The 3Rs in the treatment of laboratory animals #

Keywords: 3Rs; animal experimentation; animal welfare; scientific ethics; bioethics; humane science; moral status of animals; laboratory animals; research methodology.

Introduction #

The Three Rs (3Rs) were outlined in The Principles of Humane Experimental Technique¹ in 1959. The creation of ‘The Principles’ was preceded by a project of the Universities Federation for Animal Welfare (UFAW) to promote animal welfare as an integral component of reliable research involving animals. The idea behind the UFAW’s project was that science, rather than political rhetoric, should be the way to achieve animal welfare objectives². In other words, the idea arose of shaping ‘good science’ to influence animal welfare.

The authors of ‘The Principles’ are W. Russell and R. Burch. Russell was a biologist, educated as a zoologist at Oxford University, and had various interests including biological, psychoanalytic, behavioural, historical, and sociological sciences. He was a researcher at the UFAW and a project manager. Burch, on the other hand, acted as a ‘field assistant,’ carrying out quantitative and qualitative mapping of animal studies³.

As the abbreviation indicates, the 3Rs include three basic principles: Replacement, Reduction, and Refinement. Their aim is to avoid animal research wherever possible, to reduce the amount of research, and to limit the harm done to animals in experiments⁴. The Replacement aims to replace animal research with alternative methods as much as possible or to avoid it altogether. Reducing the number of laboratory animals is possible through statistical and methodological evaluations of the number of animals actually needed. The Refinement aims to minimise the negative effects of research procedures on laboratory animals.

The Three Rs are now widely known around the world. They are mentioned in various national and regional acts, policies, journals⁵; they are also common among research organisations and animal advocates⁶. It can be said that the 3Rs are the most authoritative rules for the treatment of laboratory animals, which the world looks up to. The problem, however, is that there is no consensus among biologists, philosophers, legislators, and other actors as to how each of the 3Rs principles applies⁷. Thus, following the concept becomes more challenging.

To date, there are several perspectives on what the concept of the 3Rs is. In particular, principles can act as both a methodological and ethical framework for conducting modern research involving animals⁸. Thus, the principles of the 3Rs can be seen in two ways: as an ethical category and as a scientific category.

The 3Rs as an ethical category #

Equating the 3Rs with ethical rules is particularly popular in today’s scientific community. The use of the 3Rs in research provides some evidence that researchers are committed to maintaining high ethical standards when working with laboratory animals⁹. Empirical research also shows that scientists see the 3Rs in their practice as a way of meeting their ‘moral obligations’ to animals¹⁰. Indeed, at first glance, it can be said that using a smaller number of animals or replacing them with alternative models is clearly in their interests, not to suffer as a result of the research. The 3Rs can thus present themselves as principles of ethical behaviour in relation to laboratory animals.

However, the ethical characterisation of the 3Rs is subject to active criticism. Although there is much debate as to the meaning of each principle, there are very few scientific articles linking the 3Rs and ethics¹¹. In my opinion, the main reason is the confusion of the concepts of ’ethics’ and ‘animal welfare’.

In ‘The Principles’, Russell and Burch did not focus on the ethics of laboratory research but did address the ‘welfare of animals’. If we look at each of the principles, we can see that they are aimed specifically at minimising harm to the animal. The Replacement requires the use of non-animal models in research; the Reduction aims to reduce the number of laboratory animals in general.

Refinement aims to improve the conditions in which animals are kept and treated. Neither of the principles involves considering and focusing on the interests of animals as a separate category.

It is an undeniable fact that the 3Rs principles have enabled a major breakthrough in animal welfare and the development of Animal Law¹². However, they do not include general moral principles that reflect the values underlying the ethics of research involving animals. According to Tom L. Beauchamp and David DeGrazia, at the heart of this should be the recognition of an animal’s moral status¹³. This status distinguishes an animal from an inanimate thing, thereby requiring specific rules for its treatment.

The 3Rs principles aim to regulate ‘good science’ and animal welfare, but they do not address the question of when harm to an animal would be justified. Tom L. Beauchamp and David DeGrazia propose assessing the justifiability of harming animals through an analysis of the ‘social benefit’ of the experiment¹⁴. This concept is very similar to utilitarianism, which argues for harming the smallest number of animals in order to achieve the greatest positive effect for the largest number. The main challenge for researchers is to properly assess the ‘benefit’ of potential future outcomes while also considering the welfare of the animals used to achieve those outcomes.

