Suzuki E, Takahashi Y, Aida S, Kimula Y, Ito Y, Miura T
Department of Clinical Laboratories, University Hospital, University of Tsukuba, Japan.
Toxicology. 1992;71(3):223-32. doi: 10.1016/0300-483x(92)90025-a.
Changes in the surface structure of Clara cells in the terminal bronchioles following exposure of rats to 0.4 ppm ozone (O3) for 14 days were evaluated and compared to the content of pulmonary cytochrome P-450, an enzyme active in xenobiotic metabolism. Exposure to O3 caused a striking alteration of Clara cells in the terminal bronchiole. After 6 h exposure apical protrusions of Clara cells enlarged and these Clara cells formed clusters. However after 24 h exposure, the Clara cells decreased in number and flattened. They increased in number and enlarged again during the subsequent period of exposure. By the 14th day of O3 exposure the number of Clara cells had increased significantly. The content of cytochrome P-450b (IIB1), a main isozyme of pulmonary cytochromes P-450 of rats, was determined by an immuno-blotting method using anti-cytochrome P-450b antibody. The cytochrome P-450b in the rats exposed to O3 increased significantly to 1.37- and 1.81-times that of the control on the 7th and 14th days, respectively. Immuno-electron microscopy demonstrated that cytochrome P-450b was localized abundantly in endoplasmic reticulum of Clara cells. Morphological alterations in Clara cells appear to be closely related with changes in the cytochrome P-450b content of the lung.
评估了大鼠暴露于0.4 ppm臭氧（O₃）14天后终末细支气管中克拉拉细胞表面结构的变化，并与肺细胞色素P - 450（一种在外源生物代谢中具有活性的酶）的含量进行了比较。暴露于O₃导致终末细支气管中的克拉拉细胞发生显著改变。暴露6小时后，克拉拉细胞的顶端突起增大，这些克拉拉细胞形成簇状。然而，暴露24小时后，克拉拉细胞数量减少并变扁平。在随后的暴露期间，它们的数量增加并再次增大。到O₃暴露第14天时，克拉拉细胞的数量显著增加。使用抗细胞色素P - 450b抗体通过免疫印迹法测定大鼠肺细胞色素P - 450主要同工酶细胞色素P - 450b（IIB1）的含量。暴露于O₃的大鼠中的细胞色素P - 450b在第7天和第14天分别显著增加至对照的1.37倍和1.81倍。免疫电子显微镜显示细胞色素P - 450b大量定位于克拉拉细胞的内质网中。克拉拉细胞的形态学改变似乎与肺细胞色素P - 450b含量的变化密切相关。
