Hyperoxia during colon surgery is associated with a reduction of xanthine oxidase activity and oxidative stress in colonic mucosa

Abstract

BackgroundGut 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 (FiO2) attenuates the oxidative stress, reducing xanthine oxidase (XO) activity in colonic mucosa as a possible mechanism during colon surgery.MethodsTwenty-four cancer patients who underwent elective colon resection were randomly assigned to either 0.30 FiO2 or 0.80 FiO2 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.ResultsOxygen partial pressure in arterial blood was higher in the 0.80 FiO2 group than in the 0.30 FiO2 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 FiO2 group than in the 0.30 FiO2 group. Otherwise, XO enzymatic activity and XO/(XO + XDH) ratio in colonic mucosa were lower in the 0.80 FiO2 group than in the 0.30 FiO2 group.ConclusionsXO 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.