Space mice
Scientists have proved the possibility of "cosmic" conception of children
Japanese biologists have successfully raised healthy mice using sperm that was stored on board the ISS in frozen form for almost a year, according to an article published in the journal PNAS (Wakayama et al., Healthy offspring from freeze-dried mouse spermatozoa held on the International Space Station for 9 months).
"If humanity starts living in space, then we will need technologies that allow us to freeze sperm and store it for a long time. The problem is that the radiation level on the ISS is 100 times higher than on Earth. We have shown that although radiation damages sperm DNA, it does not affect the viability and fertility of offspring," write Sayaka Wakayama from Yamanashi University and her colleagues.
The high level of radiation in outer space, as scientists say, is today one of the main dangers to human life and the main obstacle to turning us into a "cosmic species". This radiation poses the greatest threat to germ cells, which need to go through several phases of division before they become ready for fertilization.
The first experiments on the reproduction of insects, fish, sea urchins and other animals, which were carried out on board the ISS, showed that nothing prevents procreation in weightlessness, but such experiments were not carried out on mammals. In addition to this, experiments to assess the viability of offspring were not carried out in principle due to the technical impossibility of breeding hundreds of mice or other animals on board the station at the same time.
Wakayama and her colleagues solved this problem by sending on board the ISS not live rodents, but frozen stocks of their sperm, which spent about nine months on board the station, and then were returned to Earth in May 2014.
Then the scientists used these samples of genetic material to fertilize eggs, implanted them into the wombs of surrogate mothers and monitored how "high-quality" the offspring turned out. At the same time, scientists compared the DNA structure in "cosmic" spermatozoa and their usual "cousins" that had lain frozen on Earth for a similar amount of time.
As these experiments have shown, a long stay in space really affected the quality of sperm, making it more susceptible to mutations. This effect was not significant – all the "space" mice were born as healthy as their "terrestrial" cousins, and they suffered from about the same diseases as individuals from the control group. When they grew up and left offspring, the number of mice was about the same as that of their "terrestrial" peers who had never flown into space.
Photo from an article in PNAS
Such experimental results, according to scientists, suggest that a long stay in space should not greatly interfere with the prospects of procreation, and that frozen eggs and sperm stored on board space stations or ships can be successfully used to maintain the human population in space.
In addition, reserves of such frozen genetic materials, according to Wakayama and her colleagues, can be created on Earth to protect humanity from extinction and its rapid recovery after a possible meteorite fall or anthropogenic disasters.
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23.05.2017