Mouse sperm is kept on the International Space Station for nine months, gave rise to healthy pups, a new study reveals.
This finding suggests that the animals, perhaps including humans, may one day reproduce safely in space, researchers said.
This work also raises the possibility of a “doomsday vault” for sperm cells in the space, which can contribute to the conservation of animal species of disasters on Earth, such as the Global Seed Vault in Svalbard, Norway, for plant species. The sperm-safe idea is similar to one depicted in a novel by the author of “A Game of Thrones,” the scientists added. [The Human Body in Space: 6 weird Facts]
If humans ever want to live permanently in space, they need to ensure that they and all the animals of the farm that they can reproduce, said study senior author Teruhiko Wakayama, a reproductive biologist at the University of Yamanashi Kofu, Japan, and his colleagues.
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However, in the area is dangerous. For example, the average daily radiation dose on the International Space Station (ISS) is more than 100 times higher than that on Earth, and can damage the sperm and eggs that give rise to most of the animals offspring, the researchers said.
To examine whether the damage that space radiation could do to potential animal offspring, the researchers provided samples of freeze-dried mouse sperm in the space. (Freeze-drying retains the items quickly by freezing them and then subjecting them to a high vacuum that dehydrates. Freeze-dried ice cream is often known as “astronaut ice cream.”)
This mouse sperm was stored on the ISS, 288 days from August 2013 to May 2014, at temperatures of minus 139 degrees Fahrenheit (minus 95 degrees Celsius). The sperm was then returned to Earth and compared with lyophilized samples which were stored on Earth, in the same time under similar circumstances.
The researchers have found evidence that in the space preserved sperm or something more DNA damage than the Earth-preserved samples.
“This was a little surprising, because the storage period was only nine months,” said Wakayama Space.com.
The scientists then employed in vitro fertilization techniques, the use of both the space – and the Earth-preserved sperm to produce embryos which were transferred into female mice. The average birth rate of the two types of samples were similar, and the ratio of men and women in the two types of pups fell within the normal range, the researchers said. In addition, analyses of the puppies taken appeared to be only minor differences between the two types of mice, and the pups of space preserved sperm was to develop into adults with normal fertility.
All in all, the researchers say that their findings suggest that the DNA damage seen in the space of the preserved semen was largely restored in the embryos after fertilization. Previous research has been done for almost 40 years has established that the egg-cells have a great potential for the repair of damaged DNA, the scientists explain.
These findings suggest that a healthy animal offspring could be produced with semen preserved in the space, and artificial insemination techniques, the researchers said. Many domesticated animals have already been produced using artificial insemination.
“If the people living in the area for a very long time, then we want to eat steak,” Wakayama said.
The scientists noted that freeze-dried sperm can be stored at room temperature for up to two years, and in a freezer almost indefinitely. This increases the possibility that a sperm bank in space could assist in the protection of animal species of disasters on Earth, the researchers said. Wakayama took a similar idea that was suggested in the science fiction book “Tuf Voyaging” by George R. R. Martin, the author of “A Game of Thrones.”
For example, the spaces in lava tubes on the moon are cold, protected from space radiation by thick foundation and isolated from the Earth. “Therefore, semen could be preserved forever” on the moon, Wakayama said. Still, he added that this notion of “too preliminary to say, it is a good idea if it is possible.”
The scientists detailed their findings online today (May 22) in the journal Proceedings of the National Academy of Sciences.
Follow Charles Q. Choi on Twitter @cqchoi . Follow us @Spacedotcom , Facebook and Google+ . Originally published on Space.com .