1xx - parte libro

8/3/2019 1xx - parte libro

1/4

Humane endpoints and the importance of training

Jann HauDepartment of Physiology, Division of Comparitive Medicine, Uppsala University, BMC Box 570,75123 Uppsala, Sweden

Summary

Continuous renement of experimental protocols resulting in the introduction of the earliestpossible endpoint requires competence, commitment and the collaboration of all staffcategories associated with animal care and animal experimentation. An intimate knowledgeof the normal biology and behaviour of the species in question is necessary for thedevelopment of relevant observation checklists on which to base the endpoint. Education and

training are thus essential prerequisites for continued optimization of animal welfare duringexperimental procedures.

When an experiment or test leads to thedeath of an animal as the endpoint and ispreceded by suffering or pain, the design ofthe experiment needs to be scrutinized forpossible changes allowing the introduction ofeuthanasia prior to suffering and pain per-ception. Euthanasiaor the humane killingof animalsmay obviously be essentialwhen using animals in biomedical research.However, the term humane endpoint indi-cates that certain endpoints in biomedicalresearch are not humane and that it is pos-sible to introduce more humane endpoints incertain experiments by terminating them atan earlier stage, such as when clinical orphysiological changes indicative of the effectof the treatment or procedure become iden-

tiable. In other words, the search to mini-mize pre-death suffering in those biomedicalexperiments where it occurs may also betermed renement in accordance with theThree Rs of Russell and Burch (1959).

Replacement and reduction are more easyconcepts to deal with than renement. Con-sequently, renement has been termed theCinderella of the Three Rs (Hau & Carver1994), a term later adopted by van Zutphen(1998), because renement in laboratory

animal experimentation requires compe-tence, commitment and the collaboration ofall staff involved in the care of animals andanimal experimental procedures.

Examples of renement byintroducing more humane endpointsearlier

It is important to emphasize that the maj-ority of animals used in biomedical researchnever experience severe stress, suffering andpain. They may be deprived of stimuli andlive in fairly sterile and barren environments,but the importance of the need for enrich-ment and, particularly, for a suitable socialenvironment is gaining general recognitionin the biomedical community (Anonymous1993). It is quite obvious from the currentscientic literature on laboratory animalhusbandry that improvements in the cageenvironment and housing in appropriate

social groups are being introduced into Euro-pean animal facilities (Blom et al. 1993,Jacobs et al. 1995, Baumans & van de Weerd1996, Saibaba et al. 1996, Augustsson & Hau1999).

Renement with respect to the alleviationof fear, pain and distress in animals duringexperiments is also taking place in experi-mental laboratories by the use of improvedmethods such as the increased use of imagingand telemetric techniques, and by changing

experimental designs based on animal wel-fare considerations. It is, nevertheless, a factthat many experiments of longer duration ine.g. toxicity and carcinogenicity studies, as

Humane endpoints in animal experiments for biomedical research 71


2/4

well as studies of autoimmunity and infec-tious diseases, often have death as a result ofthe treatment as the ultimate endpoint. Thisendpoint may also be a requirement of theregulatory authorities according to the

European Pharmacopoeia.This should not, however, discourage sci-

entists from attempting to introduce earlierendpoints and, as a minimum, euthanasia ofmoribund animals. Study directors and prin-cipal investigators should, as a general rule,be asked to justify the endpoint of death fol-lowing a period of suffering as a necessarycomponent of the experiment. The followingis an example of how earlier endpoints can beintroduced and accepted by the authorities.

In an application to our regional EthicsCommittee a group of researchers wantedpermission to use a mouse model of swineerysipelas, infecting mice with Erysepelo-thrix rhusiopathiae and using death as theendpoint, as stipulated in the EuropeanPharmacopoeia. The Ethics Committeequestioned the need to use death instead ofsigns of clinical disease, and the scientistssuccessfully convinced the European Phar-macopoeia to allow the euthanasia of theanimals once behavioural and clinical signshad been observed, indicating that theanimals were moribund.

