[Objective] Effects of co-exposure of Di-(2-ethylhexyl) phthalate and Benzo(a)pyrene on CYP1A1 and CYP3A4 enzyme activities were investigated in HepG2 cells.
[Methods] HepG2 cells were treated with either 64.0 μmol/L B(a)P alone or DEHP alone (62.5,125.0,250.0,500.0,1 000.0 μmol/L) or DEHP at the indicated concentrations plus 64.0 μmol/L B(a)P or dimethyl sulfoxide (DMSO,solvent control,<1 ‰) for 48 h and 72 h.The cell proliferation was evaluated by CCK8 assay.The activities of CYP 1A-associated deethylation of ethoxyresorufin (EROD) and CYP3A-associated ethoxycoumarin-O-deethylation (ECOD) were measured.Expressions of CYP1A1 and CYP3A4 at mRNA and protein were detected by quantitative real time PCR method and Western blot,respectively.
[Results] The cell viability was decreased significantly in all co-exposure of B(a)P and DEHP groups compared with the controls (P<0.01).However,the EROD and ECOD activities significantly increased,when compared with the DEHP alone treated group (P<0.05,P<0.01).Only up-regualtion of CYP1A1 transcriptional levels were observed in all co-exposure of B(a)P and DEHP groups.However,the levels of mRNA and protein expression of CYP3A4 were increased (P<0.01),when compared with the DEHP alone treated group.
[Conclusion] Co-exposure of DEHP at certain concentrations and B(a)P (64.0μmol/L) induced the increases in the EROD and ECOD activities,as well as the CYP1A1 transcriptional level and the CYP3A4 transcriptional and protein levels.
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