Silibinin Improves Fructose-induced Lipid Accumulation And Activates Autophagy In HepG2 Cells

Studies found that autophagy is relevant to ontogenesis,oxidative damage protection,malignant tumor cells proliferation and neurodegenerative diseases.Recent studies showed that autophagy is associated with lipid metabolism.Lipid metabolism mainly happened in the liver.Lipid metabolism disorders can cause obesity-related disease,such as NAFLD,T2 DM and metabolism syndrome.Silibinin(SIL)is a kind of flavonoid compounds extracted from plants.It is found that silibinin can protect liver,reduce blood lipid and has anti-cirrhosis,immunity-improving and antioxidant effect.SIL can also protect myocardial function,resist cirrhosis of the liver.Clinical trial studies showed that SIL can improve hepatic steatosis,improve insulin sensitivity,however,the underlying mechanisms remain unclear.Our study aims to observe the effect of silibinin in Hep G2 cells exposed to high fructose and the impact on the level of autophagy,to explore the mechanism of silibinin improve lipid metabolism and autophagy and to provide experimental foundation and theoretical basis for clinical medication.Objective:To explore the effect of SIL on hepatic steatosis and the possible association with autophagy.Method:The degree of hepatic steatosis in Hep G2 cells was observed by oil-red O staining and triglyceride content detection.The effect of SIL on autophagy was tested by the Autophagy Detection Kit,and the protein expression of Sterol Regulatory Element Binding Protein 1(SREBP-1),Fatty acid synthase(Fas),light chain 3B(LC3B),beclin-1,p62,AMP activated kinase(AMPK),and mammalian target of rapamycin(m TOR)were examined by western blots.Results:1.The effect of silibinin on lipid accumulation induced by high fructose in Hep G2 cells.After 48 h of high fructose intervention,intracellular lipid deposition increased and triglyceride content increased in high-fructose group compared with control group(P?0.05),After SIL intervention,lipid deposition was reduced and intracellular triglyceride content was decreased(P?0.05).2.The effect of silibinin on autophagy.Using a fluorescence microscope,compared with control and high-fructose groups,after silibinin intervention,the extracellular green fluorescence increased,SIL was found to induce autophagy.3.Silibinin improves lipid accumulation through inducing autophagy.Compared with control group,the protein expressions of SREBP-1,and Fas were increased by high-fructose incubation(P?0.05,P?0.01),while the protein expressions of light chain 3B and beclin-1 were decreased and SREBP-1,Fas,and p62 were increased by autophagy inhibition(P?0.05,P?0.01).In contrast,opposite results were found in the SIL intervention group.4.The effect of silibinin on AMPK-m TOR pathway.Compared with control group,the protein expressions of m TOR were increased by high-fructose incubation(P?0.01),The protein content of m TOR was decreased,while phosphorylated-AMPK was increased in the SIL group compared with the high-fructose group(P?0.05,P?0.01).Conclusions:1.SIL can improve lipid accumulation in Hep G2 cells exposed to high-fructose incubation.2.SIL can activate autophagy.3.SIL could improve lipid accumulation in Hep G2 cells exposed to high-fructose incubationby inducing autophagy.4.Silibinin could induce autophagy through the AMPK-m TOR signaling pathway to improve lipid accumulation in Hep G2 cells.