People and medicin5. Molecule to medicine. The 3 Rs.

people and medicine

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The 3 Rs

The overall trend since the 1970s is that the numbers of animals used in tests is dropping (although numbers go up or down year by year). The number of procedures carried out each year in the UK is now about half that of 20 years ago. This is partly due to advances in scientific knowledge and techniques which have enabled animals to be replaced or the number of animals used to be reduced.

Although the overall trend in animal testing is downwards, there is an increase in some new types of research, such as genetic research. The study of new problems that arise suddenly such as the new variant CJD (Creutzfeldt-Jakob Disease) can also lead to increases in numbers in the short term.

You can try the Attitudes to animals activity on animal testing.

The 3 Rs
	Most people who work with animals in research and development of new medicines are committed to the principle of the ‘3 Rs’. The 3 Rs stand for Refine, Reduce and Replace and were originally proposed in 1959 by two English scientists, William Russell and Rex Burch, as a way to minimise the use of animals in research without compromising the quality of scientific work. The 3 Rs are now accepted as the basic principles of good laboratory animal welfare.
Refinement
	Refinement involves the development of new methods to reduce possible distress to laboratory animals. An example of this is the use of new technology to monitor animals’ internal organs during a procedure instead of surgery. Microelectronic radio transmitters can be used to monitor the internal temperature of ferrets that have been given influenza to see whether new drugs are effective. Ferrets are one of the few animals other than humans that suffer from flu. Refinement also involves ways of improving animal well–being, including enriching their environment.
Reduction
	Reduction means obtaining the best quality and most precise information using the smallest possible number of animals. Modifying the design of experiments and making sure they are carried out well ensures that the results produced are reliable and it eliminates the need to repeat tests. New scientific developments and statistical methods mean that much smaller numbers of animals can be used to give equally meaningful scientific results. For instance, advances in mass spectrometry allow scientists to analyse what happens to different drugs when they are given to one animal, rather than giving each drug to different animals (as in the past). Developments in molecular biology such as polymerase chain reaction (PCR) can lead to dramatic reductions in numbers of animals used. For example, previously, in order to find out how much virus was in the body of a mouse treated with a drug, scientists had to kill the mouse humanely to obtain enough virus to test. To study the effect of the drug over a course of treatment it was necessary to kill a number of mice at different stages during the experiment. Scientists can now take a swab from a mouse’s ear skin and use PCR technique to multiply and obtain the amount of virus. They can also take swabs from the same mouse at different points in time to follow the course of treatment for as long as necessary.
Replacement
	Replacement involves using alternatives to animals. In some cases this can mean only partial replacement as animal tissues or cells may be needed initially. Developments in molecular biology now allow scientists to use mammalian cell lines which are immortal and replicate in "test tubes". This type of work allows robotic techniques to be used to test thousands of compounds a day without using animals as in the past.