The Signaling Mechanism Of Magnolol Intervenes In Lipid Accumulation And Inflammatory Responses

Non-alcoholic fatty liver disease is one of the most common chronic liver diseases in the world,which often associated with obesity,nonalcoholic fatty hepatitis,liver cirrhosis and metabolic diseases,such as type 2 diabete and liver cancer.Liver cirrhosis and liver cancer seriously can lead to death.Magnolol is a kind of lignin isolated from Chinese medicine of Magnolia offcinalis,which serves various biological functions,including antifungal,anti-oxidant,anti-cancer and hepatoprotective effects.Oleic acid is a kind of free fatty acids,it is the main substance that contributes to non-alcoholic fatty liver disease,which can induce the lipid accumulation of HepG2 cells.Tyloxapol is a surfactant that inhibits lipase activity and arouses hyperlipidemia in mice.Chinese medicine is widely researched and applied in clinical treatment because of the little side-effects and low cost.In our experiment,we take advantage of oleic acid to stimulate the human liver cancer(HepG2)cells as a model of nonalcoholic fatty liver disease in vitro.The activation of correlative signaling pathways was detected to confirm the molecular mechanism and effects of magnolol in this experiment by using MTT to select non-toxic concentration,exploiting oil red O staining to observe lipid content in Hep G2 cells,checking triglyceride(TG),tumor necrosis factor alpha(TNF-α),reactive oxygen species(ROS),Western Blot and immunofluorescence.The results suggested that oleic acid significantly induced lipid accumulation and TG increase and promoted the release of TNF alpha and ROS,while magnolol improved these effects.Western Blot results showed that magnolia activated the AKT/AMPK/PPARα signaling pathways and inhibited the protein expression of SREBP-1c and MAPKs/NF-κB inflammatory signaling pathway.Furthermore,the results of immunofluorescence represented that the expression of P-AMPK,P-AKT and PPARα were activated and the protein expression of SREBP-1c was restrained.In addition,tyloxapol obviously enhanced the content of serum triglycerides and serum total cholesterol elevation in mice model of tyloxapol-stimulated,it could also arouse the accumulation of lipid droplet and lipid in mice liver;Magnolol significantly inhibited the increase of total cholesterol(TC)and triglyceride(TG)in the blood,and reduced the amount of vacuoles and lipid accumulation in the liver.Western Blot results showed that the phosphorylation expression of AKT and AMPK was activated by magnolia,the protein expression of PPARα was up-regulated,and the protein expression of SREBP-1c was inhibited.Above all,magnolol possessed obvious the abilities of anti-lipid accumulation and anti-inflammatory,which maybe provide to make certain value for NAFLD and other related diseases and explore new drug research.