Animal testing: it’s one of the most polarizing topics one can bring to the conversational table. Though indications are that the use of lab animals may be on the decline, there’s no doubt that their sacrifices have improved the efficacy of medical treatments and extended the lifespans of humans and animals alike.
What can be learned from the tiny, humble fruit fly that could possibly benefit human beings? Possibly the answer to the largest question: “What are we?” Fruit flies of the species Drosophila Melanogaster have proven to be invaluable subjects in teasing out new theories in the field of genetic studies.
(image via: Tom_1903)
Fruit flies have short lifespans that allow scientists to observe how genetic characteristics are passed down through many generations in a very short – to us – time period. Fruit flies also possess short chromosomes with a simple genome that has already been sequenced, making it easier to isolate one or more particular genes when conducting a study.
African Clawed Frogs
“Lab Frogs”… it’s not a term that really rolls off the tongue, but African Clawed Frogs of the species Xenopus Laevis are used by the tens of thousands each year, mainly in developmental research and DNA studies. The eggs and embryos of these amphibians are self-contained systems that have the extra bonus of being transparent.
(image via: Kuribo)
African Clawed Frogs were the first vertebrates to be successfully cloned, and in 1992 several Xenopus Laevis specimens were sent into orbit aboard the space shuttle Endeavour in order to observe whether reproduction and embryonic development were possible in a zero-gravity environment.
Roughly 9 out of every 10 animals used in testing procedures is either a mouse or a rat, and most of those are albinos with white fur and red eyes. As many as 20 million rats and mice are subjects in animal testing performed each year in the United States alone, and to that figure can be added much smaller numbers of gerbils, hamsters and guinea pigs. In many ways, rodents are the vertebrate equivalent of fruit flies: they are small in size, easy to handle, and grow quickly in the course of short lifespans.
(image via: Purdue University)
Though mice and rats may seem similar, they have different uses when it comes to animal testing. Lab mice are ideal for studies of inherited human disease and illness, while rats are preferred for cancer research and toxicology experiments.
Albino rabbits have achieved a high level of visibility among animal rights advocates due to their longstanding use in eye irritancy tests conducted to ensure the safety of cosmetics and personal use products by humans: the infamous Draize Test. Introduced in 1944 by toxicologists in the employ of the FDA, the test is performed on rabbits because their eyes tear less than those of other mammals. Further, the lack of pigment in the eyes of albino rabbits allows researchers greater facility to observe any effects of the chemicals being tested. Partly as a result of pressure from anti-testing groups and also due to the fact that most substances commonly used in consumer products have already been tested, the Draize Test is performed much less often then in the past.
Rabbits are the ideal mammal used to produce polyclonal antibodies as they are larger than mice, easy to handle, and exhibit vigorous antibody production. Though chicken eggs are the preferred vector for production of polyclonal antibodies, the Immunoglobulin Y they produce has some incompatibilities for human use due to the distance inherent in their phylogenetic relationship.
The USDA’s Animal Welfare Report for 2005 states that approximately 66,000 dogs were used for animal testing in USDA-registered facilities over the course of the year. Dogs are typically chosen for their compatibility in human cardiological, endocrinological, and osteoarthritic studies.
(image via: TIME)
Dogs occupy an especially heroic place in the annals of animal testing though the USDA – or the United States in general – have no connection with the honor. Instead, our Cold War rival the Soviet Union deserves credit for selecting nearly 60 different dogs to act as pathfinders on the long and difficult road to manned space flight. Though most of the Soviet space dogs returned from their dangerous missions, many did not, including the most famous dog to orbit the Earth: Laika.
Monkeys are the most commonly selected NHPs, or “Non-Human Primates”, due to their similarity to humans. It’s a double-edged sword, however: they’re like us and that’s a plus for medical research but it also brings serious moral issues into play. Approximately 12,000 to 15,000 Rhesus monkeys, Cynomolgus monkeys, Squirrel monkeys and Owl monkeys are imported into the United States each year for the purposes of animal testing.
(image via: National Geographic)
Rhesus monkeys are the “face” of primate animal testing and the green-glowing example above illustrates the role such creatures have in transgenic experimentation. While implanting a jellyfish gene that enables test subjects to emit an eerie phosphorescent glow may seem strange to say the least, down the road such research may provide cures for inherited human genetic illnesses and disorders such as Huntington’s Disease.
Chimpanzees are perhaps the most controversial animal testing subjects. As of 2006, 1,133 chimpanzees were being kept in U.S. primate centers. As a function of their intelligence, chimps are used in a wide range of psychological research though they have also proved to be invaluable in ongoing AIDS research.
(image via: MNN)
While the Soviet space program launched dogs into orbit, the United States instead chose monkeys and chimpanzees to be their animal astronauts. One of the most famous of the pioneering “space chimps” was named Ham. On January 31st, 1961, after a year and a half of training, Ham blasted off from Cape Canaveral on a 16 minute and 39 second long suborbital spaceflight. Ham successfully performed several tasks on his flight, proving that such activities could be performed by human astronauts.
By the late 1980s and early 1990s, DNA imaging techniques and medical computer modeling had greatly reduced the need for chimpanzees for scientific research. Problem was, nearly 2,000 former research subjects had no place to go – releasing them into the wild was not an option. In 1997, passage of the Chimpanzee Health Improvement, Maintenance, and Protection (CHIMP) Act saw $30 million allocated for the establishment of chimp sanctuaries like the 200-acre Chimp Haven (above, top), located in rural northern Louisiana. Another large retirement facility, created by Dr. Carole Noon and called Save the Chimps (above, lower left), is located on the Atlantic coast near Fort Pierce, Florida. Providing a stress-free retirement is really the least we can do for our closest animal relatives.
(image via: Opposing Views)
19th century French physiologist Claude Bernard once wrote, “the science of life is a superb and dazzlingly lighted hall which may be reached only by passing through a long and ghastly kitchen.” While certainly true in 1865, the need for such a “kitchen” has grown less as the years have passed. Should animal testing come to a complete end some day, that would be a great day indeed but until then (and for long after), the highest level of gratitude and respect is owed to those who gave their lives for the improvement of ours.