Mitochondrial Ca2+ flux and respiratory enzyme activity decline are early events in cardiomyocyte response to H2O2
Mitochondrial Ca2+ flux and respiratory enzyme activity decline are early events in cardiomyocyte response to H2O2
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DOI：
10.1016/j.yjmcc.2004.04.001
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发表时间：
2004-07-01
影响因子：
5
通讯作者：
Marín-García, J
中科院分区：
文献类型：
--
作者：
Long, XL;Goldenthal, MJ;Marín-García, J
氧化应激参与线粒体凋亡，在缺血性心脏病和心力衰竭中起关键作用。心肌细胞暴露于H2O2导致氧化应激和线粒体功能障碍。在这项研究中，我们调查的时间顺序的心肌细胞反应H2O2处理的心肌相关事件。在时间范围从10到90分钟后H2O2处理，呼吸复合物I，II，IV和V，和柠檬酸合酶活性，线粒体Ca2+通量，细胞内氧化，线粒体膜电位和凋亡进展的水平进行了测定。复合物II和IV的活性水平显着降低20分钟内H2O2暴露，而复合物I和V，柠檬酸合酶不受影响。H2 O2暴露20和60分钟后，线粒体膜电位下降，同时细胞内氧化，复合物I活性下降和凋亡进展仅在60分钟后检测到。（[Ca2+]（m））检测到[Ca2+]（m）的早期积累发生在5至10分钟之间。用钌红或环孢菌素A预处理心肌细胞可消除H2 O2诱导的复合物II和IV活性下降，表明[Ca2+]（m）通量和线粒体渗透性转换孔开放的开始可能先于观察到的早期酶下降。我们的研究结果表明，[Ca2+]（m）流量代表了H2O2心肌细胞损伤的早期关键事件，之前可能导致线粒体呼吸活性水平降低，随后细胞内氧化积累，线粒体膜去极化和凋亡进展伴随着复合物I活性下降。(C)2004爱思唯尔有限公司保留所有权利。
Oxidative stress is involved in mitochondrial apoptosis, and plays a critical role in ischemic heart disease and cardiac failure. Exposure of cardiomyocytes to H2O2 leads to oxidative stress and mitochondrial dysfunction. In this study, we investigated the temporal order of mitochondrial-related events in the neonatal rat cardiomyocyte response to H2O2 treatment. At times ranging from 10 to 90 min after H2O2 treatment, levels were determined for respiratory complexes I, II, IV and V, and citrate synthase activities, mitochondrial Ca2+ flux, intracellular oxidation, mitochondrial membrane potential and apoptotic progression. Complexes II and IV activity levels were significantly reduced within 20 min of H2O2 exposure while complexes I and V, and citrate synthase were unaffected. Mitochondrial membrane potential declined after 20 and 60 min of H2O2 exposure while intracellular oxidation, declining complex I activity and apoptotic progression were detectable only after 60 min. Measurement of mitochondrial Ca ([Ca2+](m)) using rhodamine 2 detected an early accumulation of [Ca2+](m) occurring between 5 and 10 min. Pretreatment of cardiomyocytes with either ruthenium red or cyclosporin A abrogated the H2O2-induced decline in complexes II and IV activities, indicating that [Ca2+](m) flux and onset of mitochondrial permeability transition pore opening likely precede the observed early enzymatic decline. Our findings suggest that [Ca2+](m) flux represents an early pivotal event in H2O2 cardiomyocyte damage, preceding and presumably leading to reduced mitochondrial respiratory activity levels followed by accumulation of intracellular oxidation, mitochondrial membrane depolarization and apoptotic progression concomitant with declining complex I activity. (C) 2004 Elsevier Ltd. All rights reserved.