Abstract:

 OBJECTIVE: To explore the dose- and time-dependent effect on cell cycle of human bronchial epithelial cells (16HBE) and epithelioid lung fibroblasts cells (W138) exposed to benzo[a]pyrene. METHODS：The untreated group of 16HBE and W138 cells were used as negative control group and the dimethyl sulfoxide (DMSO) group as solvent control. 16HBE and W138 cells were exposed to different concentrations of BaP (1，2，4，8，16 and 32 μmol/L) for 24 hours. 16HBE and W138 cells exposed to 16 μmol/L BaP were collected at different time points (0，1，2，4，8，12 and 24 h).  16HBE and W138 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 assess the cell cycle. RESULTS：Compared with the negative control group，the proportion of S phase cells was significantly increased as BaP exposure dose and time increased (P<0.05). With the extension of recovery time 2-12 h (with normol cell culture condition)，the proportion of S phase 16HBE cells increased (P<0.05) compared with negative group (32.43%). At 24 h of recovery time the proportion of S phase (24.52%) showed no significance (P>0.05) compared with negative group (26.41%). The proportion of S phase W138 cells with the extension of recovery time 0-4 h increased (P<0.05)，compared with negative group (32.42%). The proportion of S phase cells decreasd at 8 h of recovery time with no significance between the negative group (32.42%) and recovery 24h group (32.89%).  CONCLUSION：BaP exposure could lead to 16HBE and W138 cell cycle arrested in S phase，but G1 and G2 did not change significantly.

Key words: benzo (a)pyrene, human bronchial epithelial cells, epithelioid lung fibroblasts cells, cell cycle