What hibernating animals can teach astronauts

(ORDO NEWS) — When bears and “ground squirrels” fall into hibernation, they stop eating and live until spring only at the expense of fat reserves accumulated in the body. Usually, such prolonged fasting and inactivity significantly reduces muscle mass and function, but sleepers do not suffer this fate. How they manage to avoid this remains a mystery.

Now, in a study published in the journal Science, a University of Montreal biologist has figured out why, and his findings could have implications for the future of space travel. By studying a North American terrestrial squirrel, Matthew Regan confirmed a theory known as “urea nitrogen rescue” dating back to the 1980s.

According to this theory, hibernating proteins use the metabolic cunning of their gut microbes to convert nitrogen contained in urea, a waste compound normally excreted in the urine, and use it to build new tissue proteins.

How can this discovery be useful in space? Theoretically, Regan believes, it will help astronauts minimize their own muscle wasting problems caused by microgravity suppression of protein synthesis, which they are now trying to reduce with intense training.

If a way could be found to increase muscle protein synthesis in astronauts’ muscles by reducing urea nitrogen, they could achieve better muscle condition during long journeys into deep space in spaceships too small for conventional exercise equipment, the argument goes.

“Because we know which muscle proteins are downregulated during spaceflight, we can compare those proteins to those that are upregulated when urea nitrogen is rescued during hibernation,” said Regan, who led the study while a postdoc at the University of Wisconsin-Madison.

He now continues his work with a Canadian Space Agency Research Grant in Udam, where he was appointed Assistant Professor of Animal Physiology in the Department of Biological Sciences last year.

“If,” Regan continued, “the proteins formed during spaceflight are the same as those form

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