Abstract: OBJECTIVE:To explore the correlations of BPDE-DNA adducts and cell cycle in human bronchial epithelial cells (16HBE) exposed to benzo(a)pyrene. METHODS:16HBE cells were exposed to BaP at concentrations of 0, 1, 2, 4, 8, 16 and 32 μmol/L for 24 hours. 16HBE cells exposed to 16 μmol/L BaP were collected at different times points (0, 1, 2, 4, 8, 12 and 24 h), and cells exposed to 16 μmol/L for 4 h were collected after different recovery times (0, 1, 2, 4, 8, 12 and 24 h). Flow cytometry was used to evaluate the cell cycle. BPDE-DNA adducts were evaluated by enzyme linked immunosorbent assay (ELISA) and fluorescent immunohistochemistry method. RESULTS:Compared with the control group, the proportion of S phase cells were significantly increased with increasing concentration and exposure time (P<0.05 or P<0.01). The proportion of S phase cells of 16HBE increased at early recovery (4-12 h), but they underwent a significantly reduction with increasing recovery time. Compared with the normal control (26.41%), there was not a significantly difference at 24 h recovery (24.52%). Compared with the normal control, the levels of BPDE-DNA adducts were significantly elevated with increasing concentration and exposure time (P<0.01). Compared with the recovery a t 0 h, the adducts were significantly inereased at 1 h recovery (P<0.01), and then the level of adducts decreased gradually with increasing recovery time. Regression analysis showed that the proportions of S phase cells and BPDE-DNA adduct levels conformed to the Cubic equation (R²=0.386, P=0.01). CONCLUSION: There was a close correlation between S phase arrest and levels of BPDE-DNA adduct induced by BaP.

Key words: benzo(a)pyrene, cell cycle, BPDE-DNA adduct, human bronchial epithelial cell