It may also be possible to introduce earlierendpoints by rening the animal model sys-tem. I can give an example of this from ourown laboratory in which we developedrened mouse models for the study ofmycotic infections. Traditionally mice havebeen used for screening the virulence of fungi

and the efcacy of antimycotic drugs by thesystemic injection of large doses of fungiusing death as the endpoint. We developed amodel of localized candidiasis by inducingmycotic mastitis in lactating female mice.Hence the infection remains localized andthere are no macroscopic clinical signs ofdisease (Guhad et al. 1995). The model issensitive and can be used to distinguish thevirulence of different Candida strains(Guhad et al. 1998). There are no signs of

stress or suffering in the infected animalsprior to euthanasia.

Mellor and Morton (1997) have addressedthe need for improving the understanding of

the pathophysiological processes underlyingthe effects of an experiment. They correctlyargue that the introduction of earlier end-points may be less difcult to achieve inexperiments where the biological mechan-

isms are better known (e.g. vaccine trials)than in those where the toxicity of newchemical compounds is being investigated.

The importance of teaching andtraining for the renement andintroduction of earlier endpoints

The most important means for improving thewelfare of the animals used in biomedicalresearch is educationnot just of laboratory

animal technicians, scientists and laboratoryanimal specialists, but also of the generalpublic and special interest groupsabout thetrue needs of animals. The aim is to providethe animals with a low stress environment inwhich pain and suffering are reduced to anabsolute minimum. The Euro-pean require-ment for competence in all staff categoriesassociated with laboratory animal care andexperimentation, and the resulting estab-lishment of mandatory education in Eur-opean countries is thus to be welcomed as amost important contribution to laboratoryanimal welfare.

Detailed curricula for courses in four dif-ferent categories (AD) for technicians, sci-entists and laboratory animal specialists havebeen established by FELASA working groups.These may set appropriate standards forfuture European courses in laboratory animalscience and welfare. An important compo-

nent of the mandatory competence courses isethics and the increasing awareness of thenecessity to ensure that animals are treatedwith care and responsibility based on anunderstanding and knowledge of the biologyand behaviour of the relevant species. This isperhaps particularly important for the short(80 h) FELASA category C courses for scien-tists, because the use of animals in researchis a completely novel subject to many youngbiomedical scientists. Of major importance

for ensuring the humane treatment of ani-mals is a thorough introduction to the biol-ogy, and true behavioural needs, of thespecies most commonly used as laboratory

72 Humane endpoints in animal experiments for biomedical research


3/4

animals. It is vital that all staff are taughtthat the perceptual world of an animal isdifferent from that of humans and thatimportant behavioural characteristics varybetween and within species depending on

age, gender, strain and position in theanimal hierarchy. A thorough introduction toanimal welfare and how to minimize stressand reduce fear by conditioning as well aspain assessment, and ways to eliminate painperception in animal experimentation, arealso important theoretical components ofthe education of scientists and laboratoryanimal technicians. Compassion for theanimals in experiments must be recognizedas essential for the improvements of animal

welfare. Education will ensure that thenegative impact of experiments on animalscan be assessed as objectively as possible, andanthropomorphic subjective views on howanimals perceive experimental treatment canbe avoided.

Practical training in the correct handling,sampling and administration of substancesmust be considered essential components ofany competence course in laboratory animalscience. The use of animals in the develop-ment of manual skills has been the subject ofdebate in Europe. In certain countries such asthe UK, it is not permitted to train staff usinganimals. As an exception, the use of rats isaccepted in microsurgery training pro-grammes, but a number of British surgeonshave had to learn minimal access surgicaltechniques abroad because of this strictlegislation.

The numbers of animals used in training

programmes are miniscule compared withresearch use and it must be consideredessential, from an animal welfare point ofview, for technicians and scientists to betaught how to restrain animals withoutcausing fear and stress, as well as how toanaesthetize them. Once the animals areanaesthetized, the course participants canlearn all the relevant sampling techniques aswell as the administration of substances,after which the animal is killed and dissected

for comparative anatomy. Although it isoften claimed that there is strong oppositionto the use of animals in training programmes,this is not supported by the feedback from

course evaluation forms. I have taught andtrained technical and scientic staff at alllevels in universities in Denmark, the UKand Sweden for more than 20 years, and thevast majority of students are extremely

positive about the use of animals in trainingprogrammes. It goes without saying that itis important for the trainers to show respectfor the animals used and to demonstratethoroughly how to pick up, restrain andanaesthetize the animals before the studentsdo it themselves.

