Mice on Earth may like to run on wheels, but mice in space seemingly take advantage of microgravity to run in circles bouncing off walls.
A new study of mice living aboard the International Space Station suggests that such projects could reveal Key ideas To support human travel to Mars and beyond, the scientists added.
A mission to Mars and vice versa would take years, but scientists are not sure how a crew will adapt or suffer for so long in outer space. Space flight involves exposure to microgravity, radiation, isolation and many other factors that can pose a variety of Physical and psychological risks for astronauts..
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Studying rats and laboratory mice is an obvious way for scientists to learn what effects space flight might have without endangering astronauts. "Because rodents develop and age much faster than humans, the study of rodent model organisms allows scientists to study diseases that can take years or decades to develop. humans, "lead study author April Ronca, a space bioscientist at NASA's Ames Research Center in Moffett Field, California, told Space.com.
However, previous work in rodents in space The researchers wrote in the newspaper that animals often flew in devices that were poorly equipped to reveal what they were really doing in flight and how well they were adapting to life in space. For example, in 2013, 45 male mice flew for 30 days on the Russian Bion-M1 Russian ship, but malfunctioning food dispensers and other equipment failures killed about two-thirds of the mice. The quality of the video recordings of the mice also decreased precipitously after the first week, as the debris hid the camera lenses.
So the researchers designed a new and improved hotel for rodents to send to the space station, called NASA's Habitat for Rodents. During the first two uses of this habitat, the rodent research mission of NASA-1, the scientists recorded videos of 20 female mice for 17 to 33 days. A group of similar mice were kept in the ground and monitored for comparison during each procedure.
The rodent habitat of NASA was designed to house mice in groups, which reduces their stress levels and helps scientists control their social activity. The habitat also has sports grids on its walls that mice can grab and bounce off. The habitat also provides both a relatively large space so that the mice move inwards and a smaller area where they can retreat and participate in the cuddly behavior typical of mice.
The design of NASA's Rodent Habitat also helped keep its lenses fairly clear throughout the mission. "Camera lenses are placed in the habitat in a way that reduces the exposure of the lens to debris and floating fluids," said Ronca. "More recently, a regular lens cleaning step has been incorporated into the rodent research system, which has further enhanced the quality of the image."
In these initial tests, the scientists discovered that mice in space were active and mobile throughout the experiment, exploring their habitat and engaging in the full range of behavior typical of the species, such as feeding, grooming, and piling up. The rodents adapted quickly to their new circumstances without weight, for example, by anchoring themselves to the walls of the habitat with their hind legs or tail and stretching their bodies. This posture was similar to that of mice on Earth that were standing on their hind legs to explore their environment.
During all the time they spent aboard the space station, the mice explored the entire habitat. At the end of the mission, they weighed the same as their counterparts on the ground and their coats were in excellent condition, the researchers reported, which are signs of good health.
A unique behavior was observed between seven and ten days after the launch: the younger mice, but not older, in the experiment began to run in circles around the walls of the habitat. This "career track" quickly became a coordinated group activity. The researchers noted that this seemed similar to the exercises in which the human crew participated routinely.
But scientists are not sure why these mice started running laps. Mice given the chance to run on a wheel in nature will do as much as captive mice, suggesting that spinning of all kinds is something that mice like to do. Or such a circuit is the kind of abnormal repetitive behavior that previous research has shown that animals perform under stress. However, the researchers believe that stress was not a likely cause of this circle in space, because the mice had excellent health, showed no obvious signs of stress and, otherwise, behaved normally.
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Of course, the unique conditions imposed by space flights could have been incited by circles. Bones in the inner ears of mice and humans help the body maintain balance, but in microgravity, the constant sensation of freefall experienced in orbit may feel uncomfortable. The researchers noted that the circles can generate forces to stimulate the inner ear and help rodents to feel comfortable. In the future, scientists plan to identify the molecular and cellular changes that occur in mice to help identify the causes of the circles, Ronca said.
And the shorter life of mice can help scientists shed light on long-term human space flight. "The mice flew for up to 37 days, which is about 18 months for humans," Ronca said. "The results of long-term rodent studies are important in learning how to protect the health of astronauts who will embark on long-term exploration missions, and can help treat diseases on Earth such as suppressed immune systems, muscle atrophy and loss. that is".
The scientists detail his findings Online on April 11 in the journal Scientific Reports.