Ozone-induced lamellar body responses in a rat model for alveolar injury and repair
Exposure of adult rats to 3 ppm ozone for 8 hours results in diffuse alveolar damage with well-defined sequential stages of bronchiolo-alveolar injury and repair. This model is characterized by acute pulmonary edema showing high concentration of lavage fluid protein that is maximally elevated at 24 hours with return to control level at recovery (96 hours). Using techniques that enable optimal preservation of lamellar body ultrastructure, it was demonstrated morphometrically that expansion of the vacuolated lamellar body (LB) compartment is an early, transient LB response of the type II cell to acute injury. This change appears to be initiated by increased LB secretion. The reparative stage, 24-48 hours postexposure, begins with hypertrophy rather than hyperplasia of many type II cells, resulting in a 3-fold increase of mean type II cell volume at 48 hours. During this stage there is also significant expansion of the total LB compartment with corresponding increased LB storage of surfactant disaturated phosphatidylcholine (DSPC) per type II cell. At recovery, 96 hours, the lungs contained twice the normal numbers of type II cells, but the total size of lamellar body compartment per type II cell as well as the DSPC content of the isolated lamellar body pool returned to normal levels. In contrast, accumulating surfactant DSPC in lavage fluid increased progressively throughout the reparative and recovery stages presumably due in part to parallel increase in type II cell numbers at 48 and 96 hours. Additional changes of surfactant included abnormal secretion of densely coiled lamellar bodies that accumulated in alveolar spaces at the expense of tubular myelin.
- Research Organization:
- Univ. of South Florida, Tampa (USA)
- OSTI ID:
- 6834851
- Journal Information:
- Am. J. Pathol.; (United States), Journal Name: Am. J. Pathol.; (United States) Vol. 132:2; ISSN AJPAA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMALS
BIOLOGICAL MODELS
BIOLOGICAL RECOVERY
BIOLOGICAL REPAIR
BODY
ESTERS
LAVAGE
LIPIDS
LUNGS
MAMMALS
MORPHOLOGICAL CHANGES
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
ORGANS
OZONE
PHOSPHOLIPIDS
PROTEINS
RATS
RECOVERY
REPAIR
RESPIRATORY SYSTEM
RODENTS
SECRETION
TOXICITY
ULTRASTRUCTURAL CHANGES
VERTEBRATES