To observe the alteration in the expression of DNA repair enzymes hOGG1 and hMYHa and the change in 8-OHdG levels in the HBx gene-transfected cells HepG2/HBx and to explore the mechanisms of the HBV-associated hepatocellular carcinoma, the gene-transfected cells HepG2/HBx which stably expressed HBx was established, and the effect of HBx on the cell cycle and proliferation of HepG2 was examined. By using the β-actin as the interior control, real-time polymerase chain reaction （Real-time qPCR） was employed to quantitatively detect the expression of DNA repair enzymes hOGG1 and hMYHα in the HepG2/HBx, the control cells HepG2 and HepG2 transfected with pcDNA3.1 vector （HepG2/pDNA3.1）. The 8-OHdG levels were determined by HPLC/ECD in the established gene-transfected cells HepG2/HBx and the control cells HepG2 and HepG2/pcDNA3.1. Our results showed that the expression of DNA repair enzyme hMYHα in the HepG2/HBx （0.021±0.007） was significantly lower than that of HepG2 （0.099±0.041） （P〈0.05） and HepG2/pDNA3.1 （0.121±0.005） （P〈0.05）. However, the no significant differences existed in the expression of DNA repair enzyme hOGG1 among the three cell strains （P〉0.05）. The 8-OHdG level in the HepG2/HBx was significantly higher than that in HepG2 and HepG2/pcDNA3.1 （P〈0.05）. It is concluded that HBx gene may inhibit the expression of DNA repair enzyme hMYHα mRNA to impair the ability to repair the intracellular DNA oxidative damage, to increase the oxidative DNA-adduct 8-OHdG and to affect the nucleotide excision repair function, thus participate in the occurrence and development of hepatocellular carcinoma.
