Morin C, Zini R, Albengres E, Bertelli A A E, Bertelli A, Tillement J P
Department of Pharmacology, University of Paris XII, France.
Drugs Exp Clin Res. 2003;29(5-6):227-33.
We have previously shown, as have other authors, that trans-resveratrol (E-resveratrol, 3,4,5-trihydroxy-E-stilbene) reduces reactive oxygen species (ROS) generation of mitochondria freshly isolated from healthy rat brains and that it also counteracts the effect of uncouplers (CCCP) on mitochondrial respiration and oxidative phosphorylation. Two main mechanisms have been shown: firstly, a scavenger effect toward O2- and secondly inhibition of complex III ROS generation. We now report on the effects of resveratrol in a pathological model that mimics the ischemia followed by the reperfusion process which may occur in the human brain. Isolated brain mitochondria were submitted first to hypoxia then to reoxygenation. The aim of this study was to determine the extent of mitochondrial damage induced by this experimental model, to demonstrate which mitochondrial functions were altered and to quantify the extent to which they were prevented by resveratrol. Resveratrol was either added to mitochondria freshly isolated from healthy rat brains or was injected by subcutaneous chronically implanted pumps (0.5, 2 and 10 mg/kg/day for 7 days). The rats were then sacrificed and mitochondria were extracted from brains. To evaluate the respective effects of hypoxia and reoxygenation on mitochondrial functions and the relevant effects of resveratrol, this drug was added (first protocol) either before the complete process (i.e., hypoxia and reoxygenation), or after anoxia before reoxygenation. We found that resveratrol prevented alterations of mitochondrial functions. This substance partly counteracted the decrease in respiratory control and the increase in ROS generation. It fully inhibited the alteration of membrane fluidity and the mitochondrial step of the apoptotic process (evidenced by cytochrome c release and membrane potential collapse). The effects of resveratrol were concentration-dependent (in vitro) or dose-dependent (ex vivo, second protocol). They were not significantly different when the drug was added before or after hypoxia, which suggests that in this model, reoxygenation was the most deleterious process and the stage at which resveratrol was most effective.
我们之前与其他作者一样表明，反式白藜芦醇（E - 白藜芦醇，3,4,5 - 三羟基 - E - 芪）可减少从健康大鼠脑新鲜分离的线粒体中活性氧（ROS）的产生，并且它还能抵消解偶联剂（CCCP）对线粒体呼吸和氧化磷酸化的影响。已显示出两种主要机制：第一，对超氧阴离子（O₂⁻）的清除作用；第二，抑制复合物Ⅲ的ROS生成。我们现在报告白藜芦醇在一种模拟人类大脑可能发生的缺血再灌注过程的病理模型中的作用。分离的脑线粒体首先经历缺氧，然后再进行复氧。本研究的目的是确定该实验模型诱导的线粒体损伤程度，证明哪些线粒体功能发生了改变，并量化白藜芦醇预防这些改变的程度。白藜芦醇要么添加到从健康大鼠脑新鲜分离的线粒体中，要么通过皮下长期植入的泵注射（0.5、2和10毫克/千克/天，持续7天）。然后处死大鼠并从脑中提取线粒体。为了评估缺氧和复氧对线粒体功能的各自影响以及白藜芦醇的相关作用，该药物在完整过程（即缺氧和复氧）之前添加（第一种方案），或者在缺氧后复氧前添加。我们发现白藜芦醇可预防线粒体功能的改变。这种物质部分抵消了呼吸控制的降低和ROS生成的增加。它完全抑制了膜流动性的改变和凋亡过程的线粒体步骤（通过细胞色素c释放和膜电位崩溃证明）。白藜芦醇的作用在体外是浓度依赖性的，在体内（第二种方案）是剂量依赖性的。当药物在缺氧之前或之后添加时，其效果没有显著差异，这表明在该模型中，复氧是最有害的过程，也是白藜芦醇最有效的阶段。
