Reactive oxygen species production in energized cardiac mitochondria during hypoxia/reoxygenation: modulation by nitric oxide.
Reactive oxygen species production in energized cardiac mitochondria during hypoxia/reoxygenation: modulation by nitric oxide.
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DOI：
10.1161/circresaha.108.180869
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发表时间：
2008-10-10
影响因子：
20.1
通讯作者：
Weiss JN
中科院分区：
文献类型：
--
作者：
Korge P;Ping P;Weiss JN
线粒体是缺血/再灌注损伤中活性氧的重要来源。当从缺血心肌中分离时，线粒体表现出由于电子传递复合物的损伤而增加的ROS产生。为了研究其机制，我们研究了缺氧/复氧对离体供能心脏线粒体ROS产生的影响。ROS的产生，跟踪使用Fe 2+催化，H2 O2依赖H2 DCF氧化或Amplex红，是相似的常氧和缺氧，但在复氧过程中显着增加，缺氧的持续时间成比例。相反，如果线粒体迅速从常氧状态转变为接近缺氧状态（[O2]< 1 μM），则在复氧过程中H2 DCF氧化速率的增加明显减弱。为了在复氧期间引起H2 DCF氧化速率的稳健增加，缺氧必须足够严重以引起部分但不完全的呼吸链抑制（如通过膜电位的部分耗散和增加的NADH自发荧光所示）。与其心脏保护作用一致，一氧化氮（·NO）在这些条件下消除了增加的H2 DCF氧化，以及减弱ROS诱导的基质[Fe 2 +]增加和抗霉素引起的乌头酸酶抑制。总的来说，这些结果表明：a）足以引起部分呼吸抑制的缺氧比接近缺氧对线粒体的损伤更大; B）·NO抑制ROS诱导的电子传递复合物的损伤，可能是通过在谷胱甘肽存在下形成·NO-Fe 2+复合物来抑制羟基自由基的形成。
Mitochondria are an important source of reactive oxygen species (ROS) implicated in ischemia/reperfusion injury. When isolated from ischemic myocardium, mitochondria demonstrate increased ROS production as a result of damage to electron transport complexes. To investigate the mechanisms, we studied effects of hypoxia/reoxygenation on ROS production by isolated energized heart mitochondria. ROS production, tracked using Fe2+-catalyzed, H2O2-dependent H2DCF oxidation or Amplex Red, was similar during normoxia and hypoxia, but markedly increased during reoxygenation, in proportion to the duration of hypoxia. In contrast, if mitochondria were rapidly converted from normoxia to near-anoxia ([O2]< 1 μM), the increase in H2DCF oxidation rate during reoxygenation was markedly blunted. To elicit the robust increase in H2DCF oxidation rate during reoxygenation, hypoxia had to be severe enough to cause partial, but not complete, respiratory chain inhibition (as shown by partial dissipation of membrane potential and increased NADH auto-fluorescence). Consistent with its cardioprotective actions, nitric oxide (•NO) abrogated increased H2DCF oxidation under these conditions, as well as attenuating ROS-induced increases in matrix [Fe2+] and aconitase inhibition caused by antimycin. Collectively, these results suggest that a) hypoxia sufficient to cause partial respiratory inhibition is more damaging to mitochondria than near-anoxia; b) •NO suppresses ROS-induced damage to electron transport complexes, probably by forming •NO-Fe2+ complexes in the presence of glutathione which inhibit hydroxyl radical formation.