OBJECTIVEThe aim of the present study is to explore the effects of exhaustive exercise-induced oxidative stress on the antioxidant capacity and diformability of rat red blood cells.

METHODSRats were divided into three group (n = 10): sedentary control (C), exhaustive running exercise (ERE) and moderate running exercise (MRE) groups. Animals in the ERE group started treadmill running at a speed of 20 m/min speed with a 5% gradient, and reached a speed of 25 m/min with gradient 15% in 20 min. Running was continued until exhaustion. MRE group rats running at a speed of 20 m/min with a 5% gradient for 40 min. The levels of free thiol in erythrocyte membrane protein, lipidperoxidation levels and membrane protein components were analyzed. The red blood cell deformability of different groups was also observed.

RESULTSThe results showed that red blood cells were damaged by severe oxidative stress and the anti-oxidative capacity decreased significantly under exhaustive exercise conditions. Besides, lipid peroxidation and protein sulfhydryl cross-link based clustering of membrane were found after exhaustive exercise, and polymers high molecular weight (HMW) was formed. The elongation index (EI) was found to decline significantly in the ERE group compared with the C and MRE groups under shear stress (control group, 0.41 +/- 0.01 at 3 Pa and 0.571 +/- 0.008 at 30 Pa; ERE group, 0.314 +/- 0.013 at 3 Pa and 0.534 +/- 0.009 at 30 Pa; P < 0.05 and P < 0.01, respectively).

CONCLUSIONThese exercise-induced oxidative injure result in a significant decrease in deformability of rat erythrocytes, which in turn leads to dysfunction in the microcirculatory.