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Introduction
It is usually dangerous to give out a new medication to people without checking its safety levels. The outcomes are catastrophic since the drug may be poisonous to individuals, leading to severe illness or death. There is a significant similarity between humans and animals, making it necessary for experimental studies to consider the use of animal subjects in medical experiments. Mammals are usually the common animals used in these experiments because of their similarities in major organs such as the brain, lungs, and hearts. Most of these mammals include pigs, mice, rabbits, and rats. Furthermore, they are preferred because they provide a reasonable idea regarding the outcome of the drug when used by humans. Simple animals such as worms and fruit flies are also used to predict the outcome of lab experiments on humans, especially in genetic research. The biological content passed down from one generation to another helps determine humans characteristics and immune systems. This essay focuses on the necessity of animal testing by showing the success of its use and also its failure and bringing out the need for other alternatives.
Animal Testing Based on History
Animal experiments have been significantly used throughout biomedical research. It was first used by Greek scientists such as Aristotle, Erasistratus, and Galen. Its use has a significant impact in the current medicine areas as it is the source of pathology, pharmacology, physiology, and anatomy. Animal testing importance is traced back to Ibn Zuhr, an Arab physician in Spain. Ibn Zuhr identified the need to conduct animal testing experiments in surgical procedures before being applied to human patients (ProCon, 2021). In the current years, there has been a wide criticism regarding animal testing in biomedical research by groups that protect animal rights. Various laws have been passed to ensure that the procedures are conducted humanely. These ethics began as early as the 17th century, and regulations were at the peak during the 19th century.
In the 20th century, animal testing was an essential practice in biomedical research. In 1937, the pharmaceutical industry in the United States of America came up with sulfanilamide using diethylene glycol (DEG), leading to mass poisoning (Snellings et al., 2017). The manufacturers of the drug were not aware of the issue. This led to the act of Federal Food, Drug, and Cosmetic Act requiring safety in 1938, which required the drugs to be tested on animals before being marketed for human consumption. In the late 1950s and early 1960s, drug fiasco was used as a painkiller and tranquilizer for headaches, coughs, insomnia, and colds. The drug was also identified to significantly reduce morning sickness among pregnant women, and most of them used the drug. The effects were catastrophic as more than 10,000 babies born had malformations such as missing limbs. The drug was later withdrawn from the market from 1961 to 1968. The above cases show the importance of animal testing on a historical basis. It is imperative to note that drugs need to be tested before being consumed by humans to prevent tragedy.
The Need for Animal Testing
Major medical breakthroughs in the history of medicine have been achieved through animal testing. In the 1920s, relieving diabetes symptoms was found by a surgeon. The surgeon discovered that the high level of sugar in an individuals blood is because the pancreas is not able to produce the required level of insulin or the cells of a person are not properly responding to the produced insulin. The surgeon later injected the insulin into various dogs and studied the outcome (Tanner, 2018). The results were positive, which has saved many lives since the finding of the drug. Animals form a significant part of the medical industry as most medical trials are first carried on them. Various diseases that pose a substantial threat to human existence have been battled with the help of animal testing procedures. Additionally, these tests have helped develop critical medical practices that save many lives worldwide. The simple practices include using anesthetics during medical surgeries, the treatment of cancer, and antibiotics. The discoveries in animal experimentation have significantly promoted individuals life spans.
Successful Case Studies on Animal Testing
Ebola
Ebola is deadly virus that affects animals as well humans. In 2014, there was an Outbreak of Ebola in West Africa, which claimed more than 11,310 lives and infected approximately 28,000 people ( Animal Research Achievements, 2022). The virus causes hemorrhagic fever in both humans and some mammals. Many scientists worldwide have tried to create the vaccine, and the preliminary outcomes have proven successful through animal research. The successful nature of the trials is because the virus originates from primates. The virus is the primary cause of death among the primates such as gorillas and chimpanzees; hence the role of animal testing in the development of the vaccine cannot be rolled out ( Animal Research Achievements, 2022). In 2013, a trial of the Ebola vaccine was conducted on six chimpanzees, and the outcome was fruitful as it was safe and effective in creating an artificial immune response. However, the outcome in monkeys was a bit different as they only had partial protection, which lasted for about ten months after the introduction of the vaccine in their body (Bausch, 2021). This has resulted in expanded studies on the area to develop lasting protection, hence the prospects for creating booster shots.
