Space Pups from Freeze-Dried Mouse Sperm Stored in ISS for 6 Years Are Large, Healthy

Japanese researchers found that the mouse sperm that was frozen and stored in the International Space Station (ISS) for six years and exposed to high levels of cosmic radiation was able to produce a large, healthy brood of "space pups."

The freeze-dried sperm was rehydrated after it was brought back to Earth and has now resulted in the birth of 168 young, free of genetic defects in mice. That is contrary to the stories written in comic books or science fiction books, which often tell a story of an organism having defects due to radiation.

The study on these amazing space pups, entitled "Evaluating the long-term effect of space radiation on the reproductive normality of mammalian sperm preserved on the International Space Station," was published in Science Advances.

Freeze-Dried Mouse Sperm Aboard the ISS

The story of the freeze-dried mouse sperm began in 2013 when Japanese developmental biologist Teruhiko Wakayama, now the director of Advanced BiotechnologyCenter at the University of Yamanashi, and colleagues launched three boxes of the freeze-dried sperm to the ISS for a study.

Phys.org reported that Wakayama was inspired by the science fiction of Heinlein and Asimov and once dreamt of becoming an astronaut.

The study's goal is to observe what will be the effect of cosmic radiation on the DNA of the offspring produced with the sperm and whether if any genetic mutations would be passed on.

They chose the freeze-dried sperm because it can be preserved at room temperature and only requires a small amount of space, according to ZME Science. The entire setup was only about the size of a pencil, reducing the costs of flying to and storing in the space station.

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Freeze-Dried Mouse Sperm Produced Healthy Space Pups

It has been known that radiation could have drastic effects on the DNA, and space radiation has been one of the concerns for scientists in a while as astronauts engage in lengthy missions in low orbit.

Space agencies from around the world are developing technologies that could protect astronauts from the long-term effects of radiation that could cause mutations in the DNA.

Fortunately for the space pups produced from the freeze-dried mouse sperm stored in the space station, they appear to have no difference between offspring in the control group, Phys.org reported.

They also observed that even in the next generation of these space pups, when they randomly mated, there were no genetic mutations, and they appeared normal as well.

Wakayama said that the process of freeze-drying the sperm increased its tolerance to cosmic radiation compared to fresh sperm because it does not contain water inside the cell nucleus and cytoplasm. The team said that the sperm could be stored for up to 200 years in the ISS.

In the case of human sperms, the team cautioned that further studies are needed. Effects of radiation on frozen female eggs and fertilized embryos must be investigated first before taking the next step.