Prevention and Treatment of Chlorine Gas Induced Injury to the Pulmonary System

说明(申请人提供)：氯(C12)是一种中等溶解、高活性的氧化性气体，广泛用于净水、制药和化学品制造以及作为一种有效的消毒剂。暴露在氯气中的人在头6-24小时内可能会出现轻微症状。然而，在这一潜伏期之后，可能会出现以富含蛋白质的浮肿和低氧血症为特征的严重肺损伤。目前，导致这种损伤的细胞和生化事件还没有被阐明。我们认为，C12及其水解产物与一氧化氮(NO)相互作用形成的活性氧氯和氮中间体(RON)启动了自蔓延链式反应，其产物破坏了肺泡上皮细胞，降低了其产生和分泌表面活性物质的能力，并主动转运钠(Na)离子，维持着一种紧密的半渗透屏障。因此，在暴露于C12后不久，全身应用活性物种清除剂(如抗坏血酸、N-乙酰-半胱氨酸(NAC)和去铁胺，以及增加表面活性物质水平、离子转运和细胞旁阻力的药物(如沙丁胺醇(一种长效b-激动剂)和最近发现的一种基于TNFa(TIP肽)凝集素区域的多肽)将减少肺损伤、发病率和死亡率。这一假设将通过暴露大鼠肺泡II型(ATII)上皮细胞融合单层(特异性AIM#1)或大鼠(特异性AIM#2)至C12(50-200ppm，30分钟)来检验，并在暴露后0.5、6、12和24小时测量以下指标：肺功能的生理和生化指标(包括表面活性物质的功能和组成)、肺在体内和体外转运离子的能力、体内明显的肺水肿、大鼠肺泡腔和血浆中的炎性细胞因子水平、动脉血气和pH，以及低活性物种清除剂(抗坏血酸、NAC)，分别于暴露后0.5、6、12、24和48h。在特定的AIM#3中，我们将评估气管内滴注抗坏血酸、抗坏血酸和去铁胺、沙丁胺醇和TIP多肽以及雾化沙丁胺醇在延长C12暴露后呼吸衰竭大鼠存活方面的疗效。这项研究的主题既及时又重要：美国每年生产超过2500万吨氯，其中大部分通过铁路运输，可用作化学武器。

DESCRIPTION (provided by applicant): Chlorine (C12) is a moderately soluble, highly reactive oxidant gas, used extensively for water purification, manufacturing of Pharmaceuticals and chemicals and as a potent disinfectant. Persons exposed to chlorine gas, may experience mild symptoms for the first 6-24 hours (h). However, following this latency period, severe lung injury, characterized by protein-rich edema and the onset of hypoxemia may develop. Presently, the cellular and biochemical events leading to this injury have not been elucidated. We propose that reactive oxygen-chloride and nitrogen intermediates (RONS), formed by the interaction of C12 and its hydrolysis products with nitric oxide (NO), initiate self-propagating chain reactions, the products of which damage alveolar epithelial cells decreasing their ability to produce and secrete surfactant, actively transport sodium (Na+) ions and maintain a tight, semi-permeable barrier. Thus, systemic administration of reactive species scavengers (such as ascorbate, N-acetyl-cysteine (NAC), and deferoxamine, as well as agents that augment surfactant levels, ion transport and paracellular resistance (such as albuterol (a long acting b-agonist) and a recently described peptide based on the lectin region of TNFa (tip peptide), shortly after exposure to C12 will decrease lung injury, morbidity and mortality. This hypothesis will be tested by exposing either confluent monolayers of rat alveolar type II (ATII) epithelial cells (SPECIFIC AIM # 1) or rats (SPECIFIC AIMS #2) to C12 (50-200 ppm for 30 min) and measure the following indices at 0.5, 6, 12 and 24 h post exposure: physiological and biochemical indices of lung function (including surfactant function and composition), ability of the lungs to transport ions in vivo and in vitro and clear pulmonary edema in vivo, levels of inflammatory cytokines in the rat alveolar space and in the plasma, arterial blood gases and pH, as well as levels of low reactive species scavengers (ascorbate, NAC) at 0.5, 6, 12, 24 and 48 h post exposure. These measurements will be repeated following intravenous injections of NAC, ascorbate and deferoxamine as well as albuterol and the tip peptide, every 6 h post exposure for 48 h. In SPECIFIC AIM #3 , we will assess the efficacy of intratracheally instilled ascorbate, NAC, deferoxamine, Infasurf (a surfactant replacement mixture), albuterol and the tip peptide, as well as aerosolized albuterol, in prolonging survival of rats with respiratory failure post C12 exposure. The subject matter of this research is both timely and important: more than 25 million tons of chlorine is manufactured annually in the United States and the majority of this gas is transported by rail and can be used as a chemical weapon.