Oxidative stress in the renal medulla

肾髓质的氧化应激

• 批准号: 6656539
• 负责人: THOMAS L PALLONE
• 金额: $ 33.6万
• 依托单位: GEORGETOWN UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-09-01 至 2003-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6656539
• 关键词: NAD(P)H dehydrogenase; angiotensin /renin /aldosterone hypertension; angiotensin II; dopamine receptor; fluorescent dye /probe; isozymes; kidney circulation; laboratory mouse; nitric oxide; nitric oxide synthase; oxidative stress; renal medulla; superoxide dismutase; vasomotion

In addition to their role in countercurrent exchange, descending vasa recta (DVR) are resistance vessels through which blood flow to the renal medulla is supplied. The general hypothesis of this program project grant is that a fundamental mechanism that leads to hypertension is enhanced production of reactive oxygen species (ROS). The general hypothesis to be tested in this subproject is that, during hypertension, increased ROS production in the medulla leads to reduction of nitric oxide (NO) bioavailability and enhanced vasomotor tone of DVR. Preliminary data shows that angiotensin II (AngII) enhances ROS formation in DVR and nephrons and that blockade of ROS formation increase DVR NO formation and blunts vasoconstriction. We will explore our central hypothesis our central hypothesis with the following specific aims. In aim 1 we will test the hypothesis that ROS formation modulates NO generation in outer medullary DVR (OMDVR) isolated from the vascular bundles and outer medullary nephrons isolated from the interbundle region. As an index of NO bioavailability, we will test the effect of AngII induced hypertension on OMDVR vasodilation by acetylcholine. We will also directly measure ROS and NO generation ROS and NO generation by OMDVR and interbundle nephrons using fluorescent probes. In aim 2 we will determine which of the enzymes responsible for ROS and NO generation is modulated during AngII induced hypertension. We will measure NADPH oxidase, eNOS, nNOS and ecSOD expression in OMDVR and nephrons by real time PCR, western blot of outer medullary homogenates, in situ hybridization and immunocytochemistry. We will also test the effect of NADPH oxidase, eNOS and nNOS gene deletion in ROS and NO generation. In aim3, we will test the hypothesis that hypertension is accompanied by a decreased in oxidant defense mechanisms. In aim 3, we will test the hypothesis that hypertension is accompanied by a decreased in oxidant defense mechanisms. We will examine the effects of gene deletion of extracellular superoxide dismutase and the dopamine D5 receptor on ROS generation and NO bioavailability. We will also determine the extent to which the D5 receptor acts through hemeoxygenase.

除了它们在逆流交换中的作用外，降瓦萨直肠（DVR）是电阻容器，提供了流向肾脏髓质的血管。该计划项目授予的一般假设是导致高血压的基本机制是增强活性氧（ROS）的产生。在此次要介绍中要检验的一般假设是，在高血压期间，延髓中的ROS产生增加导致一氧化氮（NO）生物利用度和增强DVR的血管舒缩张力的降低。初步数据表明，血管紧张素II（ANGII）增强了DVR和肾单位中的ROS形成，而ROS形成的阻断会增加DVR无形成，并钝化血管收缩。我们将以以下特定目标探讨我们的中心假设的中心假设。在AIM 1中，我们将检验以下假设：ROS的形成可以调节从髓质束和从束间区域分离的髓质外肾肾脏中分离出的外髓质DVR（OMDVR）中的任何产生。作为无生物利用度的指数，我们将测试ANGII诱导高血压对乙酰胆碱OMDVR血管舒张的影响。我们还将使用荧光探针直接测量ROS，而无需OMDVR和Interbundle肾接发电。在AIM 2中，我们将确定哪种负责ROS的酶，并且在ANGII诱导的高血压期间没有任何产生。我们将通过实时PCR，髓质外匀浆的蛋白质印迹，原位杂交和免疫细胞化学的实时PCR测量OMDVR和Nephrons中的NADPH氧化酶，eNOS，NNOS和ECSOD表达。我们还将测试NADPH氧化酶，eNOS和NNOS基因缺失在ROS和无产生中的作用。在AIM3中，我们将检验以下假设：高血压伴随着氧化剂防御机制的降低。在AIM 3中，我们将检验以下假设：高血压伴随着氧化剂防御机制的降低。我们将研究细胞外超氧化物歧化酶和多巴胺D5受体对ROS产生的基因缺失的影响，无生物利用度。我们还将确定D5受体通过血红素加氧酶作用的程度。