Laboratory Rats are celebrities in the science field when it comes to testing and experiments. Although Mice (mouse) and Rats are of a different specie and distantly related to Humans, they share striking physiological and anatomical features. These shared similarities between humans and mice make the mice an excellent candidate for research simulations.
Rats and Mice(distinct species) have impacted the world of science in many ways, and we owe a lot to these creatures. Laboratory Rats are not the closest of relatives to humans but remain the most widely used species of the animal kingdom. This is widely owed to the battle between animal right activist and scientists. The preferred candidate for laboratory simulations would be the chimpanzees and other monkeys, but these creatures are difficult to conceal in the labs.
Where Do Laboratory Rats and Mice Come From?
In the United States, the Rat Resource and Research Center (RRRC) and Mutant Mouse Regional Resource Center (MMRC). The MMRRC is one of four regional centers spread across the United States. The two rodent-centric Resource Centers’ mission is to act as repositories for key rat and mouse strains/stocks for biomedical research. The Facilities;
- 1) Import these crucial animal models
- 2) Cryopreserve embryos and/or sperm as a way of storing and banking the models, and;
- 3) Function as distribution centers for sending the animals or cryopreserved materials to researchers all over the globe who employ these models in their study.
Other countries have different organizations that regulate the production and use of laboratory rats for experimentation.
Why Do We Experiment on Laboratory Rats?
“Researchers study rats and mice because they are very similar to people genetically,” according to the Foundation for Biomedical Research (FBR). “About 95 percent of all lab animals are rats and mice bred specifically for research.”
Symptoms of Human disease can be replicated in rats; they can feel feverish, have high and low blood pressure, and other symptoms that are caused by human disease. Cancer can also be stimulated and replicated in laboratory rats, making them the most suitable candidates to carry out trials on.
The laboratory rat has benefited greatly from cardiovascular medicine, neuronal regeneration, wound healing, diabetes, transplantation, behavioral studies, and space motion sickness research. Rats have also been routinely utilized to evaluate the efficacy and safety of pharmaceuticals. As humanity continues to increase its understanding of the rat genome, it should witness remarkable improvement in models in all of these research fields.
Almost every disease-linked human gene has a rat equivalent. Researchers should be able to use this information to construct rat genetic models of human illness.
Economic Advantage of Using Laboratory Rats and Mice
The use of rodents for study offers financial benefits: mice and rats are tiny and need minimal room or money to keep, have short gestation duration but high numbers of offspring, and have a relatively quick growth to maturity and short life spans. Mice, for example, have a gestation period of 19–21 days, maybe weaned at three to four weeks of birth, and achieve sexual maturity at five to six weeks of age, allowing for the rapid generation of large numbers of mice for research.
Interesting Read: How The Human body Fought Sickle Cell Disease With Another Disease
#1 Drug Development
Drug development occurs in several steps, which are expensive, time-consuming, and dangerous. Identifying substances with the expected therapeutic outcome is the first step scientists take during drug research and development. To do this, they need to carry out tests on the supposed target and study the outcome of the experiment. All drugs must meet the standard set by the International Society of Substance Use Professionals (ISSUP).
In order to meet those standards, Scientists must follow strict guidelines and principles to meet the requirements of ISSUP. Scientists must rely on test samples for the study of drugs and their development. Laboratory Rats are ideal for comparative medicine research because they have strikingly similar anatomy and physiology to that of humans.
Mice have been used to test carry out lots of “trial and error” experiments of drugs. Since they have similar reactions to the pharmaceutical compounds, they can be “treated” with the test drugs and observed for results. Some novel pharmaceutical products are required to pass mandatory screening whereby they would first be tested on animals like rats and mice before there are used in human clinical trials.
