, food and cosmetics industries.