Polycyclic aromatic hydrocarbon coated onto Fe2O3 particles:: assessment of cellular membrane damage and antioxidant system disruption in human epithelial lung cells (L132) in culture

The aim of this study was to investigate the oxidative effects of Fe2O3, benzo(a)pyrene (B(a)P) and pyrene, alone or in association (B(a)P or pyrene coated onto Fe2O3 particles), in normal human embryonic lung epithelial cells (L132) in culture. We evaluated: (i) membrane integrity, through fatty acid release (stearic acid, oleic acid, linoleic and linolenic acids, homolinolenic acid, arachidonic acid) and malondialdehyde (MDA) production; and (ii) antioxidant status, through enzymatic and non-enzymatic antioxidant defenses (superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR), glutathione status, beta-carotene). Fe2O3 did not induce any change in L132 cells. In pyrene-treated cells, SOD induction (P < 0.05), glutathione oxidation (P < 0.05) and beta-carotene consumption (P < 0.001) may counteract free radicals (FR)-induced damage. However, in B(a)P-incubated cells, SOD inactivation (P ( 0.05), GR increases (P ( 0.05), glutathione oxidation (P ( 0.05) and beta-carotene decreases (P < 0.001) showed high disruption of antioxidants, thereby allowing FR-induced damage (i.e. arachidonic acid release, P < 0.01; MDA production, P(0.01). Our main finding was that both associations caused higher FR-induced damage (i.e. MDA production. P < 0.001; SOD inactivation, P(0.01) than either chemical alone, Several mechanisms could account for this result: enhanced uptake of Fe2O3 particles and/or greater availability of polycyclic aromatic hydrocarbons (PAHs). Wt hypothesized also that Fe2O3 and polycyclic aromatic hydrocarbons are more deleterious by virtue of their associations being able to produce higher oxidative effects than either chemical alone. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.