Professor Colin Blakemore works at Oxford University Medical School doing research into eye problems and believes that animal research has given humans many benefits:The use of animals has been central to the development of anaesthetics, vaccines and treatments for diabetes, cancer, developmental disorders…most of the major medical advances have been based on a background of animal research and development.
There are those who think the tests are simply unnecessary. The International Association Against Painful Experiments on Animals is an organization that promotes the use of alternative methods of research which do not make animals suffer. Their spokesman Colin Smith says:
Animal research is irrelevant to our health and it can often produce misleading results. People and animals are different in their reactions to drugs and in the way their bodies work. We only have to look at some of the medical mistakes to see this is so.
But Professor Blackmore stresses:It would be completely irresponsible and unethical to use drugs on people that had not been thoroughly tested on animals. The famous example of thalidomide is a case for more animal testing, not less.
The birth defects that the drug produced were a result of inadequate testing. If thalidomide were invented today, it would never be released for human use because new tests on pregnant animals would reveal the dangers.
Another organization that is developing other methods of research is FRAME. This is the Fund for the Replacement of Animals in Medical Experiments. It recognises that many experiments still have to be done on animals and is aiming for Reduction, Refinement and Replacement of animals in experiments. In 1981, it established a research programme to improve and expand non-animal testing. Increasingly, new technology is making it easier for us to find alternative methods of testing.
Computer models can be used to simulate the way that cells work and to try to predict the toxicity of chemicals. Data from previous animal experiments is used to develop a computer model which will predict what will happen if you add a chemical with an unknown biological effect to a substance. The eventual aim of computer modeling is to reduce the number of animals used in experiments.
The Lethal Dose 50 test (LD50) may also be replaced. In the original test, all the animals in a test group are given a substance until half of them die. The test indicates toxicity. A method using a fixed amount, which gives the same eventual information but uses fewer animals and does not require that they die, may replace the LD50. Many other new techniques are now available that enable more research to be done in the test tube to see if chemicals produce harmful biological effects.
The number of animals used in laboratory tests has declined over the last 20 years. This is partly due to alternatives and partly to the fact that experiments are better disigned so fewer need to be used - healthier animals provide better experimental results. For example, it used to take 36 monkeys to test a sample of polio vaccine, now it takes only 22. Also, lack of money has reduced the number of animals used - they are expensive to buy and expensive to keep.
Birmingham University now has Britain's first department of Biomedical Ethics. Professor David Morton of the department is involved in animal research and is concerned with reducing animal suffering as much as possible. Animals spend 95% of their time in their cages and refinement also means making their lives better when not undergoing tests. This includes keeping them in more suitable cages, allowing social animals like dogs to live together and trying to reduce the boredom that these animals can experience.
In Professor Morton's laboratory, rabbits live together in large runs, filled with deep litter and boxes that they can hide in. The researchers have also refined some experiments. In the US, one experiment in nerve regeneration involves cutting a big nerve in a rat's leg, leaving its leg paralysed. In Morton's lab, the researcher cuts a small nerve in the foot. He can see if it can regrow and the rat can still run around its cage.
Even with these new developments in research, only a tiny proportion of all tests are done without using animals at some stage. The use of animals in experiments cannot stop immediately if medical research is to continue and consumer products are to be properly tested, and Professor Blakemore believes that sometimes there are no alternatives:
Wherever possible, for both ethical and scientific reasons, we do not use animals. But cells live in animals and we can only really see how they behave when they are inside animals. We cannot possibly reproduce in a test tube or a computer model all the complex reactions of the body to a drug or a disease. When it comes to research into heart disease and its effects on the body, or diseases of the brain for example, we do not have adequate substitutes for the use of animals.
As research techniques become more advanced, the number of animals used in experiments may decrease, but stopping testing on animals altogether is a long way away.为科学而献身