Animals often find a place in our homes as pets. They are funny and give us a good time. People benefit from the animals in many other ways also. However, in the scientific world animals are primarily used for laboratory testing purposes.
Animal studies are routinely conducted to evaluate the efficacy and safety of medicinal and cosmetic products. Frequently, this is the first phase of testing of a new drug under evaluation. Animal testing eliminates the risk of causing any harm to human beings if the new drug or product is potentially toxic.
On successful completion of testing on animals, the new drug or substance is tested on humans. Currently, different types of animal testing are used with somewhat varied purposes. These tests are conducted on different animals such as rats, mice, rabbits, guinea pigs, cats, dogs and monkeys. Let’s have a look at some of these major tests where animals are used.
The objective of the test is to determine the short-term toxicity or poisoning potential of the substance under test. Typically, these tests determine the Lethal Dose – LD 50. This is the lowest dose at which minimum 50% of the animals tested die due to acute dose related toxicity.
These tests are carried out to determine the toxic potential of experimental drugs, deodorants, food additives, hairsprays, disinfectants, and household cleaners. The animals are administered these chemicals by inhalation, injection or oral route (forced feeding). This test measures the effect of a single dose on the animal.
Repeated Dose Toxicity Study
These tests are carried out to determine the toxic effects over a longer time. The chronic effects on various organs of the animal are studied for long periods. Studies are frequently carried out on rats for 90 days.
These tests are carried out on different animals to evaluate the absorption, distribution, metabolism, and excretion profile of an experimental drug. The tests can be performed on different species of animals.
Irritancy Tests or Draize Tests
These are one of the types of animal tests for cosmetics, toiletries, and other household products. They carried out on laboratory animals for evaluating the irritation potential of these products. These tests can determine the degree of irritancy a product can cause when used by humans. Such tests are normally performed on rabbits over a period of 7 days. The substance under test is repeatedly applied on the eyes of the animal to determine its irritation potential.
Skin Corrosion Test
This test measures skin responses such as itching, swelling or corrosive damage to the skin. The test is normally performed on rabbits after shaving a patch of its skin.
Skin Sensitization Test
This test is used to evaluate the allergic potential of a substance. The substance is normally injected on the shaved skin of guinea pigs. Multiple doses of the substance are applied on the animal to study allergic reactions.
Rats and other rodents are highly prone to cancer. The cancer producing potential of a substance can be effectively studied on rats. The animal is killed and the tissues of various organs are studied for any evidence of cancerous growth.
These tests are designed to study whether the substance has potential for making genetic changes. The bone marrow of the animal is studied for any chromosomal change. Rats are frequently used for these tests.
Dermal Penetration Test
This test determines how effectively a substance is absorbed through the skin. The amount of the substance in the animal’s bloodstream is measured for this purpose.
Reproductive Toxicity Tests
These tests are carried out to find any adverse effect of the substance on reproductive organs. Tests are also performed on pregnant female animals to find out any adverse effect on fetus and offspring.
These tests are performed to study the effect of pesticide on the nervous systems. These are mostly performed on rats and hens. The tests can be designed for longer duration of 90 days or even one year.
The ecological effect of a substance is studied on different species of fishes. Both short-term and long-term tests are performed.
Pyrogens are substances found in gram-negative bacterial cells. These cause increase in body temperature. The pyrogen contamination in a substance can be tested on rabbit by observing its increase in body temperature.
Many of the animal testes listed here cause extreme pain to the animals. Often, sacrificing the life of the animal becomes necessary for these scientific studies. The different types of animal testing are conducted in accordance to animal protection laws and various regulations for such laboratory tests.