The unsung hero of science has been infected, dissected, genetically modified, cloned and subjected to fatal doses of tracks by The Prodigy to test the impact of music on a drug-addled brain. The laboratory rodent here is being used as a living piece of research apparatus, a key element in a scientific study on toxicology.

Last year, 2.3 per cent of the 2,714,726 animals used in research in the UK were sheep, cows and pigs, while monkeys made up 0.1 per cent. Rodents accounted for 82 per cent of the total.

The scientist can only learn so much from laboratory tests on molecules, cells and tissue, from computer modelling, from investigating the health of individual humans or from large-scale population studies. The living body is a complex entity that involves the interaction of billions of components on many levels and in a vast number of overlapping ways.

There are many questions that scientists would like to answer, thrown up by the western way of living and the desire for a long and healthy life. A fair proportion of these cannot be probed without resorting to experiments on a live organism where the risks involved preclude the use of human subjects. The laboratory rodent has become a useful compromise for developing therapies and diagnostics, conducting the fundamental biological research that underpins them, and in testing products to ensure their safety.

After tens of millions of years of separate evolution, rodents and humans still have a great deal in common, from basic organ function to shared diseases. So long as the science is good and the questions asked of the rodent are not ill-advised, the approach can be powerful. Parallels in our genetic code have become increasingly significant. The mouse genome was completely sequenced earlier this year, soon after the publication of our own species’ genetic directory. Work on the rat genome is under way.

The rise of the transgenic rodent is responsible for the recent reversal in the long-term decline in the number of animals used in scientific experiments. A multitude of genetically modified mice can now be ordered from mouse libraries by scientists wanting to subject biological mysteries to more sophisticated analyses than has been previously possible. Such experiments are seen as an essential tool by all but a handful of the researchers seeking new therapies, and a vast majority of the doctors who hope to administer them.

The list of medical breakthroughs owing a debt to the laboratory rodent is long, including vaccines, antibiotics, transplant and surgical techniques, and drugs from cancer treatments to antidepressants. Scientists are confident there are further advances to come, from stem cell treatments for Alzheimer’s disease to gene therapies for cystic fibrosis.

And the lab rat will have been at the heart of them all.

STEVE FARRAR

Weblinks

The Research Defence Society: www.rds-online.org.ukhome.html

National Anti-Vivisection Society: www.navs.org.ukhomepage.html

Home Office’s animal procedures: www.homeoffice.gov.ukccpdabcu.htm

Opposition to European plan for 50 million animal tests: http:www.guardian.co.ukArchiveArticle0,4273,4286426,00.html

Steve Farrar is science correspondent for The Times Higher Education Supplement