In 2015, a discovery was made, which entails using inhalable vaccines administered to the macaques monkeys. The vaccine was effective as it neutralized the Ebola virus by producing the immune response in macaques monkeys respiratory system. Previously, the vaccine has proven to be effective among monkeys and not humans. This has provided the researchers with hope, as most monkeys could not survive the effects of Ebola (Walsh et al., 2017). The use of aerosol vaccine does not require expertise in the medical area; hence can be easily used by anyone following the instructions. The continued experiments on non-human primates are critical in enhancing the safety of the vaccine. Ebola virus continues to evolve, hence the need to monitor the changes via monkeys to prevent further spread. Rhesus, marmosets, and macaques have the same Ebola infection as humans, thus providing significant test subjects for the Ebola virus vaccine (Gross et al., 2018). This provides a promising future for the virus and the possibility of its eradication.
Artificial Blood
Fresh blood requires proper storage measures and the maximum days that it can be stored is 42 days hence the need for regular blood donation. Currently, artificial blood is being created to become substitutes for the natural blood for transfusions, especially during emergencies such as trauma patients, those that have been injured and require blood transfusion urgently, and the patients undergoing complex or lengthy surgeries. Identification of the blood substitute has been a challenging issue (Haldar et al., 2019). However, animal testing and experimenting have proven to be effective in this project. For decades, mice and rats have been significantly used to provide the necessary information concerning blood components. In 1968, perfluorochemicals (PFC) were used as a blood substitute in mice experiments. The PFC is a vital blood alternative that has been approved by the FDA because of its efficiency, although it is not widely used. The improved version of the PFC is being developed by blood scientists, and mice and rats are used to test the bloods effectiveness.
A significant challenge in this research is the protein hemoglobin. The red blood cells have hemoglobin, which transfers oxygen from the lungs to other body parts. However, when it is not properly isolated, it could damage the blood vessels and the tissues ( Animal Research Achievements, 2022). This has made the researchers come up with hemoglobin that is encased in synthetic polymers (Shaffer, 2020). The effect of these synthetic polymers is being studied on rabbits to identify their impact on the aorta to develop identical reactions when introduced to the human body. This has to be proven successful in animals before significant trials on humans. Another avenue for artificial blood is stem cell-based blood. These trials have been conducted on humans after a series of successful experiments of animal tests.
Polio
Between the 1940s and 1950s, more than 35,000 people were infected with polio every year. It is among the horrifying diseases that were not known to be infectious until Ivar Wickmans discovery in 1905. Wickman tracked its spread, which appeared controversial, but in 1908, Edward Popper and Karl Landsteiner found out the specific cause of polio through the use of monkeys. This led to the development of the polio vaccine by using cows, mice, and monkeys (Tzeng et al., 2018). The disease has been known to be devastating as it circulated at a lower level. However, polio reached an epidemic in the early 20th century, which prompted critical research to curb the disease. Several vaccines were tried, but the outcomes were unproductive.
In 1935, multiple teams tried the vaccine with humans and chimpanzees without success, and in 1954, an inactive polio vaccine was created through the kidney cells of the monkey. The vaccine was proven effective, and approximately 2 million children were vaccinated (Guindo et al., 2018). With continuous use of animal testing, an oral polio vaccine was developed by Albert Sabin in 1960 with the help of about 150 chimpanzees, 9,000 monkeys, and 133 humans who volunteered to be part of the research. The global campaign to eradicate polio was first initiated in 1988 to eliminate it in developing nations. Currently, more than 99% of polio incidences have been eliminated (Thompson & Kalkowska, 2020). This portrays how animal testing is important in managing life threatening infections.