#2 Stem Cell Research
Stem cells are undifferentiated somatic cells that can differentiate into all types of somatic cells. They are very important in stem cell research. Laboratory rats and mice have a unique property that makes them most suitable for stem cell research. Mice can be bred to lack immune response, which could be exploited in the transplant of stem cells from humans to mice. A major setback in stem cell research is the reaction of implants from one body to another. Since other animal immune systems would reject the cells of the human implants, the mice are the perfect recipients for stem cell research.
Also, the similarity in physiology also makes the rats and mice suitable candidates for stem cell research. Scientists can exploit the metabolism and physiological similarities to map out the metabolism of drugs, toxicological studies, and pharmacological studies which is then used to measure the efficacy of the clinical trial and to obtain safety data.
#3 Human Behavior
Rats have been used in the laboratory to understand the pattern of “risk and reward” and also to understand the genetic relevance of certain psychiatric diseases. Environmental interventions can alter anxiety levels in rats throughout development. Many of these interventions involve subjecting mice to a sort of stress and then assessing their anxiety levels. To understand the neurobiology underlying this impact, stress has been widely investigated in mice since it can induce or aggravate anxiety-related diseases in people.
In a study funded by the National Institute of Alcohol Abuse and Alcoholism grants, the scientists used mice as a model to get an idea of how humans weigh risk and take decisions based on calculated risk(and underlying environmental conditions).
In this experiment, the classic push and pull lever was used to deliver a specific amount of reward. The study aimed to investigate the risk-taking potential of the mice under different conditions- especially under the influence of alcohol. The study revealed that under the influence of alcohol, rats took a lot more miscalculated risk. The implication of this to human behavior is the idea that under the influence of alcohol, a person might take decisions he wouldn’t take without alcohol.
The observation of insensitivity to risk at higher alcohol concentrations has implications for our understanding of alcohol abuse. The concentration of alcohol is an important determinant of demand for alcoholic beverages. With “stronger” drinks, the seeking behavior can become insensitive to risk, suggesting that alcohol seeking behavior is more likely to persist under risky or partial reinforcement conditions.
In another study carried out by Cornell Medical College (WCMC) and funded by the National Institutes of Health. Using a Rat model in the laboratory, Scientists identified a modified gene that is associated with anxiety-related disorders. The study demonstrated that individuals with the modified gene may face difficulty in controlling an anxious-related response to environmental stimuli.
In layman’s terms, let’s say the altered DNA of the gene was present in the laboratory rats, and that gene responds to a certain phobia. Whenever the rats face the phobia, they are triggered to act fear it no matter how they try to resist.
They compared the data collected from the mice and compared it with that obtained from people with similar altered genes. The researchers concluded that “both the mice and humans found to have the alternation in the BDNF gene took significantly longer to ‘get over the innocuous stimuli and stop having a conditioned fear response,” said Fatima Soliman,
The discovery might aid researchers in developing novel treatment ways to treat anxiety illnesses such as phobias and post-traumatic stress disorder in people (PTSD). Although complex, the use of Rats and Mice models in laboratories may help scientists approach mental illnesses in
#4 Bone-Tissue Development
Mice have proven to be very helpful in the study of bone and tissue development. Musculoskeletal disorders(disorders of the bone and muscles) are an ache to health professionals who have limited ethical case studies or samples for experimentation. Bone and Tissue disorder investigation has attracted a lot of attention as there are many disorders with severe economic impact and are a threat to life and livelihood.
According to WHO, approximately 1.71 billion people have musculoskeletal conditions around the globe. In the United States, the economic cost of musculoskeletal conditions amounts to 250 billion dollars annually. Bone and Tissue disorders that have the most severe economic impact are osteoarthritis, Osteosarcoma, rheumatoid arthritis, spinal disorders, and much more.
Rats and mice had already been used as models for research since the 1960s. At that time, numerous studies were made investigating the embryonic rat forelimbs and other early stages of development.
Today, Scientists practice a system of a culture known as Ex vivo bone culture. It involves studying bone physiology and the effects of hormones on the bone. It was through these studies that we have come to understand that bone formation is heavily influenced by ions like phosphorous, calcium, and magnesium.
