Non-alcoholic steatohepatitis (NASH) is a chronic metabolic syndrome and the CFLAR-JNK pathway can reverse the process of NASH. Although silibinin is used for the treatment of NASH in clinical, its effect on CFLAR-JNK pathway in NASH remains unclear. This study aimed to investigate the effect of silibinin on CFLAR-JNK pathway in NASH models both in vivo and in vitro. The in vivo study was performed using male C57BL/6 mice fed with methionine- choline-deficient diet and simultaneously treated with silibinin for 6 weeks. The in vitro study was performed by using mouse NCTC-1469 cells which were respectively pretreated with oleic acid plus palmitic acid, and adenovirus-down Cflar for 24 h, then treated with silibinin for 24 h. After the drug treatment, the key indicators involved in CFLAR-JNK pathway including hepatic injury, lipid metabolism and oxidative stress were determined. Silibinin significantly activated CFLAR and inhibited the phosphorylation of JNK, up-regulated the mRNA expression of Pparα, Fabp5, Cpt1α, Acox, Scd-1, Gpat and Mttp, reduced the activities of serum ALT and AST and the contents of hepatic TG, TC and MDA, increased the expression of NRF2 and the activities of CAT, GSH-Px and HO-1, and decreased the activities and expression of CYP2E1 and CYP4A in vivo. These effects were confirmed by the in vitro experiments. Silibinin prevented NASH by regulating CFLAR-JNK pathway, and thereby on one hand promoting the β-oxidation and efflux of fatty acids in liver to relieve lipid accumulation, and on the other hand inducing antioxidase activity (CAT, GSH-Px and HO-1) and inhibiting pro-oxidase activity (CYP2E1 and CYP4A) to relieve oxidative stress.
Keywords: 2-NBDG, 2-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl) amino)-2-deoxyglucose; ALT, alanine aminotransferase; AST, aspartate aminotransferase; Acox, acyl-coenzyme A oxidase X; Akt, serine–threonine protein kinase; CAT, catalase; CFLAR; CFLAR, caspase 8 and Fas-associated protein with death domain-like apoptosis regulator; CYP2E1, cytochrome P450 2E1; CYP4A, cytochrome P450 4A; Cpt1α, carnitine palmitoyl transferase 1α; Fabp5, fatty acid-binding proteins 5; GSH-Px, glutathione peroxidase; Gpat, glycerol-3-phosphate acyltransferase; HE, hematoxylin–eosin; HO-1, heme oxygenase 1; IR, insulin resistance; IRS1, insulin receptor substrate 1; JNK, c-Jun N-terminal kinase; Lipid accumulation; MAPK, mitogen-activated protein kinase; MCD, methionine- and choline-deficient; MCS, methionine- and choline-sufficient; MDA, malondialdehyde; MT, Masson–Trichrome; Mttp, microsomal triglyceride transfer protein; NAFLD, non-alcoholic fatty liver disease; NASH; NASH, nonalcoholic steatohepatitis; NF-κB, nuclear factor κB; NRF2, nuclear factor erythroid 2-related factor 2; OA, oleic acid; ORO, oil red O; Oxidation stress; PA, palmitic acid; PI3K, phosphatidylinositol 3-hydroxy kinase; Pnpla3, phospholipase domain containing 3; Pparα, peroxisome proliferator activated receptor α; SD, Sprague–Dawley; Scd-1, stearoyl-coenzyme A desaturase-1; Silibinin; Srebp-1c, sterol regulatory element binding protein-1C; TC, total cholesterol; TG, triglyceride; pIRS1, phosphorylation of insulin receptor substrate 1; pJNK, phosphorylation of c-Jun N-terminal kinase.