Parkinsons Disease
More than 1 million people in the United States of America are diagnosed with Parkinsons disease every year. The current population with this disease from a global perspective is approximately 10 million ( Animal Research Achievements, 2022). The outcome of this disease varies from one person to another making it difficult to identify the exact cause of the infection. Numerous research is still ongoing for possible treatments despite the condition being associated with environmental and genetic effects (Kin et al., 2019). The use of animal models in the study of this disease has proven effective, and certain findings are associated with the possible treatment of Parkinsons disease. The most common animals used include the mice, as it has helped understand the treatment of one symptom. Additionally, the rabbits have also proven to be effective in that Avid Carlson identified the significance of dopamine in regaining movement control in the brain (Buhidma et al., 2020). Carlson discovered that when a rabbit is injected with the L-dopa, the brain is able to control movement. However, the effect fades with time, resulting in the need for further studies.
Monoamine oxidase (MAO) inhibitor was identified, and when administered on marmosets and rats, it was able to improve the effectiveness of the L-dopa. The use of deep brain stimulation (DPS) was approved by the FDA after successful implantation in monkeys. This technique involves regulating the nerve circuitry that later creates symptoms vital in treating the disease among individuals who have not shown positive results with drugs. This method has helped more than 80,000 patients having the disease. The model has been extended with trials on rats and monkeys, where gene therapy is used to promote the enzyme secretion in the brain that alleviates the symptoms (Barker & Björklund, 2020). The current development of the disease has focused on the alpha-synuclein protein, which is common in some patients with Parkinsons disease. Initially, this protein was found in monkeys, and the study was extended to humans. The outcome is satisfactory as it has helped create a blood test to identify this disease at a primary stage for early treatment administration. Despite the disease not having a cure at the moment, animal research has proven effective in relieving some symptoms, hence showing a promising future.
Drawbacks of Animal Testing
Every year, millions of animals such as birds, monkeys, hamsters, rabbits, dogs, mice, frogs, fish, guinea pigs, rats, and cats are killed in the research laboratories for drug, cosmetic testing, medical training, experimentation, and lessons. Before the animal is killed, they are subjected to inhumane conditions such as drilling holes into their skulls, crushed spinal cords, inhaling toxic chemicals, burning skin, and being immobilized inside devices for a significant time ( Animal testing facts and statistics, 2022). Additionally, the animals are deprived of natural conditions that are important for their survival. The animals are treated as laboratory equipment which will be disposed of after use. The People for the Ethical Treatment of Animals (PETA) produced a documentary to provide the public with the necessary information regarding animal testing. This documentary film shows how animals are mistreated to enrich the medical research area (Lockwood, 2019). Furthermore, it showed that animal testing is considered mandatory for students who want to complete their diplomas hence being forced to conduct deadly experiments on animals. The documentary also portrays that apart from the physical pain the animals undergo, they suffer from psychological trauma.
Limitations of animal testing
Various reasons explain the failure of animal testing regarding results translation from animals to humans. It is in conjunction with the animal models used and how the animals are used to generate the required results. The biochemistry surrounding animals and humans in metabolism, distribution, and absorption forms a critical difference (Knight, 2019). This affects the mechanisms of action and the biological effects hence the variation in the organ systems and the magnitude of the effects. The animal characteristic also poses a significant challenge in that they usually do not have the human risk factors resulting from the complex system in the human body. The toxicity test in animals is based on the maximum doses that can be tolerated, resulting in chronic dosing (Fontana et al., 2020). The condition in which they are subjected also explains the varying outcome as the environment plays a critical role in the effectiveness of the doses, which makes outcomes of experiments to have false-positive results (Pound & Hoitinga, 2018). The compounds that are not usually considered toxic have positive results during the animal tests, which affects the validity and reliability of the affirmative results attained from the experiments.
The routes of exposure are also a significant issue among the animals. This includes the inhalation used by animals and humans tend to differ significantly, and in the process, the drugs tested in animals that require extrapolation have resulted in uncertainty. The animals are subjected to stressors that affect the outcome of the experiments (Norman, 2019). These stressors include the dose administration process, where the tube is used to administer toxic chemicals into the esophagus. The effect of stressors is that it alters the animals hormonal and immune system, making the outcome of experiments unpredictable (Hartung, 2019). This promotes the alteration of drug effects while monitoring the animals progress. The issue is critical, especially when the process requires accurate identification of the animals cognitive, behavioral, and psychological characteristics.