Thus, it can be said that shifting the emphasis of the 3Rs principles towards animal welfare, rather than towards a moral assessment of research, does not allow them to be called ’ethical’. It is therefore necessary to analyse what original meaning Russell and Burch put into each of the principles.

The 3Rs as a scientific category #

As mentioned earlier, science and ethics have been in constant conflict. On the one hand, there is the need to satisfy the human need for reliable scientific knowledge. On the other hand, there is a need to consider the welfare of animals as creatures capable of experiencing pain and suffering. In other words, there is a conflict between the natural sciences and the humanities, which is due to their characteristics as well. Natural sciences are accurate and factual, whereas the humanities are evaluative.

‘The Principles’ were developed by Russell and Burch as an attempt to end this conflict¹⁵. Moreover, they were based on a certain moral vision, which would unite the values of science and the humanities. The natural sciences and humanities together should reinforce each other and develop in the future¹⁶. Thus, ‘The Principles’ introduce the concept of ‘scientific humanism’: this is the term through which the original meaning of the 3Rs can be understood.

It is important to note that Russell and Burch’s proposal was, in fact, the idea of a new applied science. The idea was, in other words, to create a ‘good science,’ the aim of which was to improve the treatment of laboratory animals while improving the quality of scientific experiments¹⁷. Animal welfare would be achieved precisely through good laboratory practice.

In order to link ‘science’ and ‘animal welfare,’ ‘The Principles’ introduce two key terms: humanity and inhumanity. Humanity is the final goal of the 3Rs principles, achieved by reducing inhumanity. Inhumanity encompasses the range of unpleasant psychological conditions that experimental animals may experience¹⁸. If an animal experiences pain, distress, or other discomfort during the research process, this is a manifestation of inhumanity.

The new science, according to Russell and Burch, must be humane. It is humanity that leads to the humane treatment of animals, based on kindness and benevolence. This ‘humanity’ consists of reducing the suffering of laboratory animals during the experiment.

‘The Principles’ was not originally conceived as a work of moral philosophy. On the contrary, Russell and Burch developed a practical strategy of replacement, reduction, and refinement¹⁹. The 3Rs principles are not a catalogue of methods or clear rules. They are general fundamental ideas that lead to a humane science²⁰. In the following, it is necessary to examine each principle in more detail and see how it relates to its contemporary interpretation.

REPLACEMENT #

According to ‘The Principles’, the Replacement is the substitution of animals for non-sentient, non-intelligent material. Such material may include plants, micro-organisms, and other objects whose nervous system is almost atrophied. Russell and Burch distinguish between relative replacement, where living organisms are used, and absolute replacement. Absolute replacement stands as the absolute ideal, where the possibility of a laboratory animal being stressed is completely excluded²¹.

Thus, it is important to understand that Russell and Burch look at good science precisely in terms of reducing inhumanity, i.e., reducing the stress caused to animals. In the Replacement, similarly, the aim is to remove stress from laboratory animals, not to remove their use altogether. It can be said that the principle of Replacement is a highly technical way of reducing stress in animals by simply not using them.

Russell and Burch also do not use the term ‘alternatives’ in their description of the Replacement. Indeed, the “replacement by alternative methods” began to take shape in the scientific community and became associated with the 3Rs already after the publication of ‘The Principles’²². Replacing animal models with alternative methods is a more complex process. On the one hand, there is a clear ethical and scientific need to develop new non-animal research methods. On the other hand, the same ethics do not allow unknown responses, such as cell cultures, to be investigated directly in humans²³. Therefore, gaining confidence in the reliability of a new method and its use in humans may be possible by initially testing it on animals. Often, the number of animals needed for this may exceed that which would be used in the in vivo method²⁴. In other words, it is a vicious circle: developing new methods is necessary to reduce the number of animals, but developing those methods requires the use of animals. This conflict is an example of the modernisation of the original 3Rs to current realities and ethical standards.

Another example of the difference between the modern interpretation of the 3Rs principles and the original meaning of Russell and Burch is that they do not intend a total Replacement²⁵. As already mentioned, the aim of the 3Rs is to achieve humane science without compromising the quality of research outputs and the needs of society. In particular, by replacing animals with non-sentient models, it is possible to reduce the cost of research (a benefit to science), and it also contributes to the idea of humanity, as the public would prefer not to use laboratory animals²⁶.

