EFFECTS ON AIRWAY PERMEABILITY AND CYTOSKELETON

大鼠呼吸道上皮细胞中的细胞骨架元素将 被调查为03和N02可能的胞内靶点。在……里面 体外器官维持系统将被用来a)促进对In的控制 体外暴露于03(0.2至0.8 ppm)或N02(0.5至5 ppm)或 细胞骨架活性物质；b)测量这些物质对 渗透性和细胞骨架结构；以及c)比较 与03和N02产生的试剂进行比较，以确定是否 它们的作用机制可能涉及相同或相关的细胞骨架 组件。观察到的影响将与每种气体的量有关。 被气管组织滞留。体外实验将与 选择体内研究，以寻求体外-体内相关性。 初步观察表明，黄连的作用机制 细胞骨架活性药物，如细胞松弛素B，它破坏细胞的稳定 细胞骨架和增加通透性，可能类似于03和 N02，这也增加了渗透性。稳定细胞骨架的药物， 如鬼臼毒素和激动素，可能会拮抗这些气体的影响。 体外器官维护系统允许大鼠受控暴露 气管导管在测量气体滞留量中的作用。经粘膜 将通过应用示踪剂分子(99mTC-DTPA，~3H-葡聚糖， ~(125)I-BSA)对气管粘膜和浆膜表面取样 标签的外观。光镜和电子显微镜下的免疫细胞化学 将被用来表征各种细胞骨架组件及其 与通过紧密连接或内吞小泡的运输有关。 冻结断口将被用于紧密连接的形态测量。 这项研究的目的是确定增加的机制 接触03或N03时的呼吸道上皮通透性。添加了一条 好处可能是验证了体外系统对阿司匹林毒性的测试 气体和气雾剂。这样的系统可以用于人类呼吸道 在体外维护和暴露的组织有助于推断动物数据 在评估人类暴露的风险方面。

Cytoskeletal elements in the airway epithelial cells of the rat will be investigated as the possible intracellular target sites for 03 and N02. In vitro organ maintenance systems will be used to a) facilitate control of in vitro exposure to 03 (0.2 to 0.8 ppm) or N02 (0.5 to 5 ppm) or cytoskeleton-active agents; b) measure the effects of these agents on permeability and cytoskeletal structure; and c) compare effects of the agents with those produced by 03 and N02 in order to determine whether their mechanisms of action may involve the same or related cytoskeletal components. The observed effects will be related to the amount of each gas retained by tracheal tissue. In vitro experiments will be paralleled by selected in vivo studies in order to seek in vitro-in vivo correlations. Preliminary observations suggest that the mechanisms of action of cytoskeleton-active drugs such as cytochalasin B, which destabilizes the cytoskeleton and increases permeability, may be similar to that of 03 and N02, which also increase permeability. Cytoskeleton-stabilizing drugs, such as phalloidin and kinetin, may antagonize the effects of these gases. In vitro organ maintenance systems permit controlled exposure of rat tracheal tubes in measurement of quantity of gas retained. Transmucosal flux will be measured by applying tracer molecules (99mTc-DTPA, 3H-dextran, 125I-BSA) to the tracheal mucosa and sampling at the serosal surface for appearance of label. 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 will be employed in morphometry of tight junctions. The purpose of this study is to identify mechanisms of increased respiratory epithelial permeability upon exposure to 03 or N03. An added benefit may be the validation of an in vitro system for testing toxicity of gasses and aerosols. Such a system might be used for human respiratory tissue maintained and exposed in vitro to aid in extrapolating animal data to man in assessing risk of human exposure.