Protecting effect of vitamin E supplementation on submaximal exercise-induced oxidative stress in sedentary dogs as assessed by erythrocyte membrane fluidity and paraoxonase-1 activity.

Abstract The aim of this placebo-controlled study was to investigate the effects of oral vitamin E supplementation for 10 weeks on exercise-induced oxidative damage in untrained dogs. Eight dogs were randomly assigned to a supplementation ( n =  4) or control ( n =  4) group and underwent two isolated submaximal exercise sessions, 10 weeks apart. Blood was collected during each session to measure erythrocyte membrane fluidity (EMF), paraoxonase-1 (PON1) activity, plasma malondialdehyde (MDA) and vitamin E concentrations. These biomarkers were measured in venous blood samples collected before ( t 0 ), just after ( t , EMF only) and 1 d ( t  + 1 d) and 7 d ( t  + 7 d) after the dogs ran on a treadmill. Prior to vitamin E supplementation, exercise induced a significant decrease in PON1 activity, EMF, vitamin E concentration and a significant increase in MDA concentration at t  + 1 d. After a 10 week vitamin E supplementation period, these exercise-induced changes in PON1 activity, EMF and MDA concentration were still significant in the control group, but not in the supplemented group. These results suggested that vitamin E supplementation had a protective effect on submaximal exercise-induced oxidative damage in sedentary dogs.