Examination of Molecular Mechanisms on Vascular Formation and Stress Response of Early Zebrafish Embryos in Simulated and Real Microgravity

Space is a hostile environment that can cause numerous health hazards in astronauts, including alterations in the vascularization system and high rates of muscle atrophy. Therefore, understanding the molecular pathways mediating space-induced alterations in human physiology is necessary for making future missions successful. The goal of this study was to use zebrafish (Danio rerio) embryos as a unique model to study molecular mechanisms of simulated and real microgravity effects on vascularization system and stress response. To simulate microgravity, we exposed zebrafish embryos to a two-dimensional clinorotation device starting 1-day postembryonic fertilization (pdf) and lasting for a maximum of four days. Changes in multiple genes expression were measured by q-PCR. Thus, we used the KDRL-BSY zebrafish strain with the blue fluorescently labeled vascular system allowing us to image vascularization system using confocal microscopy. Our preliminary results indicated that only a small proportion of genes were affected by clinorotation with the most prominent effect observed on day 5. Our next goal was to confirm our findings by exposing zebrafish embryos (days 2 and 3 pdf) to microgravity during the suborbital flight aboard Blue Origin’s New Sheppard vehicle in the spring of 2019. Our data indicates that in contrast to clinorotation, zebrafish embryos exposed to suborbital flight had the up-regulated expression of multiple genes families, with the most profound effect observed in vascular endothelial growth factors and heat shock proteins.