A new study from the University of Yamanashi in Japan has found that it is possible to preserve sperm for space travel, opening up new possibilities for human trips to Mars and beyond.
It may be possible to preserve sperm for space travel, opening up new possibilities for human trips to Mars and beyond.
The discovery was made after healthy mouse offspring were born using freeze-dried mouse sperm preserved for nine months in space.
For humans to live on space stations or other planets long term, colonies will likely have to store sperm and egg samples for reproduction, the researchers said.
And while sperm is damaged by long-term solar radiation exposure, the researchers found that any damage is repaired during embryo development.
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‘In the future, humans likely will live on large-scale space stations or in other space habitats for several years or even over many generations, ‘ the researchers, led by the University of Yamanashi in Japan, wrote in their paper.
‘If humans ever start to live permanently in space, assisted reproductive technology using preserved spermatozoa will be important for producing offspring.
‘However, radiation on the International Space Station (ISS) is more than 100 times stronger than that on Earth, and irradiation causes DNA damage in cells and gametes.’
The effect of this radiation on sperm cells could pose serious reproductive problems for space-dwelling organisms, including humans, the researchers said.
To test whether this radiation irreparably damages sperm, the team dispatched samples of freeze-dried mouse sperm to be stored on the ISS for 288 days.
The sperm were preserved in freezers at -95°C (-139 °F) from August 2013 to May 2014.
Following the samples’ return to Earth, the sperm were compared with control samples preserved on Earth during the same period under similar conditions.
The research found that long-term space travel did slightly damage the DNA of the space-preserved samples, compared with the control samples.
But the study also found that this DNA damage did not hinder the sperms’ ability to fertilise eggs.
The researchers fertilised mouse embryos with sperm from either space-preserved or control samples and transferred them into female mice.
The team found that the average birth rates of pups from space-preserved sperm samples were very similar to pups conceived using control samples.
The sex ratio of mouse pups from space-preserved sperm was found to be normal, and genetic analysis revealed only minor DNA differences from control pups overall.
The research found that pups from space-preserved sperm developed into adults with normal fertility, suggesting that the DNA damage observed in the space-preserved sperm samples was largely repaired during embryo development.
According to the authors, the results demonstrate the possibility of producing healthy mammalian offspring from sperm preserved in space.
