Human sperm motility in a microgravity environment

Abstract

<b>Background and Aims:</b> We carried out clinostat and parabolic flight experiments to examine the effects of a microgravity (µG) environment on human sperm motility. <b>Methods:</b> Semen samples were obtained manually from 18 healthy men (aged 27.4 ± 5.4 years) who had given their informed consent. In clinostat experiments, samples that were left stationary were used as a stationary control. Samples rotated vertically and horizontally were used as a rotation control and a clinostat rotation, respectively. In parabolic flight experiments using a jet plane, sperm motility was compared for each parameter at µG, 1G and 2G. The state of 1G during the flight was used as a control. Sperm motility was determined using an automatic motility analyzer HT-M2030 in a microgravity environment. <b>Results:</b> All parameters of sperm motility tended to be lower in clinostat rotation compared with rotation control at both low-speed and high-speed, but the differences were not statistically significant. In parabolic flight, sperm motility and parameters of linear movement were decreased (<i>P</i> < 0.05). There was no significant difference between µG and 2G, but sperm motility was significantly decreased at µG than at 1G. <b>Conclusions:</b> Our findings suggest that sperm motility is reduced under µG. (Reprod Med Biol 2005; <b>4</b>: 161-168).