Nuclear factor erythroid 2-related factor 2 (Nrf2) plays an important role in adipocyte differentiation. (A) Nrf2 knockdown 3T3-L1 and C3H10T1/2 cells were cultured in an adipocyte differentiation medium for seven days. Representative image of Oil Red O staining. Original magnification, ×200. Bar, 100 μm. (B) Oil Red O-positive cells were counted. Data are expressed as the mean ± SD (n = 4). * p < 0.05. (C) 3T3-L1 and C3H10T1/2 cells were cultured in an adipocyte differentiation medium with or without omaveloxolone (Omav, a Nrf2 activator) (50 nM) for seven days. Representative image of Oil Red O staining. Original magnification, ×200. Bar, 100 μm. (D) Oil Red O-positive cells were counted. Data are expressed as the mean ± SD (n = 4). * p < 0.05.