During spaceflight, a wide variety of physical (radiation and microgravity) and psychological stress factors (such as isolation, heavy workload and disturbed sleep pattern) can adversely affect astronauts' health by impairing their immune system. Several of these factors might compromise astronauts' resistance to infections and other iseases. In this PhD study, ground-based models were used to simulate space conditions, including radiation (X-rays, mixture of neutrons/γ-rays) and microgravity. Using in vitro experiments, different cell types (immune cells, fibroblasts and endothelial cells) were exposed to these space-simulated conditions in order to better understand the biological and molecular mechanisms induced by space stressors. In a first part, we assessed the formation of DNA double strand breaks (DSB) and apoptosis in human peripheral blood mononuclear cells exposed to X-rays. DSBs are known to be the most critical DNA lesion induced by ionizing radiation. Furthermore, we investigated whether chronic exposure to simulated space conditions affected gene expression of human blood cells exposed to simulated microgravity (by using the Random Positioning Machine) and/or irradiation conditions (mixture of neutrons and γ-rays). Finally, fibroblast cells were sent into space during the Foton M3 mission. Using an optimized procedure, these in vitro experiments allowed to highlight DSB formation.
|Place of Publication||Louvain-la-Neuve, Belgium|
|State||Published - 20 Jan 2012|