Surviving Acidity

A new study reveals clues to the naked mole-rat’s ability to thrive in underground environments with high levels of carbon dioxide.

Sep 25, 2012
Jef Akst

Naked mole-rats live together in tight, enclosed burrows in African soil, where poor ventilation results in a buildup of carbon dioxide, making the environment extremely acidic. Such conditions would be intolerable to most mammals. But according to a study was published online this week on PLOS ONE, not only do mole-rats survive in such conditions, they seem entirely unaffected, staying in acidic conditions much longer than rats, mice, or a closely related mole-rat species that is not normally exposed to such acidity.

When placed in a system of cages with areas of acidic air and areas of clean air, most rodents actively avoided the acidic fumes. This response is regulated by a collection of nerves in the brainstem called the trigeminal nucleus, which is activated by specialized nerve fibers in the mole-rat’s nose and results in mucus secretion, rubbing of the nose—suggesting that the animals are in pain—and withdrawal from the area. The naked mole-rats showed no activity in the trigeminal nucleus when exposed to acidic air, however, and spent as much time in the acidic areas as they did areas with clean air.

Studying such acidity-resistant animals as the mole-rat could provide clues about pain tolerance and relief in other animals, including people, Thomas Park, professor of biological sciences at UIC and principal investigator of the study, said in a press release. “Studying an animal that feels no pain from an acidified environment should lead to new ways of alleviating pain in humans.”

And pain relief isn’t the only thing scientists hope to learn from the small African rodents. In the recent feature story, “Underground Supermodels,” Park describes the animals’ ability to withstand oxygen deprivation without brain damage, with possible implications for heart attack and stroke victims; their apparent resistance to all types of cancer; and their incredibly long lives, longer than any other rodent, throughout which they seem to stay as healthy as a young pup.