Biomedical research is a broad area of science that discovers ways to prevent and treat diseases that cause illness and death in people and animals. Utilising biotechnological techniques, biomedical researchers investigate biological processes and diseases with the ultimate goal of developing effective new medicines, therapies, treatments and cures.
The use of animals in biomedical research is essential for the development of new effective methods and improving existing methods for diagnosing and treating diseases that affect humans and animals. Scientists use animals to learn more about health problems and to ensure the safety of new medical treatments. Medical researchers need to understand all things about health problems before they develop ways to treat them.
Some diseases and health problems involve processes that can only be studied in living organisms. Therefore, animals are necessary for medical research to avoid impractical or unethical issues relating to the use of humans for biomedical research.
A variety of animals act as very useful models for studying diseases afflicting animals and humans. Animals are biologically similar to humans and have short life cycles. Due to short life cycles, animals can be easily studied throughout their life span or across several generations. And also, researchers can easily control the environment around animals such as diet, temperature and lighting which would be difficult to do with people.
Model of choice
Around 95 percent of research animals are rats, mice and other rodents that are bred specifically for laboratory research. Dogs, cats and non-human primates account for less than one percent of all the animals used in research.
Rodents play an invaluable role in biomedical research.
Reducing reliance on higher-order species, rodents have become the animal model of choice for biomedical research. Because their physiology and genetic makeup closely resemble those of humans, and because these similarities are strong enough to give researchers an enormously powerful and versatile mammalian system to investigate human diseases, rodents are mainly used for studying nerve damage treatments, causes of some cancers, effects of nutrition on aging, Alzheimer’s disease research, spinal cord injury, drug addiction and regulation of cholesterol.
Dogs and people often get the same diseases, ranging from heart disease to cancer. Dogs are used for the investigation of insulin treatments for diabetics, studying cardiovascular diseases and blindness, organ transplantation techniques, pacemaker implantation, hip and other joint replacement surgery.
Researchers study dogs in medical and scientific research that often yields treatments that help not only people but also dogs. Another type of animals used for laboratory research is non-human primates. Most of these animals are species of monkeys, not chimpanzees or other great apes. The polio vaccine, blood transfusions and organ transplantation could not have been possible without research with non-human primates.
In addition, rabbits are used for corneal transplants, cardiovascular diseases, drugs that lower cholesterol and help to stop the hardening of the arteries, and anthrax vaccine research.
Early Greek physician-scientists, such as Aristotle and Erasistratus performed experiments on living animals.
In the 17th century, William Harvey researched on numerous animal species to study blood circulation. Across Europe, the use of animals in scientific research began to expand over the 19th century. In recent years, using animals for biomedical research has come under severe criticism by animal protection and animal rights groups. Laws have been passed in several countries to make the practice more ‘humane’.
Animals were used in most medical advances of the 20th century, including insulin, the polio vaccine, penicillin and the elimination of smallpox. The effectiveness of penicillin as an antibiotic was proven in mice in 1940, the asthma inhaler was manufactured after tests on guinea pigs in 1970 and anti-retroviral drugs against HIV were discovered using monkeys in 1990.
Animals are mostly used as models of biomedical research to discover medicines and treatments for Covid-19. In particular, research with ferrets, monkeys and genetically altered mice allowed scientists to gain greater knowledge about how the virus was passed between individuals and how it affected the cells of the body.
EARA member Ghent University in Belgium, in collaboration with the University of Texas and the National Institutes of Health, USA, investigated treatments using animals such as llamas and alpacas and discovered that llama antibodies are effective in neutralising the coronavirus and preventing it from breaking through into host cells.
And also, all the approved vaccines were tested for safety with mice and non-human primates. Example, the Astrazeneca vaccine was made by using chimpanzee adenovirus vaccine vector.
Although there are many benefits of using animals for biomedical research, there are some cons to animal models. Some of the medicine that is used on animals will never be used.
