CELLULAR AND MOLECULAR BASIS OF LUNG TOLERANCE OF OZONE

我们的长期目标是了解细胞和分子基础 肺对臭氧潜在破坏性影响的耐受性(抵抗力)； 特别是，作为第一个方法，要更多地了解 肺对体内臭氧的耐受性。为此，我们提出 三个具体目标：1)继续研究锰的调节 超氧化物歧化酶基因在体内的表达 使大鼠暴露在0.25ppm或更少的臭氧中。更具体地说， 解释最近发现的10倍的差距的基础 肺组织中MnSODm RNA浓度的升高幅度和 0.25ppmO_3对肺组织中MnSOD活性的影响较小。 2)确定肺隆起的机制(S) 细菌对大鼠体内锰超氧化物歧化酶活性的影响 脂多糖(内毒素)。这种内毒素诱导的MnSOD升高 活动与几乎完全防御 否则，在没有可检测到的情况下，会产生水生臭氧浓度 铜、锌超氧化物歧化酶、过氧化氢酶或 谷胱甘肽过氧化物酶。3)鉴定终末细支气管内的细胞 A)其MnSOD基因表达对臭氧的响应 在特定目标1中使用的条件，以及b)参与 内毒素诱导条件下MnSOD基因表达增加 针对特定目标进行研究2.内毒素模型允许我们比较 “不耐受”和“耐受”肺中相同的细胞类型，并确定 如果其MnSOD基因表达对内毒素有反应的细胞 分布在整个肺中，或者以一种方式战略性地定位 这可能有望防止浮肿。为了实现这一目标，我们将使用 MnSODmRNA的原位杂交及其免疫定位 全肺超微结构定量分析。 我们认为，我们的初步数据表明，工作的各个方面都是 可行，并将提供关于主要 大气污染物和在相对被忽视的区域(分子和 抗氧化酶对臭氧的反应的细胞方面)。

Our long range goal is to understand the molecular and cellular basis of lung tolerance (resistance) to the potentially damaging effects of ozone; in particular, as a first approach, to gain more understanding of the lung's tolerance to ozone as it occurs in vivo. Toward this end we offer three specific aims: 1) To continue to study the regulation of manganese superoxide dismutase (MnSOD) gene expression in response to in vivo exposure of rats to 0.25 ppm or less of ozone. More specifically, to elucidate the basis for the recently found 10-fold disparity between the magnitude of the increase in lung concentration of MnSOD mRNA and the smaller increase in lung activity of MnSOD in response to 0.25 ppm O3. 2) To determine the mechanism(s) responsible for the elevation of lung activity of MnSOD induced by treating rats with bacterial lipopolysaccharide (endotoxin). This endotoxin-induced rise in MnSOD activity is associated with virtually complete protection against an otherwise edemogenic concentration of ozone without a detectable elevation in activity of Cu,Zn superoxide dismutase, catalase, or glutathione peroxidase. 3) To identify cells in terminal bronchioles and alveoli a) whose MnSOD gene expression is responsive to ozone under conditions used in specific aim 1, and b) that take part in the endotoxin-induced increase in MnSOD gene expression under conditions studied in specific aim 2. The endotoxin-model allows us to compare the same cell types in "nontolerant" and "tolerant" lungs and to determine if cells whose MnSOD gene expression is responsive to endotoxin are distributed throughout the lung or are strategically located in a manner that might be expected to prevent edema. To achieve this aim we will use in situ hybridization of the mRNA for MnSOD, and immunolocalization of MnSOD, in all quantitative ultrastructural analysis of the intact lung. We believe our preliminary data indicate all aspects of the work are feasible and will provide fundamental new information on a major atmospheric pollutant and in a relatively neglected area (molecular and cellular aspects of antioxidant enzyme response to ozone).