Besides, the expression levels of Nrf2-targeted antioxidant enzymes, including HO-1 (Fig. 4F, 4G) and NAD(P)H quinone oxidoreductase-1 (NQO1, Fig. 4F, 4H) decreased in Nrf2 knockout mice and T2DM mice, suggesting that Nrf2 deletion lead to the down-regulation expression of its downstream dependent genes. This evidence concerns the gene NFE2L2 and type 2 diabetes mellitus.