title: Exposure to increased pressure or hyperbaric oxygen suppresses interferon-gamma secretion in whole blood cultures of healthy humans.
abstract: This study examines the effects of hyperoxia, increased atmospheric pressure, and hyperbaric oxygen on cytokine synthesis. Five healthy volunteers were exposed to 90 min of room air, 100% oxygen, 10.5% oxygen at 2 atm abs, or 100% oxygen at 2 atm abs (HBO2). All subjects were blinded and randomly exposed to each of the 4 conditions. Immediately before entering the chamber, immediately after exposure, and 3 and 24 h later, blood was drawn and stimulated ex vivo with phorbol myristate acetate (PMA) and phytohemagglutinin A (PHA). Since lymphocytes are the primary source of PMA/PHA-induced interferon-gamma (IFN-gamma), these results were expressed as IFN-gamma production per 10(6) lymphocytes. Following the HBO2 exposure, PMA/PHA-stimulated lymphocytes released 51% less IFN-gamma than cells obtained before the exposure. This suppression persisted for 24 h following HBO2 (P < 0.05). Surprisingly, increased atmospheric pressure alone also inhibited IFN-gamma secretion (P < 0.05). Room air and hyperoxia alone had no significant effect upon IFN-gamma release. HBO2's anti-inflammatory effect may, in part, be due to inhibition of IFN-gamma release.
authors.affiliation: Wound Care and Hyperbaric Medicine Program and the Department of Medicine, Baystate Medical Center, Tufts University School of Medicine, Springfield, Massachusetts, USA.
authors.forename: E V
authors.initials: EV
authors.lastname: Granowitz
authors.forename: E J
authors.initials: EJ
authors.lastname: Skulsky
authors.forename: R M
authors.initials: RM
authors.lastname: Benson
authors.forename: J
authors.initials: J
authors.lastname: Wright
authors.forename: J L
authors.initials: JL
authors.lastname: Garb
authors.forename: E R
authors.initials: ER
authors.lastname: Cohen
authors.forename: E C
authors.initials: EC
authors.lastname: Smithline
authors.forename: R B
authors.initials: RB
authors.lastname: Brown
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001274:Atmospheric Pressure; D015496:CD4-Positive T-Lymphocytes / Q000378:metabolism; D004311:Double-Blind Method; D006400:Hematocrit; D006801:Humans; D006931:Hyperbaric Oxygenation; D007371:Interferon-gamma / Q000378:metabolism*; D007958:Leukocyte Count; D008214:Lymphocytes / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D010976:Platelet Count; D013997:Time Factors
chemical_list: D007371:Interferon-gamma