Overview

• A peer-reviewed report in Stem Cell Reports demonstrates that mouse spermatogonial stem cells cryopreserved aboard the ISS for six months restored fertility and produced healthy offspring after transplantation.
• Analysis of first-generation mice showed normal gene expression and no visible abnormalities, indicating space storage did not impair germ cell function.
• Unexpectedly, the cryopreservation chemicals caused more cell loss than six months of microgravity and radiation exposure aboard the ISS.
• Researchers warn that the lifespan, health and fertility of these mice and their descendants remain untested, preventing definitive conclusions about effects on humans.
• The Kyoto University team plans to examine additional samples still stored on the ISS and track subsequent generations to assess multi-generational impacts.