Rodents in Science

By: Jee Min Lee

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For centuries, rats have had a notorious reputation as pests. According to research conducted by Richard A. Gibbs, et al, rodents can spread infectious diseases such as cholera and bubonic plague, which wiped out two thirds of Europe’s population. Rats also reduce world’s food supply by eating about 20 percent of the world’s harvest. Despite their negative impacts on humans, rats have been contributing to humans’ well-being. The research by Richard A. Gibbs, et al, indicates that rodents are a widely-used mammal model for physiology, nutrition, and biomedical research nowadays. Rodent experiments aid in human’s health from diabetes to addictions to cancer (293-294). As it continues to yield beneficial results, rat experiments should be emphasized and further researched to utilize rats to their full potential.  

The first question that rises from laboratory rat research is, why rats? In fact, William D. Stansfield’s Death of a Rat: Understanding and Appreciation of Science states that chimpanzees are the best candidates for medical research; chimpanzees are physically and genetically similar to humans. Stansfield notes that chimpanzees share 98 percent of DNA sequence with humans. Such primates, however, are an endangered species that the United States is forbidden to import for medical research and other purposes (50). On the other hand, rodents are hardly ever going to go extinct. Laboratory rats can reproduce several offspring periodically. Researchers can also save purchase and management expenses with rat experiments by inbreeding adult rats to produce more offspring and keeping several rats together in one cage. Though rodents may not be as genetically similar to humans as primates, rats are 90 percent genetically similar to humans (Jha and Howard 178). Such high genetic similarity have led scientists to revise the rat genome project. Considering all the practical benefits of rodent experiments, rats are better experimental recipients than chimpanzees.

With several advantages over chimpanzees, rodents have been used to study genes that cause obesity. Obesity has become a popular concern as technology and modern urban lifestyle demote movement while promoting unhealthy meals and lifestyles. Development of transportation and machines for mass production make work get done faster, but the unhealthy factory food products and stress from exigencies at work trigger people to release stress through unhealthy diets. Besides such conditional causes, researchers also found a genetic cause for obesity and diabetes through rat experiments. According to a Telegraph article, “‘Fat Gene’ May Lead to a Thin Pill,” Oxford University researchers recently reproduced an experiment conducted in 2007 that discovered a possible link between the FTO gene and obesity. In the experiment, rats with extra copies of the FTO gene weighed more than normal rats: female rates weighed 22 percent and male rats weighted 10 percent more than normal rats after 20 weeks of observation (“Fat Gene”). Extra copies of FTO genes won’t cause much weight difference in humans, but the experiment was successful in pointing out the direct relationship between obesity and FTO genes.

Such certainty about the FTO gene opens a greater potential of producing effective thinning pills. With more research on FTO regulation, scientists can produce thinning pills that will prevent hereditary obesity. Obese patients with type 2 diabetes, heart disease, or cancer can seek better well-being by taking anti-FTO medicine. The discovery and reproducibility of the FTO rat research itself is a great step forward towards humans’ health.

Laboratory rats are also used in experiments for another prevalent disease, cancer. Treatments for early discovery of the disease can cure or abate the growth of cancerous tumors.  However, not enough sound cures exist. Among the various cancers, breast cancer is rising as one of the major concerns. This October, Northwest Missouri State University promoted breast cancer awareness by selling pink paper ribbons. Food companies are donating money through Cups-of-Hope. Fortunately, recent rat experiments discovered that losartan can possibly treat breast cancer (Jha). According to the experiment, losartan, a common blood pressure drug, can shrink a breast cancer tumor by decreasing the overactive effect of AGTR1 gene (Jha). The full potential and possible future side effects of losartan need further studies, but the discovery itself is great progress in breast cancer research. The discovery motivates breast cancer patients to keep fighting. With both rat and human genomes going under revision (Gibbs 294), further studies can be conducted on AGTR1 genes and correctly convert a rat’s AGTR1 gene activity to that of a human’s. 

