Protective Effect Of Schisandra Polysaccharides On NAFLD Induced By High-Fat Diet In Mice And Its Mechanisms

Objective: To observe the protective effect of Schisandra polysaccharides on high-fat diet-induced non-alcoholic fatty liver disease(NAFLD) in mice and study its mechanisms.Method: A mouse NAFLD model induced by high-fat diet was established. 10 Mice chosen randomly separation were used as normal control group, which were fed with normal diet, and the rest of mice were used to establish the NAFLD mouse model, which were fed with high-fat diet. 4 Weeks later, all mice were allowed to fast for 12 h, and then, their blood samples were collected from eyeball vein. Serum total cholesterol(TC) and triglycerides(TG) contents in the samples were tested for confirming hyperlipidemic mouse model was successful. All hyperlipidemic mice were randomly divided into model group,low-dose and high-dose Schisandra polysaccharide groups, and positive control group. 10 mices in each group. After the administration for 12 w, all the mices were sacrificed, and detect TC, TG and LDL-C(low density lipoprotein cholesterol) levels of the serum of mice in each group, and TC、TG in liver to observe the effect of Schisandra polysaccharides on blood lipid and liver lipid.GPT(glutamic pyruvic transaminase) and GOT(glutamic oxaloacetic transaminase) levels of the serum of mice in each group were detected to observe the effect of Schisandra polysaccharides on liver functions of mice with NAFLD; the liver tissue was stained with HE method to observe the effect of Schisandra polysaccharides on changes in the liver histopathology;SREBP-2/LDLR/HMGCR, the key factor in the cholesterol metabolism in liver tissue was detected by Western Blot method.Results: Compared with those in the control group, C57BL/6 mices feed with hyperlipid diet, the TC and TG levels in serum were significantly increased(P<0.01), Indicating that the mices had a hyperlipemia. After go on administration, compared with those in the control group, TC、TG、LDL-C、GPT and GOT levels in serum of NAFLD group were significantly increased,TC and TG levels in liver tissue were significantly higher, and HE staining showed a structural disorder and a significant hepatic steatosis in the hepatic lobule of mice. Indicating that the establishment of NAFLD mouse model successfully. Compared with those in the model group, serum TC rats, TG,LDL-C, GPT and GOT levels in Schisandra polysaccharide- treated groups were significantly reduced, and the TC and TG levels in the liver tissue were also significantly reduced. HE staining showed that the hepatic lobule of mice in Schisandra polysaccharide-treated groups was normal in the structure and the hepatic steatosis was significantly improved. Western Blot results showed that compared with those in the control group, expression levels of SREBP-2, LDLR and HMGCR protein of mice in NAFLD model group were significantly increased, while those in Schisandra polysaccharide-treated group were significantly reduced.Conclusion: Schisandra polysaccharide has a certain therapeutic effect on high-fat diet-induced non-alcoholic fatty liver disease in mice. Themechanismmay be related to the express of the key protein SREBP-2/HMGCR/LDLR in liver cholesterol metabolism downregulation, and regulation of the balance of hepatic cholesterol metabolism.