Alternative to using protected animals / Main text……8-11
References…….12 – 15
Animal studies are a crucial part of medical research and essential to the understanding in biology Use of Laboratory Animals in Biomedical and Behavioural Research, 1988). The use of animal models is widely recognised as it enables scientists the opportunity of physiology understanding, pathogenesis of disease, and action of drugs (Simmons, 2008). In 2018, the home office published its annual statistics which shows the total amount of animals used for that year, being approximately 3.52 million (2018 statistics on use of animals in research in UK | British Society for Immunology, 2019). Animals used for scientific purposes within the UK are ruled by the animals scientific (‘Animals Scientific Procedures) Act 1986, Section 1.,’ 2019). Animal reproduction, animal housing, and maintenance of any protected animal that has to be used for research, should be categorised into the regulation of the 3Rs and the protection of laboratory animals (Guidance on the Operation of the Animals (Scientific Procedures) Act 1986., 2014). William Russel and Rex Burch were two authors who published a book in 1959, The principles of Humane Experimental Technique. Within the book the concept of the 3Rs was created: replacement, reduction, and refinement (Ferdowsian and Beck, 2011). The 3Rs is a tool invented to reduce the number of animals used for scientific research and to make sure all animals are treated humanely. The aim of this critical review is to talk about finding and using an alternative method for scientific research. A good example of an alternative would be the use of 3D modelling, more precisely three- dimensional (3D) culture systems which are able to replicate tissue-like structures of any species including humans, providing a suitable alternative instead of animal use (Chaicharoenaudomrung, Kunhorm and Noisa, 2019).
Throughout history, research animals have provided some of the most lifesaving opportunities towards science. Antibiotics, vaccination, blood transfusion, dialysis, organ transplant, chemotherapy, bypass surgery or joint replacement are only a few examples made possible due to animal testing and research (Medical Advances Foundation for Biomedical Research, 2016). Other examples of medical breakthroughs comprise of Polio, a deadly paralyzing disease, which killed thousands of people before a vaccine was created in 1908 by Dr Karl Landsteiner and Dr Erwin Popper; who injected monkeys with the extracts of the spinal cord of a boy who died from polio. The disease would then be passed from monkey to monkey, this then provided a vital model of the disease (Development of the polio vaccine, 2014). Coronary heart disease is a common but serious condition, where the blood vessels supplying the heart become narrowed or blocked causing high cholesterol. (Nichols, Townsend, Scarborough and Rayner, 2013). Beta blockers a form of treatment used to treat angina, was first developed by Sir James Black and colleagues who worked alongside him at ICI. By conducting screening studies by using ex vivo guinea pig heart muscle and observation in anaesthetised cats, permitted them to record on how the cardiovascular system functions. Two researchers, Kevin Ng, and John Vane in 1981 conducted studies on the first development of the ACE inhibitor Captopril, which was used as a treatment against hypertension, limiting the potential risk of stroke and heart attack. This discovery would have never been made if anaesthetised dogs who were administered with the peptide angiotensin l, when administered into the dog, the peptide passes through the heart to the lungs then returns back to the heart. Furthermore, the peptide gets switched to angiotensin II, that makes blood vesicles constrict while increasing blood pressure (Larouche‐Lebel et al., 2019. The most recent pandemic COVID-19 caused by the virus SARS-CoV-2. Was first identified in China in December 2019, approximately caused over 200,000 deaths internationally, just in the first four months. Vaccines are currently being developed from the use of animal models funded by MRC (Impact of animal research in the COVID-19 response – Research – Medical Research Council, 2020). World-wide businesses for example Schwarzkopf and Henkel, are two companies that conduct testing on animals both directly in their development process as well as through contracted third-parties use animal models such as rats, mice , hamsters, and lower primates when developing new products (Chen et al, 2020, Is Schwarzkopf Cruelty-Free and Vegan? -, 2020) Acknowledgement of how vital animal research is demonstrated in world-wide circumstances. AALAS, The American association for Laboratory Animal Science association, established in 1950, recognised the importance of animal research. Their code of ethics is based upon 11 steps one of which “ promote and encourage the highest level of ethics within the profession of laboratory animal science” (American Association for Laboratory Animal Science, 2020), (Brønstad et al., 2016).
Legislation was brought in by the UK with the aim of ensuring all laboratory animals are protected. Documented as ASPA “Animals scientific procedures act 1986” states, All vertebrate species, and cephalopod species are considered protected. When the protected animal has reached two thirds of its gestation or incubation period and can individually feed for itself. However, it must be known that a cephalopod in its embryonic form is not a protected animal (‘Animals (Scientific Procedures) Act 1986, Section 1.,’ 2019). Animal reproduction, animal housing, and maintenance of any protected animal should be categorised into the regulation of the 3Rs and the protection of laboratory animals (Guidance on the Operation of the Animals (Scientific Procedures) Act 1986., 2014).
