OXIDATIVE STRESS AND KIDNEY OXYGEN USAGE

描述（由申请人提供）：肾脏氧化应激是由超氧化物的主要来源NADPH氧化酶（NOX）和清除超氧化物、超氧化物歧化酶（SOD）的肾内酶之间的平衡决定的。肾氧化应激通过改变肾功能，包括血管收缩、溶质和电解质潴留增加以及肾小管功能障碍，促进全身性高血压的发生。钠的重吸收是肾脏的主要能量需求，氧化应激降低了氧对Na+运输的有效利用。我们建议测试氧化应激对肾脏氧气使用的影响，并确定Na+重吸收需要更多氧气的机制。在一系列测量基因缺失小鼠体内单肾元功能和体外测量PT细胞功能的实验中，我们将确定氧利用功能障碍的特定位点。在目标1中，我们将通过使用单基因缺失小鼠来验证氧气的低效利用依赖于NOX和SOD之间的平衡这一假设。在目标2中，我们将研究氧气低效利用的机制，重点关注近端小管（PT）中的Na+重吸收。在一系列体内和体外实验中，我们将评估急性和慢性氧化应激下PT的细胞完整性和功能。我们将检查PT细胞的细胞旁和细胞外功能。在目标3中，我们将检验与血管紧张素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小管肾小球反馈的增强，从而导致肾血流量减少和肾血管阻力增加的假设。这些研究应该为肾脏氧气使用与氧化应激和高血压相关的促血管收缩事件之间的关系提供新的和有价值的信息。

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.