Simulated microgravity alters sperm navigation, fertilization and embryo development in mammals

Area of Science:

• Reproductive Biology
• Space Medicine
• Developmental Biology

Background:

• Long-duration space missions necessitate understanding reproduction in microgravity.
• Sustaining human life beyond Earth requires addressing reproductive health in altered gravitational environments.

Purpose of the Study:

• To investigate the effects of simulated microgravity on mammalian sperm function, fertilization, and early embryo development.
• To assess species-specific responses to microgravity in human, mouse, and pig reproductive systems.

Main Methods:

• Utilized a dual-axis 3D clinostat to simulate microgravity.
• Employed microfluidic channels for sperm navigation assessment and in vitro fertilization (IVF) with time-lapse monitoring.
• Analyzed blastocyst development and lineage in human, mouse, and pig embryos under simulated microgravity.

Main Results:

• Microgravity impaired sperm's directional navigation and fertilization capacity in a species- and time-dependent manner.
• Progesterone partially restored human sperm navigation under simulated microgravity.
• Microgravity during fertilization affected pig blastocyst development and altered cell counts in pig and mouse embryos; prolonged exposure delayed mouse embryo development.

Conclusions:

• Reproductive processes exhibit both resilience and vulnerability under simulated microgravity.
• Optimizing peri-conception environments is crucial for successful reproduction in space.
• Further research is needed to mitigate microgravity's impact on fertility for future space exploration.