Also, using the same method, Scientists have cultured bone into its fundamental and preliminary stages of development. More complicated technology has been formulated that allows scientists to almost perfectly mimic the environment of a living organism in a petri dish. A system known as a “3D bioreactor“ can be used to investigate biomechanical forces that partake in the development of bones and tissue in 3D. Sort of like the 3D printer.
#5 Tissue-Organ Transplant
You may already know the difficulty in obtaining organs for human transplant is extremely difficult. As a matter of fact, there is always a long waiting list for transplants at any hospital, with many patients dying before they get the transplant. Another common problem is donor-recipient compatibility. Because the immune system would fight anybody, it does not recognize as its own, organ transplants are liable to fail due to rejection by the immune system of the recipient.
In 2017, Science reached a major milestone when researchers from japan were able to use laboratory rats as incubators for the production of mice pancreas. They genetically modified parent rats such that their offspring were incapable of producing their pancreas. They then extracted stem cells from mice and injected them into the embryo of the rats. The rat offsprings developed into adults with the pancreas gland, but it was the gland of mice.
Today, doctors have attempted transplanting organs from pigs to humans. Although Organs from rats or mice cannot be transplanted to humans, they can be used as case studies or models to understand the immune defence mechanisms and how to exploit them to serve humanity.
Aside from transplant operations, studies can be conducted on tissue and organ diseases more easily in rats and mice as compared to studying humans (to avoid breaking every code of ethics). Furthermore, laboratory rats and mice provide scientists with room for unhindered studies and investigation.
Another study in Japan demonstrated the capability of growing complete organs from stem cell implants with minimal complications in the rats. Just like the previous study where rats were genetically modified to lack a pancreas, the rats in this study did not develop kidneys. Stem cells were implanted in the modified embryos, which develop until the stage of childbirth.
The stem implants functioned properly, consequently differentiating to a functional kidney. The newborns, however, didn’t live long as the modified gene was also discovered to be linked with a sense of smell. The incapability of detecting milk led them to starve and eventually die.
#6 Drug Toxicology
Toxicological studies on laboratory rats and mice are frequently conducted to assist assess the safety of a wide range of compounds that may be detrimental to people, animals, and the environment. These tests are performed on novel items such as pharmaceuticals, home, and industrial chemicals, agrochemicals, and food additives.
Some of these chemicals are examined for their ability to irritate, elicit physiological responses, cause cancer, have a teratogenic influence on growing babies in the womb, and have a detrimental effect on fertility. Rats could also be used to evaluate the dosage required with respect to body mass and how much dose would be considered lethal or abusive.
#7 Neurological Studies and Diseases
For well over a century, rats and mice have been the major model organisms used in biomedical research. However, other species such as non-human primates, zebra-fish, fruit flies, and roundworms are also utilized. In recent years, there has been a change in rodent-based research, with mice quickly replacing rats as the primary model of choice in Neurological study.
As a result, the proportion of neuroscience-related research utilizing mice has risen from approximately 20% in the 1970s and 1980s to around 50% in recent years. Deficits in social cognition are a characteristic of a range of diseases, including schizophrenia, ASD, ADHD, and bipolar disorder. In fact, human illnesses using animal models are better understood than those without.
The study of social cognitive impairments is relevant in the research of various disorders, particularly ASD, for which a significant number of genetic models have been produced. According to a recent study, at least 70 distinct genetic mice models have been studied in connection to ASD.
In ADHD (attention deficit hyperactivity disorder), laboratory rats known as SHR rats(Spontaneously hypertensive rats) possess a random mutation in their genes which triggers high blood pressure. However, for some periods before puberty, they exhibit hyperactivity, lack of concentration, and impulsiveness. These symptoms make them suitable models for the study of ADHD in humans who also exhibit similar symptoms.
