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Title: Influence of exposure regimen on nitrogen dioxide-induced morphological changes in the rat lung

Abstract

Experiments were performed to study the influence of concentration, exposure pattern, and length of exposure on the degree and extent of morphological alterations in the NO/sub 2//sup -/ exposed rat lung. Four weeks of continuous exposure to 20 mg NO/sub 2//m/sup 3/ consecutively revealed damage and loss of cilia, replacement of desquamated type I pneumocytes by type II pneumocytes resulting in a cuboidal epithelial lining, an influx of alveolar macrophages, and hypertrophy and hyperplasia of the bronchiolar epithelium. The animals recovered almost completely from the induced lesions within 8 days. Continuous exposure to 1, 2.5, or 5 mg/m/sup 3/ displayed minimal alterations in the 5 mg/m/sup 3/ group. The effects increased with exposure time. Intermittent or continuous exposure to 20 mg NO/sub 2//m/sup 3/ resulted in minor differences after 4 weeks. The onset of the lesions was delayed and the massive influx of alveolar macrophages in the continuously exposed animals failed to appear in the intermittently exposed animals. This work demonstrates that in subacute experiments: (1) Concentration plays a more important role in inducing pulmonary lesions than exposure time when the product of concentration and time is kept constant. This effect is stronger during intermittent exposure than during continuous exposure.more » (2) Continuous exposure seems to be a more important factor with regard to a macrophage response than intermittent exposure. (3) The rat lung has a large capacity to repair almost completely from damage caused by short-term NO/sub 2/ exposure.« less

Authors:
; ; ;
Publication Date:
Research Org.:
National Institute of Public Health and Environmental Hygiene, Bilthoven, Netherlands
OSTI Identifier:
6905162
Resource Type:
Journal Article
Journal Name:
Environ. Res.; (United States)
Additional Journal Information:
Journal Volume: 41:2
Country of Publication:
United States
Language:
English
Subject:
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.; LUNGS; MORPHOLOGICAL CHANGES; NITROGEN DIOXIDE; TOXICITY; BIOLOGICAL REPAIR; CHRONIC EXPOSURE; DOSE-RESPONSE RELATIONSHIPS; RATS; TIME DEPENDENCE; ANIMALS; BIOLOGICAL RECOVERY; BODY; CHALCOGENIDES; MAMMALS; NITROGEN COMPOUNDS; NITROGEN OXIDES; ORGANS; OXIDES; OXYGEN COMPOUNDS; RECOVERY; REPAIR; RESPIRATORY SYSTEM; RODENTS; VERTEBRATES; 560300* - Chemicals Metabolism & Toxicology

Citation Formats

Rombout, P J.A., Dormans, J A.M.A., Marra, M, and van Esch, G J. Influence of exposure regimen on nitrogen dioxide-induced morphological changes in the rat lung. United States: N. p., 1986. Web. doi:10.1016/S0013-9351(86)80141-4.
Rombout, P J.A., Dormans, J A.M.A., Marra, M, & van Esch, G J. Influence of exposure regimen on nitrogen dioxide-induced morphological changes in the rat lung. United States. https://doi.org/10.1016/S0013-9351(86)80141-4
Rombout, P J.A., Dormans, J A.M.A., Marra, M, and van Esch, G J. 1986. "Influence of exposure regimen on nitrogen dioxide-induced morphological changes in the rat lung". United States. https://doi.org/10.1016/S0013-9351(86)80141-4.
@article{osti_6905162,
title = {Influence of exposure regimen on nitrogen dioxide-induced morphological changes in the rat lung},
author = {Rombout, P J.A. and Dormans, J A.M.A. and Marra, M and van Esch, G J},
abstractNote = {Experiments were performed to study the influence of concentration, exposure pattern, and length of exposure on the degree and extent of morphological alterations in the NO/sub 2//sup -/ exposed rat lung. Four weeks of continuous exposure to 20 mg NO/sub 2//m/sup 3/ consecutively revealed damage and loss of cilia, replacement of desquamated type I pneumocytes by type II pneumocytes resulting in a cuboidal epithelial lining, an influx of alveolar macrophages, and hypertrophy and hyperplasia of the bronchiolar epithelium. The animals recovered almost completely from the induced lesions within 8 days. Continuous exposure to 1, 2.5, or 5 mg/m/sup 3/ displayed minimal alterations in the 5 mg/m/sup 3/ group. The effects increased with exposure time. Intermittent or continuous exposure to 20 mg NO/sub 2//m/sup 3/ resulted in minor differences after 4 weeks. The onset of the lesions was delayed and the massive influx of alveolar macrophages in the continuously exposed animals failed to appear in the intermittently exposed animals. This work demonstrates that in subacute experiments: (1) Concentration plays a more important role in inducing pulmonary lesions than exposure time when the product of concentration and time is kept constant. This effect is stronger during intermittent exposure than during continuous exposure. (2) Continuous exposure seems to be a more important factor with regard to a macrophage response than intermittent exposure. (3) The rat lung has a large capacity to repair almost completely from damage caused by short-term NO/sub 2/ exposure.},
doi = {10.1016/S0013-9351(86)80141-4},
url = {https://www.osti.gov/biblio/6905162}, journal = {Environ. Res.; (United States)},
number = ,
volume = 41:2,
place = {United States},
year = {Mon Dec 01 00:00:00 EST 1986},
month = {Mon Dec 01 00:00:00 EST 1986}
}