A study conducted in a Hindlimb Unloading (HU), Dextran Sulphate Sodium (DSS) colitis induced mouse model in simulated microgravity conditions revealed an overall predisposition to colitis.67 When compared to the ground control mice, the mice exposed to microgravity had an associated early onset of colitis, a fourfold increase of segmented filamentous bacteria, more than a twofold decrease in regulatory T cells (Treg) absolute numbers as well as a reported twofold increase in colonic IL-1β and circulating neutrophils. This evidence concerns the gene IL1B and colitis.