The ethics of research involving animals - Nuffield Council on ...

T h e e t h i c s o f r e s e a r c h i n v o l v i n g a n i m a l s
Summary
7.14 This chapter has described the use <strong>of</strong> GM <strong>animals</strong> in the study <strong>of</strong> human disease. <strong>The</strong> vast
majority <strong>of</strong> <strong>animals</strong> that are genetically modified for this purpose are mice, rats and
zebrafish. Although an animal model cannot be considered as an exact replica <strong>of</strong> a human
disease, scientists working in the field have found that there are <strong>of</strong>ten sufficient similarities
to make informative comparisons. Even when <strong>animals</strong> do not present disease symptoms that
are similar to those <strong>of</strong> humans, useful information may still be discovered regarding gene
function. For example, individual genes can be identified that are involved in specific facets
<strong>of</strong> even complicated disease processes.
7.15 <strong>The</strong> number <strong>of</strong> <strong>animals</strong> required to establish an individual genetic line carrying a particular
mutation currently ranges from 50 to several hundred. Over the next 20 years, a major
increase in the production <strong>of</strong> GM <strong>animals</strong> is expected. <strong>The</strong> total number <strong>of</strong> mice used in
mutagenesis and phenotyping studies in the UK is likely to be <strong>of</strong> the order <strong>of</strong> several million
each year.
7.16 As with all <strong>animals</strong> kept in laboratories, the welfare <strong>of</strong> GM <strong>animals</strong> depends to a
considerable degree on non-experimental conditions such as housing and handling. Specific
issues relating to the way the <strong>animals</strong> are produced may be raised because <strong>of</strong> the large
numbers involved. Care needs to be taken to create environments that are appropriate for
the <strong>animals</strong> with regard to their basic species-specific needs, particularly concerning space,
enrichments and interactions with other <strong>animals</strong>. Welfare issues may also be raised by the
particular genetic modification. <strong>The</strong>se may be severe if the <strong>animals</strong> are affected by, for
example, a neurodegenerative disease. We have also described genetic modifications that
have yielded useful results with regard to human disease but which do not appear to
produce adverse effects on animal welfare. <strong>The</strong> main problems in assessing the welfare <strong>of</strong>
GM <strong>animals</strong> are that (i) in most cases <strong>of</strong> forward or reverse genetic screens, the implications
for welfare cannot be predicted (see paragraph 4.57); and (ii) it can sometimes be difficult to
detect and measure more subtle adverse welfare effects (see paragraphs 4.3-4.7, 4.18 and 7.10).
CHAPTER 7 GENETICALLY MODIFIED ANIMALS IN THE STUDY OF HUMAN DISEASE
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