Research Animals

Research animals are animals that humans use solely for scientific and product testing. They are used in medical and veterinary investigations and training; in the testing of drugs, cosmetics, and other consumer products; and in educational programs. The Scientific American (August 4, 2004) estimates that as many as one hundred million animals per year (mostly mice and rats) may be used in research, testing, and medical and veterinary training programs.

Living animals used as specimens to test drugs and products, practice medical and surgical procedures, and investigate diseases and bodily systems are called laboratory animals. Laboratory animals often die from these procedures or are euthanized by researchers after they are no longer needed. The plight of laboratory animals has been a major issue for animal rights advocates since the 1970s.

ive animals are used in modern medical research because some of their bodily systems mimic those of humans. This makes them useful test subjects for drugs, vaccines, and other products intended for humans. They are also useful training tools for doctors,pharmacists, surgeons, and veterinarians who need to drug administration, practice medical procedures, such as inserting a catheter, administering anesthesia, or performing operations.

People who support the use of animals in research are passionate in their belief that the benefits to people far outweigh the consequences to animals. They point out the important medical and veterinary advances that have resulted. On the contrary, animal rights activists uniformly condemn this use. The most extreme activists have broken into laboratories, released animals, and physically harassed the researchers involved. Animal welfarists work to minimize the pain these animals experience during testing and to improve their living conditions.

HISTORYEarly Times

Vivisection on animals and humans dates back to at least the ancient Greeks and Romans. During the third and second centuries BC human bodies were vivisected and dissected at the medical school in Alexandria, Egypt, by Herophilus and Erasistratus. Historians believe that more than six hundred living criminals were subjected to vivisection. Human dissection and vivisection were generally forbidden throughout the rest of Egypt and in the Roman Empire because of moral concerns.

Galen (circa 130–200 AD) was a Greek physician who moved to Rome and administered to gladiators and emperors. He frequently practiced vivisection on animals, particularly goats, pigs, monkeys, oxen, and dogs. Even though Galen made some important anatomical discoveries, he relied so heavily on animal models that he developed some misconceptions about human anatomy. However, his teachings formed the basis of Western medical science well into the Middle Ages. The Catholic Church frowned on human dissection and vivisection during this period, meaning that only animals were available for anatomical study, though some adventurous souls still used humans in their research.

Medical advances achieved through animal research, selected years 1796–2003 

Year Advance (type of animal)

*Denotes Nobel Prize-winning work.

Source: "Historically, What Have Been the Tangible Benefits of Animal Research?" in CDC News: Overview of Animals in Scientific Research Fact Sheet, U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, November 16, 2006.

1796 Vaccine for smallpox developed (cow)

1881 Vaccine for anthrax developed (sheep)

1885 Vaccine for rabies developed (dog, rabbit)

1902 Malarial life cycle discovered (pigeon)*

1905 Pathogenesis of tuberculosis discovered (cow, sheep)*

1919 Mechanisms of immunity discovered (guinea pig, horse, rabbit)*

1921 Insulin discovered (dog, fish)*

1928 Pathogenesis of typhus discovered (guinea pig, rat, mouse)*

1929 Vitamins supporting nerve growth discovered (chicken)*

1932 Function of neurons discovered (cat, dog)*

1933 Vaccine for tetanus developed (horse)

1939 Anticoagulants developed (cat)

1942 The Rh factor discovered (monkey)

1943 Vitamin K discovered (rat, dog, chick, mouse)*

1945 Penicillin tested (mouse)*

1954 Polio vaccine developed (mouse, monkey)*

1956 Open heart surgery and cardiac pacemakers developed (dog)

1964 Regulation of cholesterol discovered (rat)*

1968 Rubella vaccine developed (monkey)

1970 Lithium approved (rat, guinea pig)

1973 Animal social and behavior patterns discovered (bee, fish, bird)*

1975 Interaction between tumor viruses and genetic material discovered (monkey, horse, chicken,,  mouse)*

1982 Treatment for leprosy developed (armadillo)

1984 Monoclonal antibodies developed (mouse)*

1990 Organ transplantation techniques advanced (dog, sheep, cow, pig)*

1992 Laproscopic surgical techniques advanced (pig)

1995 Gene transfer for cystic fibrosis developed (mouse, nonhuman primate)

1997 Prions discovered and characterized (hamster, mouse)*

1998 Nitric oxide as signaling molecule in cardiovascular system discovered (rabbit)*

2000 Brain signal transduction discovered (mouse, rat, sea slug)*

2002 Mechanism of cell death discovered (worm)*

2003 Non-invasive imaging methods (MRI) for medical diagnosis developed (clam, rat)

Biomedical Research

The vast majority of research animals are used in biomedical research. Biomedicine is a medical discipline based on principles of the natural sciences, particularly biology and biochemistry.