Expensive practice
Because of that, animals sacrifice their lives without a reason. It can be an expensive practice because scientists have to take care of laboratory animals. The structure of an animal’s body is not exactly similar to the structure of a human’s body.
Therefore, some drugs that are not harmful to animals can be harmful to humans. And also, drugs and products that could be harmful to animals but can still be highly beneficial to humans.
Researchers should have specific skills including surgery and anesthetics. There are some difficulty in repeating the process due to lack of finance, complex nature of the research and unskilled researchers.
There are cheaper alternatives to animal tests such as micro dosing.
They can provide more accurate results than animal tests. For example, an artificial animal skin is used as a test subject instead of animal skin. Virtual reconstructions of human cells performed using computer models can predict the toxicity levels of chemicals, eliminating the need to inject animals with poisons to obtain data. Using animal model cannot be trusted in determining long-term effects.
Although animal experiments give us an estimation regarding how drugs affect human physiology, they might not be the best for offering sufficient knowledge about the long-term effects of these medicines. For example, mice only live for a few years while humans for several decades.
Therefore, it is not possible to determine the long-term effects of drugs using mice experiments. And also, it can cause development of new diseases. If animal testing is done inappropriately, there can be more harm instead of good.
Viruses can escape from the testing centres or laboratories and cause a pandemic.
Over four million animal models are used each year for biomedical research in the UK. Animals feel pain and fear just as we do. If we accept that animals have rights, using animals for research is not acceptable.
To help minimise the harm to animals during laboratory experiments, researchers follow a set of principles called ‘three Rs’: Replace, Reduce and Refine.
Replace means the use of alternative techniques such as cell culture, computer modelling or human volunteers instead of animals where possible.
Reducing is the reduction of the number of animals in research by improving other experimental techniques and sharing information with other researchers with regards to similar experiments. Refining means the way that animals are used to minimise any stress or pain by using less invasive techniques, improving medical care and using painkillers to manage pain.
Alternative models can also be used to avoid the ethical issues of using animal models. Vivo models and ex vivo models are alternative models that can be used instead of animal model. Vivo models are those in which the effects of various biological entities are tested on whole, living organisms or cells, usually animals, including humans and plants, as opposed to a tissue extract or dead organism, for example, Artemia salina, Allium cepa and Zebrafish.
Major elements of in vivo research are animal testing and clinical trials. There are some examples of using vivo model. They are the investigation pathogenesis of disease by comparing the effects of bacterial infection with the effects of purified bacterial toxins, the development of non-antibiotics, antiviral drugs, new drugs generally and new surgical procedures.
Misleading results
It is better suited for observing the overall effects of an experiment on a living subject.
For example, verification of efficacy in vivo is crucial in drug discovery because in vitro assays can sometimes yield misleading results with drug candidate molecules that are irrelevant in vivo.
Ex vivo is the method wherein living tissues are taken directly from a living organism and testing is carried out on them with very minimal changes to the tissue’s natural state.
Tissues may be removed in many ways, including in part, as whole organs, or as larger organ systems. Normal human dermal fibroblasts, human sebocytes, SEBO662 cell line, normal human epidermal melanocytes, reconstructed human epidermis, full thickness reconstructed skin, normal human epidermal keratinocytes can be used as ex vivo model.
There are some examples of using ex vivo models in research. They are used in bioassays, in drug testing of anticancer agents using by cancerous cell lines, like DU145 for prostate cancer, to measure physical, thermal, electrical, mechanical, optical and other tissue properties, especially in various environments that may not be life sustaining, as realistic models for surgical procedure development, to investigate into the interaction of different energy types with tissues, and to test the effect of compounds on skin biopsies.
Using animal models is safer than testing humans first, and it has a lot of benefits for humans and animals and protects a lot of lives. On the other hand, the life of an animal is important, just like the life of a human. So, the use of animals for biomedical research is controversial.