Monday, June 5, 2017

Healthy offspring from freeze-dried mouse spermatozoa held on the International Space Station for 9 months

Healthy offspring from freeze-dried mouse spermatozoa held on the International Space Station for 9 months
Proceedings of the National Academy of Sciences of the United States of America
http://www.pnas.org/content/early/2017/05/16/1701425114.full

Significance: Radiation on the International Space Station (ISS) is more than 100 times stronger than at the Earth’s surface, and at levels that can cause DNA damage in somatic cell nuclei. The damage to offspring caused by this irradiation in germ cells has not been examined, however. Here we preserved mouse spermatozoa on the ISS for 9 mo. Although sperm DNA was slightly damaged during space preservation, it could be repaired by the oocyte cytoplasm and did not impair the birth rate or normality of the offspring. Our results demonstrate that generating human or domestic animal offspring from space-preserved spermatozoa is a possibility, which should be useful when the “space age” arrives.

Abstract: 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. Here we examined the effect of space radiation on freeze-dried mouse spermatozoa held on the ISS for 9 mo at –95 °C, with launch and recovery at room temperature. DNA damage to the spermatozoa and male pronuclei was slightly increased, but the fertilization and birth rates were similar to those of controls. Next-generation sequencing showed only minor genomic differences between offspring derived from space-preserved spermatozoa and controls, and all offspring grew to adulthood and had normal fertility. Thus, we demonstrate that although space radiation can damage sperm DNA, it does not affect the production of viable offspring after at least 9 mo of storage on the ISS.

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