Animals in Research
Laboratory
Animals Contributions’ to Medicine
Research in physiology provides the scientific basis
for much of medical practice, and is thus critical for maintaining health as
well as for the diagnosis, prevention, and treatment of health problems. In
order to understand and treat disease, physiologists need to understand how
the body works under both normal and abnormal conditions before they can
develop ways to prevent and treat disease.
Since some health problems involve processes that can
only be studied in a living organism, it is necessary to perform research on
animals when it is impractical or unethical to use humans. Additionally,
research using animals has led to some of the most important medical
discoveries in history. Animal research continues to help humans, as well
as animals, live longer and healthier
lives.
What Humans Have in Common with Animals
Animal research has helped scientists to understand and
find ways to prevent and treat diseases historically (in diseases that are
no longer widespread, like polio) and at present (for health conditions that
are still prevalent), including:
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Heart disease
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Diabetes and obesity
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Neurological diseases such as Alzheimer’s and Parkinson’s
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Cancer
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Infectious diseases including AIDS and tuberculosis
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Inflammatory bowel diseases like Crohn’s disease
In these and other instances, animals make good
research subjects because they are biologically similar to humans. For
example, the immune system of mice, the cardiovascular system of dogs, and
the reproductive system of guinea pigs all function in much the same way as
in humans. Humans also share many of their genes not only with other
primates, but also with animals as far removed as mice and fruit flies.
So why use animals for research?
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Animals are used for biomedical research because it
would be wrong to deliberately expose human beings to health risks in
order to observe the course of a disease or use humans in invasive
experiments to study normal organ function.
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Animals are susceptible to the development of
many of the same health problems as humans.
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Their shorter life cycles make it easier to study
them throughout their whole life span or across several generations.
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Scientists can better control variables (such as
diet, age, weight, and physical activity), which would be difficult to do
with human patients.
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Scientists can also change an animal’s genes to study
genetic diseases that cause illness in people.
Animal research is helping to elucidate the following
human conditions:
Obesity and Diabetes People with obesity and
diabetes are at risk for a number of potentially serious complications that
can cause premature death. For instance, researchers recently used
genetically engineered mice to better understand how liver damage occurs in
people with Type 2 diabetes.
Obese and diabetic db/db mice develop marked liver fibrosis in a model of
nonalcoholic steatohepatitis: role of short-form leptin receptors and
osteopontin. American Journal of Physiology – Gastrointestinal
and Liver Physiology. 287: G1035-G1043, 2004.
Epilepsy People that are born with brain
malformations sometimes have a kind of epilepsy that is not easily treatable
with medicines. Using rats that exhibit the same kind of symptoms,
scientists at Stanford University Medical Center were able to study the
differences in how the brain functions in rats with epilepsy compared to
healthy rats.
Excitatory and Inhibitory Postsynaptic Currents in a Rat Model of
Epileptogenic Microgyria. Journal of Neurophysiology. 93: 687-696, 2005.
Parkinson’s Disease (PD) Researchers
studying the development of PD recently used a mouse model to study genetic
changes that occur in brain cells (neurons) during the earliest stages of
disease, even before the substantial loss of neurons associated with the
classic symptoms of PD occurs. These types of studies could lead to early
detection and treatment that would ultimately minimize the severity of
symptoms associated with PD.
Temporal evaluation of mouse striatal gene expression following MPTP injury.
Neurobiology of Aging. 26(5):765-775.
For more information on the historical importance of
animals in physiology, please see the
Timeline of Physiology.
How Animals Help Us Find Cures
Animals also play a critical role in development of new
drugs and new medical procedures to treat diseases. For example, studies in
animals were used to establish the safety of drugs that are widely used to
treat high cholesterol, ulcers, depression and a slew of other common
conditions and illnesses. In fact, almost every drug used in humans is
first tested in animals.
Animal studies are done first to give medical
researchers a better idea of what benefits and complications they are likely
to see in humans. If the new therapy seems promising, it is tested in
animals to see whether it appears to be safe and effective. Researchers use
animal testing to discover what toxic side effects a drug might have, what
doses are safe, and how a drug is absorbed and broken down in the body. Only
after scientists have seen that the drug can be safely and effectively used
in two or more species of animals do they begin testing in humans.
Scientists sometimes discover such drugs and procedures
using alternative research methods that do not involve animals. While there
is currently no substitute for animal testing in drug development,
scientists are continually looking for other ways to test therapies for
safety and efficacy.
How Animals Help Other Animals
Often times, animal research elucidates cures and
treatments for ailments that afflict animals and humans alike. Many of
these advances can then be used in veterinary medicine to improve the length
and quality of animals’ lives.
Veterinary medicine has benefited from discoveries
found through animal research that alleviates animal pain and sickness and
prevents disease in our pets, food animals and wildlife. Just some of the
areas where animal research has helped other animals include:
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Development and testing of animal vaccines
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Detection and prevention of infectious diseases
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Food animal health and safety
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Treatments for lameness and arthritic pain
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Development of artificial joints
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Cancer therapies
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Treatment of genetic and acquired heart problems
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Animal responses to exercise
The following articles discuss research that, while
applicable to humans, has clear implications for animal health:
How animal research is regulated
An important part of doing animal research is making
sure that laboratory animals are always treated humanely. The Animal Welfare
Act is a law that regulates the use of many animals,
including dogs, cats and primates in scientific research and drug testing.
(Click
here for more information on the Animal Welfare Act.) In addition, the
US Public Health Service Act requires that all research institutions
receiving federal funds review and approve all research projects using
vertebrate animals, and adhere to the guidelines in the “Guide for the Care
and Use of Laboratory Animals”.
Scientists care very much about the health and
welfare of their laboratory animals. In addition to having to follow the
rules put in place by their employers and the government, scientists know
that unhealthy animals do not yield reliable experimental results.
Conclusion
Animal research is vital to advancing medicine.
Physiologists will continue to learn from animals through humane research,
with the goal of improving human and animal health and longevity.
To speak with a physiologist about comparative physiology or any of the
research discussed above, please contact Donna Krupa (301) 634-7209).
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