Pulmonary toxicity of 1,1-dichloroethylene: correlation of early changes with covalent binding.
Administration of a single intraperitoneal dose of 1,1-dichloroethylene (125 mg/kg, 1,1-DCE) to mice resulted in bronchiolar injury with selective necrosis of Clara cells. Degenerative changes were manifest in Clara cells as early as 1 h following 1,1-DCE exposure, and were characterized by marked swelling of mitochondria and aggregation of chromatin against the nuclear membrane. Cell death was apparent at 2 h; by 8 h, areas of the bronchiolar epithelium were devoid of lining cells, and at 24 h, the majority of Clara cells were exfoliated. The residual epithelium consisted of flattened cells which formed a thin lining for the airway. Necrosis of Clara cells early in the course of 1,1-DCE exposure coincided with peak covalent binding of [14C]1,1-DCE and significant depression of components of the pulmonary mixed-function oxidase system; cytochrome P-450 and aryl hydrocarbon hydroxylase activity were markedly reduced but not depleted. Liver damage involving centrilobular hepatocytes was observed at 24 h in 30% of treated animals, and coincided with significant inhibition of aryl hydrocarbon hydroxylase activity; cytochrome P-450 content, however, remained unchanged. While changes in the liver evoked by 1,1-DCE were less striking, the results in lung demonstrate positive temporal correlations between structural damage, peak covalent binding and disturbances of monooxygenase enzymes.
Forkert
P G
PG
Stringer
V
V
Troughton
K M
KM
D000818:Animals; D001189:Aryl Hydrocarbon Hydroxylases / Q000378:metabolism; D002250:Carbon Radioisotopes; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D004000:Dichloroethylenes / Q000378:metabolism / Q000633:toxicity*; D004848:Epithelium / Q000648:ultrastructure; D006843:Hydrocarbons, Chlorinated / Q000633:toxicity*; D008099:Liver / Q000187:drug effects / Q000473:pathology; D008168:Lung / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*; D008297:Male; D051379:Mice; D008854:Microscopy, Electron; D008861:Microsomes / Q000378:metabolism; D008862:Microsomes, Liver / Q000378:metabolism; D014018:Tissue Distribution
D002250:Carbon Radioisotopes; D004000:Dichloroethylenes; D006843:Hydrocarbons, Chlorinated; D003577:Cytochrome P-450 Enzyme System; D001189:Aryl Hydrocarbon Hydroxylases; C035384:1,2-dichloroethylene