In Vivo Detection of Free Radical Generation

本研究的目的是更好地了解自由基参与炎症反应的机制，从分子/细胞生物学到整个动物，最终到人类，并推进自由基介导的疾病过程的基础和临床研究。总体而言，该项目测试了以下假设：1）自由基是糖尿病和炎症复杂发病机制中的致病分子; 2）特定的生化途径参与触发自由基的产生，自由基可能充当与人类疾病相关的炎症反应的介质和/或调节剂。在这项研究中，由内毒素、外毒素、链脲佐菌素、丙酮等引起的体内自由基产生已在炎症、肺炎、糖尿病和酮症等特定疾病状态中显示。 研究成果： （一） 糖尿病和酮症中的自由基中间体。我们已经提供了ESR和免疫自旋捕获数据在体内自由基形成的机制，发生在链脲佐菌素诱导的糖尿病，并有助于脂质过氧化和蛋白质硝化在肝脏和肾脏。研究表明，iNOS参与羟自由基介导的脂质过氧化反应，因为iNOS过度表达与检查的器官中自由基产生增加相关。此外，我们已经表明，丙酮，糖尿病酮症模型的管理，也可以导致蛋白质氧化和脂质过氧化，通过自由基依赖性机制也主要由iNOS过表达驱动。 ii）第二阶段 炎症中的自由基产生。超抗原（SEB）诱导的间质性肺炎（IP）中自由基的产生依赖于黄嘌呤氧化酶、铁和NO的诱导。结论：巨噬细胞毒素、黄嘌呤氧化酶抑制剂、铁螯合剂或诱导型一氧化氮合酶抑制剂可能是间质性肺炎肺泡炎和纤维化的潜在治疗药物 3.金属和有毒化学品产生的自由基。阻燃剂的广泛使用会对环境造成危害，因此确定其毒性机制是有意义的。在所有溴化阻燃剂中，3，3 '，5，5'-四溴双酚A（TBBPA）的产量最大。通过过氧化氢的芬顿反应产生的羟基自由基在体内与DMSO反应产生甲基自由基，该甲基自由基被POBN捕获。这些观察结果表明，TBBPA在大鼠中的肝毒性可能是由于在体内产生的羟基自由基的氧化还原反应涉及TBBPA代谢产物2，6-二溴氢醌及其相应的半醌自由基的结果。

The goal of this study is to better understand the involvement of free radicals in the mechanism of inflammatory responses at all levels from molecular/cellular biology to whole animals and, ultimately, to humans, and to advance both basic and clinical research in free radical-mediated disease processes. Overall this project tested the hypotheses that: 1) free radicals are causative molecules in the complex pathogenesis of diabetes mellitus and inflammation; and 2) specific biochemical pathways are involved in triggering generation of free radicals that may act as mediators and/or modulators of inflammatory reactions associated with human disease. In this study, free radical generation in vivo caused by endotoxin, exotoxin, streptozotocin, acetone and others has been shown in specific disease states of inflammation, pneumonia, diabetes, and ketosis. Research Accomplishments: i) Free Radical Intermediates in Diabetes Mellitus and Ketosis. We have provided ESR and immuno-spin trapping data for in vivo free radical formation as a mechanism that occurs in streptozotocin-induced diabetes and contributes to lipid peroxidation and protein nitration in the liver and kidneys. The studies demonstrated involvement of iNOS in hydroxyl radical-mediated lipid peroxidation since iNOS overexpression correlated with increased free radical production in the organs examined. In addition, we have shown that administration of acetone, a model of ketosis in diabetes, can also lead to protein oxidation and lipid peroxidation through a free radical-dependent mechanism also driven mainly by iNOS overexpression. ii) Free Radical Production in Inflammation. It has been demonstrated that free radical production in superantigen (SEB)-induced interstitial pneumonia (IP) depends on xanthine oxidase, iron and NO induction. It is concluded that macrophage toxicants, xanthine oxidase inhibitors, iron chelators, or inducible nitric oxide synthase inhibitors may be potential therapeutic agents against alveolitis and fibrosis in interstitial pneumonia iii)Free Radical Generation by Metals and Toxic Chemicals. Wide use of flame retardants can pose an environmental hazard so it is of interest to determine the mechanism of their toxicity. Of all the BFRs, 3,3',5,5'-tetrabromobisphenol A (TBBPA) is produced in the largest volume. The hydroxyl radical generated via the Fenton reaction from hydrogen peroxide reacts in vivo with DMSO to give the methyl radical, which is trapped by POBN. These observations suggest that the hepatotoxicity of TBBPA in rats may be due to the in vivo generation of the hydroxyl radical as a result of redox reactions involving the TBBPA metabolite 2,6-dibromohydroquinone and its corresponding semiquinone radical.