Birendra Mishra, in the Department of Human Nutrition, Food and Animal Sciences, co-authored a groundbreaking study, “Reproductive Hazards of Space Travel in Women and Men,” supported by NASA and published in the prestigious journal Nature Reviews Endocrinology.
Extended travel in deep space poses potential hazards to the reproductive function of female and male astronauts, such as exposure to cosmic radiation, microgravity, increased gravity (hypergravity), psychological stress, physical stress, and circadian rhythm disruptions. Cosmic radiation contains protons, helium nuclei, and high charge and energy (HZE) particles. Studies performed on Earth in which rodents were exposed to experimentally generated HZE have demonstrated a high sensitivity of ovarian follicles and spermatogenic cells to these particles.
Exposure to microgravity during space flight and to simulated microgravity on Earth disrupts spermatogenesis and testicular testosterone synthesis in rodents, whereas the male reproductive system seems to adapt to exposure to moderate hypergravity. Studies on the effects of microgravity on female reproduction have found it disrupted oestrous cycling and in-vitro follicle development.
Many remaining data gaps need to be addressed, including the effects of microgravity, hypergravity, and space radiation on male and female reproductive tracts; hypothalamic–pituitary regulation of reproduction and prenatal development of the reproductive system; and the combined effects of multiple reproductive hazards encountered in space.