Alho et al., (2016). Talks about the effects that may occur in cats who do not receive adequate enrichment, this may potentially lead to conditions for example: feline idiopathic cystitis, obesity, anxiety, and stress. Due to laboratory rules and regulation, all felines belonging to scientific research, have to be accommodated inside because of health reasons and hygiene. Which could potentially disrupt or affect the outcome of a particular experiment. It is vital for scientific research workers to guarantee suitable enrichment to be provided to laboratory cats in order for the animal to demonstrate their natural behaviours.
Any procedure carried out on a protected animal that may cause any suffering, pain, lasting harm, or distress comparable to or greater than that of the insertion of a hypodermic needle, the procedure is then registered as regulated, conferring to respectable veterinary practice. (Guidance on the Operation of the Animals (Scientific Procedures) Act 1986., 2014) suggests a procedure carried out on animals must only be untaken if it has a scientific or learning purpose. The reproduction of genetically engineered animals is included under the guideline of regulated procedures. Conducted in 2017, a home office report reveals roughly 15% of genetically modified animals had suffered a damaging effect, either physically or mentally because of the genetic alteration procedure (Great Britain and Home Office, 2018). Scientists can now alter pig genomes to be comparable to that of human biology (Li et al., 2015). This presents the doubt of how dependable animal models are if scientist have to alter animal genomes in the hope of making them compatible to human biology.
An ethical substitute would be a fitting alternative instead of experimenting on and using protected animals. Additional regulated procedures include the evaluation of numerous distinct toxicological endpoints containing acute oral toxicity and skin sensitisation. Oral toxicity studies consist of deciding what is the median lethal dose administrated in a substance, this is recognised as LD50 investigating (Zakari and Kubmarawa, 2016). The aim of this test is to establish the lethal dose liable for killing half the applicant animal models during a 24-hour time frame. The LD50 testing method is constantly being argued amongst animal specialists since it needs a substantial quantity of animals to gain any scientific numerical data. Where these animals are being insensitively produced in order to be killed through testing lethal doses at various toxicity levels which is deemed as merciless and an improper use of animals Buesen et al., 2016). Guinea pigs are regularly employed as test models for skin sensitisation, which comes under the category of toxicology, which has an endpoint that requires to be measured precisely, especially when creating and testing dermatology products. Because of testing a product designed for human use, this then further expands the doubt of how animals can be used to determine the products outcome as the results cannot be 100% accurate, since there is a difference between human and guinea pig biology. Scientists have to use an adjuvant, which is applied to the guinea pig. This then causes discomfort and suffering towards the guinea pig, underlining the suitability of using an alternative technique (Basketter and Kimber, 2018).
Any research project necessitates a broad design assessment in order to be approved by a governing body, who has to contemplate ethical considerations when incorporating the use of animals for the particular project which is yet to be carried out. The reason why a broad design assessment is conducted is to certify the rules of the 3R’s have been employed within the research plan (Guidance on the Operation of the Animals (Scientific Procedures) Act 1986., 2014). By implementing the 3Rs policy towards any research plan, it demonstrates how to humanly treat and use research animals, whist preventing any errors from occurring during the investigation (Kandárová and Letašiová, 2011). The definition of replacement is described as a replacement of protected animals by non-sentient material or technique. It must be clearly understood that replacement does not essentially imply you cannot use animals at all for scientific investigation, it refers to the use of other options, instead of just solely depending on animal use. When testing out a new type of substance or toxicological hazard, using and applying different alternative methods carry out the standards of reduction by limiting the amount of animals incorporated into a scientific experiment, refinement is specified as the limitation of the rate or cruelty of practices performed for investigation.
A principle known as absolute replacement is a concept designed to get rid of animals from scientific research and procedures while finding suitable alternatives (Parker and Browne, 2014). In recent times, scientists can now use mathematical and computer models as an alternative as well as incorporating the use of human tissues, cells and developed cell lines (NC3Rs, 2020). Further research has concluded, without the use of animal test models, this would then produce insufficient data (MacArthur, 2018).
