Medical Benefits

Animal Research has brought about many medical benefits. This page discusses a handful of examples where animal testing has been instrumental in the development of a medical treatment.

Americans are living longer, healthier lives and we owe much of that success to biomedical research,” said Robert Palazzo, Ph.D, President of the Federation of American Societies for Experimental Biology (FASEB)

Below is just a small selection of the major medical breakthroughs made possible by animal research. These treatments have been used to save or improve the lives of many millions of people worldwide. For more referenced case histories of past and current treatments developed using animals download the booklet “Medical Advances and Animal Research”, produced by UAR.

Also take a look at the timeline of medical advances made possible by animal research.


Penicillin
Blood transfusion
Tuberculosis
Macular degeneration
Asthma
Meningitis
Kidney Transplants
Breast cancer
Parkinson’s disease
Insulin
What’s next?


1. Penicillin
In 1928, Alexander Fleming noticed that staphylococcus bacilli would not grow on a culture medium accidentally contaminated with a mold, Pencillim notatum. But test tube experiments failed to show the antibiotic properties he expected. Ten years later, Oxford chemists Ernest Chain and Howard Florey were working on antibacterial substances. Penicillin wasn’t a top priority. But when Chain injected two mice with it, they remained healthy. Delighted by this apparent lack of toxicity, Florey then decided to give his full attention to penicillin.
The animal experiment
Only by 1940 was enough penicillin available for testing. Eight mice were infected with a deadly dose of 110 million streptococci bacteria. One hour later, four of them were injected with penicillin. These survived but the untreated ones died. Florey said, “It looks like a miracle”.
Why animals?
The amount of penicillin needed to treat a human is 3,000 times greater than for a mouse. Without these early whole animal proofs on toxicity and effectiveness, penicillin would not have been developed further.
What’s it done for humans?
It revolutionized the ability to treat bacterial infections, which were a major cause of death. This simple animal test led directly to the saving of literally millions of lives, both human and animal.


2.Blood transfusion
The first successful blood transfusion was performed on a dog by Richard Lower in 1666 and perfected in dogs by 1907. Clotting was prevented by the addition of sodium citrate and citrated blood was shown to be safe for transfusion to dogs in 1914.
The animal experiment
In 1915 Richard Lewisohn determined the maximum safe concentration of citrate that could be used when transfusing blood into a dog. The following year two doctors, Peyton Rous and Joseph Turner at the Rockefeller Institute, New York showed that blood treated with citrate and glucose could be stored for as long as three weeks in rabbits and safely transfused back into the animals. Later work established longer storage times for human blood.
Why animals?
Much blood transfusion research is done in test tubes, but animals were used to establish the safety of citrated blood.
What it’s done for humans?
Blood transfusion is used after injury and surgery and to treat cancers and anaemia. Open heart surgery would not be possible without it.


3. Tuberculosis
A century ago, TB was a common cause of death. In 1907, there were 117,000 cases in Britain. It was also endemic among farm animals. Robert Koch isolated and identified the bacteria responsible, showing that it reproduced the disease when introduced into experimental animals.
The animal experiment
In 1943, Selman Waksman and Albert Schatz, soil microbiologists working at Rutgers University, New Jersey, injected streptomycin, the product of a soil bacteria isolated in a sick chicken, into guinea pigs infected with TB. It completely suppressed the TB without harming the guinea pigs.
Why animals?
Antibiotics need to be trialled in living organisms as there is no way of knowing whether they will penetrate tissue at the site of an infection. TB is unusual in having multiple infection sites.
What it’s done for humans?
This was the first effective treatment for TB, both human and animal. It saved millions of lives.


4. Macular degeneration
Macular degeneration is the commonest cause of blindess in adults in the developed world. It is caused by the abnormal growth of blood vessels behind the macular, the part of the retina responsible for detailed vision.
The animal experiment
In 1998, a team in Liverpool announced a new surgical treatment for this condition. It involves opening the eye, detaching the retina and moving it to a new position, where it is held in place with a tuck. Called macular relocation, this technique was perfected in the eyes of monkeys, cats and rabbits starting in the 1960s.
Why animals?
Although vision surgery can be practised on the eyes of human cadavers, there is no way of knowing whether vision has been restored successfully.
What’s it done for humans?
Macular relocation is one of a large number of sight-saving surgical procedures, many now performed routinely, which are based on techniques perfected in animals.


5. Asthma
Asthma is the result of an allergic reaction of the airways. It is a chronic illness affecting 3 million people in Britain, including one in eight children. It kills around 2,000 people every year in the UK.
The animal experiments
Not one, but many animal experiments made bronchodilators, which relax smooth muscle in the airways, possible. First the frog work of Henry Dale and Otto Loewi in the 1920s, which established the chemical nature of neurotransmitters, such as noradrenaline, which act on receptors in the lungs. Then, further extensive animal work in the late 60s, particularly on guinea pigs, made safe long-lastingbronchodilators available.
Why animals?
There are no tissue cultures that mimic any of the symptoms of asthma, although its cellular mechanisms are studied in vitro.
What’s it done for humans?
Salbutamol and terbutraline, the most widely used bronchodilators, have prevented many thousands of deaths and enabled those with asthma to live more active lives.


