Frozen sperm retains viability in outer space: Study

According to recent research frozen sperm retains its viability in outer space conditions.

As part of a recent study, investigators said that the lack of difference in a range of sperm characteristics observed in frozen sperm samples exposed to microgravity and those maintained in ground conditions 'open the possibility of safely transporting male gametes to space and considering the possibility of creating a human sperm bank outside Earth'.

According to the team of researchers, while the effects of microgravity on the cardiovascular, musculo-skeletal and central nervous systems are well known and tested in space flight, relatively little is known about the effects of different gravitational environments on human sperm and eggs. Some studies suggest a significant decrease in the motility of human fresh sperm samples, but nothing has been reported on the possible effects of gravitational differences on frozen human gametes, in which state they would be transported from Earth to space.

The findings were discussed in ESHRE 35th Annual Meeting.

The study was performed using a small aerobatic training aircraft (CAP10), which can provide short-duration hypogravity exposure. The plane executed a series of 20 parabolic manoeuvres, providing 8 seconds of microgravity for each parabola. Overall, ten sperm samples obtained from ten healthy donors were analysed after exposure to the different microgravities found in space and ground gravity.

The sperm analysis comprised a full range of measurements currently performed for fertility testing - concentration, motility, vitality, morphology, and DNA fragmentation - and results found no difference whatsoever in any of the parameters between the microgravity space samples and the control group samples from Earth.

Researchers explained that there was 100% concordance in DNA fragmentation rate and vitality, and 90% concordance in sperm concentration and motility. These minor differences, she added, were more probably related to heterogeneity of the sperm sample than to the effect of exposure to different gravity conditions.

"If the number of space missions increases in the coming years, and are of longer duration, it is important to study the effects of long-term human exposure to space in order to face them. It's not unreasonable to start thinking about the possibility of reproduction beyond the Earth," said Montserrat Boada, lead author of the study.