Étude de l’effet de la rHuEpo sur le stress oxydant à l’exercice

Summary: Introduction: Erythropoietin (EPO) is known to exert at high concentration antioxidative and antiapoptotic effects. Which is the effect of EPO administration at the usual doses on exercise-induced oxidative stress? Patients and methods: Thirty-six Wistar rats were divided into four groups : C (controls), CE (exhausted), T (treated), TE (treated and exhausted). Groups T and TE were treated by human recombinant Epo (rhuEpo [EPREX®]) at a dose of 50 UI/kg three times a week during 6 weeks. The rats in groups C and CE were treated by saline. After a period of habituation on treadmill, rats of groups CE and TE performed an exercise-test until exhaustion at 25 m/min with a slope of 15 %. We measured NADPH oxidase activity in muscle, red cell antioxidant enzymes (Glutathion peroxydase [GPx] and superoxyde dismutase [SOD]) and markers of plasma lipid peroxydation (malondialdehyde [MDA] and F2 isoprostanes [F2IsoP]). Synthesis of facts: EPO treatment increases hematocrit by 11.9 % (46.2 vs 55.1) without any increase in time of running until exhaustion. Exercise increases muscle NADPH oxidase activity (p =0.0245), increases plasma isoprostanes and red cell GPx activity (p =0.0049) while plasma MDA and red cell SOD are unchanged. The effect of exercise is not modified by rhuEpo. Conclusion: While there is no evidence for an effect of either Epo, or the rise it elicits in O2 transfer, on blood markers of oxidant stress after exhausting exercice in rats, exercise increases the quantity of circulating antioxidant enzymes. [Copyright &y& Elsevier]