It is noted that the experimentation on animals is done with the view that animals are a critical factor in the progression of medical research. Most of the experiments conducted on animals do not significantly contribute to human health improvement, making animal use in medical experimentation questionable (Knight, 2019). Most of the artificially induced diseases in animals, such as mice, rats, and monkeys, are significantly different from those that affect humans. The success of these experiments has been problematic because animals differ from humans in multiple biological processes. This has made the application of animal testing findings challenging. Many instances have occurred where the cure that has been positively tested among the animals does not significantly affect humans.
Failed Case Studies on Animal Testing
HIV/AIDS vaccine
More than 85 vaccines for HIV/AIDS have been developed and have proven to be successful among non-human primates. None of those vaccines has been effective among humans (Barouch et al., 2018). Additionally, the vaccine has been identified to make the human immune system susceptible to the virus (Ibeh & Ashano, 2018). This shows a significant failure of animal testing despite the animals being subjected to various mistreatments (Pollara et al., 2019). The amount spent on developing this vaccine is significantly large, hence the need to eradicate animal testing.
Stroke Research
A stroke is a condition that affects the brains functionality through interference with the supply of blood to the brain leading to neurologic impairments. The effect of stroke is dependent on the part of the brain that has been affected. The cerebral blood supply is affected because of ischemia or hemorrhage (Narayan et al., 2021). Stroke is ranked among the leading causes of death and long-term disability among older people. In the study of stroke models that could help identify the treatment of the condition, the human stroke is dissimilar among people making it difficult to identify a single animal model that could help understand its effect (SchmidtPogoda et al., 2019). When studied in animals, the impact of stroke on the animal brain has a varying effect making it ineffective to be used in humans. Furthermore, the nervous system in humans is more complex than that of the animals such as mice and rats.
The rodents used have a Gyrencephaly trait, while the humans have a lissencephalic trait in their brain. The grey matter of the brain also poses a significant challenge as 90% of the brain tissue of the rodents is composed of grey matter while that of humans is only 50%. The subcortical white matter strokes are prevalent and account for 25% of the strokes (Kringe et al., 2020). This makes it challenging as animals have a significant low content of the grey matter. The posterior communicating arteries diameter (CoA) of animals such as pigs and sheep are similar to the anterior cerebral arteries. However, the CoA diameter is half in humans, reducing the blood flow in the posterior CoA among humans than in animals (Narayan et al., 2021). The baboons also differ because their bilateral anterior cerebral arteries are linked with numerous arteries, while it is only a single vessel in humans. This affects the understanding of the stroke effects in humans, thereby affecting the efficacy of the developed treatment or drug.
Arthritis
Rheumatoid arthritis (RA) is a disorder that attacks the joints and has affected more than one percent of the worlds population. The disease causes deformity in humans, and multiple studies have been conducted on animals to identify suitable treatments (Keen, 2019; Wang et al., 2021). Treatment was effective among the green monkeys and other animal species. The rofecoxib (Vioxx) drug used in monkeys was effective, and in humans, it caused heart in more than 140,000 people and deaths ranging from 60,000 to 100,000 (Leenaars et al., 2020). The drug was withdrawn from the market in 2004 after massive adverse effects (Goll & Kvien, 2020). The outcome of this drug has shown that animal testing is not significant in determining the effects of drugs hence the need to identify other methods for medical research.
Funding and Accountability
The members of the public fund animal testing through various ways such as taxations, purchase of lottery products and consumer goods, charity, and donations. The government funding and granting agencies such as the NIH form the largest fund source for animal testing and experimentation programs. More than 47% of the NIH funding projects involve animal testing, and in 2020, there $42 billion was allocated to the research and development area which conducts experiments on animals ( Animal Research Achievements, 2022). Others, such as the American Cancer Society, utilize donations to fund animal testing. Furthermore, most of the projects financed by the National Multiple Sclerosis Society projects involve animal experimentation ( Animal Research Achievements, 2022). Despite the public being the top sponsor of animal experiments, they are provided with less information regarding the outcome of the animal experiments. Most laboratories keep the sensitive information regarding animal experiments hidden to prevent the public from knowing the effects the project has on the animals.
