Toxic effect of polycyclic aromatic hydrocarbons (PAHs) on co-culture model of human alveolar epithelial cells (A549) and macrophages (THP-1)

Polycyclic aromatic hydrocarbons (PAHs) are particulate matter bound environmental contaminants known to cause adverse effects on human health. The toxicity of carcinogenic PAH such as benzo[a]pyrene (BaP) has been extensively investigated, whereas other PAHs have received less attention. The present work investigated the toxic effects of three less investigated PAHs with distinct molecular weights in comparison to BaP on co-culture model of human epithelial lung cells (A549) and macrophages (THP-1). Due to the involvement of more than one cell type in the response to PAH exposure, the new co-culture model is considered to be suitable for the prediction of undesired toxicological effects of PAHs. To do so, the co-culture was established and exposed to 0–400 µM of phenanthrene (PHE), fluoranthene (FLA), and, benzo [ghi] perylene (BghiP) for 24 h. Subsequently, cytotoxicity, micronucleus formation, and cytokine excretion were analyzed. The results revealed that the viability of A549 cells decreased after being exposed to increasing concentrations of PAHs. The formation of micronuclei in binucleated cells (BNC) was found more frequently in cells treated with PAHs in comparison to the untreated group, indicating the genotoxic effect of these compounds. Moreover, an exposure to PAHs enhanced the pro-inflammatory cytokine, i.e., interleukin-6 secretion, while diminished the anti-inflammatory cytokine, i.e., interleukin-10. In summary, PAHs possess negative effects on A549 and THP-1 co-culture model, implying an adverse effect on human health when coming into contact with these chemicals via respiration.