In fact, when the chemical Ritalin is administered to the Rats, they become stabilized and almost asymptomatic. A similar scenario is seen in humans when they are also given the same compound for ADHD, this implies that there is a relationship in both conditions in the rats and humans.
#8 How Laboratory Mole Rats Resist Cancer
Cancer is becoming a growing social and economic burden as the world’s population ages because cancerous growth necessitates genetic mutation and cell multiplication, both of which occur incrementally in many tissues with a longer lifespan. While finding a cure for cancer is important, finding a technique to avoid it is clearly preferable. In fact, cancer prevention research has made significant advances in the scientific, social, and economic realms in recent decades.
Many trials in mice and rats employing various chemical agents have demonstrated great cancer prevention efficiency. However, comparable cancer prevention experiments in humans need decades of agent consumption, but rats’ short lifespans cannot provide information on long-term safety.
Naked mole-rats have a laboratory lifetime of 30-33 years and are thus regarded as a superior animal type for chemoprevention experiments. This species, on the other hand, possesses remarkable biological characteristics, such as resistance to cancer, diabetes, cardiovascular disease, immunodeficiency, and atherosclerosis.
The immunity to cancer was one feature of the mole rats that troubled scientists. It was previously considered that naked mole-rats nearly never had cancer because their healthy cells were resistant to being transformed into malignant cells.
“The results were a surprise to us and have completely transformed our understanding of cancer resistance in naked mole-rats. If we can understand what’s special about these animals’ immune systems and how they protect them from cancer, we may be able to develop interventions to prevent the disease in people.” – Dr Walid Khaled
However, researchers at the University of Cambridge have demonstrated for the first time that genes known to cause cancer in other rodent cells can also cause cancer in naked mole-rat cells.
# 9 Drug Addiction in Laboratory Rats
Rats and mice have been used as models for the study of alcohol, cocaine, methamphetamine, and heroin addictions. This is accomplished by using the “risk-reward” lever system. Rats have been observed also to become addicted to some of the narcotics, making it easy for scientists to study the biochemistry of the addiction.
Cocaine is one of the most addictive recreational drugs, and one of the primary reasons for its widespread usage is the way it encourages users to seek out additional highs. In 2018, cocaine was implicated in over 14,000 deaths in the United States, and death tolls around the globe are said to amount to 750,000 per year since 2017. yet approaches for dealing with the drug’s misuse have so far proven ineffectual, both in decreasing long-term compulsive cocaine use and preventing death from overdose.
#10 Is Social Media a Rat Experiment?
If you find yourself sharing more and more material on Instagram as a result of the “likes,” it’s because your brain is allegedly being conditioned to act like a rat in search of food. At least, that is the conclusion of recent research undertaken by an international group of experts.
One in every four young people is said to have an unhealthy connection with their smartphone, seeking “likes” and spending hours glued to their displays like a moth to a flame. According to a new study, the obsessive effect of social media on humans is quite comparable to a lab rat pushing food buttons.
Scientists at New York University have demonstrated how fundamental reward learning behavior drives social media activity, particularly users’ efforts to get likes. While the motivations for this conduct in humans are obviously complicated, it follows the same fundamental pattern of behavior found in many species like laboratory rats when pursuing rewards.
A study was done to demonstrate the urge of people to maximize the number of “likes” they receive. They observed that people in the study posted more often to increase the average number of “likes” they were getting from their social media pages. This has been described to be exactly the same behavioral principle behind the laboratory rats pressing a lever and expecting some form of reward.
Laboratory Rats serve as an excellent alternative to clinical trials. If thorough testing and evaluation are carried out on the rats before scientists proceeds with human trials, we might minimize and even completely avoid having to risk human lives. Rats have been used for the past 100 years for scientific studies. Considering that their physiology is similar to that of humans and are relatively easier to maintain, they not only serve heroic purposes but minimize the economic cost of carrying out trials on larger animals like monkeys.