Alternative to using protected animals / Main text
The use of animal models in research is frequently limited by accessibility of test models, possibility of testing techniques, and ethical concerns about distress or pain produced to live subjects. Additionally, animal models may not sufficiently calculate the clinical efficacy of therapeutics for certain human tissue types (Elliott and Yuan, 2011). In the early 90s Tissue engineering was described by Langer and Vacanti as an interdisciplinary field that was brought in to overcome disadvantages of organ transplantation for instance, donor shortage, need of immunosuppressive therapy (Caddeo, Boffito and Sartori, 2017). The use of cell cultures is one of the various techniques represented which can be bioengineered into replicating living tissue of any animal species (3D Biomatrix, 2011). In the 1970’s a pediatric orthopaedic surgeon at the children’s hospital W.T. Green, M.D in the aim of generating new cartilage, the procedure required using chondrocytes that seeded onto spicules of bone and implanted in nude mice. Unfortunately, the experiment was a failure, however the surgeon accurately determined that with the advent of pioneering biocompatible materials it would be possible to generate new tissue by seeding viable cells onto correctly shaped scaffolds. (Vacanti, 2006) From that point this would then mark the beginning of a new medical breakthrough where the investigation would be later reappointed by Drs. Burke and Yannas of the Massachusetts General hospital and M.I.T who produced a dermal skin tissue sample that originated from neonatal fibroblast in collagen gels the technique would be applied in the aim of stimulating the growth of skin cells, a technique known as bio-scaffolding (Hodges and Atala, 2014). Because of Yannas and bell and their discovery in skin tissue growth, the scientific advancement can be applied towards skin grafts in burn vitamins, including other medical uses (Jelinek, 2013).
There are a few procedures involved when producing a 3D cell culture; one technique would be to implant required cells into a matrix usually made of collagen, or gel which is then set aside to cultivate. Another method of producing a 3D culture would be pulsar laser deposition, mentioned by Jelinek. Further approaches in producing a 3D culture mention the use of human skin applied from the extracellular matrix as a bio-ink, this can then be applied to print and construct an exact replica of a tissue section (Kim et al, 2018). Investigation carried out about the technique concluded in contrast to the other method of collagen-based skin tissue, it remained more durable, less prone to reduction in size and showed to have greater dermal excretions and barrier functions.
The pharmaceutical sector is one of the main areas in the medical field that requires the use of 3D printing/ biomaterials (Heinonen, 2015). A good example of when 3D biomaterials has been applied is in the medical advancement of cornea eye surgery. Usually a patient that undergoes cornea replacement surgery, would receive the cornea of a rabbit. Although a success within most patients, investigation has shown that using a 3D cell culture grown replica of a human cornea produced higher reproducibility and fewer irregularity in results when corresponding to the rabbit cornea. For this, it can be drawn towards using 3D cell culture as a suitable alternative (Hahne et al, 2012). Additional treatments consist of stem cell research. Scientists are able to precisely duplicate the exact micro-environment that stem cells require in order to survive comprising the capability of cell to cell signals, and the exact physical structure of the cell from 3D scaffolding. Other areas in which this can be applied to is human chronic liver disease, where animal models in the form of rats are used (Lui et al, 2018).
By using 3D biomatrices it allows scientists to copy (hphs) human primary hepatocytes instead of using rats or porcine hepatocytes. By scientists applying 3D biomatrices into their research, this presents an effective alternative in comparison to animal models. 3D biomatrices has revolutionised many medical issues such as necrosis and dedifferentiation which can now be treated effectively because of 3D biomatrices (Mirdamadi et al, 2020). Likewise, oncology researchers use 3D cell cultures when investigating proangiogenic factors such as, chemoattractants and angiogenesis of cancer cells (Katt et al, 2016).
3D biometrics can duplicate several systems; blood vessels and neural vessels can be replicated just in one culture. This allows researchers to examine how an organ functions when effected by disease. A good example of this is the heart muscle and cancer cells (Sung and Beebe, 2014, Arslan et al, 2019). Before 3D biometrics was available, scientists would have used animal subjects for research that caused suffering and fatalities (VUMC, 2020).
3D cell cultures are a relatively new appraisal, and with it comes the need for further information and engagement since public awareness towards the subject area is absent. 3D cell cultures require neural and brain tissue. Some medical investigations have highlighted the prospect tissue cultures are living and therefore are able to covey neural function (Quadrato et al, 2017). Other issues incorporate the crossing of species DNA since each animal has a unique cardiovascular system (Monahan-Earley, Dvorak and Aird, 2013). And when transplanted into a different species it is unknown whether or not the animal model can express, natural neurological functions for instance, enjoyment or discomfort (Vermeulen et al, 2017, Farahany et al, 2018).
Researchers need to utilize the concept of the 3Rs when in the preparation phase of creating the 3D biomatrices, including where the particular tissue sample originates from. A scientific experiment conducted in Japan use stem cells, taken from rat embryos and directed to develop spinal cord tissue in other rats who had severed spinal cords (Hokkaido University, 2016,) Although the experiment was a success, it resulted in the countless killing of healthy rats. This underlines how suitable 3D cell culture is, since it does not require the use of animal models.
Animals have a fundamental contribution to the progression of medical research. However, researchers including the public need to have a clear understanding when it comes to animal testing, including the particular forms of legislations that must be followed and applied. Additionally, the suitable replacements that are available to use instead of using animal models for example 3D biomatrices, cell culture, and biomatrix and how these techniques can be applied within the science and medical fields.
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