Who needs men in space! Virility of sperm in microgravity means all-women crews could head to the stars armed with sperm banks
A human sperm bank in space could be a possibility in the future, suggests new findings. Preliminary results have shown that frozen human sperm samples, when exposed to microgravity, remain viable in outer space conditions and were "just as active and concentrated" as on Earth. The results are fascinating, say scientists as it opens the possibility of safely transporting frozen sperm samples into space and creating a human sperm bank outside the Earth.
"Although it has to be confirmed with further studies, 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 of creating a human sperm bank outside the Earth. Of course, not just microgravity, radiation is another important effect to be taken into consideration and should also be studied deeply," Dr. Montserrat Boada from Dexeus Women's Health in Barcelona tells MEA WorldWide (MEAWW).
The findings suggest that if sperms can survive in space-like conditions, it could one day help establish colonies on Mars or other habitable planets.
When questioned if the results imply that if one can successfully create human sperm banks in space, it will be possible to replace male astronauts with an all-women crew, Dr. Boada tells MEAWW that this was not the objective of the study. She, however, said that "assisted reproduction techniques are likely to be the most common method of reproduction outside the Earth because natural conception is believed to be difficult there."
Dr. Boada also shares that studies investigating the effects of altered gravity on humans are required, "especially if we think that in the near future, life and even reproduction outside the Earth could be a challenge to be faced." She adds, "To have gametes and embryos stored in a bank outside the Earth will be very important not only to make human reproduction possible but also to guarantee diversity, which is very important in maintaining the species."
The results of the study were presented at the 35th annual meeting of the European Society of Human Reproduction and Embryology in Vienna from June 23 onwards by Dr. Boada, whose group worked with microgravity engineers from the Polytechnic University of Barcelona. The findings, according to Dr. Boada, suggest that it is "not unreasonable to start thinking about the possibility of reproduction beyond the Earth."
The research team explained that while the effects of microgravity on the cardiovascular, musculoskeletal and central nervous systems are well known and tested in space flight, relatively little is known about the impact of different gravitational environments on human sperms and eggs. "Some studies suggest a significant decrease in the motility (the ability to move independently) 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," shares Dr. Boada.
She adds, "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."
The study was conducted using a small aerobatic training aircraft (CAP10), which can provide short-duration hypogravity exposure. The Aeroclub Barcelona-Sabadell of Spain was responsible for the parabolic flights for creating microgravity conditions. "The plane did a series of 20 parabolic maneuvers, providing 8 seconds of microgravity for each parabola," says the team.
For the sperm analysis, the research team tested the full range of measurements currently done for fertility testing, which includes concentration, motility, vitality, morphology, and DNA fragmentation. Overall, 10 sperm samples obtained from 10 healthy donors were analyzed after exposure to the different microgravities found in space and ground gravity.
The researchers found that the frozen samples exposed to microgravity conditions remained as healthy as those kept on the ground, and there were no significant differences in the parameters used to analyze them.
"Results found no difference whatsoever in any of the parameters between the microgravity space samples and the control group samples from the earth. There was 100% concordance in DNA fragmentation rate and vitality, and 90% concordance in sperm concentration and motility. These minor differences were more probably related to the heterogeneity of the sperm sample than to the effect of exposure to different gravity conditions," reveals Dr. Boada.
Meanwhile, more detailed investigations are required to understand the impact of space-like conditions on sperm for a longer duration of time. Accordingly, Dr. Boada and her group will now move on to validate the results and then to larger sperm samples, more extended periods of microgravity, and even fresh sperm.
"This study is only the first step of a big project and more research is required to validate the results with a larger sample. We want to continue our work with frozen sperm samples and also with fresh sperm samples. Different platforms are also being taken into consideration. We are trying to find longer periods of microgravity for a better evaluation of the possible effects of microgravity on human gametes. We are also thinking of going further and evaluating the effects of microgravity not only on human sperm samples but also on oocytes and embryos," she tells MEAWW.
Dr. Boada noted that one reason for using frozen sperm in this study was the known effect of radiation on fresh sperm. "Radiation impairs the quality and viability of human sperm, and these effects are expected to be greater on fresh sperm than on frozen samples, which are cryopreserved in special cryostraws and transported in cryotanks. So our first step was to investigate gravity conditions and frozen sperm samples. Our best option will be to perform the experiment using real spaceflight, but access is very limited," says Dr. Boada.