Morin enhances hepatic Nrf2 expression in a liver fibrosis rat model

AIM: To investigate whether morin can reduce hepatic fibrosis by activating the NF-E2-related factor 2 (Nrf2) signaling pathway. METHODS: Twenty male Sprague-Dawley rats were randomly divided into four groups: control group, morin group, carbon tetrachloride (CCl(4)) group, and morin + CCl(4) group. Rats in both the CCl(4) and morin + CCl(4) groups were injected intraperitoneally with CCl(4) at a dose of 2 mL/kg twice a week. Rats in both the morin and morin + CCl(4) groups were treated orally with morin at a dose of 50 mg/kg twice a week. Control rats were treated with vehicle only twice a week. At the end-point of the 8 wk of the experimental period, serum AST, ALT, and ALP were measured, and the liver specimens were obtained for pathological assessment. Real-time PCR and Western blot methods were used to analyze the expression of α-smooth muscle actin (α-SMA), collagen I, collagen III, Nrf2, heme oxygenase (HO-1), and quinone oxidoreductase 1 (NQO1) using frozen liver specimens. RESULTS: Morin-treated rats in the morin + CCl(4) group had less hyperplasia of fiber tissue, minimal inflammatory cells, and less body weight loss with favorable liver enzyme measurements compared to rats treated with CCl(4) only. Additionally, morin-treated rats had significantly lower mRNA and protein expression of α-SMA, collagen I, and collagen III, but significantly higher mRNA and protein expression of Nrf2, HO-1, and NQO1 compared to rats treated with CCl(4) only (P < 0.05). CONCLUSION: Morin could play a protective role by inducing the expression of Nrf2 and its downstream antioxidant factors (HO-1 and NQO1) and reducing the expression of α-SMA, collagen I, and collagen III in CCl(4)-induced liver fibrosis rats.