Distal airway remodeling in rats chronically exposed to ozone
The morphologic changes in the centriacinar region of lungs from 14 rats exposed to either filtered air (8) or 0.95 ppm ozone (6) 8 hours daily for 90 days were examined morphologically and morphometrically. Rats were killed with an overdose of sodium pentobarbital administered intraperitoneally, the trachea cannulated, and thoracic viscera and lungs removed from the chest. Lungs were fixed via intratracheal instillation of a paraformaldehyde/glutaraldehyde cacodylate buffered fixative at 30 cm water pressure. Lung volumes were determined by weight displacement and the left lung lobe was sectioned transversely into 12 slabs. Three slabs from the cranial, middle, and caudal thirds of the lobe were embedded in paraffin and studied by light microscopy. With these sections, we estimated the volume of proximal bronchiole, terminal bronchiole, respiratory bronchiole, and combined alveolar duct/sac within the lung. Bronchioles dissected from preselected regions of the right middle lobe were studied by transmission electron microscopy. Dissected terminal airways were sectioned in a longitudinal plane through their midlumen. From these dissected airways, 4 subregions of the centriacinus were then examined: (1) terminal bronchiole, (2) respiratory bronchiole, (3) centriacinar alveolar duct wall, and (4) centriacinar alveolar septa. The results of this study showed that after chronic ozone exposure, there was a 13 to 21% decrease in terminal bronchiole luminal diameter but no significant change in total terminal bronchiole volume. Analysis of measured volume and diameter changes in the terminal bronchiole, coupled with volume increases in respiratory bronchiole, support the conclusion that respiratory bronchiole (RB) is formed from the centriacinar alveolar duct.
- Research Organization:
- Univ. of California, Davis (USA)
- OSTI ID:
- 7024748
- Journal Information:
- Am. Rev. Respir. Dis.; (United States), Journal Name: Am. Rev. Respir. Dis.; (United States) Vol. 137:4; ISSN ARDSB
- Country of Publication:
- United States
- Language:
- English
Similar Records
A comparison of terminal airway remodeling in chronic daily versus episodic ozone exposure
Centriacinar alterations in lungs of cats chronically exposed to diesel exhaust
Related Subjects
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMALS
BODY
BRONCHI
CHRONIC EXPOSURE
ELECTRON MICROSCOPY
LUNGS
MAMMALS
MICROSCOPY
MORPHOLOGICAL CHANGES
ORGANS
OZONE
RATS
RESPIRATORY SYSTEM
RODENTS
TOXICITY
TRANSMISSION ELECTRON MICROSCOPY
VERTEBRATES