The ethics of research involving animals - Nuffield Council on ...
The ethics of research involving animals - Nuffield Council on ...
The ethics of research involving animals - Nuffield Council on ...
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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<br />
mice have direct counterparts in humans (paragraph 7.2). Most biomedical scientists<br />
maintain that the similarities between mice and humans are sufficient to make informative<br />
comparis<strong>on</strong>s. Furthermore, the differences may be as instructive as the similarities when<br />
investigating the mechanistic basis <str<strong>on</strong>g>of</str<strong>on</strong>g> disease (paragraph 7.10). Scientists using <str<strong>on</strong>g>animals</str<strong>on</strong>g> in<br />
this field therefore maintain that careful analysis <str<strong>on</strong>g>of</str<strong>on</strong>g> mouse models can provide significant<br />
informati<strong>on</strong> <strong>on</strong> the functi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> genes in mammalian disease processes (paragraph 7.10).<br />
Other species with suitable genomes for comparative studies such as the zebrafish and the<br />
rat are being increasingly used (paragraphs 7.11-7.13).<br />
10.18 Informati<strong>on</strong> from mouse models has enabled scientists to investigate the relati<strong>on</strong>ship<br />
between mutati<strong>on</strong>s and the nature and severity <str<strong>on</strong>g>of</str<strong>on</strong>g> the disease they cause. <str<strong>on</strong>g>The</str<strong>on</strong>g> glucokinase<br />
gene in diabetes is <strong>on</strong>e such example. <str<strong>on</strong>g>The</str<strong>on</strong>g> use <str<strong>on</strong>g>of</str<strong>on</strong>g> the mouse model shaker1 has also led to<br />
the discovery <str<strong>on</strong>g>of</str<strong>on</strong>g> a gene causing pr<str<strong>on</strong>g>of</str<strong>on</strong>g>ound hearing loss in both mice and humans (see<br />
paragraph 7.9). Mouse models are also important for investigating how <strong>on</strong>e disease can<br />
produce varying symptoms in different individuals. Indirect changes, for example in levels<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> a protein or a horm<strong>on</strong>e, may prove to be more suitable therapeutic targets than the<br />
genes themselves, as in the case <str<strong>on</strong>g>of</str<strong>on</strong>g> patients with neurodegenerative disorders (see<br />
paragraph 7.9). <str<strong>on</strong>g>The</str<strong>on</strong>g> use <str<strong>on</strong>g>of</str<strong>on</strong>g> GM <str<strong>on</strong>g>animals</str<strong>on</strong>g> can entail a wide range <str<strong>on</strong>g>of</str<strong>on</strong>g> welfare implicati<strong>on</strong>s, as<br />
the <str<strong>on</strong>g>animals</str<strong>on</strong>g> involved usually suffer from the disease being studied for the durati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> their<br />
lives (paragraph 4.57). <str<strong>on</strong>g>The</str<strong>on</strong>g>y are also likely to be the subject <str<strong>on</strong>g>of</str<strong>on</strong>g> procedures carried out to<br />
characterise the different stages <str<strong>on</strong>g>of</str<strong>on</strong>g> the disease, including blood, metabolic and behavioural<br />
tests. <str<strong>on</strong>g>The</str<strong>on</strong>g> very low success rates in producing a strain <str<strong>on</strong>g>of</str<strong>on</strong>g> animal that can serve as a disease<br />
model also require attenti<strong>on</strong> (see Box 5.6).<br />
CHAPTER 10 SUMMARY OF SECTION 2<br />
Animal use by the pharmaceutical industry (Chapter 8)<br />
10.19 Use <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>animals</str<strong>on</strong>g> within the pharmaceutical industry is a crucial part <str<strong>on</strong>g>of</str<strong>on</strong>g> the <str<strong>on</strong>g>research</str<strong>on</strong>g> and<br />
development process for new medicines. <str<strong>on</strong>g>The</str<strong>on</strong>g> number <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>animals</str<strong>on</strong>g> used by the<br />
pharmaceutical industry has fallen over the last two decades due to the applicati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> new<br />
technologies, new materials and increased use <str<strong>on</strong>g>of</str<strong>on</strong>g> computati<strong>on</strong>al analysis (see paragraph<br />
8.4). In the UK in 2003, 36 percent <str<strong>on</strong>g>of</str<strong>on</strong>g> the total number <str<strong>on</strong>g>of</str<strong>on</strong>g> procedures performed <strong>on</strong> <str<strong>on</strong>g>animals</str<strong>on</strong>g><br />
were undertaken by the commercial sector.<br />
10.20 Relatively small numbers <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>animals</str<strong>on</strong>g> are used in the early stages <str<strong>on</strong>g>of</str<strong>on</strong>g> drug discovery,<br />
particularly in the identificati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> targets for possible medicines. Many <str<strong>on</strong>g>of</str<strong>on</strong>g> the <str<strong>on</strong>g>animals</str<strong>on</strong>g> used<br />
at this stage are GM mice. <str<strong>on</strong>g>The</str<strong>on</strong>g>y are used to ascertain whether, for example, specific<br />
receptors might resp<strong>on</strong>d to chemical compounds which can be developed into new<br />
medicines. Animal models that reproduce relevant aspects <str<strong>on</strong>g>of</str<strong>on</strong>g> human genetic c<strong>on</strong>diti<strong>on</strong>s,<br />
such as sickle cell anaemia, can be used to test how people affected by the disorder may<br />
react to different chemical compounds (see paragraph 8.16).<br />
10.21 Sixty to eighty percent <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>animals</str<strong>on</strong>g> used by the pharmaceutical industry are involved in the<br />
process <str<strong>on</strong>g>of</str<strong>on</strong>g> characterising promising candidate medicines (Table 8.1). Rodents are most<br />
comm<strong>on</strong>ly used, but larger <str<strong>on</strong>g>animals</str<strong>on</strong>g>, including rabbits, dogs and primates, are also used (see<br />
paragraph 10.24). Before a potential medicine is tested in human trials, the regulatory<br />
authorities must ensure that it has an acceptable balance <str<strong>on</strong>g>of</str<strong>on</strong>g> safety and efficacy, usually<br />
requiring data obtained from animal tests. Twenty five percent <str<strong>on</strong>g>of</str<strong>on</strong>g> the total number <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
procedures using <str<strong>on</strong>g>animals</str<strong>on</strong>g> in 2002 in the UK were c<strong>on</strong>ducted for the purpose <str<strong>on</strong>g>of</str<strong>on</strong>g> ‘applied<br />
human medicine’. Once a medicine is in clinical trials, animal tests c<strong>on</strong>tinue to be carried out<br />
(paragraphs 8.27 and 8.29).<br />
10.22 For certain biological compounds such as vaccines, animal testing is required for each batch<br />
that is produced, to ensure potency and safety (see paragraphs 8.35-8.36). Depending <strong>on</strong><br />
the type <str<strong>on</strong>g>of</str<strong>on</strong>g> test there can be serious welfare implicati<strong>on</strong>s. For example, if death is the<br />
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