Controversial Topic: Rats in the Lab

Have you ever heard of a rat guillotine? How about a rat gas chamber? Probably not, as the morbid realities of animal research are not often discussed. These are just two of many tools used to euthanize rats after the experiments scientists subject them to conclude. Science is not as glamorous as some might think, especially animal research which can be quite gruesome. However, animal research is critical in science. It has led to countless life-saving medicines and treatments including vaccines, cancer drugs, and organ transplants. The discoveries that result from animal research have vastly improved human lives. The arguments for and against rat research are both very compelling leading to many controversies surrounding the practice.

Rat Guillotine
Source: https://www.sciencedirect.com/topics/agricultural-
and-biological-sciences/decapitation

Rat CO2 Gas Euthanasia Chamber
Source: https://www.researchgate.net/figure/Chamber-used-for-
carbon-dioxide-exposure-Gas-is-introduced-through-the-tube-at-
the-top_fig3_5422283

 

Rats and mice are the most commonly used animals in research and the results of that research have been undeniably beneficial to the human race. Research on rats has led to countless scientific discoveries in neuroscience, psychology, pharmacology, toxicology, and genetics. In neuroscience, rats have been used to improve our understanding of the brain and decision making. In psychology, they have been used to better understand addiction and social behaviors. In pharmacology, they have been used to test the functions of countless drugs in the body, and in toxicology they have been used to test the toxicity of countless substances. The experiments that lead to these discoveries are not always ethically sound, but the reality is that rat research is critical to many fields. For example, it would be impossible to develop safe new medicines and bring them to market without animal testing. Currently there are countless discoveries in the making that rely on animal research such as scientists attempting to grow human organs in pigs and sheep for transplanting into humans (Servick, 2019), and scientists experimenting with the relatively new CRISPR-Cas9 gene editing technology in rats (Bakondi et al., 2016).

Now that we've talked about the benefits of rat research for humans, let's look at it from a rat's perspective. Research rats begin their lives in mass-breading facilities. They are individually transferred to small, clear, plastic boxes with food and water, and sold to research labs across the world. They get little to no physical or mental stimulation in their habitats and live overall dull lives. However, this is likely the best part of their lives. They have no idea what awaits them once the experiments they were bred to be subjects in begin.

Rat cages in a research facility
Source: https://www.science.org/content/article/tiny-cages-make-sluggish-lab-rats

The Animal Welfare Act of 1966 is meant to protect research animals from mistreatment by limiting what types of experiments researchers can subject animals to, but guess what animals are exempt from the act... rats and mice of course. They are deemed too critical to research, and too unimportant because of their status as pest species to be protected. Because of this there is a lack of data on how many rats are used yearly in labs and what kind of treatment they receive, but Larry Carbone sheds some light on this in a study published in Nature. He says, "I estimate that 111.5 million rats and mice were used per year in this period. If the same proportion of RM [rats and mice] undergo painful procedures as are publicly reported for AWA-covered animals, then some 44.5 million mice and rats underwent potentially painful experiments" (Carbone, 2021). Almost half of them undergo potentially painful experiments, so let's discuss what those experiments actually entail.

Remember earlier when I mentioned that rats are used in addiction research? Well in one famous study called Rat Park, some rats were placed in "parks" where they enjoyed all types of enrichment, while others were placed in small boxes with no enrichment. Both groups were given access to morphine that they could self-administer whenever they want. Unsurprisingly, the group without enrichment took more morphine, leading the researchers to conclude that quality of life affects drug addiction. But let's think about this from the perspective of one of the rats. Imagine you are placed in a small box with no friends, boring food, no sunlight, and only drugs. Now it seems quite cruel, doesn't it. And how about neuroscience research? Well, some recent studies are experimenting with implanting human brain cells into rats (Recanatesi et al., 2022). How would you feel if someone put rat brain cells in your brain? And toxicology research? Well, what that really means is that rats are intentionally given higher and higher doses of substances such as pesticides, drugs, and food additives to determine how toxic or carcinogenic they are. They are slowly poisoned to death.

Rats hanging out in Rat Park
Source: https://www.brucekalexander.com/articles-speeches/rat-park/148-addiction-the-view-from-rat-park

In order to analyze the results of these studies rats often need to be euthanized first so that samples of their brain, organs, and bones can be analyzed. Rats also need to be euthanized often simply to end their suffering with cancer, addiction, chronic illnesses, and chemical toxicity after the experiments they are subjected to conclude. The euthanasia process can itself be quite brutal. In the US, AVMA guidelines say that it is okay to euthanize rats by blunt force trauma to the head, decapitation, focused beam microwave irradiation, breaking their necks, placing them in carbon dioxide or carbon monoxide gas chambers, and even getting them drunk to the point of death (Shomer et al., 2020). In that last case, the deaths are not quick. According to one study, "At the end of the experimental period, the animals that did not die during the experiment were euthanized by injecting each with 0.5 mL of 70% ethanol intraperitoneally; at this dose, rats demonstrated gross loss of muscle control, coma, and death within 2-4 min." An ex-lab technician Lindsay Oliver sums up rat euthanasia in a chilling quote: "I know those pit of stomach feels when you hear the air escaping from an animal’s lungs, or little feet scurrying inside of a gas chamber before the silence hits" (Oliver, 2020).

Animal testing can be extremely dark and depressing, but it truly is critical. Animal testing isn't perfect and doesn't always provide results that are consistent with what would happen in human trials, but the reality is that it is the best option we have. Some types of studies can be done in vitro with tissue cultures, but these studies are not as reliable since they don't give the full picture of what goes on inside a living body. In some cases, computer modeling can also be used, but the technology is not advanced enough to accurately model a living being. And clinical testing in humans is also an option but very few people support that idea for obvious reasons. Unfortunately, animal testing is the best option we have right now for many types of research.

Rat research is a complex ethical issue with many pros and cons. The treatment of rats in research labs is often extremely inhumane and unethical, but at the same time the discoveries that result from these studies often save human lives. Most people choose to simply overlook rat research and forget it exists, while enjoying the benefits of it every single day, but we should not forget the ethical concerns. They must be acknowledged, and we must work towards developing better alternatives to animal research. Improving in-vitro methods and computer modeling are both realistic ways to reduce the use of animal testing in science and potentially create even better testing methods. With enough advancement in computer modeling, we could model how substances interact with the human body instead of using animal bodies as a somewhat inaccurate proxy. For so long we have used rats to enable research that improves human lives at the expense of rat lives. It is about time we direct some of our research efforts towards ending this practice.