La Jornada – Sperm from mice kept six years in the ISS generated healthy “space hatchlings”

Washington. Japanese researchers found that sperm from mice exposed to high levels of radiation for six years produced healthy “space hatchlings,” according to a study published in the journal Friday. Science Advances.

The sperm was stored lyophilized (dehydrated and frozen) on the International Space Station (ISS). Once on Earth he was rehydrated and 168 offspring free of genetic defects were sired.

Teruhiko Wakayama, a biologist and lead author of the study, explained that there are few differences between mice fertilized with sperm that were in space and those confined to Earth.

“All the pups were normal in appearance and when the genes were examined, no abnormalities were found,” he noted.

In 2013, Wakayama and colleagues from the Japanese University of Yamanashi sent three boxes to the ISS for study, each containing 48 vials of lyophilized sperm.

The objective was to determine how long exposure to radiation from space could damage the DNA of reproductive cells or if mutations were generated, which could be a problem for our species in future space exploration and colonization missions.

What was sent to the plant returned to Earth for fertilization in the first nine months, then after two years and finally after six, and hundreds of births were generated.

The lyophilized sperm for the experiment was chosen because it can be preserved at room temperature rather than needing a freezer.

The vials were also very small and lightweight, about the size of a small pencil, which reduced shipping costs.

When the “space mice” reached adulthood, they mated randomly, and the next generation seemed normal too.

Wakayama, who heads the Center for Advanced Biotechnology at Yamanashi University, said: “In the future, when the time comes to migrate to other planets, we will need to maintain the diversity of genetic resources not only for humans, but also for pets and domestic animals.

“For cost and safety reasons, the stored cells are likely to be transported in spacecraft rather than live animals,” he added.

Reaching other planets means leaving the safety of Earth’s atmosphere and its magnetic field, which also extends for about 400 kilometers above the station.

Deep space is full of strong radiation, both from solar particles and from cosmic rays that arrive from outside the solar system.

Eruptions on the solar surface generate particles that can have devastating impacts on human health and can penetrate the spacecraft of the current generation.

According to Wakayama, the freeze-drying process increases its tolerance compared to fresh sperm, since the former does not have water within the cell nucleus and cytoplasm.

Freeze-dried sperm can be stored for up to 200 years in an orbital device, the study authors consider.

Humanity may want to spread its genetic resources off-planet in the event of a disaster on Earth, the article adds.

The study warns that the effects of space radiation on female eggs and fertilized embryos still need to be investigated before taking a new step into the space age.

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