Lycopene reversed the intracellular redox imbalance induced by carcinogens in vivo and in vitro. (A, B) The level of 8-OhdG, 4-HNE in mouse skin of the indicated groups (n=3). (C) The DCFH-DA staining was used to detect ROS production in the indicated groups (n=3). (D) The GSH/GSSG ratio in mouse skin of the indicated groups (n=3). (E) The activities of SOD, GR, GPx and CAT in mouse skin of the indicated groups (n=3). (F) Total mRNA was isolated and analyzed to determine the levels of cat, sod1, gpx1, gsr, gclc and gclm expression using real-time qPCR in mouse skin of the indicated groups (n=3). (G) The effect of lycopene on GSH/GSSG ratio in lycopene-pretreated JB6 P+ cells with TPA stimulation (n=3). (H) The effect of lycopene on level of 4-HNE in vitro with TPA stimulation (n=3). (I) The mRNA levels of cat, sod1, gpx1, gsr, gclc and gclm were detected by real-time qPCR in lycopene-pretreated JB6 P+ cells with TPA stimulation (n=3). House-keeping gene gapdh was used as internal control. The data are presented as the mean ± SD. *p < 0.05, **p < 0.01 and ***p < 0.001 (versus DMBA/TPA or TPA).