Animal experimentation is the use of non-human animals in experiments that seek to control the variables which affect the behaviour or biological system through vigorous study. In 2018, 3.52 million procedures which involved living animals were carried out in the United Kingdom(1). 1.8 million of them were for experimental purposes. These procedures included using non-human animals in scientific studies for purposes such as basic research and the development of treatments, safety testing of pharmaceuticals and other substances. The rest were for creating and breeding of GA animals(1).
Proponents of animal testing say that development of medicine since 20th century was made due to animal research. Verification of new substances found or synthesised would be necessary for checking medical values or side effects. However, it is highly unpredictable what the outcome of these new substances would be in theory. Hence, it is necessary to perform experimentation using animals which have similar genes to humans. For example, most anaesthetics and insulin, which is common treatment for diabetes were previously developed through experimentation on animals.
Secondly, the welfare and rights of model animals are carefully considered beforehand to ensure no harm comes to the animals. Communal animals usually get traumatised when there is no social stimulus. This in turn leads to abnormal behaviours. The 3Rs principle was introduced to provide a framework for not exploiting animals without consideration(7). The 3Rs stand for Reduction, Refinement, and Replacement. Reduction refers to methods which can minimise the number of animals used per experiment or study in order to be consistent with the firm scientific aims. Refinement alludes to methods that minimise or avoid the pain, suffering, lasting harm and distress can be raised to enhance the welfare of said animals. Using the appropriate anaesthesia and analgesia to reduce pain is an example of refinement. Finally, replacement refers to methods which directly replace or avoid the use of animals in experiments.
People who disagree with animal testing claim it is unreliable. TGN1412 was successfully confirmed as safe and efficacious in preclinical studies both in vitro and in vivo. However, when it is administered to six healthy human volunteers with a dose 500 times smaller than known safe in animal trials, all six of the human volunteers suffered from life-threatening conditions, such as multiorgan failure(6). Nonetheless, practolol was introduced for treatment for heart diseases after it was deemed safe for human, approximately 2,450 adverse reaction in patients including 40 casualties, and 200 life-threatening conditions were reported after administration(5).
Vice versa, Penicillin, which is safe for human has fatal reaction on the most of rodents. This shows that even some non-human animals have a lot of similarities in their gene expression, but it cannot be said that animal experiments are perfectly safe. Moreover, only 1.16 percent of diseases are shared both in human and non-human animals.
Alternatively, non-animal methods can substitute for animal testing. Many studies are being performed to help develop and utilise methods to replace animals in testing of new products and the investigation of diseases. In vitro methods, and in silico models suggested(1), (9).
In terms of in vitro testing, organ-on-chips are invented by Harvard’s Wyss Institute(9). In this technology, human organ cells are extracted and cultivated into chips. These allow a simulation of the structure and function of human organs and its organ systems. Instead of crude animal experiments, the chips can be used in drug testing and toxicity testing(4). Several precedents prove that they can replicate human physiology, diseases and drug responses. In addition, they give more reliable and accurate results than animal experiments. For instance, Eye-chips, one of the products from Harvard’s Wyss Institute, closely replicates the physiology and responses of human eyes(4).
Regarding in silico modelling, quantitative structure-activity relationships (QSARs) is one of the methods used. It is a computer-based technique which can predict the biological effect of chemical compounds based on mass data; similarities to existing substances, knowledge of human biology, mathematical and statistical relations(8).
In conclusion, some think animal testing is acceptable, since it is essential to make successful progress on medical research without animal testing. Moreover, the welfare of experimental animals are fairly considered. On the other side, animal experimentation is disagreed as there are the alternatives and previous examples of failure on applying results from animal experimentation to testing on human. In my opinion, alternatives are reasonably ethical and efficient.