No abstract

Polycyclic aromatic hydrocarbons (PAH) are organic compounds found in the contaminated atmosphere of Mexico City, where the PAH present with highest concentration is benzo[ghi]perylene [B[ghi]p]. We recently demonstrated that double-stranded breaks in DNA appear after 3h of exposure, whereas cellular changes and activation of aryl hydrocarbon receptor (AHR) pathway occur after 48h in bronchial cells under exposure to B[ghi]p, these findings have led us to explore if the AHR pathway participates in morphological changes and genotoxic effects due to B[ghi]p in human NL-20 bronchial cells. Cells of the NL-20 human bronchial line were exposed to B[ghi]p in the presence, or absence, of the AHR receptor antagonist, CH-223191. Cell viability was quantified by the MTT assay, which revealed 76 and 66% at 6h and 24h, respectively (p<0.001), regardless of the presence of CH-223191. RT-qPCR showed an increase in the expression of the AHR and CYP1A1 cytochrome genes only after 24h of exposure, and the expression was inhibited by CH-223191. Genotoxicity assays revealed the presence of comets, nuclear buds (NB) and DNA fragmentation in cells exposed to B[ghi]p after 6h and in cells exposed to B[ghi]p plus CH-223191 at 24h. These results verify that B[ghi]p induces morphological and genotoxic effects, and these effects are independent of the AHR pathway.