Nitric Oxide Transport Mechanisms: Model and Experiments

描述（由申请人提供）：本研究的总体目标是提高我们对血液和组织中一氧化氮（NO）、血红蛋白、氧气、二氧化碳和硫醇之间复杂相互作用的理解。近年来，关于血液中NO的产生和运输以及可能影响这些过程的各种因素提出了许多假设，但对NO的真正作用和运输机制仍然存在分歧。几个具体的问题仍然存在(1)细胞内钙、氧、剪切应力和硫醇水平的复杂相互作用如何影响内皮细胞产生并传递到组织的NO的数量？(2)亚硝基硫醇或亚硝基血红蛋白（SNO-I-Ib）是否作为一种便利的载体机制，将NO储存并运送到需要它的地方？(3)数学建模是否有助于确定NO最可能的转运机制？本研究旨在通过结合体内、体外实验研究和数学建模来回答这些问题。实验研究旨在为数学建模提供重要信息，并将用于测试模型有效性和评估一氧化氮转运的假设机制。体外研究将在平行板流室中进行，使用大鼠内皮细胞。使用神经体液介质刺激一氧化氮释放，并在基础条件下测量。附加条件，包括改变氧气和二氧化碳水平，各种水平的剪切应力和添加硫醇将被施加。体内研究将在大鼠肠系膜的小动脉和小静脉中进行。在正常生理条件下，在缺氧和高碳酸血症期间，以及在硫醇、剪切应力和红细胞压积水平改变的情况下，将测量NO水平。这些干预措施对一氧化氮生产、运输和分配的影响将被测量，纳入数学模型，并用于测试其在各种条件下的有效性。该数学模型将模拟一氧化氮在微循环和组织中的产生、质量运输、反馈调节和生化作用机制。从验证模型中获得的定量数据将用于预测体内无法测量的参数，分析假设并进一步了解NO的产生和运输机制，并用于塑造未来的实验研究。了解一氧化氮转运机制在临床上很重要，因为一氧化氮调节的改变与病理生理条件有关

DESCRIPTION (provided by applicant): The general goal of the proposed research is to improve our understanding of the complex interaction between nitric oxide (NO), hemoglobin, oxygen, carbon dioxide, and thiols in the blood and tissue In recent years, many hypotheses have been suggested regarding the production and transport of NO in the blood and various factors that may affect these processes However, disagreement still exists over the true mechanisms of action and transport of NO. Several specific questions remain (1) How do the complex interactions of intracellular calcium, oxygen, shear stress, and thiol levels affect the amount of NO produced by the endothelium and delivered to tissue? (2) Do nitrosothiols or nitrosylhemoglobin (SNO-I-Ib) act as a facilitated carrier mechanism by storing NO and transporting it to areas where it is needed? (3) Can mathematical modeling assist in determining the most probable transport mechanisms for NO? The proposed research seeks to answer these questions using a combination of in vitro and in vivo experimental studies and mathematical modeling Experimental studies have been designed to provide vital information for the mathematical modeling and will be used to test model validity and evaluate hypothesized mechanisms of NO transport In vitro studies will be conducted in a parallel-plate flow chamber using rat endothelial cells. Nitric oxide release will be stimulated using neurohumoral mediators and measured under basal conditions. Additional conditions, including altered oxygen and carbon dioxide levels, various levels of shear stress and addition of thiols will be imposed. In vivo studies will be conducted in the arterioles and venules of the rat mesentery. NO levels will be measured under normal physiological conditions, during hypoxia and hypercapnia and under altered thiol, shear stress and hematocrit levels. The effects of these interventions on NO production, transport, and distribution will be measured, incorporated into the mathematical model, and used to test its validity under various ranges of conditions. The mathematical model will simulate the production, mass transport, feedback regulation, and biochemical mechanisms of action of NO in the microcirculation and tissue. Quantitative data obtained from the validated model will be used to predict parameters that cannot be measured in vivo, analyze the hypotheses and further the understanding of NO production and transport mechanisms, and used to shape future experimental studies. Understanding NO transport mechanisms is important clinically since altered NO regulation has been implicated in pathophysiological conditions