Ethics of Research involving animals
Summary
9.44 In this chapter we have surveyed the ways in which animals are used in safety assessments of compounds including medicines, household chemicals, agrochemicals and industrial chemicals. Various species are used, most commonly rodents and also larger animals including rabbits, dogs and primates. Chemicals (including potential medicines) are assessed for their potential to be hazardous to humans, and estimates of the risk of adverse effects from particular levels of exposure are produced. Most toxicity testing is undertaken in the context of legal and regulatory requirements governing the use of particular types of chemical in different parts of the world.
9.45 A range of tests are described including: inhalation, skin irritancy, genotoxicity, acute dosing, repeated dosing and effects on developing fetuses. We observed that a full complement of toxicity tests for a pharmaceutical compound that reaches the market usually involves between 1,500 and 3,000 animals. Adverse welfare effects may arise from the environment in which animals are kept, and may therefore depend on housing and handling conditions (see Paragraphs 4.37–4.47). Specific welfare implications resulting from toxicity procedures depend on dosing and sampling methods, and the effects of the chemical. While toxicologists emphasise that many procedures affect animals only in minor ways, certain groups of animals, especially those in the positive control group, will be subjected to tests leading to overt signs of toxicity during an experiment, which means that significant pain and distress could occur, depending on the type of toxicity elicited. We consider ways of replacing, refining and reducing these effects in Chapters 11 and 12. In the next chapter, we summarise the discussion presented in Chapters 5–9, and consider in particular arguments about the scientific validity of animal research