title: Effect of solar particle event radiation and hindlimb suspension on gastrointestinal tract bacterial translocation and immune activation.
abstract: The environmental conditions that could lead to an increased risk for the development of an infection during prolonged space flight include: microgravity, stress, radiation, disturbance of circadian rhythms, and altered nutritional intake. A large body of literature exists on the impairment of the immune system by space flight. With the advent of missions outside the Earth's magnetic field, the increased risk of adverse effects due to exposure to radiation from a solar particle event (SPE) needs to be considered. Using models of reduced gravity and SPE radiation, we identify that either 2 Gy of radiation or hindlimb suspension alone leads to activation of the innate immune system and the two together are synergistic. The mechanism for the transient systemic immune activation is a reduced ability of the GI tract to contain bacterial products. The identification of mechanisms responsible for immune dysfunction during extended space missions will allow the development of specific countermeasures.
authors.affiliation: Division of Infectious Diseases, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhou
authors.forename: Houping
authors.initials: H
authors.lastname: Ni
authors.forename: Minghong
authors.initials: M
authors.lastname: Li
authors.forename: Jenine K
authors.initials: JK
authors.lastname: Sanzari
authors.forename: Eric S
authors.initials: ES
authors.lastname: Diffenderfer
authors.forename: Liyong
authors.initials: L
authors.lastname: Lin
authors.forename: Ann R
authors.initials: AR
authors.lastname: Kennedy
authors.forename: Drew
authors.initials: D
authors.lastname: Weissman
mesh_terms: D000818:Animals; D018988:Bacterial Translocation / Q000502:physiology*; D005260:Female; D041981:Gastrointestinal Tract / Q000276:immunology* / Q000382:microbiology*; D019417:Hindlimb Suspension; D051379:Mice; D008813:Mice, Inbred ICR; D019445:Solar Activity