The University of Yamanashi team has achieved a significant breakthrough successfully developing a fertilized mouse egg into a blastocyst at an orbiting lab. The blastocyst stage marks the first differentiation of cells, with inner cell mass cells becoming the fetus and trophectoderm cells forming the placenta. This groundbreaking research, published in the journal iScience, involved sending 720 two-cell frozen mouse embryos to the International Space Station (ISS) using a specially designed device. This device also facilitated the handling of the early mouse embryos astronauts.
The team thawed and cultured the embryos for four days, with 360 embryos cultured in the Japanese Kibo experiment module under 1G of gravity, equivalent to Earth’s gravity. The remaining 360 embryos were cultured in a zero-gravity environment. Following the culturing process, the embryos were fixed in formalin and sent back to Earth for comparison with embryos from a similar test conducted on Earth.
The results revealed that over 60% of the embryos from the Earth test developed into blastocysts, while the rate stood at 29.5% for the embryos in the 1G space test and 23.6% for the zero-gravity test. This indicates that embryos can develop normally until they reach the blastocyst stage even under zero-gravity conditions. However, further research is needed to determine whether they can implant and grow properly, according to Teruhiko Wakayama, a professor at the University of Yamanashi.
Additionally, the study found that the differentiations, rate of DNA damage, and gene expressions of blastocysts developed in zero-gravity did not differ from those in other settings. It is worth noting that the inner cell mass cells in three of the 12 blastocysts examined in detail from the zero-gravity test were observed to be clustered in two places, suggesting the possibility of developing into identical monozygotic twins.
This groundbreaking research opens up new possibilities for understanding embryonic development in space and its potential implications for mammalian reproduction. The University of Yamanashi team’s success in cultivating mouse embryos in a zero-gravity environment demonstrates the adaptability of embryos in such conditions. The study paves the way for further investigations into the long-term effects of space travel on mammalian reproduction and the potential for human reproduction in space.