Animal research: right or wrong?

The debate rages on: Should researchers experiment on animals to save human lives?

Scientist Tim Townes carefully withdraws a little white mouse from a cage in his lab. As the rodent tries to wriggle out of his hand, Townes injects into its body a hypodermic needle full of an experimental drug. Days later, he extracts a blood sample from the mouse. A few drops of blood on a glass slide are all he needs to examine the specimen under his microscope. A researcher at the University of Alabama at Birmingham, Townes nods with satisfaction as he scans the results.

Previously, Townes genetically engineered the mouse. He altered its genes (chemical instructions that, influence how certain characteristics develop) so the rodent would carry human sickle-cell disease. This blood disorder, which often leads to severe pain, anemia, and organ defects, afflicts more than 70,000 Americans.

Now, because of Townes' experimental drug, the mouse's red blood cells, some originally sickle-shaped, have become rounder--like normal human blood cells. That means the drug is working: Oxygen-carrying cells flow more easily through the mouse's blood vessels. Using his "designer" mice, Townes plans to test, treatments to relieve or even cure sickle-cell disease.

HEATED CONTROVERSY

Suppose you knew someone with sickle-cell disease. Would you approve of Townes' experiment--seven if it meant that the mouse suffers or dies? This question lies at the heart of a burning debate in science: Should animals he tested for an array of human needs--from medical treatments to cosmetics? And if so, what limits should be placed on animal research?

Last year, the U.S. Department of Agriculture (USDA) reported that 1,345,739 warm-blooded animals--such as dogs, cats, monkeys, and rabbits--were used in research, testing, or experiments. That number doesn't cover mice and rats, which account for 85 to 90 percent of a lab animals, or more than 15 million. (The USDA doesn't regulate the use of rodents in labs.) Experts estimate that the total number of animals used for research in the U.S. exceeds 17 million each year. Most of the animals are painlessly put to death after experiments.

The variety of tests performed on animals is nearly endless. Scientists inject animals with experimental drugs to see how effectively they treat AIDS, cancer, and hundreds of other diseases. Doctors perform medical procedures like organ transplants on animals before testing them on humans. Researchers test chemicals--like those used in kitchen cleaners or eye shadow--on animals' skin or eyes to see if the final product will irritate humans.

Yet many opponents passionately argue that animal testing is invalid, unnecessary, and cruel. Their key arguments:

* Animals and humans biologically differ from each other. So results from animal experiments can't be applied accurately to humans.

* Humane alternatives to much of animal research, such as tissue samples and computer models, already exist.

* Animals have rights. When scientists engage in animal research, "they violate the rights of an animal to be free from unnatural diseases, injuries, or mental and behavior problems," says John McArdle, a biologist with the American Anti-Vivisection Society (AAVS), once an animal researcher himself.

The majority of scientists and researchers acknowledge the controversy over animal rights. "No researcher enjoys using animals," says Peter Danilo, a senior researcher at Columbia University in New York. But most scientists believe animal testing is crucial to battling human diseases. And they offer arguments to those put forth by opponents of animal research:

* Animals, especially mammals, are very similar to humans. In the past century medical treatments first tested on animals have conquered a range of human diseases, including diphtheria (studied in horses) and diabetes (dogs). Continuing research is invaluable to fighting today's killers, like cancer and AIDS.

* Alternatives to animal research, such as computer models, can supplement but not replace the need to test treatments on living organisms.

* Animals also benefit from research. Scientists have found treatments for rabies, feline leukemia, and distemper.

ANIMALS VS. HUMANS

The vast majority of animal research is devoted to finding cures for human diseases, But animal-rights supporters like McArdle believe such research is useless. The way in which a disease or treatment affects an animal can be very different from how it affects humans, lie argues.

For example, no animal contracts AIDS. A virus similar to HIV (human immunodeficiency virus, which causes AIDS), called simian, immunodeficiency virus, or HIV, attacks monkeys. "But humans don't get that disease, and monkeys don't get ours," McArdle explains. So injecting HIV into primates to study the virus, as scientists do at, the New England Regional Primate Research Center, is a waste of precious time and money, he insists.

Not so, say animal researchers. While no animal is completely identical to humans, some have particular organ systems (like the heart, lungs, or liver) that are very similar to those of human beings. By using dogs' hearts as a model, Danilo, for instance, studies how the heart functions when it's healthy and when it's diseased. In most cases, Danilo needs to kill dogs and remove their hearts. But because of his research, pharmaceutical companies have gained a better understanding of how their drugs affect children with heart disease.

