title: Ultrastructural alterations of rat lung exposed to pyrolysis products of polytetrafluoroethylene (PTFE, Teflon).
abstract: Ultrastructural changes of the lung tissues were evaluated in rats exposed to the pyrolysis products of Teflon at 380 degrees C., 400 degrees C;, and 450 degrees C., respectively, for 4 hours. At 450 degrees C. Teflon evolved numerous tiny particles (0.02 to 0.04 mum.), which were considered to be the toxic material, and at 550 degrees C., in addition to the tiny particles, large spherical particles (0.7 to 5.0 mum) were found. No particles were observed in the pyrolysis product produced at temperatures between 380 degrees C. and 425 degrees C. There were no clinical symptoms or lung alterations induced at temperatures below 425 degrees C colloidal carbon injected as a marker of increased vascular permeability did not pass through the alveolar capillary endothelium. At 450 degrees C. (approximate lethal temperature) rats revealed severe respiratory difficulty, pulmonary edema, hemorrhage, and necrosis of the tracheobronchial epithelium. The membranous pneumocytes appear to be vulnerable to the Teflon fume causing cytoplasmic swelling, bleb formation, fragmentation, and denudation. Similar changes were found in the endothelial cells, but to a much lesser extent. When Teflon fume generated at 450 degrees CnWAS FILTERED THROUGH A Millipore filter (pore size 0.2 mum.), rats revealed only slight degenerative changes in the superficial tracheobronchial epithelium, but no clinical signs.
mesh_terms: D000818:Animals; D006358:Hot Temperature; D008168:Lung / Q000187:drug effects* / Q000473:pathology; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D011138:Polytetrafluoroethylene / Q000633:toxicity*; D011654:Pulmonary Edema / Q000473:pathology; D051381:Rats
chemical_list: D011138:Polytetrafluoroethylene