Postischemic Hyperoxia and Cerebral Energy Metabolism

描述(由申请人提供)： 我们目前感兴趣的领域是脑缺血后再灌注期氧分压的影响。具体地说，我们建议的研究调查氧化应激在再灌注损伤中的作用。我们建议研究高氧(100%O2)和常氧(21%O2)在犬心脏骤停和复苏10分钟临床相关模型后再灌注的差异。我们假设高氧复苏会导致针对关键代谢酶的氧化应激增加，导致酶活性降低和细胞葡萄糖代谢降低。我们将利用核磁共振波谱监测在高氧或常氧复苏的缺血后动物体内[1]-13C-葡萄糖的代谢。为了研究代谢酶活性的变化，我们将重点研究丙酮酸脱氢酶复合体(PDHC)，这是一种催化丙酮酸氧化脱羧为乙酰辅酶A的线粒体酶。我们假设缺血/再灌注后氧化应激增加，并以PDHC为靶点，导致酶活性下降。氧化应激的标志物3-硝基酪氨酸将被用于监测氧化应激对PDHC的靶向。

DESCRIPTION (provided by applicant): Our current area of interest is the effects of oxygen tension during the reperfusion period following cerebral ischemia. Specifically, our proposed research investigates the role of oxidative stress in reperfusion injury. We propose to study the difference between hyperoxic (100% O2) versus normoxic (21% O2) reperfusion following a 10 minute clinically relevant model of canine cardiac arrest and resuscitation. We hypothesize that hyperoxic resuscitation leads to increased oxidative stress which targets key metabolic enzymes, causing decreased enzyme activity and lower cellular glucose metabolism. We will utilize nuclear magnetic resonance spectroscopy to monitor metabolism of [1]-13C-glucose in postischemic animals resuscitated with either hyperoxia or normoxia. To investigate changes in metabolic enzyme activity, we will focus on the pyruvate dehydrogenase complex (PDHC), a mitochondrial enzyme that catalyzes the oxidative decarboxylation of pyruvate to acetyl-coenzyme A. We hypothesize that oxidative stress increases following ischemia/reperfusion and targets the PDHC, causing decreased enzyme activity. 3-nitrotyrosine, a marker of oxidative stress will be implemented to monitor targeting of oxidative stress to the PDHC.