(A) Nuclear extracts from Nrf2^+/+ and Nrf2^–/– MEFs were assayed for NF-κB DNA-binding activity by EMSA 30 minutes after LPS (0.5 μg/ml) and or TNF-α (10 ng/ml). The major NF-κB bands contained p65 and p55 subunits, as determined by the supershift analysis using p65 and p55 antibody. (B) Quantification of NF-κB DNA-binding was performed by densitometric analysis. All values are mean α SEM (n = 3) and are represented relative to respective vehicle control. (C) NF-κB–mediated reporter activity in MEFs of both genotypes challenged with LPS (0.5 μg/ml) and TNF-α (10 ng/ml). At 24 hours after transfection with p–NF-κB–Luc vector, cells were treated with LPS and/or TNF-α for 3 hours, and then luciferase activity was measured. Data are mean α SEM from 3 independent experiments (n = 3) and are represented relative to respective vehicle control. (D) Immunoblot of IκB-α and p–IκB-α protein in Nrf2^+/+ and Nrf2^–/– MEFs after LPS (0.5 μg/ml) or TNF-α (10 ng/ml) stimulus. (E and F) Quantification of IκB-α (E) and p–IκB-α (F) protein in Nrf2^+/+ and Nrf2^–/– MEFs by densitometric analysis. Data are mean α SEM (n = 3) and are shown as relative to respective vehicle control. (G) IKK activity in Nrf2^+/+ and Nrf2^–/– MEFs after LPS (0.5 μg/ml) or TNF-α (10 ng/ml) stimulus. (H) Quantification of IKK activity in Nrf2^+/+ and Nrf2^–/– MEFs by densitometric analysis. Densitometric units are normalized to IKKα. Data are mean α SEM (n = 3) and are relative to respective controls. *Differs from vehicle control of the same genotype. ^†Differs frowild-type treatment group. P < 0.05.