Effect of antioxidant supplementation on leucocyte expression of reactive oxygen species in athletes.

OBJECTIVE: Previous studies have shown that leucocytes, in particular granulocytes, have an enormous capacity for reactive oxygen species (ROS) production, and that this can be influenced by the physical activity of the individual. Theoretically, endurance-trained athletes could profit by increasing their intake of antioxidants, thus neutralizing increased ROS production. The aim of the present investigation was to study the effect of dietary antioxidant supplementation on leucocyte ROS expression and total plasma antioxidant status (TAS) in endurance-trained athletes over the course of 4 weeks. METHODS: Eighteen athletes were recruited for the study. A randomized, double-blinded, placebo-controlled crossover study of 4 weeks of antioxidant supplementation (BiO-Antioxidant 2.1 (400 mg vitamin C and 180 mg vitamin E d(-1)) and BiO-Quinon Q10 (200 mg d(-1) was performed. Flow cytometry was applied to examine the leucocyte expression of ROS using the ROS-sensitive probes dihydroethidium and dihydrorhodamine 123. The Randox Total Antioxidant Status kit was used to measure the plasma TAS of the athletes. RESULTS: After 4 weeks of antioxidant supplementation, we observed no significant differences in ROS levels in granulocytes and monocytes either basally or after in vitro stimulation with phorbol myristate acetate. Plasma TAS did not change significantly during the intervention period. CONCLUSIONS: We observed no influence of 4 weeks of dietary antioxidant supplementation on oxidative stress status. Based on these findings, there is no rationale advising athletes to ingest antioxidant supplements in addition to their regular diet if that includes daily recommended doses of vitamins.

LeuCAM and reactive oxygen species during long-term exercise combined with sleep and energy deficiency.

INTRODUCTION: During the Norwegian military ranger-training course, cadets are exposed to prolonged physical exercise combined with sleep-, energy-, and food deficiency. The open-window postexercise hypothesis indicates that after hard physical activity, there is an increased risk of contracting infectious diseases. PURPOSE: The purpose of the present study was to determine leukocyte reactive oxygen species (ROS) levels, total antioxidant status (TAS), leukocyte expression of the cell adhesion molecules CD62L and CD11b, and plasma levels of soluble adhesion molecule L-selectin before, during, and in the recovery phase of a military ranger-training course. METHODS: Ten cadets from the Norwegian Military Academy were recruited to the study. Flow cytometry was used to study the intracellular levels of ROS in leukocytes (basally, as well as after in vitro stimulation with phorbol myristate acetate (PMA)), applying the probes dihydroethidium (DHE) and dihydrorhodamine 123 (DHR) and the leukocyte expression of adhesion molecules CD62L and CD11b. ELISA was used to assess the plasma levels of soluble L-selectin, and TAS in plasma was measured using the ABTS+ reduction assay kit. RESULTS: The basal levels of ROS as well as PMA-stimulated ROS in leukocytes declined gradually during the ranger-training course, being lowest on the last day (P < 0.05). The level of TAS increased (P < 0.01) during the course. A striking decrease (P < 0.001) was observed in leukocyte CD62L expression and was sustained even after 3 d of recovery. The leukocyte expression of CD11b remained unchanged. CONCLUSION: The ranger-training course leads to a partial exhaustion of the leukocyte ROS-generating machinery and to a nearly total extinguishing of leukocyte CD62L expression. These changes may support the open-window hypothesis indicating reduced ability to combat microbial invasions before total restitution.

Marathon running leads to partial exhaustion of ROS-generating capacity in leukocytes.

PURPOSE: The aim of the present study was to investigate the changes occurring in leukocyte levels of reactive oxygen species (ROS) and total blood plasma antioxidant capacity (TAS) as a result of a marathon/half-marathon race. METHODS: Fourteen men participating in the Oslo Marathon 2000 and 8 women and 8 men participating in the Oslo Half-Marathon 2001 were recruited to the study. Flow cytometry and the ROS-sensitive probe dihydroethidium (DHE) were used to study the intracellular levels of ROS in circulating leukocytes. Both basal ROS levels as well as the capacity of leukocytes to respond with ROS synthesis upon a defined in vitro stimulus, i.e., phorbol myristate acetate (PMA) was assessed before and immediately after the races. TAS was measured using the ABTS+ reduction assay kit. RESULTS: The basal levels of ROS in leukocytes were either not significantly changed (men, 3-25% reduced) or reduced 33% (women, P < 0.01) as a result of the marathon/half-marathon race. After the marathon race, the capacity of leukocytes to produce ROS upon PMA stimulation was reduced, i.e., 6% (granulocytes) (P < 0.001) and 23% (monocytes) (P < 0.01) residual capacity compared with the prerace situation. A 22-30% reduction (P < 0.05) in monocyte ROS response was seen also as a result of the half-marathon race, whereas the granulocyte ROS response was maintained at the prerace level (19% (women) and 15% (men) reduction, NS)). TAS increased significantly (11-19%, P < 0.05) after both races. CONCLUSIONS: The present results indicate an exhaustion of leukocyte ROS-generating mechanisms after prolonged strenuous exercise. This may partly explain the observation that athletes are more sensitive to attract infectious diseases if exposed to pathogenic micro-organisms during the immediate period after intensive physical activity.