Therefore, the Russell and Burch Replacement principle is not aimed at completely replacing animal models with alternative models. The main aim of the Replacement is to strive for good, humane science that, on the one hand, minimises stress on laboratory animals and, on the other hand, produces equally valid and accurate research results. This differs from the modern view of the Replacement, which aims for a complete switch to alternative research methods.

REDUCTION #

The Reduction in ‘The Principles’ refers to the reduction in the number of animals used to obtain information of a certain volume and accuracy²⁷. It is important to note that Russell and Burch do not specifically put a ‘minimisation’ of the number of laboratory animals within the meaning of this concept, as is used in the modern interpretation. Firstly, determining a ‘minimum’ number of laboratory animals is a very complex task. At the design stage of an experiment, it is often impossible to guess what number of animals should be used to obtain a particular result. Following the principle of the Reduction, as in the desire to use a small number of animals, can lead to experimental results that are difficult or impossible to interpret²⁸. Therefore, following the Reduction principle in today’s reality requires a balance with the Replacement principle.

Secondly, Russell and Burch point out that it is the desire to minimise, rather than reduce, the number of laboratory animals that may deter researchers from conducting more comprehensive and extensive experiments²⁹. As already mentioned, the results of a study are not always predictable and cannot always be obtained immediately after the procedure has been completed. Large scientific research requires smaller-scale, step-by-step experiments. Reducing the number of laboratory animals should not lead to an inadequate number of them for a future experiment.

Therefore, according to ‘The Principles’, the Reduction is also aimed at conducting humane, good science. On the one hand, the number of animals should indeed be reduced, becoming smaller, as this will reduce the stress caused to them. On the other hand, such a reduction should also result in the acquisition of information of a certain quality and accuracy. In other words, while taking animal welfare into account, the needs of science to provide the most comprehensive data must also be considered.

REFINEMENT #

The Refinement includes any decrease in the frequency or severity of inhumane procedures applied to those animals that are still to be used in research³⁰. This principle appears in Russell and Burch’s concept as a separate method of eliminating inhumanity, as it explicitly focuses on how sentient laboratory animals should be treated.

The concept of the Refinement is a broad one, and nowadays includes the housing of laboratory animals in conditions that allow their basic needs (biological, psychological, and others) to be met and in conditions that cause the least amount of stress³¹. Russell and Burch do not list specific examples of how inhumanity can be reduced through the Refinement. However, in contemporary research science, we can find methods such as reduction, removal of pain/stress through the use of analgesic drugs, and the development of new in vivo techniques. It can also include the development of methods that improve the care, housing, handling, and procedures for animals³².

Important to note is that the mere development of technologies that do not allow an animal to be killed for a procedure is not enough. In particular, new methods of handling laboratory animals may require constant manipulation (e.g., injections). Researchers must also consider the stresses that animals experience during such ‘routine’ procedures³³. One option for solving this problem could be to train laboratory animals to come in for non-invasive procedures on their own. A good example is the Superstar Rats project, carried out by an American laboratory. Over a period of several months, researchers trained laboratory rats, using positive reinforcement, to voluntarily walk up to the researcher’s hands and follow a marker (to stand on a scale, for example)³⁴. This project is a good illustration of how the Refinement can be followed through a method of training.

In addition, the results of the project showed how such training affected the human-animal relationship. In particular, the researcher developed an emotional bond with the animal, and the line between ‘pet’ and ’laboratory animal’ became blurred³⁵. In my view, such practices in research laboratories have the potential to develop a more humane attitude towards animals and, as a consequence, a greater consideration of their interests.

The Refinement, therefore, within the meaning of ‘The Principles’ and in current scientific practice, is a very broad concept and includes all actions to reduce the inhumane treatment of laboratory animals. Researchers may use a variety of methods to reduce pain and stress, but the possible negative effects of new technologies must always be taken into account.

Conclusion #

Hence, the 3Rs in the meaning of Russell and Burch are not an ethical concept, aiming to consider the moral interests of animals. Rather, on the contrary, the 3Rs are anthropocentric in that they represent the idea of ‘good science,’ which requires the researcher to have a clear conscience. ‘The Principles,’ although aimed at achieving humanity, are also the basis for future development and the design of new technologies. They should not jeopardise the progress of science.

