Ear biopsy weights in Nrf2 WT and KO mice after UVB exposure. (A) Nrf2WT and KO mice were treated with or without a single dose of UVB (300 mJ/cm2). The mice were sacrificed 1 week after UVB irradiation. Ear punches (6 mm in diameter) were taken and weighed. (B) The ratio of the ear punch weight in UVB-treated versus control skin suggested that Nrf2 significantly protected against the UVB-induced increase in ear punch weight (p < 0.05). The data are presented as the mean ± SEM.