Effects of antioxidant supplementation and exercise training on erythrocyte antioxidant enzymes.
Erythrocytes transport oxygen to tissues and exercise-induced oxidative stress increases erythrocyte damage and turnover. Increased use of antioxidant supplements may alter protective erythrocyte antioxidant mechanisms during training.


OBJECTIVE
To examine the effects of antioxidant supplementation (alpha-lipoic acid and alpha-tocopherol) and/or endurance training on the antioxidant defenses of erythrocytes.


METHODS
Young male Wistar rats were assigned to (1) sedentary; (2) sedentary and antioxidant-supplemented; (3) endurance-trained; or (4) endurance-trained and antioxidant-supplemented groups for 14 weeks. Erythrocyte superoxide dismutase (SOD), glutathione peroxidase (GPX), and catalase (CAT) activities, and plasma malondialdehyde (MDA) were then measured.


RESULTS
Antioxidant supplementation had no significant effect (p > 0.05) on activities of antioxidant enzymes in sedentary animals. Similarly, endurance training alone also had no effect (p > 0.05). GPX (125.9 +/- 2.8 vs. 121.5 +/- 3.0 U x gHb(-1), p < 0.05) and CAT (6.1 +/- 0.2 vs. 5.6 +/- 0.2 U x mgHb(-1), p < 0.05) activities were increased in supplemented trained animals compared to non-supplemented sedentary animals whereas SOD (61.8 +/- 4.3 vs. 52.0 +/- 5.2 U x mgHb(-1), p < 0.05) activity was decreased. Plasma MDA was not different among groups (p > 0.05).


CONCLUSIONS
In a rat model, the combination of exercise training and antioxidant supplementation increased antioxidant enzyme activities (GPX, CAT) compared with each individual intervention.
Marsh
Susan A
SA
School of Human Movement Studies, The University of Queensland, Brisbane, Queensland, Australia, 4072.
Laursen
Paul B
PB
Coombes
Jeff S
JS
D000818:Animals; D000975:Antioxidants / Q000008:administration & dosage*; D002374:Catalase / Q000097:blood*; D019587:Dietary Supplements; D004912:Erythrocytes / Q000187:drug effects / Q000201:enzymology*; D005979:Glutathione Peroxidase / Q000097:blood*; D008297:Male; D010805:Physical Conditioning, Animal / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D013482:Superoxide Dismutase / Q000097:blood; D008063:Thioctic Acid / Q000008:administration & dosage*; D024502:alpha-Tocopherol / Q000008:administration & dosage*
D000975:Antioxidants; D008063:Thioctic Acid; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D024502:alpha-Tocopherol