MECHANISM OF AIR POLLUTANT INDUCED AIRWAY PERMEABILITY

拟议的研究将调查a）控制气道的机制 渗透性，B）吸入后早期损伤的细胞内位点 大鼠暴露于O3和NO2，和c）阻断或逆转污染物的手段 增加渗透性。 我们实验室的初步研究表明，气管和 吸入后支气管肺泡对大分子的通透性 大鼠暴露于03。 增加的渗透性似乎导致，在 至少部分来自紧密连接的扰动。 基于我们 肌动蛋白和肌球蛋白分布的初步观察 顶端的细胞质和紧密连接的纤毛 上皮细胞，也基于类似的行动， 污染气体和细胞分裂素干扰药物，我们建议， 细胞骨架是污染物可能的细胞内靶位点， 它在调节紧密连接渗透性中起关键作用。 我们还预测了细胞骨架在囊泡运输中的作用， 像其他系统一样。 拟议的研究考虑到 广泛的比较细胞增殖活性药物与污染气体， 可能逆转药物对污染物的影响。 各种 将对指标进行分析，以实现预期目标。 大鼠将暴露于0.2-0.8 ppm O3或5-25 ppm NO2。 治疗与 细胞因子去稳定（秋水仙素和细胞松弛素B）或稳定 （鬼笔环肽和激动素）药物将单独或在 与污染物暴露的结合。 粘膜对 将使用同位素跟踪大分子（摩尔重量469至69，000） 在这个实验室中引入的标记程序大约有两个 几年前，现在已经很成熟了。 分子输运动力学 在不同的实验条件下进行比较。 将采用光镜和电镜免疫细胞化学方法， 表征各种细胞骨架成分及其与 通过紧密连接或内吞囊泡运输。 冷冻断裂 将对复制品进行形态测定分析，以检测紧密的 药物治疗后的连接深度和膜内链，或 污染物暴露。 上皮细胞的表面形态， 细胞膜和细胞间隙的形成， 通过扫描电子显微镜， 显微镜

The proposed study will investigate a) mechanisms which control airway permeability, b) intracellular sites of early injury following inhalation exposure of rats to 03 and N02 and c) means to block or reverse pollutant induced increased permeability. Pilot studies from our laboratory demonstrate an increase in tracheal and bronchoalveolar permeability to macromolecules following inhalation exposure of rats to 03. The increased permeability appears to result, at least in part, from the perturbation of tight junctions. Based on our preliminary observations on the distribution of actin and myosin in the apical cytoplasm and in close vicinity of tight junctions of ciliated epithelial cells and also based on the similarities in the actions of pollutant gases and cytoskeleton-disrupting drugs, we propose that the cytoskeleton is a likely intracellular target site for pollutant and that it plays a critical role in the modulation of tight junction permeability. We also anticipate the role of cytoskeleton in vesicular transport in airways as in other systems. The proposed studies take into account an extensive comparison of cytoskeleton-active drugs with pollutant gases and possible reversal of pollutant effects by the drugs. A variety of indicators will be analyzed to achieve the projected goals. Rats will be exposed to 0.2-0.8 ppm O3 or 5-25 ppm NO2. Treatments with cytoskeleton-destabilizing (colchicine and cytochalasin B) or stabilizing (Phalloidin and kinetin) drugs will be carried out either alone or in combination with pollutant exposures. Changes in mucosal permeabilities to macromolecules (mol wt 469 to 69,000) will be followed using isotope labeling procedures which were introduced in this laboratory about two years ago and are now well established. Kinetics of molecular transport under various experimental conditions will be compared. Immunocytochemistry by light and electron microscopy will be employed to characterize various cytoskeletal components and their relation to transport through tight junctions or endocytic vesicles. Freeze fracture replicas will be analyzed morphometrically to detect fine changes in tight junctional depth and intramembranous strands following drug treatments or pollutant exposures. Surface morphology of epithelial cells, injuries to cell membranes and formation of intercellular spaces resulting from retraction of adjacent cells will be monitored buy scanning electron microscopy.