The 3RS
Animal research results in various drawbacks such as physical pain and psychological trauma. However, sometimes it is impossible to avoid animal experimentation hence the need for the 3RS, which guides how animals are treated in the laboratory. The 3RS includes the replacement, reduction, and refinement, which help in experimentation (Tanner, 2018). Replacement involves the identification of the various option that could be used in the place of animals. Reduction entails developing multiple methods that help lower the number of animals used in the experiment (Díaz et al., 2021). Refinement focuses on improving the condition of the animals by reducing the suffering conditions that the animals face during the experimentation. Although the work of the 3RS is declining with time, various organizations focus on ensuring the success of these programs.
Replacement
Organ on Chip Technology and Human Tissue
The organ-on-chip replacement of animal testing works with the cell and tissue culture. The organ-on-chip is the latest innovation from developing the vitro cell culture technology. The technology is also used in cosmetics to test the effect of new cosmetics. It provides a significant outcome in testing the new drug and therapies in the medical area (Wu et al., 2020). Research shows that the vitro test is more powerful than animal testing because of the high predictive power. The organ on chops is designed such that they are able to recreate the human bodys natural physiology and the functionality of the body cells (Taylor, 2019). The human living cells are placed on the chips together with the fluidic channels that represent the blood in the same way as the body. Its flexibility enables the chips to be able to create breathing movements as well as the contraction and relaxation of the muscles. Every chip has an organ such as the brain, lung, intestine, or liver. The chips are made transparent to enable the medical researcher to perceive the organ responses in terms of behavior and functionality at the cellular and molecular levels.
The growing need for the organ-on-chip method is because of the failures accompanying animal testing and the regulations requiring care for the animals being used in biological experiments. However, despite the breakthrough in using the vitro cells as a replacement for animal testing, the models do not significantly display the outcomes expected in the human body. This has resulted in misleading results which are being generated from the experiments. The use of animal cells is because of its convenience rather than scientific (Wu et al., 2020). The human cells are very difficult to generate from the human body, with few donors. There is a significant problem with the human cells cell lineage, hence having a significant outcome with the human tissue. Testing the drugs efficacy with these cells leads to misleading results, hence the need for better predictions. The key challenges include biological, practical, scale, and economic requirements.
First, the biological requirement entails the retrieval of the cells. It is easier to extract animal cells than human cells, making it ineffective as the animal cells have a problem with the drugs efficacy. The human tumor cells derived are not helpful because they do not represent healthy tissues. The stem cells provide significant results, but they are costly, complex, and require a lengthy procedure to ensure their success (Wu et al., 2020). Despite having various donors for the human tissue, there is a significant problem with the cryopreservation tone able to match the required time for experimental analysis. However, cryopreservation affects the functionality of the cell.
Secondly, practical requirements focus on the technology that makes up the procedure. For new technological innovations in the medical area to attain regulatory acceptance, it has to fulfill repeatable and robust methods. This makes it challenging as most of the organs on chip have not met this target. Additionally, setting up this method requires complex procedures, making the procedures only be conducted by the design companies (Wu et al., 2020). However, promising research in this area is not yet successful. Kirkstall laboratory has developed an organ-on-chip stationed in more than 70 research centers such as educational institutions. Third, the scale requirement is based on the differing nature of the organ on chip discoveries. There is a significant divergence in the requirement of scale rating on the screen because of the numerous compounds. This makes it difficult for the researchers to test the compounds (Wu et al., 2020). Lastly, there are few products in the markets resulting from the organ-on-chip. This makes it challenging to assess the possible cost of replacing animal testing with this method.
Cells and Tissue Cultures
The cell and tissue culture are used together with the organ-on-chip, which entails the growth of cells outside the body of an organism. They are kept in an environment suitable for their survival for medical research instead of using animals. The cells and tissue cultures are significant in the testing procedure of drug efficacy before being administered to humans (Uysal et al., 2018). For example, skin cells test whether the drugs lead to irritation. In producing the monoclonal antibody, vaccine, interleukin, and hormone, cell and tissue cultures have proven effective. Toxicology reports are currently dwelling on these cultures as they promote the success of new drugs.
