Evidence that erythrocytes are highly susceptible to exercise oxidative stress:: FT-IR spectrometric studies at the molecular level

We tested the hypothesis that usual exercise oxidative stress strongly affects erythrocytes viability. A 120-min physical exercise with progressive intensity was used as a model of oxidative stress. FT-IR spectrometry was used to determine structural changes in erythrocyte contents (phospholipids, proteins, lactate, and glucose) from blood samples taken every 20 min. Carbonyl formation from amino acid residues (P = 0.03) and hemoglobin unfolding (P = 0.01) could be identified as main protein denaturation markers during oxidative stress. Higher unsaturation level (P = 0.001) in phospholipids fatty acyl chains were also observed while VO2 increased (P < 0.05). The increase in lactacidosis affected primarily hemoglobin unfolding (P = 0.02). Finally, two distinct cellular events occurred during oxidative stress: I - phospholipids peroxidation correlated to VO2, but lactacidosis and hemoconceptration remained secondary factors; 2 - hemoglobin denaturation was mainly observed through unfolding and carbonylation, and lactacidosis and hemoconcentration were important contributing factors. (c) 2005 International Federation for Cell Biology. Published by Elsevier Ltd. All rights reserved.