Effects of space flight on the immunohistochemical demonstration of connexin 26 and connexin 43 in the postpartum uterus of rats

Abstract

The effect of space flight in a National Aeronautics and Space Administration shuttle was studied in pregnant rats. Rats were launched on day 11 of gestation and recovered on day 20 of gestation. Pregnancy was allowed to proceed to term and rats delivered vaginally on days 22-23, although flight animals required more labour contractions to complete the delivery process. Pups were placed with foster dams and connexin 26 and 43 were examined in the uterus of flight animals approximately 3 h after delivery. Space flight did not affect uterine connexin 26, localized primarily in epithelial cells of the endometrium, but decreased connexin 43, the major gap junction protein in the myometrium. It is suggested that decreased connexin 43 alters synchronization and coordination of labour contractions, resulting in a requirement for more contractions to complete the delivery process.

Detrimental Effects of Microgravity on Mouse Preimplantation Development In Vitro

“…Thus far, female rats at several different stages of pregnancy have been launched into space. These data provide clear evidence that rats kept in space at µG during the latter half of their pregnancies are able to sustain normal body weight gains and to support the growth and development of their gestating offspring [46]–[50]. These results were consistent with those for other species, especially urodeles [51] and fish [3], [52].…”

Simulated Microgravity Compromises Mouse Oocyte Maturation by Disrupting Meiotic Spindle Organization and Inducing Cytoplasmic Blebbing

“…Fertilization can occur normally under microgravity and preimplantation embryo development might require 1 g environment [6], [15]. Rats kept in space during the latter half of their pregnancies are able to support the growth and development of their gestating offspring [40], [41]. As female astronauts suppress their menstrual cycles during spaceflight [42], relatively little is known about the effect of spaceflight on female reproduction.…”

Extraterrestrial Gynecology: Could Spaceflight Increase the Risk of Developing Cancer in Female Astronauts? An Updated Review

“…Space-flown pregnant rats gave birth at the expected time; however, they exhibited twice as many 'lordosis' contractions during labor coupled with decreased uterine myometrial connexin 43 (gap junction) protein expression relative to controls, suggesting changes to the uterine smooth musculature tone with exposure to microgravity. However, the duration of labor, maternal weight gain, miscarriage/stillbirth rate, litter size, neonatal birthweight, placentophagia, and maternal care patterns were not significantly different from ground controls [40,41]. Importantly, NIH.R1 and R2 offspring were flown for the second half of the rats' gestational period, after organogenesis was complete, and returned to Earth for parturition.…”