While treatments for individual diseases are under research, a fundamental cure, stem cell research, is also attracting attention in the medical field. The value and potential of stem cell research is highly anticipated in the world’s medical and health fields. According to Nancy Snow’s Stem Cell Research: New Frontiers in Science and Ethics, stem cells have two characteristics that make them suitable for promoting a specific growth of transplantable cells: stem cells can maintain a growing stem cell population by continuous cell division, and they can be programmed into a variety of specific cell and tissue types (17). Before being programmed, stem cells are like empty folders, able to save orders given by the DNA sequence and function in distinctive roles as specific cells or tissues. Such newly programmable cells can produce cells and tissue that patients lack, such as red blood cells, muscles, and even organ tissues.

Between adult stem cells and embryonic stem cells, adult stem cells function as a more preferable medical research resource. By utilizing patients’ adult stem cells, the newly transplanted cells or tissues will face less resistance from the patients’ immune system, which means the treatment can avoid lethal side effects and efficiently treat the patients. Unlike embryonic stem cells, adult stem cells can be researched without facing ethical concerns. According to Nancy Snow’s Stem Cell Research: New Frontiers in Science and Ethics, adult stem cells are generated from adult body tissues such as bone marrow and neural stem cells. The book also provided examples of adult stem cells being used for various cancer, lupus, multiple sclerosis, sickle-cell anemia and immune-deficiency treatments, as well as for growing new body structures and tissues including cartilage, bone, cornea and cardiac tissues (17-18). Careful study of adult stem cells can bring great medical innovation in repairing and replacing human cells.

Rodents have been playing a big role in the study of adult stem cells. Mice experiments have been crucial in finding alternative stem cell sources of embryos. “Mice Join Clone Club” by Sean Henahan reports that researchers at University of Hawaii successfully cloned two generations of mice with the Honolulu technique, which micro-injects a donor nucleus to the egg, in 1998. The cloned mice helped to identify a new stem cell able to be re-programmed from existing adult skin cells. The mice specimen showed that the new stem cells functioned like the genuine skin stem cell (Henahan). With such results, scientists can hope for further discoveries and understandings of stem cells and their potentials through mice cloning. According to Dr. Ian Wilmut, the Roslin Institute researcher who successfully cloned Dolly the sheep, studies on mice can help scientists to “understand the basic mechanism involved in the ‘reprogramming’ of adult cells” (Henahan).

Rodents have been part of the expansion and growth of human civilization. Though their reputation has been notorious for causing harm on public health, rodents are attracting interests from science and medical departments as one of the highly anticipated sources of medical innovation. Mice experiments have just introduced traits of specific diseases and their possible cures, but the boundless potential of mice stem cell research can find a definite answer for those diseases. As research on rodents provided the first step toward better well-fare, it will continue to help researches to take further leaps forward.

Works Cited –

“‘Fat Gene’ May Lead to a Thin Pill.” Telegraph. 15 Nov, 2010: n. pag. Web.15 Nov, 2010.

Gibbs, Richard A, et al. “Genome Sequence of the Brown Norway Rate Yields Insights into Mammalian Evolution.” Nature (2004): 493-521. Web. 14 Nov. 2010.

Henahan, Sean., “Mice Join Clone Club.” Access Excellence. 22   July, 1998: n. pag. Web. 13 Nov 2010.

Howard, Walter E., Animal Rights vs. Nature. California: Walter E. Howard, 1990. Print.

Jha, Alok. “Of Mice and Medicine: If a Treatment Works on Rodents, Will It Cure US?” Guardian. 4 Aug, 2009: n. pag. Web. 22 Oct, 2010.  

Snow, Nancy., Stem Cell Research: New Frontiers in Science and   Ethics. Indiana: University of Notre Dame, 2004. Print. 

Stansfield, William D., Death of a Rat: Understanding and Appreciations of Science. New York: Prometheus Books, 2000. Print.

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