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The accumulation of iron-dependent lipid peroxides is one of the important causes of NAFLD. The purpose of this study is to explore the effect of dehydroabietic acid (DA) on ferroptosis in nonalcoholic fatty liver disease (NAFLD) mice and its possible mechanisms. DA improved NAFLD and reduced triglycerides (TG), total cholesterol (TC), and lipid peroxidation level and inhibited ferroptosis in the liver of HFD-induced mice. DA binds with Keap1 to form 3 stable hydrogen bonds at VAL512 and LEU557 and increased nuclear factor erythroid 2-related factor 2 (Nrf2)-antioxidant response elemen (ARE) luciferase activity. DA promoted the expression downstream of Nrf2 such as heme oxygenase-1 (HO-1), glutathione (GSH) and its peroxidase 4 (GPX4), so as to eliminate the accumulation of reactive oxygen species (ROS) and reduce lipid peroxides malondialdehyde (MDA) in the liver. DA inhibited ferroptosis and increased the expression of key genes such as ferroptosis suppressor protein 1 (FSP1) in vitro and vivo. In all, DA may bind with Keap1, activate Nrf2-ARE, induce its target gene expression, inhibit ROS accumulation and lipid peroxidation, and reduce HFD-induced NAFLD.

Investigation of the fluorescence behavior of a pyrene functionalized chitosan film (PSC-CS) to some quenchers, including KI, CH3NO2 and Cu(NO3)2, has revealed that the monomer emission from the PSC-CS film increased rather than decreased, whereas the excimer emission decreased with the increase of time of duration after addition of KI or Cu(NO3)2. Both the increasing and decreasing processes could last as long as 20 min to 40 min. Unlike that observed in the system containing KI or Cu(NO3)2, for CH3NQ2 system, both the monomer emission and the excimer emission increased with introduction of the quencher, but the excimer emission only started to increase after an hour-long induction period. The position of the excimer emission of the PSC-CS film did not change very much with addition of KI or Cu(NO3)2. However, addition of CH3NO2 made the excimer emission blue shifted for at least 20 nm indicating formation of distorted excimers or partially overlapped excimers. The fluorescence response of the film to external additions is sensitive but is low in selectivity. This property may make the film use as a novel sensing material for monitoring the purity of water.