Intermittent Hypoxia Prevents Myocardial Mitochondrial Ca2+ Overload and Cell Death during Ischemia/Reperfusion: The Role of Reactive Oxygen Species
Intermittent Hypoxia Prevents Myocardial Mitochondrial Ca2+ Overload and Cell Death during Ischemia/Reperfusion: The Role of Reactive Oxygen Species
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DOI：
10.3390/cells8060564
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发表时间：
2019-06-01
期刊：
影响因子：
6
通讯作者：
Yang, Kun-Ta
中科院分区：
文献类型：
--
作者：
Chang, Jui-Chih;Lien, Chih-Feng;Yang, Kun-Ta
据记载，活性氧（ROS）有助于氧化应激，导致疾病，如缺血性心脏病。近年来，越来越多的证据表明，类似于缺血预处理的短期间歇性缺氧（IH）可产生心脏保护作用。然而，IH诱导的心脏保护作用的潜在机制仍不清楚。本研究的目的是确定IH暴露是否可以增强抗氧化能力，这有助于心肌细胞对氧化应激和缺血/再灌注（I/R）损伤的心脏保护。原代乳鼠心肌细胞培养在IH条件下，振荡O2浓度在20%和5%之间，每30分钟。MTT法进行检查细胞活力。检测Annexin V-FITC和SYTOX绿色荧光强度及caspase 3活性分析细胞死亡情况。获得DCFDA、Fura-2、Rhod-2和TMRM的荧光图像，以分别分析ROS、胞质Ca 2+、线粒体Ca 2+和线粒体膜电位。采用RT-PCR、免疫细胞荧光染色和抗氧化活性测定等方法检测抗氧化酶的表达。结果表明，IH诱导O2-（-.）并保护心肌细胞免受H2 O2和I/R诱导的细胞死亡。此外，IH还能减轻H2 O2诱导的Ca 2+失衡和线粒体膜去极化，从而减轻I/R诱导的Ca 2+超载。此外，IH处理还能提高Cu/Zn SOD和Mn SOD的表达量、总抗氧化能力和过氧化氢酶活性。阻断IH增加的ROS产生可消除IH对Ca 2+稳态和抗氧化防御能力的保护作用。两者合计，我们的研究结果表明，IH保护心肌细胞对H2 O2和I/R诱导的氧化应激和细胞死亡，通过维持Ca 2+稳态以及线粒体膜电位，上调抗氧化酶。
It has been documented that reactive oxygen species (ROS) contribute to oxidative stress, leading to diseases such as ischemic heart disease. Recently, increasing evidence has indicated that short-term intermittent hypoxia (IH), similar to ischemia preconditioning, could yield cardioprotection. However, the underlying mechanism for the IH-induced cardioprotective effect remains unclear. The aim of this study was to determine whether IH exposure can enhance antioxidant capacity, which contributes to cardioprotection against oxidative stress and ischemia/reperfusion (I/R) injury in cardiomyocytes. Primary rat neonatal cardiomyocytes were cultured in IH condition with an oscillating O-2 concentration between 20% and 5% every 30 min. An MTT assay was conducted to examine the cell viability. Annexin V-FITC and SYTOX green fluorescent intensity and caspase 3 activity were detected to analyze the cell death. Fluorescent images for DCFDA, Fura-2, Rhod-2, and TMRM were acquired to analyze the ROS, cytosol Ca2+, mitochondrial Ca2+, and mitochondrial membrane potential, respectively. RT-PCR, immunocytofluorescence staining, and antioxidant activity assay were conducted to detect the expression of antioxidant enzymes. Our results show that IH induced slight increases of O-2(-.) and protected cardiomyocytes against H2O2- and I/R-induced cell death. Moreover, H2O2-induced Ca2+ imbalance and mitochondrial membrane depolarization were attenuated by IH, which also reduced the I/R-induced Ca2+ overload. Furthermore, treatment with IH increased the expression of Cu/Zn SOD and Mn SOD, the total antioxidant capacity, and the activity of catalase. Blockade of the IH-increased ROS production abolished the protective effects of IH on the Ca2+ homeostasis and antioxidant defense capacity. Taken together, our findings suggest that IH protected the cardiomyocytes against H2O2- and I/R-induced oxidative stress and cell death through maintaining Ca2+ homeostasis as well as the mitochondrial membrane potential, and upregulation of antioxidant enzymes.