Microgravity effects on frozen human sperm samples

Abstract

This work was approved by the Ethics Committee and Review Board of the Center Consent to participate: Study participants were informed of the procedure and gave their consent to participate by signing the informed consent. Availability of data and material: All relevant data are within the paper Code availability: Not applicable Authors' contributions: M. Boada and A. Perez-Poch conceived the study; D.V. González conducted the parabolic flights; M. Ballester and S. García-Monclús performed the seminal tests; S. García performed statistical analysis, M. Boada, A. Perez-Poch, M. Ballester, S. García-Monclús and A.Veiga analyzed the data and wrote the paper; All authors read, reviewed and approved the final manuscript.

Effects of space flight on sperm function and integrity: A systematic review

“…Boada et al reported that the exposure of healthy donors to parabolic flight did not affect sperm count, as no significant changes between the experimental and control groups (39.01 ± 32.02 × 10 6 /ml versus 39.29 ± 36.53 × 10 6 /ml) was observed. This result reinforces the previous hypothesis that sperm is protected against microgravity by freezing them in comparison to the fresh ones ( Boada et al, 2020 ). Additionally, Kumar et al showed that after exposure to occupational ionizing radiation, the total sperm count was not affected, as there was no statistically significant difference between the exposed and non-exposed men (64.16 ± 4.40 × 10 6 /ml versus 68.44 ± 5.98 × 10 6 /ml) ( Kumar et al, 2013 ).…”

“…Samples exposed to microgravity had a mean of 13.33 ± 5.12% sperm fragmentation, while control samples had a mean of 13.88 ± 6.14%. The mean percentage of SDF was similar in both groups ( Boada et al, 2020 ).…”

“…The sperm motility of frozen samples exposed to microgravity and control samples showed comparable results. There were no statistically significant differences in the percentage of sperm motility (frozen samples at 21.83 ± 11.69 versus controls at 22.54 ± 12.83) ( Boada et al, 2020 ). Other studies that exposed ejaculated sperm to parabolic flights reported a decrease in total sperm motility (control 45.33 ± 23.98 versus microgravity 26.85 ± 21.60% ( p = 0.004), and progressive motility (control 32.15 ± 23.35 versus microgravity 18.53 ± 17.34% ( p = 0.007)), and thought that the reason behind this might be due to chemical changes in the intracellular environment during microgravity exposure ( Ikeuchi et al, 2005 ).…”

“…A summary of the key information from these articles is shown in Table 1 . These articles included five studies from Japan (23.8%), four studies from China (19.04%), four studies from Russia (19.04%), three studies from the United States (14.2%), one study from India (4.76%), one study from the United Kingdom (4.76%), one study from Australia (4.76%), one study from Egypt (4.76%), and one study from Spain (4.76%) ( Tash and Bracho, 1999 ; Tash et al, 2002 ; Kamiya et al, 2003 ; Sasaki et al, 2004 ; Ikeuchi et al, 2005 ; Ding et al, 2011 ; Kumar et al, 2013 ; Li et al, 2013 ; Yan et al, 2013 ; Zhou et al, 2016 ; Wakayama et al, 2017 ; Olejnik et al, 2018 ; Usik and Ogneva, 2018 ; Fuller et al, 2019 ; Matsumura et al, 2019 ; Ogneva et al, 2020a ; Boada et al, 2020 ; Ogneva et al, 2020b ; Said et al, 2020 ; Ogneva, 2021 ). Seventeen of the articles conducted the experiment on Earth (fifteen simulations and two occupational exposures), three of the studies performed the experiment on the International Space Station (ISS), and one of the articles conducted experiments during a Space Shuttle mission.…”

“…Four articles did not mention the sample size ( Tash et al, 2002 ; Ogneva et al, 2020b ; Said et al, 2020 ; Ogneva, 2021 ), but in the remaining studies, the reported sample sizes ranged between 12 and 560 subjects. Thirteen articles were exclusively performed on microgravity ( Tash and Bracho, 1999 ; Tash et al, 2002 ; Kamiya et al, 2003 ; Sasaki et al, 2004 ; Ikeuchi et al, 2005 ; Ding et al, 2011 ; Masini et al, 2012 ; Usik and Ogneva, 2018 ; Matsumura et al, 2019 ; Ogneva et al, 2020a ; Boada et al, 2020 ; Said et al, 2020 ; Ogneva, 2021 ), while seven articles were performed on ionizing radiation ( Kumar et al, 2013 ; Li et al, 2013 ; Zhou et al, 2016 ; Wakayama et al, 2017 ; Olejnik et al, 2018 ; Fuller et al, 2019 ; Ogneva et al, 2020b ), and only one article conducted combined experiments on both microgravity and ionizing radiation ( Yan et al, 2013 ).…”