title: FemHab: The effects of bed rest and hypoxia on oxidative stress in healthy women.
abstract: Independently, both inactivity and hypoxia augment oxidative stress. This study, part of the FemHab project, investigated the combined effects of bed rest-induced unloading and hypoxic exposure on oxidative stress and antioxidant status. Healthy, eumenorrheic women were randomly assigned to the following three 10-day experimental interventions: normoxic bed rest (NBR;n= 11; PiO2 = 133 mmHg), normobaric hypoxic bed rest (HBR;n= 12; PiO2 = 90 mmHg), and ambulatory hypoxic confinement (HAMB;n= 8: PiO2 = 90 mmHg). Plasma samples, obtained before (Pre), during (D2, D6), immediately after (Post) and 24 h after (Post+1) each intervention, were analyzed for oxidative stress markers [advanced oxidation protein products (AOPP), malondialdehyde (MDA), and nitrotyrosine], antioxidant status [superoxide dismutase (SOD), catalase, ferric-reducing antioxidant power (FRAP), glutathione peroxidase (GPX), and uric acid (UA)], NO metabolism end-products (NOx), and nitrites. Compared with baseline, AOPP increased in NBR and HBR on D2 (+14%; +12%;P< 0.05), D6 (+19%; +15%;P< 0.05), and Post (+22%; +21%;P< 0.05), respectively. MDA increased at Post+1 in NBR (+116%;P< 0.01) and D2 in HBR (+114%;P< 0.01) and HAMB (+95%;P< 0.05). Nitrotyrosine decreased (-45%;P< 0.05) and nitrites increased (+46%;P< 0.05) at Post+1 in HAMB only. Whereas SOD was higher at D6 (+82%) and Post+1 (+67%) in HAMB only, the catalase activity increased on D6 (128%) and Post (146%) in HBR and HAMB, respectively (P< 0.05). GPX was only reduced on D6 (-20%;P< 0.01) and Post (-18%;P< 0.05) in HBR. No differences were observed in FRAP and NOx. UA was higher at Post in HBR compared with HAMB (P< 0.05). These data indicate that exposure to combined inactivity and hypoxia impairs prooxidant/antioxidant balance in healthy women. Moreover, habitual activity levels, as opposed to inactivity, seem to blunt hypoxia-related oxidative stress via antioxidant system upregulation.
authors.affiliation: Department of Automation, Biocybernetics and Robotics, Jozef Stefan Institute, Ljubljana, Slovenia; tadej.debevec@ijs.si.
authors.forename: Tadej
authors.initials: T
authors.lastname: Debevec
authors.affiliation: Center of Research and Innovation on Sports, University Claude Bernard Lyon 1, Villeurbanne, France;
authors.forename: Vincent
authors.initials: V
authors.lastname: Pialoux
authors.affiliation: Center of Research and Innovation on Sports, University Claude Bernard Lyon 1, Villeurbanne, France;
authors.forename: Sabine
authors.initials: S
authors.lastname: Ehrström
authors.affiliation: Center of Research and Innovation on Sports, University Claude Bernard Lyon 1, Villeurbanne, France;
authors.forename: Alexandra
authors.initials: A
authors.lastname: Ribon
authors.affiliation: Department of Environmental Physiology, Swedish Aerospace Physiology Centre, Royal Institute of Technology, Stockholm, Sweden;
authors.forename: Ola
authors.initials: O
authors.lastname: Eiken
authors.affiliation: Department of Automation, Biocybernetics and Robotics, Jozef Stefan Institute, Ljubljana, Slovenia;
authors.forename: Igor B
authors.initials: IB
authors.lastname: Mekjavic
authors.affiliation: ISSUL, Institute of Sport Sciences, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland; Department of Physiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland.
authors.forename: Grégoire P
authors.initials: GP
authors.lastname: Millet
mesh_terms: D000328:Adult; D000975:Antioxidants / Q000378:metabolism; D001510:Bed Rest; D015415:Biomarkers / Q000378:metabolism; D002374:Catalase / Q000378:metabolism; D005260:Female; D005979:Glutathione Peroxidase / Q000378:metabolism; D006801:Humans; D000860:Hypoxia / Q000378:metabolism / Q000503:physiopathology*; D008315:Malondialdehyde / Q000378:metabolism; D009573:Nitrites / Q000378:metabolism; D009589:Nitrogen Oxides / Q000378:metabolism; D018384:Oxidative Stress / Q000502:physiology*; D013482:Superoxide Dismutase / Q000378:metabolism; D014443:Tyrosine / Q000031:analogs & derivatives / Q000378:metabolism; D014527:Uric Acid / Q000378:metabolism; D016387:Women's Health
chemical_list: D000975:Antioxidants; D015415:Biomarkers; D009573:Nitrites; D009589:Nitrogen Oxides; D014527:Uric Acid; C002744:3-nitrotyrosine; D014443:Tyrosine; D008315:Malondialdehyde; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase
keywords: antioxidant; inactivity; nitrosative stress; normobaric hypoxia; prooxidant