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Naked mole-rats can survive near-suffocation

21 Avril 2017

Leading such an extreme subterranean life has bestowed naked mole-rats with some pretty impressive talents. It all ultimately has to do with the naked mole-rat's metabolism. They also wallow in excrement gathered at a communal toilet, presumably to give the colony averaging 80 members a common identifying odor. They're immune to types of chronic pain and the irritant in chilli peppers. That's an unusually long time for animals their size. In English: "Can these disgusting penis-animals cure cancer?"

A new study from the University of IL in Chicago suggests that naked mole rats can live up to 18 minutes without oxygen by changing the way they metabolise simple sugars. The findings, published today in the journal Science, could one day help researchers figure out how to keep humans healthy when oxygen gets cut off by strokes or heart failure.

The study can be found at j.mp/mole-rats.

"Fructose-driven glycolysis supports anoxia resistance in the naked mole-rat" (science.aab3896) co-authors are Bethany L. Peterson, Gregory Blass, Brigitte M. Browe, Daniel T. Applegate, Victoria Gavaghan, Vince G. Amoroso and Vidya Govind of UIC's Laboratory of Integrative Neuroscience; Richard D. Minshall and John Larson of the UIC College of Medicine; Gary R. Lewin, Jane Reznick, Damir Omerbaši?, Tetiana Kosten, Ole Eigenbrod, Valérie Bégay, P. Henning J.L. Kuich, Christin Zasada, Stefan Kempa, Wiebke Hamann, Michael H. Radke and Michael Gotthardt of the Max Delbru?ck Center for Molecular Medicine and Ewan St. J. Smith, now at the University of Cambridge; and Nigel C. Bennett and Heike Lutermann of the University of Pretoria. When oxygen gets very low - as it so often does underground when you're surrounded by hundreds of other naked mole rats - these little guys can convert fructose into energy as opposed to glucose, which requires oxygen. This energy source is less efficient than oxidizing glucose, but it's far better than nothing.

"They looked completely fine", he says. Their air frequently is so depleted of oxygen that most other animals couldn't survive.

That's a particularly fantastic trait to have for an animal that spends a lot of time underground, and could fall victim to cave-ins and other situations where oxygen becomes scarce. But in these tunnels, carbon dioxide can account for 7 to 10 percent of the warm, close air.

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Next, the researchers chose to see how the mole-rats dealt with zero percent oxygen.

At oxygen levels low enough to be fatal to humans within minutes, the creatures kept going for at least five hours. Mice died in less than 15 minutes. Naked mole-rats are even protected from pulmonary edema, which is another aspect of oxygen deprivation. They lost consciousness in about 30 seconds, but tried to breathe for a little over four minutes.

THOMAS PARK: They have evolved under such a different environment that it's like studying an animal from another planet. "And the naked mole-rats surprised everybody, I think".

This sturdiness was also found in tests on isolated hearts from the naked mole-rats. The creatures even survived 18 minutes with no oxygen - their bodies just switched over to fructose fuel. Mouse heart function was severely damaged. As soon as oxygen levels returned to normal, the naked mole-rats switched back to metabolizing glucose.

Though fructose is usually toxic, people metabolise it in the kidney and liver. A lack of oxygen. Molecular fructose "pumps" - which are typically only found in the intestines, not the brains, of other mammals - carry this fructose to their brain cells. Without this metabolic pathway, cells can't produce adenosine triphosphate (ATP), a chemical unit of energy currency. If we actually listened to these guys instead of roasting them for being fugly, we might be able to help heart attack and stroke sufferers.

Naked mole-rats can survive near-suffocation