An important feature of training courses isthe instruction and training in the methodsof humane killing. All animals should beguaranteed a humane killing either as the

endpoint of an experiment or immediatelyafter the experiment is nished. Severalguidelines on acceptable euthanasia methodshave been issued, following extensive con-sultation of laboratory animal scienceexperts, which ensure that all laboratoryanimals can be humanely killed at the end ofan experiment. Some euthanasia techniquesrequire more skill than others, and in parti-cular physical methods like cervical disloca-tion or killing conscious animals by shootingwith either a free bullet or captive bolt,should only be attempted by experiencedpersonnel who have received sufcienttraining to allow them to use these methodscondently and effectively.

Conclusion

Knowledge and competence obtainedthrough education and training in all staff

categories are essential for the continuousrenement of animal experimentation. Thesearch for early endpoints in projects andtests where death is used as the endpointmust be given a high priority. However, inaddition to competence, the way forward alsorequires commitment and collaboration.

Commitment in both scientic and tech-nical staff is needed to improve the welfare ofanimals in experiments and to searchactively for ways and means of terminating

experiments as early as possible. We shouldsearch actively for behavioural, clinical andphysiological parameters that may be used asindices of the effect of treatment rather than

Humane endpoints and training 73


4/4

death or the obvious moribund state of ananimal.

Collaboration through good communica-tion between laboratory animal technicians,scientists, laboratory animal veterinarians,

institutional certicate holders and the reg-ulatory and inspection authorities is vital forprogress in this area. Mistrust, particularlybetween scientists and ethics committeesand license-issuing authorities, may hinderthis development, and efforts should be madeto establish frictionless contact and colla-boration between all personnel involved inlaboratory animal experimentation.

References

Anonymous (1993) A predator's compassion(Editorial). Lancet 341, 131112

Augustsson H, Hau J (1999) A simple ethologicalmonitoring system to assess social compatibility ingroup housed laboratory rhesus macaques. MedicalPrimatology (in press)

Baumans V, van de Weerd HA (1996) Enrichment oflaboratory animal housing: basic need or luxury. In:Frontiers in Laboratory Animal Science. Proceed-

ings of the Joint ICLAS, Scand-LAS and FinLAS

meeting, Helsinki 1995 (Nevalainen T, Hau J,

Sarviharju M, eds). Scandinavian Journal ofLaboratory Animal Science 23(Suppl 1), 935

Blom HJM (1993) Evaluation of Housing Conditionsfor Laboratory Mice and Rats (PhD thesis) TheNetherlands: University of Utrecht

Guhad F, Jensen HE, Aalbaek B, Rycroft A, Hau J(1995) A murine model for the study of mycoticmastitis. Journal of Comparative Pathology113,31525

Guhad FA, Jensen HE, Aalbaek B, et al. (1998)Mitogen-activated protein kinase-defective Can-

dida albicans is avirulent in a novel model oflocalized murine candidiasis. FEMS MicrobiologyLetters 166, 1359

Hau J, Carver JFA (1994) Renement in laboratoryanimal science: is it a Cinderella subject, and isthere conict and imbalance within the 3Rs?Scandinavian Journal of Laboratory Animal

Science 21, 1617Jacobs H, Smith N, Smith P, et al. (1995) Zebra

Finch behaviour and effect of modestenrichment of standard cages. Animal Welfare 4,39

Mellor DJ, Morton DB (1997) Humane endpoints inresearch and testing. Synopsis of the workshop. In: Animal Alternatives, Welfare and Ethics (vanZutphen LFM, Balls M, eds). Amsterdam: ElsevierScience, pp 2979

Russell WMS, Burch RL (1959) The Principles ofHumane Experimental Technique (Special edition,1992). Potters Bar: UFAW

Saibaba P, Sales GD, Stodulski G, Hau J (1996)Behaviour of rats in their home cage: daytimevariations and effects of routine husbandryprocedures analyzed by time samplingtechniques. Laboratory Animals 30,

1321van Zutphen LFM (1998) Renement, the

Cinderella of the 3Rs. In: The Ethics of AnimalExperimentation. European Biomedical ResearchAssociation

74 Humane endpoints in animal experiments for biomedical research

1xx - parte libro

Documents