Nrf2 siRNA was designed according to the sequence of human Nrf2 available in GenBank. The sequences of Nrf2 siRNA were; sense: GCUGCUCAGAAUUGCAGAAT (5′–3′), antisense: UUCUGCAAUUCUGAGCAGCTT (5′–3′). The sequences of negative control (NC) siRNA were; sense: UUCUCCGAACGUGUCACGUTT (5′–3′), antisense: ACGUGACACGUUCGGAGAATT (5′–3′). 5 × 104 HepG2 cells were platted in 24-well plate. Twenty-four hours later, 15 pmol Nrf2 siRNA and NC siRNA were, respectively, transfected into the cells with 1.5 μl Lipofectamine 2000. Twenty-four hours after transfection, replace the culture medium to DMEM solution containing 10% FBS and 1 mM LA or ALA. After incubation at 37°C for 24 h, the cells were harvested for GSTA1 mRNA, CYP2A6 mRNA and protein detection.
