title: Effect of pre-breathing oxygen at different depth on oxidative status and calcium concentration in lymphocytes of scuba divers.
abstract: OBJECTIVE
  In-water pre-breathing oxygen at various depths reduces decompression-induced bubble formation and platelet activation, but it could induce side effects such as oxidative stress. The aim of this study was to investigate the effect of in-water pre-breathing oxygen, at different depths, on the oxidative status and intracellular calcium ([Ca(2+) ]i) of peripheral blood lymphocytes isolated from six divers. They participated in a 4-diving protocol. Two week recovery time was allowed between successive dives. Before diving, all divers, for 20 min, breathed normally at sea level (dive 1), 100% oxygen at sea level (dive 2), 100% oxygen at 6 msw (dive 3), 100% oxygen at 12 msw (dive 4). Then they dived to 30 msw for 20 min with air tank.
  
  
  METHODS
  Blood samples were collected before and after each dive. Hydrogen peroxide (H(2) O(2) ) levels, catalase (CAT) activity, mRNA expression of CAT, glutathione peroxidase (GPx) and superoxide dismutase (SOD), and the [Ca(2+) ]i in lymphocytes were measured.
  
  
  RESULTS
  The dives slightly decreased lymphocyte number and significantly reduced lymphocyte H(2) O(2) levels. CAT activity was higher after scuba diving and, dive 3 enhanced mRNA gene expression of CAT, GPx and SOD. The [Ca(2+) ]i was higher after dive 1 and 2 than pre-diving, while was maintained at pre-diving value after dive 3 and 4.
  
  
  CONCLUSIONS
  Our results suggest that pre-breathing oxygen, in particular at 12 msw, may enhance lymphocyte antioxidant activity and reduce reactive oxygen species levels. Pre-breathing oxygen in water may also preserve calcium homeostasis, suggesting a protective role in the physiological lymphocyte cell functions.
authors.affiliation: Department of Neuroscience and Imaging, Aging Research Center, Ce.S.I., 'G. d'Annunzio' University of Chieti-Pescara, Chieti, Italy.  
authors.forename: C
authors.initials: C
authors.lastname: Morabito
authors.forename: G
authors.initials: G
authors.lastname: Bosco
authors.forename: R
authors.initials: R
authors.lastname: Pilla
authors.forename: C
authors.initials: C
authors.lastname: Corona
authors.forename: R
authors.initials: R
authors.lastname: Mancinelli
authors.forename: Z
authors.initials: Z
authors.lastname: Yang
authors.forename: E M
authors.initials: EM
authors.lastname: Camporesi
authors.forename: G
authors.initials: G
authors.lastname: Fanò
authors.forename: M A
authors.initials: MA
authors.lastname: Mariggiò
mesh_terms: D000328:Adult; D002118:Calcium / Q000378:metabolism*; D002374:Catalase / Q000378:metabolism; D003665:Decompression Sickness / Q000517:prevention & control; D004242:Diving / Q000502:physiology*; D006801:Humans; D006861:Hydrogen Peroxide / Q000097:blood; D006931:Hyperbaric Oxygenation / Q000009:adverse effects / Q000379:methods; D008214:Lymphocytes / Q000378:metabolism* / Q000502:physiology; D008297:Male; D008875:Middle Aged; D016877:Oxidants / Q000097:blood; D018384:Oxidative Stress; D010100:Oxygen / Q000378:metabolism*; D010101:Oxygen Consumption / Q000502:physiology; D010102:Oxygen Inhalation Therapy; D012333:RNA, Messenger / Q000378:metabolism; D055815:Young Adult
chemical_list: D016877:Oxidants; D012333:RNA, Messenger; D006861:Hydrogen Peroxide; D002374:Catalase; D010100:Oxygen; D002118:Calcium