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Microgravity effects on frozen human sperm samples
M Boada1, A Perez-Poch2, M Ballester3
1Women's Health Dexeus, Department of Obstetrics, Gynaecology and Reproduction, Hospital Universitari Dexeus, Avinguda Carles III 71-75, 08028, Barcelona, Spain. monboa@dexeus.com.
Purpose:
Microgravity has severe effects on cellular and molecular structures as well as on metabolic interactions. The aim of this study is to investigate the effects of microgravity (μg) exposure on human frozen sperm samples.
Methods:
Sibling samples from 15 normozoospermic healthy donors were frozen using glycerol as cryoprotectant and analyzed under microgravity and ground conditions. Microgravity was obtained by parabolic flights using a CAP10B plane. The plane executed 20 parabolic maneuvers with a mean of 8.5 s of microgravity for each parabola.
Results:
Frozen sperm samples preserved in cryostraws and stored in a secure and specific nitrogen vapor cryoshipper do not suffer significant alterations after μg exposure. Comparing the study group (μg) and the control group (1 g), similar results were obtained in the main parameters studied: sperm motility (M/ml) 13.72 ± 12.57 vs 13.03 ± 12.13 (- 0.69 95% CI [- 2.9; 1.52]), progressive a + b sperm motility (%) 21.83 ± 11.69 vs 22.54 ± 12.83 (0.03 95% CI [- 0.08; 0.15]), sperm vitality (%) 46.42 ± 10.81 vs 44.62 ± 9.34 (- 0.04 95% CI [- 0.13; 0.05]), morphologically normal spermatozoa (%) 7.03 ± 2.61 vs 8.09 ± 3.61 (0.12 95% CI [0.01; 0.24]), DNA sperm fragmentation by SCD (%) 13.33 ± 5.12 vs 13.88 ± 6.14 (0.03 95% CI [- 0.09; 0.16]), and apoptotic spermatozoa by MACS (%) 15.47 ± 15.04 vs 23.80 ± 23.63 (- 0.20 95% CI [- 0.66; 1.05]).
Conclusion:
The lack of differences obtained between frozen samples exposed to μg and those maintained in ground conditions provides the possibility of considering the safe transport of human male gametes to space. Nevertheless, further research is needed to validate the results and to consider the possibility of creating a human sperm bank outside the Earth.
Trial Registration Number:
ClinicalTrials.gov: NCT03760783.
Insights
Microgravity exposure did not significantly alter frozen human sperm quality. This finding supports the safe transport of sperm for potential space exploration and future extraterrestrial sperm banks.
Area of Science:
- Space biology and reproductive medicine
- Cryobiology and gamete preservation
Background:
- Microgravity poses significant challenges to cellular and molecular structures.
- Understanding its impact on human reproductive cells is crucial for space exploration.
Purpose of the Study:
- To investigate the effects of microgravity (μg) exposure on human frozen sperm samples.
- To assess the viability and integrity of cryopreserved spermatozoa under simulated space conditions.
Main Methods:
- Sibling sperm samples from 15 healthy donors were cryopreserved using glycerol.
- Samples were analyzed under microgravity conditions achieved via parabolic flights (CAP10B aircraft).
- Key parameters including motility, vitality, morphology, and DNA fragmentation were compared to ground controls (1 g).
Main Results:
- No significant differences were observed in sperm motility, progressive motility, vitality, or morphology between microgravity and ground conditions.
- Sperm DNA fragmentation and apoptosis rates also showed no significant alterations after microgravity exposure.
- Frozen sperm samples stored in nitrogen vapor cryoshippers remained stable post-microgravity exposure.
Conclusions:
- Cryopreserved human sperm samples exhibit resilience to microgravity exposure during simulated spaceflight.
- These findings suggest the feasibility of safely transporting human gametes for space missions.
- Further research is warranted to explore the establishment of extraterrestrial human sperm banks.
