title: Changes of cytokines during a spaceflight analog--a 45-day head-down bed rest.
abstract: Spaceflight is associated with deregulation in the immune system. Head-down bed rest (HDBR) at -6° is believed to be the most practical model for examining multi-system responses to microgravity in humans during spaceflight. In the present study, a 45-day HDBR was performed to investigate the alterations in human immune cell distributions and their functions in response to various stimuli. The effect of countermeasure, Rhodiola rosea (RR) treatment, was also examined. A significant decrease of interferon-γ (IFN-γ) and interleukin-17 (IL-17) productions by activated T cells, increase of IL-1β and IL-18 by activated B and myeloid cells were observed during HDBR. The upregulation of serum cortisol was correlated with the changes of IL-1 family cytokines. In addition, a significant increase of memory T and B cell and regulatory T cells (Treg) were also detected. The uptake of RR further decreased IFN-γ level and slowed down the upregulation of IL-1 family cytokines. These data suggest that for prolonged HDBR and spaceflight, the decreased protective T cell immunity and enhanced proinflammatory cytokines should be closely monitored. The treatment with RR may play an important role in suppressing proinflammatory cytokines but not in boosting protective T cell immunity.
authors.affiliation: Key Laboratory of Medical Immunology, Ministry of Health, Department of Immunology, School of Basic Medical Sciences, Peking University Health Sciences Center, Beijing, P. R. China.
authors.forename: Xi
authors.initials: X
authors.lastname: Xu
authors.forename: Cheng
authors.initials: C
authors.lastname: Tan
authors.forename: Pingping
authors.initials: P
authors.lastname: Li
authors.forename: Shusong
authors.initials: S
authors.lastname: Zhang
authors.forename: Xuewen
authors.initials: X
authors.lastname: Pang
authors.forename: Hongju
authors.initials: H
authors.lastname: Liu
authors.forename: Li
authors.initials: L
authors.lastname: Li
authors.forename: Xiuyuan
authors.initials: X
authors.lastname: Sun
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhang
authors.forename: Hounan
authors.initials: H
authors.lastname: Wu
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Chen
authors.forename: Qing
authors.initials: Q
authors.lastname: Ge
mesh_terms: D000328:Adult; D001510:Bed Rest; D016207:Cytokines / Q000096:biosynthesis / Q000097:blood*; D006257:Head; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D008297:Male; D010936:Plant Extracts / Q000494:pharmacology; D029771:Rhodiola / Q000737:chemistry; D013026:Space Flight; D018474:Weightlessness Simulation / Q000379:methods*
chemical_list: D016207:Cytokines; D010936:Plant Extracts