Energetic particles’ fluxes and dose in the Radiation Gene Box measured by space radiation detector onboard SJ-10 satellite

New evidence and insight for abnormalities in early embryonic development after short-term spaceflight onboard the Chinese SJ-10 satellite

During space travel, radiation and microgravity are recognized to be major hazardous factors in the overall health and well-being of astronauts. Although some efforts have been made to elucidate the effects of short-term space travel on the reproductive health of astronauts and multiple  other species in a variety of in vitro and in vivo studies, it is still unclear whether space travel can cause abnormal embryonic development or if it poses any reproductive risks. Recently, Lei et al. (2020) investigated the effects of short-term spaceflight onboard the Chinese SJ-10 satellite on murine preimplantation embryonic development. In the article, the authors claimed that the developmental abnormalities after short-term spaceflight onboard the SJ-10 satellite were attributed to space radiation and that these alterations in space was equivalent to those induced by a 2 mGy dose of gamma-rays in a ground-based facility. In this commentary, we discuss the possible space environmental factors and associated mechanisms that contribute to abnormalities in early embryonic development, and the potential health risks to mammals after short-term space travel. This commentary provides new evidence and a fresh perspective on whether and how short-term space travel poses potential reproductive risks in mammals.

Development of mouse preimplantation embryos in space

The development of life beyond planet Earth is a long-standing quest of the human race, but whether normal mammalian embryonic development can occur in space is still unclear. Here, we show unequivocally that preimplantation mouse embryos can develop in space, but the rate of blastocyst formation and blastocyst quality are compromised. Additionally, the cells in the embryo contain severe DNA damage, while the genome of the blastocysts developed in space is globally hypomethylated with a unique set of differentially methylated regions. The developmental defects, DNA damage and epigenetic abnormalities can be largely mimicked by the treatment with ground-based low-dose radiation. However, the exposure to simulated microgravity alone does not cause major disruptions of embryonic development, indicating that radiation is the main cause for the developmental defects. This work advances the understanding of embryonic development in space and reveals long-term extreme low-dose radiation as a hazardous factor for mammalian reproduction.