Long stay in space in zero gravity can cause serious changes in the brain, Siberian scientists have found out by examining the state of mice that have been in orbit.
The results will make it possible to create systems for preventing and correcting the negative impact of weightlessness on the astronauts' organism. “The most interesting of the findings is about the dopamine system. We saw that the expression of its key genes declined after a month in orbit. This suggests that the dopamine system of the brain, which is normally responsible for fine coordination of actions, and in general for the control of movements, is degrading.
In the long term, such a change can lead to the development of a parkinson-like state. Because if you have a decrease in the expression of the enzyme that synthesizes dopamine, then the level of the neurotransmitter itself also decreases, and, ultimately, a motor deficit develops, "- quotes the words of a researcher at the Laboratory of Neurogenomics of Behavior at the Federal Research Center Institute of Cytology and Genetics of the SB RAS Anton Tsybko official publication SB RAS "Science in Siberia". See also Launch of the Soyuz TMA-17M manned transport vehicle.
In addition, the scientist noted changes in another extremely important structure of the brain - the hypothalamus. Here, signs of apoptosis (programmed cellular "suicide") were found, which is most likely provoked by microgravity. It has already been confirmed: both in orbit and on Earth - in experiments simulating the state of weightlessness - apoptosis of neurons increases. “This is fraught with a general deterioration in metabolism and much more. Considering that in zero gravity the body is already under attack, any change in its functioning for the worse can have quite serious consequences, "Tsybko explained.
Scientists noted that, fortunately, these changes are not fatal, and physical activity completely prevents them from occurring. In animals, physical activity is restored within a week. The brain begins to accumulate lost time again, the level of serotonin, dopamine returns to normal quite quickly. Within a month, neurodegeneration does not have time to occur.
Launching mice into space for a longer time still seems problematic. Physical education is a rescue for cosmonauts The study was carried out on laboratory mice that made a 30-day space journey on the Bion-M1 biosatellite. Scientists note that the anatomy and physiology of mice are in many ways similar to humans, our genomes coincide by 99%, so linear mice are the most suitable objects for studying the mechanisms of adaptation to weightlessness. However, there is a significant difference: astronauts, unlike mice, are able to consciously force themselves to move, they exercise more than four hours a day, which means they stimulate the motor centers in the brain and minimize the risk of damage to the dopamine system.
However, if you stay in orbit for at least two weeks and do not perform any special physical exercises, then upon returning to Earth, the condition turns out to be very difficult and a long rehabilitation is required. Bion is a series of Soviet and Russian spacecraft developed by TsSKB-Progress and intended for biological research. For 11 flights, experiments were carried out on them with 212 rats, 12 monkeys and a number of other animals. The Bion-M1 satellite was launched on April 19, 2013 and returned to Earth a month later.
In addition to mice, there were Mongolian gerbils, gecko lizards, fish, freshwater and grape snails, carpenter beetle larvae, microorganisms, algae, lichens and some higher plants on board. To date, the Bion-M1 experiment has been completed. Bion-M2 is to be launched in the coming years.
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