The question arises as to why the 3Rs principles, although so popular nowadays, are not used in accordance with their original meaning. In my view, there are two reasons. The first is the complexity of the text of ‘The Principles.’ Even Hume pointed out that the work of Russell and Burch is very difficult to read for the common person³⁶. M. Balls noted that among those who apply and follow the 3Rs principles, most have not even read the book³⁷. Moreover, the principles are not presented in the text in a sufficiently informative way to be applicable as a practical guide³⁸. Thus, researchers have to rely on the interpretation set out by others in other documents. This is linked to the second cause of misinterpretation of the original meaning of the 3Rs.

It lies in the progress and development of the scientific community since 1959. Indeed, science does not stand still; new technologies and methods of scientific assessment are developing, and certain statements in ‘The Principles’ are losing their significance. In addition, as mentioned earlier, the 3Rs were quite general and fundamental in nature. The evolving society thus has the opportunity to give additional or new meanings to each of the 3Rs, adapting them to meet contemporary needs.

The question arises: what role should the 3Rs principles play in today’s world? In my opinion, the ‘proper application of the 3Rs principles’ should be understood as following the concepts of replacement, reduction, and improvement, taking into account developing ethical norms and standards. As previously stated, the 3Rs aim to prevent unnecessary suffering inflicted on laboratory animals. However, Russell and Burch’s concept does not seek to challenge the purposes of experiments in which animals will be used³⁹. The 3Rs focus on doing ‘good science,’ direct practice, and accepting the fundamental purpose of research, whatever it may be. In my view, it is this aspect of the 3Rs that goes against contemporary ethical standards.

Animals can nowadays be useful models for the study of biology and medicine, but every research involving animals should be preceded by a substantive evaluation on a case-by-case basis⁴⁰. As Tom L. Beauchamp and David DeGrazia have mentioned⁴¹, it is necessary to analyse the research design in terms of its justification and by balancing the interests of science with the interests of animals. In other words, before applying the principles of the 3Rs to practical science, there should be justification for the use of specific animals in a particular experiment.

Using too many animals or causing unnecessary suffering to animals (i.e., not following the 3Rs) often means that researchers do not conduct sufficiently in-depth systematic reviews. This review allows us to see how previous animal research has affected science and what discoveries have already been made. A systematic review ensures that new experiments do not answer questions that have already been answered⁴². This is especially important in the case of a grant application, where the researcher needs to show the funding agency that the research is really important. If a systematic review is not carried out, many research studies may be repeated or fail to produce the expected results. Thus, systematic review and following the 3Rs principles are inextricably linked. If the research is not preceded by a systematic review to justify its aims and objectives, following the principles of the 3Rs will be an example of ‘good science’ without being animal-centered.

In this regard, I believe that the principles of the 3Rs are and should be interpreted according to the needs of contemporary society. Russell and Burch’s concept made a significant contribution to the development of the recognition of the moral value of animals, although this was not enough to enshrine it as ’ethical’⁴³. For research involving animals to be ’ethical,’ it should be preceded by an appropriate assessment. Such an assessment should focus on the interests of animals and the interests of science, while the 3Rs principles allow further advances to protect animal welfare. These two paradigms should be linked throughout the research.

Bibliography #

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Принципы 3R в обращении с лабораторными животными #

Варвара Пель

Аннотация. Настоящая статья посвящена переосмыслению первоначального значения и современного восприятия концепции Трёх Р (Replacement, Reduction, Refinement), впервые изложенной У. Расселом и Р. Берчем в работе The principles of humane experimental technique (1959). Несмотря на широкое распространение интерпретации 3R как этических принципов, регулирующих научные исследования с участием животных, автор показывает, что изначально они были задуманы как методологическая основа «гуманной науки», основанной на снижении уровня страданий, а не на признании морального статуса животных.

В статье проводится разграничение между этической и научной трактовками 3R и анализируются причины и последствия их концептуальной трансформации. Особое внимание уделяется различиям между первоначальной и современной трактовкой каждого из принципов, роли гуманитарных и естественных наук в формировании научного гуманизма, а также ограниченности 3R как универсального инструмента этической оценки экспериментов. Автор утверждает, что принципы 3R недостаточны для этического обоснования исследований на животных и должны предваряться соответствующей моральной экспертизой в каждом конкретном случае.

Таким образом, работа вносит вклад в более широкую дискуссию о границах этически допустимых форм использования животных и условиях, определяющих этическую приемлемость способов получения научного знания.

Ключевые слова: принципы 3R; эксперименты на животных; благополучие животных; научная этика; гуманная наука; биоэтика; моральный статус животных; лабораторные животные.

DOI: 10.55167/994284ba2a40