Stem cells, marijuana, frankincense and tart cherries are just a few of the intriguing and sometimes bizarre areas where scientists have looked for new ways to treat chronic pain.
Researchers at the University of Illinois at Chicago may have outdone them all.
They believe African naked mole-rats may hold important clues to treating chronic pain because of their ability to survive – and even thrive — in an acidic environment that other mammals, including humans, would find intolerable.
“Studying an animal that feels no pain from an acidified environment should lead to new ways of alleviating pain in humans,” says Thomas Park, professor of biological sciences at UIC and principal investigator of a study published online in PLOS ONE.
In the crowded burrows of the naked mole-rat, carbon dioxide builds up to toxic levels and the air becomes highly acidic. Other mammals would avoid living in such conditions. Nerves in their noses would be activated by the acidic fumes, stimulating other nerves in the central nervous system. The animals would secrete mucus, rub their noses, and withdraw or avoid the acidic fumes.
But naked mole rats don’t mind living in acidic conditions, and they have other unique qualities that may offer clues to relieving chronic pain in humans.
“They never get cancer, they are resistant to low oxygen and they don’t feel certain kinds of pain, for instance chronic pain,” says Park, who adds that naked mole rats can live for 30 years, ten times as long as other animals of the same size.
Scientists are eager to understand why naked mole rats can live pain free in acidic environments. In humans and other mammals, lingering pain from an injury is caused by acidification of the injured tissue. “Acidification is an unavoidable side-effect of injury,” Park says.
To test their theories, 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 cage was tracked. Their behavior was compared to laboratory rats, mice, and another type of mole rat that likes to live in comfortable conditions.
The naked mole-rats spent as much time exposing themselves to acidic fumes as they spent in fume-free areas. The other species avoided the fumes.
The researchers were able to quantify the physiologic response to acidic fumes by measuring a protein in the animals that is often expressed when nerve cells fire. In naked mole-rats, no such activity was found. In rats and mice, however, it was highly activated.
“I think this is going to be a gold mine for biologists and biomedical research,” says Park.
You can learn more about the naked mole rat and the research at the University of Illinois at Chicago in this video: