Hypergravity influences mouse erythrocyte membrane lipid composition and antioxidant potential

To support safe human space exploration, it is important to understand how different effectors, including gravitational forces, influence living organisms. Indeed, altered levels of gravity affect the physiological function of multiple cells, tissues, and organs in living organisms. Previous studies suggested that microgravity modifies plasma membrane permeability and cellular metabolism in erythrocyte, modifying cholesterol and phospholipid levels. However, to support human safe space exploration, it is also relevant to understand the effects of hypergravity. Therefore, the aim of this study was to investigate in vivo the impact of hypergravity on lipid phenotype and oxidative stress in mouse erythrocytes. Animals were housed in the Italian Space Agency's Mice Drawer System (MDS-ASI), a facility designed to house rodents on the International Space Station (ISS) and adapted by Thales Alenia Space to the Large Diameter Centrifuge (LDC-ESA), to expose mice to a 3×g environment for 14 days. After exposure, a tissue-sharing protocol allowed us to purify and analyze erythrocytes. Our results show that the exposure of mice to altered gravity induced the reduction of unsaturation degree in erythrocyte membranes correlated to a lower stearoyl-CoA desaturase (SCD-1) activity. Moreover, the hypergravity induced both a decline in antioxidant defences, indicated by the significant decrease in total glutathione, and a grow of the inflammatory status, supported by an increase in the AA/EPA ratio.