[Effect of polychlorinated biphenyls on DNA damage induced by benzo[a]pyrene in HepG2 cells].

Objective: To explore effects of polychlorinated biphenyl, PCB153 on DNA damage induced by benzo(a) pyrene (B[a]P) in HepG2 cells.

Methods: As target cell, HepG2 cells were treated at the concentrations of 0.1, 1, 10 and 100 micromol/L with PCB153 and at the concentrations of 12.5, 25, 50 and 100 micromol/L B[a]P respectively. DMSO was used as solvent control. Single cell gel electrophoresis (SCGE) was applied for quantitative analysis of DNA damage which was caused by treating alone or co-treating with PCB153 and B[a]P, CYP1A1 (EROD) and CYP2B1 (PROD) activities were detected by using fluorescence spectrophotometry.

Results: When compared with the solvent control, the DNA oliver tail moments were increased significantly (P < 0.01) in HepG2 cells treated with all the concentrations of B[a]P, while no significant DNA damage was observed in HepG2 cells treated with all the concentrations of PCB153. When compared with B[a]P treated alone, the DNA oliver tail moments showed a increase tendency in HepG2 cells co-treated with PCB153 (0.1, 1, 10 micromol/L) and B[a]P (50 micromol/L). But DNA oliver tail moments were increased significantly only when co-treated with 10 micromol/L of PCB153 and 50 micromol/L of B[a]P (P <0.01), while decreased significantly after co-exposuring to 100 micromol/L of PCB153 and 50 micromol/L of B[a]P (P <0.01). All concentrations of PCB153 induced significant increase in EROD and PROD activities in HepG2 cells.

Conclusion: It was suggested that the enhancement of DNA damage induced by B[a]P could be associated with the increases of CYP1A1 and CYP2B1 activities induced by PCB153 in HepG2 cells.