The protective effect of naringenin on ulcerative colitis in mice through increasing Nrf2 pathway activity

Ulcerative colitis (UC) is a chronic inflammatory disease with an increasing prevalence worldwide. Naringenin (NAR) has been proven effective in preventing UC, but its mechanism has not been fully elucidated. In this study, network pharmacology and bioinformatics methods are used to screen the genes associated with NAR and UC. A mouse model of dextran sulfate sodium (DSS)-induced UC is established. After treatment with NAR, the disease activity index (DAI) is scored, and colonic histopathology is observed via hematoxylin-eosin (HE) staining. The expressions of the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway and inflammation-related factors in the colons of UC mice are examined via western blot analysis and immunohistochemistry (IHC). The results of the animal experiments reveal that the model group of UC mice present the most severe weight loss and the highest DAI scores. After the administration of NAR, weight loss is alleviated, and DAI scores are reduced ( P < 0.05). NAR improves pathological manifestations in the mouse colon, such as reducing inflammatory cell infiltration and restoring goblet cell loss ( P < 0.05). NAR significantly increases the protein expression levels of Nrf2, heme oxygenase 1 (HO-1), and NAD(P)H dehydrogenase [quinone] 1 (NQO1) in the colon ( P < 0.05) but decreases the protein expression levels of nuclear factor kappa-B (NF-κB), tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β) ( P < 0.05), thus alleviating the inflammatory response in UC model mice.