Reduction
Biomedical researchers are focusing on developing experiments that use few animals. For example, groups of mice to test the effect of drugs are reduced. However, reducing the number of animals tends to affect the research outcome since some drug experiments require repetition to ensure success (Tanner, 2018). This has brought the need to maximize the findings of the research to reduce the chances of using other animals for clarifications (Díaz et al., 2021). When studying tumor, scientists may use more than a single animal every week to identify the variation of the tumor (Tanner, 2018). This can be reduced by scanning the animals instead of killing the animals to understand the effects of the tumor. It is also advised that scientists researching a given area share the outcome of their findings by writing articles and providing presentations, reducing the chances of repeating the same experiments. Scientific journals help lessen the effect of killing animals as the research findings are recorded and kept for future reference.
Refinement
The refinement process focuses on reducing the pain that the animals face by making the animals have good health and happiness. This is done by ensuring that the animals are placed in comfortable housing almost similar to their natural surroundings, such as having nests, hiding areas, socialization, and gnawing. Various rules help guide the development of the cages that the animals use in the laboratories. Institutions such as the University of Liverpool have focused on creating cages suitable for rats and mice by placing burrowing materials and climbing opportunities.
Furthermore, other experiments have been developed in the current period, such as imaging technologies for analyzing the internal structures of the animals. This picture provides a good background for analysis, reducing the number of animals subjected to pain (Tanner, 2018). The techniques developed include ultrasound and X-rays for internal analysis. This has reduced the number of surgeries to study the internal spread of infections. The pictures of the internal organ of the animal are taken while the animals are in good condition hence not altering their psychology which affects the outcome of the vaccine or drug (Tanner, 2018). Various chemicals are used to enable the internal parts of the animal to glow during scans. This has eased the way cancerous tumors are monitored within an animal (Díaz et al., 2021). Furthermore, the movement of drug traces is also studied through this method. This has made animal experiments easy as well as painless.
Successful Use of Animal Testing, Human Volunteers, and Cell and Tissue Culture
In late December 2019, COVID-19 was identified as a respiratory infection in Wuhan, China, and has claimed more than six million deaths and infected approximately 510 million people worldwide. The virus was ranked as the top severe respiratory infection after leading to massive deaths and infections in less than two years. However, biomedical researchers managed to develop a vaccine for the infection ( Fitting vaccine research into one year, 2021). Four effective vaccines were developed from the research, which has significantly helped in curbing the spread of this infection. During research to identify the vaccine for this deadly pandemic, vitro methods such as the organ on chip involving the cell and tissue were effective. This technology was vital in bringing out the vaccine within a limited period. The vaccines efficacy was the top priority and hence the need for a combination of technological innovations, animal testing, and human volunteers ( Fitting vaccine research into one year, 2021). The patients data provided significant input in accelerating the research and the data sharing among the scientists. The animal safety procedures were significantly followed to ensure that they were not subjected to inhuman treatments before taking them to the trials. Animal testing was necessary to ensure that the developed vaccine is safe for human use.
Animal testing and human experiments were conducted in line with organ-on-chip to provide quality results for the research. Animal data provided the researchers with evidence of safety to progress the vaccine trials to humans. The toxicity of the vaccine on the reproductive and developmental areas of the vaccine enables the scientist to extend the research and identify a possible solution to the case when used in humans ( Fitting vaccine research into one year, 2021). The animals used in this study include hamsters, non-human primates, pigs, mice, rabbits, ferrets, and rats. The information regarding the use of these animals was provided publicly, and it showed that the animals were treated with ethics.
Conclusion
In conclusion, animal testing is a significant aspect, especially in the current period where various diseases arise daily. Animal testing has proven to be significant in history of humanity as there are certain infections whose cure could not have been identified without animal testing. The most commonly used animals include pigs, mice, non-human primates, monkeys, hamsters, ferrets, rabbits, and rats. When testing a new drug, it is necessary for it to be used in animals before being marketed for consumption by humans. Without these procedures, the outcome is deadly. This is proven by multiple
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