Effects of exhaustive exercise-induced oxidative stress on red blood cell deformability / 中国应用生理学杂志

<p><b>OBJECTIVE</b>The 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.</p><p><b>METHODS</b>Rats 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.</p><p><b>RESULTS</b>The 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).</p><p><b>CONCLUSION</b>These exercise-induced oxidative injure result in a significant decrease in deformability of rat erythrocytes, which in turn leads to dysfunction in the microcirculatory.</p>

Kinetics of hemoglobin carrying and releasing oxygen / 生理学报

The purpose of the present study was to examine the kinetic process of hemoglobin (Hb) carrying and releasing oxygen. Under the standard conditions (pH 7.4, Po(2) 20 mmHg, 20 °C) the blood samples of chicken, rabbit, frog and carp were equilibrated in oxygen content analyzer with calibrated gas mixture A (0.5% CO(2) and 99.5% N(2)). Then the blood samples were exposed to gas mixture B (21% O(2), 0.5% CO(2) and 78.5% N(2)). After equilibration, the blood samples were exposed to gas mixture A again. During the whole process, Po(2) of blood samples was detected in real-time. The time spent in blood Po(2) changing from 0 to 21 kPa was recorded carefully. The results indicated that the kinetic curve of Hb carrying oxygen presented a shape of "S". It was similar to the Hb oxygen dissociation curve (Hb ODC). Based on the curve, T(50), a new kinetic parameter, was established. T(50) is the time of 50% O(2) saturation of Hb. It can reflect the efficiency of Hb carrying oxygen. Through comparing of T(50), the efficiency of Hb carrying oxygen among 4 species of animals was: frog < carp < rabbit < chicken. In the phase I of Hb carrying and releasing oxygen kinetic curve, the slope in carp was much larger than that in rabbit; the time [(1 411±6) s] of Hb releasing oxygen in chicken was longer than that in other 3 animals. These differences reflected the variety of efficiency of Hb carrying and releasing oxygen. In addition, the kinetic features of Hb carrying oxygen were likely to become an important index to evaluate the function of Hb carrying oxygen, especially in evaluating the ability of artificial blood substitute. On the basis of the analysis of the kinetic curve of Hb carrying oxygen and Hb ODC, another new important efficacy parameter E(50) was proposed. E(50) reflects the relationship between the time of 50% O(2) saturation of Hb and environmental Po(2). E(50) can be used as a synthetic index to assess the efficiency of Hb carrying oxygen.