Benzo(a)pyrene-loaded gypsum dust-induced apoptosis of human bronchial epithelial cells through the Ahr signaling pathway

Background Benzo(a)pyrene (BaP) and gypsum dust are the main components of PM2.5. At present, the specific mechanism of apoptosis induced by BaP-loaded gypsum dust has not been studied. Objectives We aimed to evaluate the toxic effects of BaP-loaded gypsum dust on bronchial epithelial cells and explore the molecular mechanism of its induction of apoptosis. Results We found that compared with gypsum group or BaP group, the 16HBE cells exposed to BaP-loaded gypsum dust had a significantly reduced survival rate that showed a concentration dependent trend. The mRNA expression of Ahr, Bax, and Bcl-2 and the protein levels of Ahr, Bax, and Bcl-2 were increased significantly (P < 0.01). However, after geldanamycin pretreatment, the expression of Ahr, Nrf2, Bax, and Bcl-2 (P < 0.01) and protein expression levels of Ahr, Bax and Bcl-2 were decreased significantly (P < 0.01). Conclusions BaP-loaded gypsum dust increases apoptosis of 16HBE cells by reducing the effective dose of BaP. Our results suggest that the mechanism of apoptosis may involve activation of the Ahr signaling pathway.