Naked mole-rats 'can survive near-suffocation'

Say what you will about naked mole-rats but their bodies have a trick that lets them survive periods of oxygen deprivation

Naked mole rats can survive 18 minutes without oxygen. Here's how they do it

Humans need an atmosphere which has at least 10 per cent oxygen to survive, but naked mole rats have evolved to live in stuffy underground burrows in the African desert which can be 15 miles long, and have little air.

They are virtually cold-blooded and the only mammal with a social structure similar to that of ants and termites. They don't get tumors, they're immune to chronic pain and the irritating components of chili peppers. Naked mole rats achieve their feat by turning to a molecular trick used by plants: They stop metabolizing glucose and start metabolizing a different sugar, fructose.

Naked mole rats are wrinkly, hairless, poop-eating, delightful creatures that live in large colonies of up to 280 animals.

When oxygen levels fall to a life-threatening level, the subterranean animal simply slows down its heart rate and switches to another metabolism system.

He also wonders whether extreme divers, who survive for relatively long periods of time without taking in any oxygen, may have unwittingly taught their bodies how to switch from using glucose to fructose in the metabolic process. The naked mole-rats could survive on fructose when oxygen was at levels that would have been fatal for humans: we would have died in a matter of minutes while the animals survived for a minimum of 5 hours under those impossible conditions. After five hours at five percent oxygen, the team made a decision to take the subjects out of their test chamber because nothing was happening. "And we put them in and fifteen minutes later they looked fine, after an hour they looked fine, and after five hours of exposure to five percent O2 they still looked fine", he continued.

Mole rats can survive for just under 20 minutes with no oxygen supply.

There is some benefit to humans in all of this.

But the researchers' findings in the naked mole rat could lead to breakthroughs in surviving heart attacks and strokes.

"They live in really challenging conditions", says Chris Faulkes of Queen Mary, University of London, who studies mole rats, but wasn't involved in the research.

"If we could activate the fructose pathway in a heart attack victim, that would extend the amount of time we have to get that victim to a medical facility where they can get resuscitated and spare the brain damage that frequently comes along with a heart attack", Park said.

The lack of GLUT5 and KHK in other organs - the brain and the heart, for instance - means the energy bound in fructose is unavailable to them, causing them to fail in low-oxygen environments.

In 0% oxygen, both the mice and mole rats quickly lost consciousness. Another interesting question is how the naked mole-rats use fructose without experiencing any of the negative effects of fructose such as obesity.

National Geographic said that usually, when there is a buildup of fructose in an organism, the body tissues will be damaged.

Thomas Park, a neuroscientist at the University of IL in Chicago, and Gary Lewin, a physiologist at the Max Delbrück Center for Molecular Medicine in Berlin, placed naked mole rats and mice in a chamber with only five percent oxygen. They have a variety of quirks which separate them from other mammals.

Unlike all other known mammals, when the brain cells of naked mole rats are deprived of oxygen they do not run out of energy and die. "The most misunderstood thing is that they're ugly". They now hope to harness lessons learned from this rodent to design future therapies for people to prevent calamitous damage during heart attacks or strokes when oxygenated blood can not reach the brain.

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