Faculty of Pharmacy, Shahid Beheshti University of Medical Sciences, Vali-e-Asr Ave., Niayesh Junction, P.O. Box: 14155-6153, 19919-53381, Tehran, Iran.
Metallomics. 2013 Jun;5(6):736-44. doi: 10.1039/c3mt00019b.
Depleted uranium (DU) is emerging as an environmental pollutant primarily due to its military applications. Gulf War veterans with embedded DU showed cognitive disorders that suggest that the central nervous system is a target of DU. Recent evidence has suggested that DU could induce oxidative stress and mitochondrial dysfunction in brain tissue. However, the underlying mechanisms of DU toxicity in brain mitochondria are not yet well understood. Brain mitochondria were obtained using differential centrifugation and were incubated with different concentrations (50, 100 and 200 μM) of uranyl acetate (UA) as a soluble salt of U(238) for 1 h. In this research, mitochondrial ROS production, collapse of mitochondrial membrane potential and mitochondrial swelling were examined by flow cytometry following the addition of UA. Meanwhile, mitochondrial sources of ROS formation were determined using specific substrates and inhibitors. Complex II and IV activity and also the extent of lipid peroxidation and glutathione (GSH) oxidation were detected via spectroscopy. Furthermore, we investigated the concentration of ATP and ATP/ADP ratio using luciferase enzyme and cytochrome c release from mitochondria which was detected by ELISA kit. UA caused concentration-dependent elevation of succinate-linked mitochondrial ROS production, lipid peroxidation, GSH oxidation and inhibition of mitochondrial complex II. UA also induced mitochondrial permeability transition, ATP production decrease and increase in cytochrome c release. Pre-treatment with antioxidants significantly inhibited all the above mentioned toxic effects of UA. This study suggests that mitochondrial oxidative stress and impairment of oxidative phosphorylation in brain mitochondria may play a key role in DU neurotoxicity as reported in Gulf War Syndrome.
贫铀（DU）作为一种环境污染物正逐渐显现，主要是由于其在军事上的应用。患有嵌入性贫铀的海湾战争老兵表现出认知障碍，这表明中枢神经系统是贫铀的靶器官。最近的证据表明，贫铀可能会在脑组织中诱导氧化应激和线粒体功能障碍。然而，贫铀对脑线粒体毒性的潜在机制尚不清楚。使用差速离心法获得脑线粒体，并将其与不同浓度（50、100 和 200 μM）的乙酸铀酰（UA）作为 U（238）的可溶性盐孵育 1 小时。在这项研究中，通过流式细胞术检测 UA 加入后线粒体 ROS 产生、线粒体膜电位崩溃和线粒体肿胀。同时，使用特定的底物和抑制剂来确定线粒体 ROS 形成的来源。通过光谱法检测复合物 II 和 IV 的活性以及脂质过氧化和谷胱甘肽（GSH）氧化的程度。此外，我们使用荧光素酶酶和 ELISA 试剂盒检测从线粒体释放的细胞色素 c 来研究 ATP 浓度和 ATP/ADP 比值。UA 导致琥珀酸连接的线粒体 ROS 产生、脂质过氧化、GSH 氧化和线粒体复合物 II 抑制呈浓度依赖性增加。UA 还诱导线粒体通透性转换、ATP 产生减少和细胞色素 c 释放增加。抗氧化剂预处理显著抑制了 UA 的所有上述毒性作用。这项研究表明，脑线粒体中的线粒体氧化应激和氧化磷酸化损伤可能在海湾战争综合征中报道的 DU 神经毒性中起关键作用。
