The harm done to human beings by not experimenting on animals is unknown, whereas the harm done to animals if they are tested on is certain. In the past five years, there have been four major UK independent inquiries into the use of animals in biomedical research: a Select Committee in the House of Lords ; the Animal Procedures Committee ; the Nuffield Council on Bioethics ; and the Weatherall Committee Weatherall et al,which specifically examined the use of non-human primates in scientific and medical research.
However, there are moves to replace the standard mouse carcinogenicity assay with other animal-based tests that cause less suffering because they use fewer animals and do not take as long. However, good science also means that a sufficient number must be used to enable precise statistical analysis and to generate significant results to prevent the repetition of experiments and the consequent need to use more animals.
Comparing different species and studying the differences and similarities between them is one way to gain insights. Nevertheless, the use of the 3Rs is crucial to continuously reduce the number and suffering of animals in research. This has already been achieved in tests for acute oral toxicity, where the LD50—the median lethal dose of a substance—has largely been replaced by the Fixed Dose Procedure, which was developed, validated and promoted between and by a worldwide collaboration, headed by scientists at the British Toxicological Society Macclesfield, UK.
For example, screening potential anti-cancer drugs uses the so-called hollow-fibre system, in which tumour cells are grown in a tube-like polymer matrix that is implanted into mice. Is it ethical to use animals in research?