Effects of exercise on markers of oxidative stress: an Ancillary analysis of the Alberta Physical Activity and Breast Cancer Prevention Trial

Abstract

BackgroundOxidative stress may contribute to cancer aetiology through several mechanisms involving damage to DNA, proteins and lipids leading to genetic mutations and genomic instability. The objective of this study was to determine the effects of aerobic exercise on markers of oxidative damage and antioxidant enzymes in postmenopausal women.MethodsThe Alberta Physical Activity and Breast Cancer Prevention Trial (ALPHA) was a two-centre, two-armed randomised trial of 320 inactive, healthy, postmenopausal women aged 50–74 years. Participants were randomly assigned to a year-long exercise intervention (225 min/week) or a control group while being asked to maintain a normal diet. Fasting blood samples were obtained and plasma concentrations of two oxidative damage markers (8-hydroxy-2′-deoxyguanosine (8-OHdG) and 8-isoprostaglandin F2α (8-Iso-PGF2α)) and two antioxidant enzymes (superoxide dismutase and catalase) were measured at baseline, 6 months and 12 months. Intention-to-treat (ITT) and per-protocol analyses were performed using linear mixed models adjusted for baseline biomarker concentrations. A further exercise adherence analysis, based on mean minutes of exercise per week, was also performed.ResultsIn the ITT and per-protocol analyses, the exercise intervention did not have any statistically significant effect on either oxidative damage biomarkers or antioxidant enzyme activity.ConclusionsA year-long aerobic exercise intervention did not have a significant impact on oxidative stress in healthy, postmenopausal women.Trial registration numberNCT00522262.

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Energy balance and gastrointestinal cancer: risk, interventions, outcomes and mechanisms

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“…The plasma is distributed into cryotube aliquots of 1 mL and buffy coat in a single 1-mL cryotube; these cryotubes are frozen and stored at −80°C at the center and used for the analyses of oxidative stress and antioxidant biomarkers. Superoxide dismutase, catalase, glutathione peroxidase enzymatic activities, and markers of DNA oxidation (8-hydroxy-2'-deoxyguanosine), prostaglandins oxidation (8-Iso Prostaglandin F 2α ) are measured in the plasma [ 50 ]. Furthermore, levels of circulating growth factors, cytokines, neutrophils, monocytes, and natural killer cells are assessed as previously described [ 51 ].…”