title: Response of fetal rat lung fibroblasts to elevated oxygen concentrations after liposome-mediated augmentation of antioxidant enzymes.
abstract: Cultured fetal rat lung fibroblasts are growth-inhibited and have increased lactate dehydrogenase release and prostaglandin synthesis in response to 50% and 95% oxygen exposure. Extended exposure to 50% oxygen, but not to 95% oxygen, was associated with tolerance to the cytotoxic effects of oxygen. Pretreatment of fibroblasts with liposome-encapsulated superoxide dismutase and catalase also conferred protection against the cytotoxic effects of 50% and 95% oxygen. Exogenous enhancement of intracellular superoxide dismutase and catalase specific activities did not attenuate the growth inhibition or increased prostaglandin synthesis associated with exposure to 50% or 95% oxygen. The growth inhibition could not be attributed to an autocrine prostaglandin effect, since inhibition of prostaglandin synthesis with 50 microM ibuprofen did not prevent O2-mediated inhibition of DNA synthesis.
authors.affiliation: Division of Neonatology, Hospital for Sick Children, Toronto, Ontario, Canada.
authors.forename: A K
authors.initials: AK
authors.lastname: Tanswell
authors.forename: D M
authors.initials: DM
authors.lastname: Olson
authors.forename: B A
authors.initials: BA
authors.lastname: Freeman
mesh_terms: D015121:6-Ketoprostaglandin F1 alpha / Q000096:biosynthesis; D000818:Animals; D002374:Catalase / Q000378:metabolism*; D002455:Cell Division; D002478:Cells, Cultured; D015232:Dinoprostone / Q000096:biosynthesis; D005347:Fibroblasts; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008081:Liposomes; D008168:Lung / Q000166:cytology / Q000196:embryology / Q000378:metabolism*; D010100:Oxygen / Q000494:pharmacology*; D051381:Rats; D013482:Superoxide Dismutase / Q000378:metabolism*
chemical_list: D008081:Liposomes; D015121:6-Ketoprostaglandin F1 alpha; D007770:L-Lactate Dehydrogenase; D002374:Catalase; D013482:Superoxide Dismutase; D015232:Dinoprostone; D010100:Oxygen