Effect of weightlessness on the development of the nervous system and peripheral analyzers inXenopus laevis larvae

Abstract

The study was carried out within the framework of a Russian-Canadian experiment aboard the Bion-10 satellite. The volume and surface area of the gray and white matter and ventricles of the brain, retina, olfactory placodes, the VIII nerve ganglia, and vascular plexus were measured in Xenopus laevis which had been in a state of weightlessness for 2 weeks since their hatching. Zero gravity was found to stimulate the growth of nerve processes, to increase the surface of the vascular plexus, and to impede the development of the retina, olfactory placodes, and VIII nerve ganglia.

Monochromatic computed microtomography using laboratory and synchrotron sources and X-ray fluorescence analysis for comprehensive analysis of structural changes in bones

“…Thus, bone and muscle tissues are kinds of 'signalling systems', showing the earliest and most obvious response to the impact of microgravity. Studies of vertebrates in microgravity have been conducted from the early 1990s (Besova et al, 1993;Besova & Savel'ev, 1993;Grinfeld et al, 1994;Savel'ev et al, 1995) to the present ISSN 1600-5767 (Roberts et al, 2008;Asadchikov et al, 2012;Sun et al, 2013). Amphibians, reptiles and mammals have been investigated.…”

Impact of Microgravity and Other Spaceflight Factors on Retina of Vertebrates and Humans In Vivo and In Vitro

“…The authors associated such morphogenetic changes with variations in the cytoskeleton and/or proliferative activity of cells in the anterior region of the embryo. On the other hand, Savel’ev et al [ 63 ] recorded a decrease in the sizes of the retina, ganglion of the VIII nerve, and olfactory placodes by 60, 22, and 17%, respectively, compared to the control group of developing X. laevis . The differences in the data obtained on ecaudate amphibian species may be explained by different factors: the developmental stages at which the animals were launched and the rearing devices used during the SFs.…”

“…In a study of eye specimens from rat pups "flown" in the NIHR1 and R2 spaceflight mission conducted by NASA, a histological examination of the retina showed no differences in development between the flight and control animal retina at E20, P1, P3, and P8 [111]. However, the retina of the experimental animals in the SF group was found to be much thinner [112].…”

“…Medaka model development [55,56,59] Gene expression [54,60] Eye, retina development [54] Amphibia Frogs Xenopus laevis Rana dybowskii Simulated microgravity Eye, retina development [62,63] Newts (Pleurodeles waltli)…”

“…Rat Mouse Spaceflight Simulated gravity onboard Simulated microgravity Eye, retina condition in adult animals [109][110][111] Eye, retina development [112][113][114] Retinal tissue and cells, molecular investigations [29,[116][117][118]; Blood circulation [121][122][123][124][125] Eye, retina condition in adult animals, molecular investigations [127] Hyper-gravity Spaceflight Simulated gravity onboard Eye, retina development [104] Cornea development [106] Chick (Gallus gallus) Hyper-gravity Eye, retina development [107] Mammals Eye, retina condition in adult animals [109][110][111] Eye, retina development [112][113][114] Retinal tissue and cells, molecular investigations [29,[116][117][118]; Blood circulation [121][122][123][124][125] Eye, retina condition in adult animals, molecular investigations [127] Rat Mouse Spaceflight Simulated gravity onboard Simulated microgravity data obtained on rodents exposed to r-μg and s-μg conditions largely explain the changes observed in astronauts during SFs (see below). The effect of high g doses on the rodent retina has also been studied preliminarily.…”