Animal researchers also argue that the very differences between animals and humans serve a vital research purpose. Scientists, for example, can investigate the mechanism in monkeys that renders them resistant to AIDS. Their findings could one day lead to a human HIV vaccine.

FINDING ALTERNATIVES

Why experiment on animals in the first place? Valid alternatives to animal testing exist, animal-rights supporters point out. In fact, the number of animals used in U.S. lab research has decreased by 50 percent in the last 10 years, due to alternative options.

In the late 1950s, British scientists William Russell and Rex Burch proposed the "three Rs" of animal research: reduce the number of animals needed for a test; refine existing tests to lessen animal pain and distress; and replace animals with other methods. This launched a movement to discover other options to animal research.

Instead of testing a drug on a whole animal, for instance, researchers now experiment in, vitro--on sample human or animal cells growing in a petri dish. Until a few years ago, the National Cancer Institute used to test 1.5 million rodents yearly with thousands of compounds to determine the effects of anti-cancer drugs. Now researchers use in vitro screening and test the compounds on cancer cells taken from human patients. "It works faster and not a single animal dies," McArdle says.

Computer models also provide a humane alternative. Say a company wants to test a new, improved household cleaner to see if it will irritate human skin. Several years ago, researchers would have shaved the fur off a rabbit and applied the new substance to its skin. If it burned the rabbit, obviously the chemical wasn't safe for humans.

Today researchers can consult a computer database of thousands of chemicals to see how a single chemical will affect humans. If a new compound's chemical structure is similar to another chemical known to cause irritation, scientists safely assume the new substance will be irritating as well. No need to try it on a bunny.

But alternatives such as cell cultures and computer models can only supplement animal research, not replace it, say some researchers. "A computer can't generate blood to test the blood sugar of a diabetic patient," says Marianne Koch of the Health Safety and Research Alliance of New York State. "A computer model can't feel pain or have a heart attack."

To understand fully how a new drug will work in a living organism, researchers must test it on a living organism. And in many cases, such as testing cancer drugs, animal testing is the law. The U.S. government forbids many treatments to be tested on humans until they have been proven safe on animals.

THE MORAL ISSUE

Perhaps the most intense argument made by foes of animal research is a moral one: To study human diseases in animals, researchers often must make the animals sick or suffer. That's what scientist Tim Townes did when he "created" designer mice to study sickle-cell disease. Deliberately inflicting disease or injury on an otherwise healthy animal violates the animal's rights, says McArdle.

Animal researchers like Danilo see little other choice. "It's a necessity to use animals because there's no other way to answer some of the questions scientists ask." Federal regulations already ensure that most research doesn't cause pain in animals. If an experiment will cause distress, animals usually receive anesthesia, or painkillers.

In the meantime, McArdle remains optimistic. "I think the majority of animal research will end within the next 20 years," he says. "I think a lot of the animal work will eventually be viewed as old science."

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RELATED ARTICLE: History of Animal Research

Animal research became wide-spread in the late 1800s--and so did the animal rights movement.

1866

New Yorker Henry Bergh founds the American Society for the Prevention of Cruelty to Animals (ASPCA). ASPCA protects the welfare of animals, especially animals used for work, like horses.

1885

Through his experiments with rabbits and other animals, French scientist Louis Pasteur develops a vaccine against rabies.

1891

Diphtheria, a severe respiratory infection, ravages the U.S. and Western Europe in the late 1800s. Scientists draw blood from a horse to produce, antibodies that will fight the disease.

1951

Christine Stevens founds the Animal Welfare Institute, an organization in the U.S. that monitors the treatment of laboratory animals.

1952

American scientist Jonas Salk develops a vaccine against polio. He bases his work on 40 years of research, during which time other scientists isolate the polio virus using monkeys, rats, and mice.

1959

British researchers William Russell and Rex Burch publish The Principles of Humane Experimental Technique, which proposes the "three Rs" of animal research. This leads to the search for alternatives to animal testing.

1966

Outrage from the American public about how animals are treated in research lab forces the government to pass the Animal Welfare Act. The law requires scientists to provide adequate care for laboratory animals.

1981

Johns Hopkins Univ. in Maryland, opens the Center for Alternatives to Animal Testing. The center awards research grants to study alternate options to animal use in the lab.

Present

The use of animals in research has dropped 50 percent over the last 10 years thanks to alternatives.