The NIH maintains the Computer Retrieval of Information on Scientific Projects (CRISP), a database of biomedical research projects that have received funding from federal agencies dating back to 1972. The CRISP database can be searched to find information about the use of animals in federally funded research projects at universities, hospitals, and other research institutions. For example, a search conducted in February 2007 using the search term dogs returned 179 projects in which dogs played a role. Information supplied about each project includes the name of the principal investigator, the name and address of the research institution, the starting and ending dates of the project, the federal agency providing funding, and a description of the project.

DRUG TESTING

According to the FDA, in "The Beginnings: Laboratory and Animal Studies" (January 30, 2006), drug companies typically test new drugs on at least two different animal species to see if they are affected differently. Animal testing is performed to determine specific characteristics, such as:

How much of the drug is absorbed into the bloodstream

Any toxic side effects

Appropriate dosage levels

How the drug is metabolized (broken down) by the body

How quickly the drug is excreted from the body

The results from animal tests tell researchers if and how new drugs should then be tested on humans.

PRODUCT TESTING

Millions of research animals are used to test products intended for industrial and consumer markets in the Worldwide. Product safety testing exposes animals to chemicals to determine factors such as eye and skin irritancy. Common product safety tests conducted with animals include:

Acute toxicity tests determine the immediate effects of chemical exposure. The LD-50 test is an example. In this test animals are exposed to chemicals through ingestion, inhalation, or skin contact to determine the concentration necessary to kill 50% of the test group within a specific time period.

Skin and eye irritancy tests determine the effects on skin and eyes of chemical exposure. One example is the Draize eye test. Rabbits are commonly used because they cannot blink and wash out the chemicals.

Subchronic and chronic toxicity tests determine the effects of long-term chemical exposure.

Genetic toxicity tests determine the effects of chemical exposure on reproductive organs.

Birth defects tests determine the effects of chemical exposure on offspring. 

Cancer potential tests determine the potential of chemical exposures for causing cancer

GENETIC ENGINEERING 

Genetic engineering is the scientific manipulation of genetic material. Animals have been the subject of genetic engineering research and experiments for several decades. Transgenic animals are animals that carry a foreign gene that has been deliberately inserted through genetic engineering. They are widely used in biomedical research and pharmaceutical development. Most of these animals are farm animals. Raising these transgenic animals for the cultivation of pharmaceutical products is known as pharming. For example, scientists have pharmed transgenic sheep and goats that produce foreign proteins in their milk. Production of these proteins could have enormous medical and industrial benefits for humans. As of early 2007, pharmed substances were still in the development stage and had not yet been commercialized.

Another growing area of genetic engineering is xenotransplantation. The term xeno comes from the Greek word xenos, meaning "foreign" or "strange." In xenotransplantation organs from animals are transplanted into humans. Research continues on the genetic engineering of pigs so that they can grow organs that will not be rejected by human bodies. Scientists believe that harvesting organs from transgenic pigs could one day solve the human organ shortage that at present exists, saving millions of human lives. The technology is almost to the point of making this possible. Some people consider this to be medical progress, but others see it as another injustice perpetrated against animals for the sake of humans, noting that there would not be an organ shortage if more people were willing to become organ donors.

Cloning is a form of genetic manipulation in which a later-born genetic twin can be produced. In July 1996 the first mammal cloned from adult cells was born, a product of research at the Roslin Institute in Edinburgh, Scotland. Dolly was cloned from an udder cell taken from a six-year-old sheep. She was a fairly healthy clone and produced six lambs of her own. Before she was euthanized by lethal injection on February 14, 2003, Dolly had been suffering from lung cancer and arthritis. An autopsy (postmortem examination) of Dolly revealed that, other than her cancer and arthritis, she was anatomically like other sheep. (See Figure 5.9.) Between 1996 and 2007 other animals were cloned, including sheep, mice, cows, a gaur (an endangered Asian ox), goats, pigs, rabbits, dogs, and cats. Not all the animals have survived, and most have been born with compromised immunity and genetic disorders. Cloning is still new technology, and the success rate is low.

Source: "Research Animals and Animal Rights. 2008.

by

AKSHAYA SRIKANTH