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Author Harkema, J. R. ♦ Hotchkiss, J. A. ♦ Griffith, W. C.
Sponsorship USDOE
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword BIOLOGY AND MEDICINE, APPLIED STUDIES ♦ BIOLOGICAL EFFECTS ♦ OZONE ♦ ELECTRON MICROSCOPY ♦ EPITHELIUM ♦ RATS ♦ RESPIRATORY SYSTEM DISEASES ♦ RESPIRATORY TRACT CELLS
Abstract The present study was designed to examine the effects of long-term ozone exposure on nasal epithelia and intraepithelial mucosubstances (IM) throughout the nasal airways of F344/N rats. Animals were exposed to 0 (controls). 0. 12. 0.5, or 1.0 ppm ozone. 6 h/day, 5 days/wk. for 20 mo. Rats were killed 1 wk after the end of the exposure. and nasal tissues were processed for light and electron microscopy. Standard morphometric techniques were used to determine epithelial cell densities and the amounts of IM in the surface epithelium lining the nasal airways. No mucous cells or IM were present in the epithelia lining the nasal lateral meatus and maxillary sinus of rats exposed to 0 or 0.12 ppm ozone. In contrast, rats exposed to 0.5 or 1.0 ppm ozone had marked mucous cell metaplasia (MCM) with numerous mucous cells and conspicuous amounts of IM in the surface epithelium lining these upper airways. Ozone-induced increases in total epithelial cells (i.e., epithelial hyperplasia) were present only in rats exposed to 1.0 ppm. The results of this study indicate that rats chronically exposed to 1.0 or 0.5 ppm, but not 0. 121 ppm. ozone can develop marked MCM with significant increases in IM in both proximal and distal nasal airways. The epithelial chances observed throughout the nasal passages of ozone-exposed rats may be adaptive responses in an attempt to protect the upper and lower respiratory tract from further ozone-induced injury.
ISSN 10441549
Educational Use Research
Learning Resource Type Article
Publisher Date 1997-12-31
Publisher Place United States
Journal American Journal of Respiratory Cell and Molecular Biology
Volume Number 16


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