Investigation of oxidative stress parameters in different lifespan erythrocyte fractions in young untrained men after acute exercise

New Findings
• What is the central question of this study?
What is the influence of a single bout of exercise on the properties of erythrocyte fractions at different ages?

• What is the main finding and its importance?
A single bout of exercise in untrained men induced oxidative stress in erythrocytes and had an influence on antioxidant defense in these cells. Old erythrocytes were more sensitive to oxidative damage than young and middle‐aged cells. Higher levels of glutathione in old erythrocyte fractions did not protect them against oxidative stress. It seems that exercise may promote the removal of old erythrocytes from the circulation.

The objective of this study was to establish the role of exercise‐induced oxidative stress in the erythrocyte fractions [young (YF), middle‐aged (MAF) and old (OF)] of young untrained men after acute exercise. Blood samples were collected before exercise, immediately after and 1 h after exercise. The maximal power generated was 292 ± 27 W, and exercise duration was 8.73 ± 0.9 min. Different optical properties and oxidative stress parameters were found in each erythrocyte fraction. Total thiols in YF and MAF after exercise and after 1 h rest were similar to values before exercise; however, in OF {32.7 ± 9.8 nmol [mg haemoglobin (Hb)]⁻¹} the concentration was lower in comparison to YF [55.5 ± 3.2 nmol (mg Hb)⁻¹] and MAF [56.8 ± 7.7 nmol (mg Hb)⁻¹] and increased 1 h later (P < 0.0002). The glutathione concentration was higher in OF [8.4 ± 0.4 nmol (mg Hb)⁻¹] than in YF [4.5 ± 0.6 nmol (mg Hb)⁻¹] and MAF [4.8 ± 0.5 nmol (mg Hb)⁻¹; P < 0.0002] and did not change after exercise or 1 h later. In OF, the peroxide level was higher after exercise [1.2 ± 0.2 nmol (mg Hb)⁻¹] and 1 h later [1.1 ± 0.2 nmol (mg Hb)⁻¹], when compared with samples before exercise [0.9 ± 0.1 nmol (mg Hb)⁻¹; P < 0.05]. Similar results were observed in YF and MAF. The level of thiobarbituric acid reactive substances (TBARS) was ∼2.5‐fold higher in OF [0.19 ± 0.04 nmol (mg Hb)⁻¹] when compared with YF [0.07 ± 0.01 nmol (mg Hb)⁻¹] and MAF [0.08 ± 0.02 nmol (mg Hb)⁻¹; P < 0.0002] and was increased after exercise, remaining unchanged 1 h later. In YF and MAF, no difference in the level of TBARS was detected after exercise or 1 h later. No difference in membrane fluidity was observed in all fractions. The erythrocyte OF appeared to be more sensitive to cellular oxidative damage.