Objective To study the benzo(a)pyrene(B[a]P)-induced mRNA expression of aromatic hydrocarbon receptor(AHR)and cytochrome P4501A1(CYP1A1)genes in rat liver.Methods Rats were injected intraperitoneally with 5,10 and 15mg/kg of B[a]P.The total RNAs were extracted from rat livers by RNA purification kit,and the mRNA expression of AHR and CYP1A1 genes was determined by reverse transcription polymerase chain reaction(RT-PCR).β-actin was used as the internal control.The mRNA expression of both AHR and CYP1A1 genes was measured at indicated time points(24,48 and 72h)after B[a]P treatment at three different concentrations(5,10 and 15mg/kg).Results The mRNA expression of AHR gene increased in a time-dependent manner at the concentration of 10mg/kg but not at 5 and 15mg/kg of B[a]P.The mRNA expression of CYP1A1 gene differed significantly at 48h and 24h in rat livers treated with 10 and 15mg/kg dosage of B[a]P.The mRNA expression of AHR and CYP1A1 genes increased with B[a]P treatment in a concentration-dependent manner.The time-dependent increase in mRNA expression was shown by AHR but not by CYP1A1 gene with B[a]P(10mg/kg)treatment.Conclusion This study demonstrates that toxic B[a]P increases the mRNA expression of both AHR and CYP1A1 genes in vivo,suggesting that B[a]P may play a role in cancer genesis by this way.
Fu-Hou Chang,Qin Yin,Jun Qi,Min-Jie Wang,Lei Fan,Rui-Lan Han Department of Pharmacology,Inner Mongolia Medical College,Huhhot 010059,China
