September 24, 2012
Naked Mole Rat Studied For Its Pain Resistance And Long, Healthy Life
John Neumann for redOrbit.com - Your Universe Online
The humble, hairless, buck-toothed digging denizen we know as the naked mole-rat could lead researchers to new treatments for pain relief in humans. Researchers from the University of Illinois at Chicago report new findings as to how these rodents have adapted to toxic carbon dioxide buildup in their dens.
As CO2 levels rise to levels that would be toxic for other mammals, the air in their dens becomes highly acidic. The naked mole-rat however, freely tolerates such unpleasant conditions, says Thomas Park, professor of biological sciences at UIC and principal investigator of the study.
The lingering pain of an injury, for example, is generally caused by acidification of the injured tissue, Park explains. “Acidification is an unavoidable side-effect of injury. Studying an animal that feels no pain from an acidified environment should lead to new ways of alleviating pain in humans.”
The secret of pain resistance in the animal can be found in its sensitive nose. In normal mammals, specialized nerve fibers in the nose are activated by acidic fumes. This stimulates the trigeminal nucleus, a collection of nerves in the brainstem, eliciting a physiological and behavioral response that protect the animal. The animal will secrete mucus and rub its nose, for example, and withdraw or avoid the acidic fumes.
For this study, researchers placed naked mole-rats in a system of cages in which some areas contained air with acidic fumes. The animals were allowed to roam freely, and the time they spent in each area was tracked.
When compared to its cousin species, the laboratory mouse, the naked mole-rats spent as much time exposing themselves to acidic fumes as they spent in fume-free areas, Park said, while the control mice avoided the fumes.
The physiologic response to exposure to acidic fumes was quantified by measuring a protein, c-Fos, an indirect marker of nerve activity that is often expressed when nerve cells fire. In naked mole-rats, no such activity was found in the trigeminal nucleus when stimulated. In the control rats and mice, however, the trigeminal nucleus was highly activated.
The naked mole-rats´ tolerance of acidic fumes is consistent with their adaptation to living underground in chronically acidic conditions, Park said.
In other naked mole-rat news, the creature is also being studied for its relative lengthy lifespan. Naked mole-rats can live for an impressive 30 years, with the ability to reproduce until its end. The tiny rodent also shows little decline in brain power or bone structure during that time.
The key to their long and healthy lives is believed to be hidden in their genes and scientists are eager to unlock those secrets, writes Tom Goodenough for The Sun-UK.
Human genetics specialist Professor Jonathan Flint, of Oxford University´s Wellcome Trust Center, says, “Ageing is not a fixed thing. There is no hard limit on how long we can live. The fact that people die at 80 or 90 is not fixed. We could theoretically go on for 200 years if we understood the biology pathways and could alter them in some way.”
The hardy mole-rats have adapted well to their fierce East African desert habitat. They eat poisonous plants, resist cancer and cope with extreme heat. Professor Rochelle Buffenstein, at the University of Texas, said, “It doesn´t matter what you throw at them, they seem to cope.”
Admittedly, the creature is not attractive, has terrible eyesight and frankly, doesn´t get out much, so perhaps living an excessively long life is not what it's cracked up to be.