Oxygen radical generation of neutrophils: a reason for oxidative stress during marathon running?

Hematological parameters and blood markers that indicate oxidative stress, such as lipid peroxides (LPO), reduced and oxidized glutathione (GSH, GSSG) , superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), were meas ured in 18 marathon runners before, immediately after the race, and after 8 days of rest. In parallel, the oxygen radical generation of neutrophils (P MN) was measured by chemiluminescence in six randomly selected runners. Aft er the race, a 4.4-fold enhanced PMN count and a 1.4-fold increased capacit y to generate oxygen radicals of the PMN (2.20 +/- 0.38 vs. 3.12 +/- 0.69 a rb. unit/10(6) cells) were found. Consequently, a 6.25-fold increased capac ity to generate oxygen radicals of the post-run blood (7.26 +/- 1.3 vs. 45. 40 +/- 10.3 arb. unit/ml blood) was calculated. This points to PMN as an im portant oxygen radical source established in the runners' blood, which coul d contribute to the oxidative stress indicated in the post-run blood by inc reased LPO (11.46 +/- 3.09 vs. 13.09 +/- 3.14 mu mol/l plasma), GSSG (0.038 +/- 0.003 vs. 0.045 +/- 0.005 mmol/l blood) and GSSG/GSH ratio (3.8 +/- 0. 5 vs. 4.1 +/- 0.6%) and by decreased SOD(15.63 +/- 1.78 vs. 14.58 +/- 1.51 10(3)U/mmol Hb) and GSH-Px (485.1 +/- 107.1 vs. 434.9 +/- 101.7 U/mmol Hb). Despite the decline of the oxygen radical source during rest, the oxidativ e stress in the blood did not decrease in all runners. (C) 2000 Elsevier Sc ience B.V. All rights reserved.