6. Meningitis
Meningitis is a feared disease, especially in children. It is caused by a variety of bacteria and viruses, but until recently, the most common in childhood was Hib (Haemophilus influenzae).
The animal experiments
The Hib vaccine was technically very difficult to develop because of a shortlived antibody response, especially in children, to the main Hib antigen, a sugar. Coupling it with a protein, a technique previously shown to protect mice against pneumonia, was shown to produce a more powerful response in mice and rabbits.
Why animals?
Vaccines cannot be developed by tissue culture alone because they are used to control infections that spread through the entire body. Animals are pivotal to vaccine research.
What’s it done for humans?
When the UK vaccination programme began in 1992, there were approximately 1,500 cases of Hib meningitis, mostly in babies, with 65 deaths and 150 children surviving with major handicap. Introduction of the vaccine has reduced the number of cases by 90%.


7. Kidney transplants
Of the 5,000 people who develop kidney failure each year in the UK, one in three would die without regular dialysis or a transplant.
The animal experiments
Surgical techniques for transplantation were perfected in dogs and pigs in the 1950s and became routine in humans. Among the scientists involved in this effort was Joseph E. Murray, who was subsequently awarded the Nobel prize in recognition of this and other work. However, rejection remained a problem. Cyclosporine, which is extracted from a species of fungus, was discovered in 1972 and found to be a potent immune suppressor in mice. Tests in humans found that it prolonged the survival of grafted kidneys. Research on transplants in dogs showed that combining cyclosporine with steroid produces a three-fold increase in survival time.
Why animals?
It would be impossible to perfect surgical techniques for transplant in tissue culture as an intact circulatory system is required.
What’s it done for humans?
About 2,000 kidney patients each year benefit from kidney transplants and more would do so if more organs were available.


8. Breast cancer
Breast cancer will affect one in 11 women during their lifetime and affects around 40,000 women each year in the UK.
The animal experiments
Animal studies in the 1950s showed that hormone changes can induce breast tumors in rats. This led to the development of Tamoxifen which blocks the growth of hormone dependent breast cancers. Further research with mice showed its possible preventive role.
Why animals?
The initial use of animals here has now meant an alternative to animals for breast cancer research. Tamoxifen work showed that lab grown cultures of human tumor cells will respond to drugs that are effective in patients. Without animal work it may not have been possible to show that the cell culture results were relevant and reliable. Animal studies, mainly rats and mice, have also been crucial in the development of monoclonal antibody treatments such as Herceptin.
What’s it done for humans?
Breast cancer is now the second most survivable female cancer, with a 77% five-year survival rate. Following tamoxifen’s introduction in the 90s, there was a 30% fall in death rates. It has now been proved that tamoxifen can also prevent breast cancer in high-risk women.


9.Parkinson’s disease
Parkinson’s Disease, which causes slowness and absence of movement as well as tremor and rigidity, can be treated with the drug l-dopa, but its initial effects do not last. There are a range of surgical treatments.
The animal experiments
Experimental surgery in monkeys identified the subthalamic nucleus as a target for treatment of Parkinson’s. Subsequently Parkinson’s was induced in macaque monkeys and then controlled by means of an electrode to the subthalamic nucleus, the brain centre responsible for the disease. Prof. Tipu Aziz of Oxford University applied the same techniques to his human patients, fitting an electrode to their subthalamic nucleus, and switching off their tremor.
Why animals?
Only people and higher animals naturally share the same symptoms of Parkinson’s, particularly tremor. There are now mouse models of Parkinson’s.
What’s it done for humans?
This technique has brought great benefits to 200,000 people with Parkinson’s.


10. Insulin
About 1.8 million people in the UK have diabetes, of which three quarters have Type 2 or late-onset diabetes. People with Type 1 or insulin-dependent diabetes have little or no insulin because the islet cells in the pancreas which normally produce it, have been destroyed. People who developed this form of diabetes, often as children or young adults, died very quickly.
The animal experiments
In 1889, Josef von Mering and Oskar Minkowksi showed that removing the pancreas from a dog produced diabetes. Insulin, however, proved difficult to isolate. In a series of classic experiments, during the summer of 1921, Canadian doctor Frederick Banting, along with student Charles Best, managed to extract insulin. They injected their extract into a diabetic dog, close to death, restoring it to health. But their extract caused high fever in patients. Biochemist James Collip then developed a purification method but the only way to check whether insulin was present and in what amount, was to measure its ability to lower blood sugar in rabbits. Since insulin overdose is fatal, this was essential. These extracts were first used in dogs, then in patients in 1922. Banting and his supervisor, Professor John Macleod, won the Nobel prize in 1923.
Why animals?
Insulin is common to many animal species. Hormones are carried in the blood, which is why only live animals would work in these experiments.
What’s it done for humans?
The development of insulin provided the first treatment for what had been a lethal disease. It is not a cure, but it has kept millions alive since its discovery.


What’s next?
Research on mouse models of motor neurone disease (MND) have demonstrated the important of a growth factor called VEGF. A single injection of a virus carrying a gene for VEGF delayed onset and slowed progression in MND mice. Work on dogs, particularly dachshunds who are prone to spinal injury and whose owners are glad to allow them to have new treatments, has prompted human clinical trials for spinal injury. Fetal stem cells injected into the brains of stroke injured rats were shown to migrate to injured areas. Such research is essential. And if it could be done in other ways, it would be.


The above piece was commissioned by the Guardian newspaper under the heading “What have Guinea Pigs ever done for us?” and published on 1st September 2005. Reproduced above with permission from author, Vivienne Parry.

Furthermore – Have a look at this timeline of medical research originally created for animalresearch.info (which has more information on each breakthrough).

Timeline of Medical Advances made possible by Animal Experiments

Benefits of animal testing