title: Hyperoxia during colon surgery is associated with a reduction of xanthine oxidase activity and oxidative stress in colonic mucosa.
abstract: BACKGROUND
  Gut manipulation during surgery may induce local oxidative stress. Supplemental inspired oxygen increases arterial and tissue oxygen partial pressures. This study examined whether a 0.80 fraction of inspired oxygen (FiO(2)) attenuates the oxidative stress, reducing xanthine oxidase (XO) activity in colonic mucosa as a possible mechanism during colon surgery.
  
  
  METHODS
  Twenty-four cancer patients who underwent elective colon resection were randomly assigned to either 0.30 FiO(2) or 0.80 FiO(2) during surgery. Malondialdehyde (MDA) and oxidized glutathione (GSSG) levels were measured in blood plasma. We also determined the enzymatic activities of XO and xanthine dehydrogenase (XDH) in the colonic mucosa after resection of the piece of colon.
  
  
  RESULTS
  Oxygen partial pressure in arterial blood was higher in the 0.80 FiO(2) group than in the 0.30 FiO(2) group (P<0.001). MDA and GSSG levels measured in blood plasma as well as MDA measured in colonic mucosa were lower in the 0.80 FiO(2) group than in the 0.30 FiO(2) group. Otherwise, XO enzymatic activity and XO/(XO+XDH) ratio in colonic mucosa were lower in the 0.80 FiO(2) group than in the 0.30 FiO(2) group.
  
  
  CONCLUSIONS
  XO may be a major source of reactive oxygen species in patients during colon surgery. Inspiring 0.80 oxygen during colon surgery increases arterial partial pressure and this treatment was associated with reduced XO activity and levels of oxidative stress in colonic mucosa.
authors.affiliation: Hospital Clínico Universitario de Valencia, Spain. jgdelaasuncion@hotmail.com
authors.forename: José
authors.initials: J
authors.lastname: García-de-la-Asunción
authors.forename: Gracia
authors.initials: G
authors.lastname: Barber
authors.forename: Diana
authors.initials: D
authors.lastname: Rus
authors.forename: Jaime
authors.initials: J
authors.lastname: Perez-Griera
authors.forename: Francisco Javier
authors.initials: FJ
authors.lastname: Belda
authors.forename: Francisco
authors.initials: F
authors.lastname: Martí
authors.forename: Eduardo
authors.initials: E
authors.lastname: García-Granero
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001784:Blood Gas Analysis / Q000379:methods; D003110:Colonic Neoplasms / Q000473:pathology / Q000601:surgery*; D005260:Female; D019803:Glutathione Disulfide / Q000097:blood; D006801:Humans; D018496:Hyperoxia; D007413:Intestinal Mucosa / Q000378:metabolism*; D008297:Male; D008315:Malondialdehyde / Q000097:blood; D008875:Middle Aged; D018384:Oxidative Stress; D010100:Oxygen / Q000378:metabolism*; D010313:Partial Pressure; D017382:Reactive Oxygen Species / Q000378:metabolism; D014968:Xanthine Dehydrogenase / Q000378:metabolism; D014969:Xanthine Oxidase / Q000378:metabolism*; D055815:Young Adult
chemical_list: D017382:Reactive Oxygen Species; D008315:Malondialdehyde; D014968:Xanthine Dehydrogenase; D014969:Xanthine Oxidase; D010100:Oxygen; D019803:Glutathione Disulfide