Polycyclic aromatic hydrocarbon coated onto Fe 2 O 3 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 Fe 2 O 3, benzo(a)pyrene (B(a)P) and pyrene, alone or in association (B(a)P or pyrene coated onto Fe 2 O 3 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, β-carotene). Fe 2 O 3 did not induce any change in L132 cells. In pyrene-treated cells, SOD induction ( P <0.05), glutathione oxidation ( P <0.05) and β-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 β-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 Fe 2 O 3 particles and/or greater availability of polycyclic aromatic hydrocarbons (PAHs). We hypothesized also that Fe 2 O 3 and polycyclic aromatic hydrocarbons are more deleterious by virtue of their associations being able to produce higher oxidative effects than either chemical alone.