Oxidative stress effects on erythrocytes determined by FT-IRspectrometry

Abstract

This study was designed to evaluate changes in erythrocyte contents during endurance moderate intensity exercise, a model of physiological oxidative stress. 16 endurance-trained subjects cycled 2 h at 55% of maximal aerobic capacity and blood was collected every 15 min. Transmission FT-IR spectrometry was used to analyze separately plasma and erythrocyte content changes during oxidative stress. Erythrocyte FT-IR spectra were corrected for hemoconcentration (Hc) before spectral areas integration of main IR absorbances belonging to phospholipids [ν_as(CH₃), ν_as(CH₂), and ν(PO)], proteins [ν(CO) and δ(N–H)], and lactate [ν(C–O)] were used to determine erythrocyte content changes. Changes in ν_as(CH₂) and ν(PO) absorbances while ν_as(CH₃) remained stable showed the magnitude of free radical attacks on phospholipids bilayer. Decrease in ν(CO) and δ(N–H) absorbances while plasma and intracellular lactate, O₂ consumption, and Hc rose were linked to hemoglobin, and possibly spectrin, denaturation. Finally, the synergistic changes found between physiological, plasmatic and erythrocyte parameters showed that FT-IR spectrometry was a sufficiently accurate and sensitive method to determine acute changes in erythrocytes during moderate, physiological, oxidative stress.