The New Lab Rat of Choice? Naked Mole Rats

Naked mole rats, originally found only in East Africa, are now making their home in laboratories around the world. According to The Associated Press, researcher Rochelle Buffenstein takes care of the largest colony in the United States—approximately 1,500 naked mole rats—at the University of Texas Health Science Center. 

Buffenstein says that until the 1990s, she and only one other group were studying the hairless rodents; she predicts that the naked mole rat will be a fixture in laboratories by 2020.

“It takes time for people to realize that an animal has got a lot going for it,” she told the AP.

The naked mole rat certainly does have a lot going for it. Regular lab mice live an average of two years but naked mole rats can live up to 30 years. In addition, the naked mole rat doesn’t get cancer, doesn’t feel pain and can withstand oxygen depravation for more than a half-hour. As a result, these tiny, almost hairless, nearly blind rodents are proving invaluable for research on longevity, pain, cancer and stroke.

Naked mole rats live in underground colonies that are led by a dominant queen, similar to the social structure of bees or wasps. Roughly three inches long, the naked mole rat spends its time in complete darkness, digging for food and working to sustain the colony and raise the young.

Although naked mole rats are sensitive to touch, they are insensitive to the pain of acid and substances like chili peppers and lemon juice, Charles Q. Choi reported for LiveScience in 2008. Neurobiologist Thomas Park, a researcher at the University of Illinois at Chicago, found that naked mole rats lack Substance P, a chemical that causes a burning sensation in mammals.

According to Park, this finding added to previous knowledge on Substance P, and may provide insight into inflammatory pain. “We’re learning which nerve fibers are important for which kinds of pain, so we’ll be able to develop new strategies and targets,” Park told LiveScience.

The brain tissue of naked mole rats can survive hypoxia, or oxygen deprivation, for longer than a half-hour—far longer than other mammalian brain tissue, ScienceDaily reported. Researchers found that the mole rat colonies, located approximately six feet below ground, offer a very small air supply that’s low in oxygen and high in carbon dioxide.

“We believe that the extreme resistance to oxygen deprivation is a result of evolutionary adaptations for surviving in a chronically low-oxygen environment,” Park told ScienceDaily. “The trick,” he explained, will be to learn how to “use this information to help people who experience temporary loss of oxygen to the brain in situations like heart attacks, stroke or drowning.”

Although naked mole rats can live to be 30 years old—“ample time for cells to grow cancerous,” according to a press release from the University of Rochester—the rodents have never been found with tumors. Vera Gorbunova and Andrei Seluanov, biologists at the university, say the naked mole rat has a “two-tier defense against cancer.” In addition to a gene called p27, which humans and other animals have, and which prevents cells from crowding together, naked mole rats have a gene called p16 that prevents cells from multiplying uncontrollably.

“Cancer cells tend to find ways around p27, but mole rats have a double barrier that a cell must overcome before it can grow uncontrollably,” the press release reported. The researchers are planning to examine the naked mole rat’s genetics more closely to see if their cancer-fighting abilities can be used in humans.

According to Paul Sherman, a professor at Cornell University, and Jennifer U.M. Jarvis, Sherman’s South African colleague, naked mole rats in the laboratory live about 10 times longer than other rodents their size. The researchers believe the naked mole rat offers insight into senescence (aging) theory, and “why some bodies wear out before others,” Cornell News explains.

Sherman and Jarvis believe the naked mole rats live longer in nature due to their habitat: In subterranean burrows, they are safer than their counterparts that live at the surface. “[G]reater fecundity with advancing age” is also a factor. Large breeding female mole rats continue to give birth to mole rat pups into old age. If old mole rats continue to make “reproductive contributions,” Cornell News reports, “there will be strong selection to postpone senescence.”

But the mole rat model may not be a perfect fit for theories that apply to humans. Due to the fact that aging occurs to every component of an organism, there isn’t a single gene responsible for aging.

Although they may not be as cute as polar bears, there are many other strange creatures that play an important role in the environment.

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