Scientists have discovered that prolonged space travel can lead to dire consequences - painful bouts of diarrhea.
In particular, when laboratory mice were placed in conditions similar to those of space flight, the balance of bacteria and the function of immune cells in their intestines changed, leading to more acute effects of intestinal inflammation.
Flying in space won't be easy
In the new study, a team of scientists led by Qing Zhi, Ph. D. and a fellow at the Center for Health Sciences at Peking University, China, tested four different groups of mice. The mice of the first and third groups were suspended by their tails at an angle of 15 degrees, head down, their hind limbs not touching the ground.
The mice of all groups had free access to food and water. The second and fourth groups of mice were not hung by their tails. As of the seventh day of the experiment, mice in any of the groups did not show signs of a noticeable deterioration in the experimentally controlled health indicators, including weight loss.
Starting from the seventh day, the mice of the third and fourth groups were given a 3% solution of sodium dextran sulfate salt with drinking water to induce inflammatory bowel diseases, while the mice of the first and second groups continued to receive unaddressed water for drinking.
By the end of the experiment, the mice of the first ("suspended") group showed a reduced number of regulatory T cells, an increased number of neutrophils, and an imbalance of pro- and anti-inflammatory cytokines in the intestinal tissues as compared to the mice of the second ("control") group. The third ("suspended and infected") group showed more severe bowel pathologies than the fourth ("control") group.
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The mice in the third group showed weight loss, more profuse rectal bleeding and damage to intestinal tissue, and an increase in the number of deaths when deliberately causing colitis in mice.
The study was published in The FASEB Journal.