According to a study published in the journal Science Advances on June 11, the “space rats” were born as a result of insemination with the sperm of mice that had been freeze-dried and preserved and orbited the planet for nearly 6 years aboard a space station. International Space.
The sperm, which had been preserved in space for 6 years, were injected into the eggs using the ICSI method, and the embryos developed normally in the laboratory after fertilization with sperm that had been frozen, dried and stored in space. Read also A look at some of the International Space Station research over the past year From the International Space Station, “Icarus” tracks and saves wild animals Will the International Space Station collide with the Earth .. When, how and where? Because of US sanctions, Russia threatens to leave the International Space Station and build a Russian station
According to a Live Science report, Japanese researchers dried the sperm of mice, a technique that allowed them to keep the sperm at room temperature for more than a year.
Drying enabled the team to cut the costs of launching sperm to the International Space Station in 2013, as they used “light and small” ampoules to store them. Once at the station, the astronauts stored them in a refrigerator at minus 95 degrees Celsius.
Some samples returned to Earth infrequently, and after 9 months, researchers found slightly more damage to sperm DNA and male gamete nucleus than the control reference samples, but fertilization and birth rates were similar, they reported in a study published in 2017.
The freeze-dried sperm showed a “strong tolerance” to space radiation. The researchers hypothesize that this may be due to a lack of water molecules inside the frozen cells because radiation causes DNA damage through free radicals produced when the active molecules interact with the water molecules inside the cells.
Long-term effects study
The researchers examined the samples by using modern instruments that measure the amount of radiation absorbed by the sperm, then tested the amount of DNA damage to the nucleus, and found that long-term storage aboard the International Space Station did not significantly damage its DNA.
After the sperm was rehydrated, they injected it into female mice, and they found that the mice gave birth to 8 healthy hens, showing no differences in gene expression compared to the controls.
According to the study, most studies of the effects of space radiation have been conducted in conditions simulating space, and this presents a challenge because space radiation includes many types of energetic particles – such as the solar wind, solar cosmic rays and galactic cosmic rays – that cannot be reproduced on Earth.
The researchers say that there is no easy way to study the long-term effects of space radiation on biological materials, because it is difficult to send animals or living cells to the International Space Station because they need constant monitoring.