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Main Title Epithelial Injury and Interstitial Fibrosis in the Proximal Alveolar Regions of Rats Chronically Exposed to a Simulated Pattern of Urban Ambient Ozone.
Author Chang, L. Y. ; Huang, Y. ; Stockstill, B. L. ; Graham, J. A. ; Grose, E. C. ;
CORP Author Duke Univ. Medical Center, Durham, NC. ;Hospital for Sick Children, Toronto (Ontario).;Health Effects Research Lab., Research Triangle Park, NC. Environmental Toxicology Div.;Southern California Edison Co., Los Angeles.
Publisher c1992
Year Published 1992
Report Number EPA-R-813113; EPA/600/J-94/079;
Stock Number PB94-141462
Additional Subjects Pulmonary alveoli ; Ozone ; Air pollution effects(Animals) ; Epithelium ; Pulmonary fibrosis ; Toxicity ; Electron microscopy ; Animal disease models ; Body weight ; Organ weight ; Vascular endothelium ; Capillaries ; Alveolar macrophages ; Reprints ;
Library Call Number Additional Info Location Last
NTIS  PB94-141462 Some EPA libraries have a fiche copy filed under the call number shown. 07/26/2022
Collation 13p
Electron microscopic morphometry was used to study the development of lung injury during and after chronic (78 weeks) exposure to a pattern of ozone (O3) designed to simulate high urban ambient concentrations that occur in some environments. The daily exposure regimen consisted of a 13-hr background of 0.06 ppm, an exposure peak that rose from 0.06 to 0.25 ppm, and returned to the background level over a 9-hr period, and 2-hr downtime for maintenance. Rats were exposed for 1, 3, 13, and 78 weeks. Additional groups of rats exposed for 13 or 78 weeks were allowed to recover in filtered clean air for 6 or 17 weeks, respectively. Rats exposed to filtered air for the same lengths of time were used as controls. Samples from proximal alveolar regions and terminal bronchioles were obtained by microdissection. The main response of type II epithelial cells was cell proliferation. The accumulation of interstitial matrix after chronic exposure consisted of deposition of both increased amounts of basement membrane and collagen fibers. Interstitial matrix accumulation underwent partial recovery during follow-up periods in air; however, the thickening of the basement membrane did not resolve.