Nrf2 or Keap1 activators, inhibitors and primary hepatocytes of WT and Nrf2-null mice have been used in some studies focused on the relationship between Nrf2 and CYP2A5 in liver (Abu-Bakar et al., 2004; Lämsä et al., 2010; Shimozono et al., 2013). Furthermore, the expression of Nrf2 can't be inhibited by inhibitors fundamentally (Jnoff et al., 2014), and the primary hepatocytes continuous passage hard. In our experiment, Nrf2 silenced and over-expressed cell models were established successfully by transfected with Nrf2 specific siRNA and pcDNA3-EGFP-C4-Nrf2 in HepG2 cells using liposome-mediated method. The eukaryotic expression vector or siRNA combined with liposome and got into cells by endocytosis to accomplish Nrf2 over expression or silencing transiently. It was observed from Figure 4 that the transfection did not showed statistically significant effect on the cell viability at both time points (24 and 48 h), and Nrf2 mRNA & protein expressions in the Nrf2 silenced and over expressed cell models were found to be declined or improved. Twenty-four hours of time-point was chosen in the current study because longer liposome effect on cells causes heavier hepatocytes
