OXIDATIVE STRESS AND KIDNEY OXYGEN USAGE

描述(申请人提供)：肾脏氧化应激由超氧化物的主要来源NADPH氧化酶(NOX)和清除超氧化物歧化酶(SOD)的肾内酶之间的平衡决定。肾脏氧化应激通过改变肾脏功能，包括血管收缩、溶质和电解质滞留增加以及肾小管功能障碍，导致系统性高血压的发生。钠的重吸收是肾脏的主要能量需求，在氧化应激过程中，用于钠离子运输的氧气的有效利用会减少。我们建议测试氧化应激对肾脏氧利用的影响，并确定Na+重吸收需要更多氧气的机制(S)。在一系列实验中，我们将在体内测量基因缺失小鼠的单个肾单位功能，并在体外测量PT细胞功能，以确定氧利用障碍的特定部位。在目标1中，我们将通过单基因缺失的小鼠来验证氧的低效利用依赖于NOX和SOD之间的平衡的假说。在目标2中，我们将研究低效利用氧气的机制，重点是近端小管(PT)的Na+重吸收。在一系列体内和体外实验中，我们将评估PT在急性和慢性氧化应激过程中的细胞完整性和功能。我们将检测PT细胞的细胞旁和跨细胞功能。在目标3中，我们将验证这样一个假设，即与血管紧张素II诱导的氧化应激相关的血压升高依赖于腺苷生成的增加和肾小球反馈的增强，从而导致肾血流量减少和肾血管阻力增加。这些研究将提供有关肾脏氧气使用与氧化应激和高血压相关的血管收缩前事件之间关系的新的、有价值的信息。 项目简介：缺血、缺乏有效的氧气输送是急性肾功能衰竭的最常见原因，肾动脉狭窄导致肾缺血是继发性高血压的第二常见原因。这些情况伴随着肾脏内严重的氧化应激。因此，了解肾脏内氧化剂和氧气的相互作用将有助于深入了解这些肾脏疾病的原因。

DESCRIPTION (provided by applicant): Renal oxidative stress is determined by the balance between the primary source of superoxide, NADPH oxidase (NOX) and intrarenal enzymes that scavenge superoxide, superoxide dismutases (SOD). Renal oxidative stress contributes to the development of systemic hypertension by alterations in renal function, including vasoconstriction, increased solute and electrolyte retention and tubular dysfunction. The reabsorption of sodium is the major energy requirement for the kidney and the efficient use of oxygen for Na+ transport is reduced during oxidative stress. We propose to test the effects of oxidative stress on oxygen usage in the kidney and to determine the mechanism(s) by which Na+ reabsorption requires greater oxygen. In a series of experiments measuring in vivo single nephron function in gene deleted mice and in vitro measurements of PT cell function we will identify specific sites of oxygen utilization dysfunction. In aim 1, we will test the hypothesis that the inefficient use of oxygen is dependent on the balance between NOX and SOD, by using single gene deleted mice. In aim 2 we will examine the mechanism of the inefficient use of oxygen, focusing on Na+ reabsorption in the proximal tubule (PT). In a series of both in vivo and in vitro experiments, we will evaluate the cellular integrity and function of the PT during acute and chronic oxidative stress. We will examine paracellular and transcellular function in PT cells. In aim 3 we will test the hypothesis that the increased blood pressure associated with angiotensin II-induced oxidative stress is dependent on increased generation of adenosine and enhancement of tubuloglomerular feedback, leading to decreased renal blood flow and increased renal vascular resistance. These studies should provide new and valuable information on the relationship between oxygen usage in the kidney and the pro-vasoconstriction events associated with oxidative stress and hypertension. Project Narrative: Ischemia, the lack of efficient oxygen delivery is the most common cause of acute renal failure and renal artery stenosis causing renal ischemia is the second most common cause of secondary hypertension. These conditions are accompanied by severe oxidative stress within the kidneys. Therefore, knowledge of the interaction of oxidants and oxygen within the kidney will provide insight into the causes of these renal diseases.