MECHANISMS OF OXIDANT PRODUCTION IN RESPIRATORY FAILURE

我们以前已经证明，高活性氧是 在肌肉紧张的情况下由横膈膜产生 刺激.此外，在设计用于模拟呼吸的条件下， 在动物模型中失败，有证据表明自由基增加 在横膈膜和血液中。本研究的主要目的是 在以下条件下确定自由基信号的来源： 呼吸衰竭所有的实验都将在井中进行- 大鼠急性呼吸衰竭模型，由 吸气阻力负荷。 我们的具体目标是： 1)为了验证羟基自由基（OH.）产生为 呼吸衰竭的后果。为了实现这一具体目标，我们将 使用新的复杂的细胞内和细胞外自旋捕获 技术和电子自旋共振（ESR）光谱来捕获OH。 和其他激进分子。我们还将定义自由基的动力学 生产过程中的发展失败，并确定是否 与气体交换系统崩溃相关的条件，例如 低氧血症，增强自由基反应。 2)我们将检验急性呼吸衰竭导致 膈肌线粒体功能的改变有利于自由基 生产在这个实验中，我们将测量呼吸能力 从呼吸衰竭的动物中分离线粒体， 线粒体在电子传递过程中产生自由基的能力 运输 3)我们将检验急性心肌梗死后自由基产生的假设， 呼吸衰竭通过非线粒体氧合酶的激活而发生 途径。两个潜在的重要候选人非线粒体自由 自由基的产生是花生四烯酸的环氧合酶途径 代谢和超氧化物产生的黄嘌呤氧化酶途径。在 为了达到这个目的，我们将阻断这些酶系统，并观察对 自由基的产生。 我们的长期目标是确定相关的细胞机制 潜在的呼吸衰竭，特别是膈肌的丧失 收缩功能，这往往与它有关。此外，我们 希望最终了解自由基在肌肉功能中的作用 并确定过量的自由基 生产，肌肉疲劳和收缩状态。

We have previously demonstrated that highly reactive oxygen species are generated by the diaphragm during conditions of intense muscle stimulation. Furthermore, in conditions designed to simulate respiratory failure in an animal model, there is evidence of increased free radicals in the diaphragm and in the blood. The primary purpose of this study is to determine the source of the free radical signals in conditions of respiratory failure. All experiments will be carried out in a well- developed model of acute respiratory failure in the rat, induced by inspiratory resistive loading. Our specific aims are: 1) To test the hypotheses that hydroxyl radical (OH.) is produced as a consequence of respiratory failure. To address this specific aim, we will use new sophisticated intracellular and extra cellular spin trapping techniques and electron spin resonance (ESR) spectroscopy to capture OH. and other radicals. We will also define the kinetics of free radical production during the process of developing failure and determine if conditions related to collapse of the gas exchange system, such as hypoxemia, potentiate the free radical response. 2) We will test the hypothesis that acute respiratory failure causes alterations in diaphragm mitochondrial function which favor free radical production. In this experiment, we will measure the respiratory capacity of isolated mitochondria from animals in respiratory failure and determine the capacity of the mitochondria to generate free radicals during electron transport. 3) We will test the hypothesis that free radical production in acute respiratory failure occurs via activation of non-mitochondrial oxygenase pathways. Two potentially important candidates for non-mitochondrial free radical production are the cyclooxygenase pathway of arachidonic acid metabolism and the xanthine oxidase pathway of superoxide production. In this aim, we will block these enzyme systems and observe the effect on free radical production. Our long term objectives are to identify the relevant cellular mechanisms underlying respiratory failure and, in particular, the loss of diaphragm contractile function which is often associated with it. Furthermore, we hope to eventually understand the role of free radicals in muscle function and determine if there is a direct link between excess free radical production, muscle fatigue and contractile state.