Pulmonary lesions in female Harlan Sprague-Dawley rats following two-year oral treatment with dioxin-like compounds.
Toxicol Pathol
; 35(7): 880-9, 2007 Dec.
Article
in En
| MEDLINE
| ID: mdl-18098034
ABSTRACT
Dioxin and dioxin-related compounds have been associated with high incidences of pulmonary dysfunctions and/or cancers in humans. To evaluate the relative potencies of effects of these compounds, the National Toxicology Program completed a series of two-year bioassays which were conducted using female Harlan Sprague-Dawley rats. The rats were treated orally for up to 2 years with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), 3,3',4,4',5-pentachlorobiphenyl (PCB126), 2,3,4,7,8-pentachlorodibenzofuran (PeCDF), and a ternary mixture of TCDD, PCB126 and PeCDF. In addition to treatment-related effects reported in other organs, a variety of pulmonary lesions were observed that were related to exposure. Pulmonary CYP1A1-associated 7-ethoxyresorufin-O-deethylase (EROD) activity was increased in all dosed groups. The most common non-neoplastic lesions, which occurred in all studies, were bronchiolar metaplasia and squamous metaplasia of the alveolar epithelium. Cystic keratinizing epithelioma was the most commonly observed neoplasm which occurred in all studies. A low incidence of squamous cell carcinoma was associated only with PCB126 treatment. Potential mechanisms leading to altered differentiation and/or proliferation of bronchiolar and alveolar epithelia may be through CYP1A1 induction or disruption of retinoid metabolism.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Benzofurans
/
Polychlorinated Biphenyls
/
Polychlorinated Dibenzodioxins
/
Lung
Limits:
Animals
Language:
En
Journal:
Toxicol Pathol
Year:
2007
Document type:
Article
Affiliation country:
Estados Unidos