Oxidative stress and COPD: the effect of oral antioxidants on skeletal muscle fatigue.
Oxidative stress and COPD: the effect of oral antioxidants on skeletal muscle fatigue.
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DOI：
10.1249/mss.0b013e3182846d7e
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发表时间：
2013-07
影响因子：
4.1
通讯作者：
Richardson RS
中科院分区：
文献类型：
--
作者：
Rossman MJ;Groot HJ;Reese V;Zhao J;Amann M;Richardson RS
氧化应激可能导致慢性阻塞性肺疾病（COPD）患者运动不耐受。本研究旨在确定急性口服抗氧化剂鸡尾酒（AOC：维生素C、E和α -硫辛酸）对COPD患者动态四头肌运动期间骨骼肌功能的影响。10例COPD患者在AOC或安慰剂（PL）后进行膝关节伸肌运动至疲劳和等时试验。运动前后四头肌最大自主收缩（MVCs）和增强抽搐力（Qtw,pot）的变化量化了四头肌疲劳。在PL条件下，等离子体电子顺磁共振（EPR）谱信号与1秒用力呼气量与用力肺活量比（FEV1/FVC）、肺功能障碍指标（r= - 0.61, p=0.02）和MVC力（r= - 0.56, p=0.04）呈负相关。AOC摄入增加了血浆抗坏血酸水平（10.1±2.2 ~ 24.1±3.8 ug/ml, p<0.05），降低了EPR光谱自由基信号曲线下面积（11.6±3.7 ~ 4.8±2.2 AU, p<0.05），但对耐力时间和股四头肌疲劳没有影响。然而，AOC降低EPR光谱信号的能力在基础自由基高（n=5, PL: 19.7±5.8至AOC: 5.8±4.5 AU, p<0.05）的人群中表现突出，而对基础自由基低（n=5, PL: 1.6±0.5至AOC: 3.4±1.1 AU）的人群影响最小。这些数据证明了直接测量的自由基与肺功能障碍之间的关系，以及AOC降低COPD氧化应激的能力。然而，自由基的急性改善似乎并不影响动态四头肌运动的表现。
Oxidative stress may contribute to exercise intolerance in patients with chronic obstructive pulmonary disease (COPD). This study sought to determine the effect of an acute oral antioxidant cocktail (AOC: vitamins C, E, and alpha-lipoic acid) on skeletal muscle function during dynamic quadriceps exercise in COPD. Ten patients with COPD performed knee extensor exercise to exhaustion and isotime trials following either the AOC or placebo (PL). Pre- to post-exercise changes in quadriceps maximal voluntary contractions (MVCs) and potentiated twitch forces (Qtw,pot) quantified quadriceps fatigue. Under PL conditions, the plasma electron paramagnetic resonance (EPR) spectroscopy signal was inversely correlated with the forced expiratory volume in one second to forced vital capacity ratio (FEV1/FVC), an index of lung dysfunction (r=−0.61, p=0.02), and MVC force (r=−0.56, p=0.04). AOC consumption increased plasma ascorbate levels (10.1±2.2 to 24.1±3.8 ug/ml, p<0.05) and attenuated the area under the curve of the EPR spectroscopy free radical signal (11.6±3.7 to 4.8±2.2 AU, p<0.05), but did not alter endurance time or quadriceps fatigue. The ability of the AOC to decrease the EPR spectroscopy signal, however, was prominent in those with high basal free radicals (n=5, PL: 19.7±5.8 to AOC: 5.8±4.5 AU, p<0.05) with minimal effects in those with low levels (n=5, PL: 1.6±0.5 to AOC: 3.4±1.1 AU). These data document a relationship between directly measured free radicals and lung dysfunction, and the ability of the AOC to decrease oxidative stress in COPD. Acute amelioration of free radicals, however, does not appear to impact dynamic quadriceps exercise performance.