Oxidant stress & ascorbic acid processing in diabetes

项目2：糖尿病的氧化应激和抗坏血酸的处理该项目的目标是研究氧化和羰基应激在糖尿病并发症发病机制中的作用。特别是，这个项目(项目2)试图测试这样一个假设，即组织培养和糖尿病大鼠因高糖引起的氧化应激与糖尿病大鼠不同，主要依赖过渡金属和醛糖还原酶。此外，我们假设许多被认为是醛糖还原酶抑制剂、抗糖化药物、生长因子、一氧化氮合酶、PKC和其他抑制剂的药物作为过渡金属螯合剂和/或抗氧化剂在大鼠中具有有益的作用。我们建议使用一种非常强大的探针来测试这些假设，即6-脱氧-6-氟抗坏血酸(F-抗坏血酸)与750 MHz 19F-核磁共振波谱相结合，以评估体内的氧化应激，同时提供第一个关于体内抗坏血酸分解代谢及其受糖尿病调节的生化洞察力。1.确定在低糖和高糖环境下体外形成的F-抗坏血酸降解产物的化学性质和形成机制。2.确定高糖环境如何影响糖尿病并发症细胞中F-抗坏血酸降解的代谢途径；3.确定大鼠和人类糖尿病对抗坏血酸代谢的影响，以及未发现的异常是否可以预测大鼠和DCCT患者糖尿病并发症的发生。使用这种新的方法，我们希望澄清关键问题：为什么大量药物在糖尿病大鼠身上成功，但在人类身上失败，这是由于糖尿病大鼠特有的氧化应激正常化，以及其压倒性的强度，掩盖了糖尿病引起的人类并发症的其他机制。如果得到证实，这一结果将对以大鼠高血糖模型为基础的抗糖尿病疗法的未来发展产生深远影响。

Project #2: OXIDANT STRESS AND ASCORBIC ACID PROCESSING IN DIABETES The objective of the Program Project is to investigate the role of oxidative and carbonyl stress in the pathogenesis of diabetic complications. In particular, this project (Project 2) seeks to test the hypothesis that the oxidative stress resulting from high glucose in tissue culture and the diabetic rat is, in contrast to the diabetic human, primarily transition metal and aldose reductase dependent. Furthermore, we hypothesize many of the drugs thought to act as aldose reductase inhibitors, anti-glycating agents, growth factors, NO synthase, PKC and other inhibitors have beneficial effects in the rat as transition metal chelators and/or antioxidants. We propose to test these hypotheses by using a very powerful probe for assessment of oxidative stress in vivo, i.e 6-deoxy-6- fluoro ascorbic acid (F-ascorbate) in conjunction with 750 MHz 19F- NMR-spectroscopy, while at the same time providing the first biochemical insight into ascorbate catabolism in vivo and its modulation by diabetes. 1. To determine the chemical nature and mechanism of formation of F- ascorbate degradation products formed in vitro in low and high glucose environment. 2: To determine how the metabolic pathways of F-ascorbate degradation in cells implicated in diabetic complications are influenced by high glucose environment, and 3. To determine how diabetes in the rat and the human affects ascorbate processing, and whether uncovered abnormalities predict development of diabetic complications in the rat and DCCT patient. Using this novel approach, we expect to clarify the critical question: Is the reason why a large number of drugs have been successful in the diabetic rat but have failed in the human due to normalization of oxidative stress that is specific to the diabetic rat and of such overwhelming intensity that it masks other mechanisms of diabetes induced complications in the human. If confirmed, this outcome would have a profound effect on the future development of anti-diabetic therapies based on the rat model of hyperglycemia.