Effects Of Lycium Barbarum Polysaccharides Combined With Aerobic Exercise On AMPK/SIRT1 Pathway In Rats With Non-alcoholic Steatohepatitis

Objective In recent years,the incidence of NASH has increased substantially.The trend has continued to increase and has become a key point of concern for health systems.Therefore,the pathophysiological mechanisms of NASH must be clarified to develop new treatment strategies,including changing lifestyles or the addition of natural plant extracts.Recently,researchers have conducted numerous studies on the pathogenesis of NASH and have identified that the AMP-activated protein kinase(AMPK)/sirtuin1(SIRT1)pathway was a significantly role of energy,which modulated lipid and glucose metabolism in hepatocytes.The purpose of this study was to investigate the effect of Lycium barbarum polysaccharide(LBP)combined with aerobic exercise on AMPK/SIRT1 pathway on high-fat diet(HFD)induced NASH in rats and to explore the potential mechanisms involved on AMPK/SIRT1 pathway.Methods After 1 week of acclimatization,SD rats were randomly divided into a normal group(Normal,n=9)and unlimited access to ordinary diet.The remaining rats were considered high-fat group(HFD)with high-fat diet.At the end of the 28 th week,the high-fat group was randomly divided into 4 groups(8 in each group),which were model group(HFD),Lycium barbarum polysaccharide group(HFD+LBP),aerobic exercise group(HFD+AE)and combined group(HFD+LBP+AE),and the intervention was performed for a period of 10 weeks.At the end of the experiment,all rats were tested for the levels of fasting blood glucose(FBG).Then animals were anesthetized and blood samples were collected through the abdominal aorta and separated by centrifugation at 3000r/min for 10 min at 4℃ to collect serum samples.Subsequently,all the rats were euthanized,and the liver tissue and visceral fat were harvested,weighed and immediately stored at-80℃.The tissues were stained with H&E and Oil Red O.Serum levels of TC,TG,HDL,LDL,AST,and ALT were measured with biochemical assay kits.Serum insulin and inflammatory factor were detected using specific ELISA kits.Determination of lipid oxidation(PPARα,PGC-1α),lipid synthesis and inflammation-related protein or m RNA expression in the Sirt-1/AMPK pathway were detected using Real-Time Quantitative PCR or Western Blot.Results(1)The pathological section revealed that NASH rats have been hepatocyte steatosis and inflammatory infiltration,and large clumps of red lipid droplets were observed.After LBP or aerobic exercise(AE)treatment,the NASH in rats exhibited significant decrease in serum levels of total cholesterol(TC),triglyceride(TG),low-density lipoprotein cholesterol,aspartate aminotransferase(AST)and alanine aminotransferase(ALT)(P<0.05).Compared with the model group,LBP with AE individual regimens led to equally improved metabolic parameters,as indicated by decreased glucose intolerance from OGTT,serum insulin,and HOMA-IR(P<0.05).A combination of LBP with AE showed the greatest benefits in the improvement of Insulin resistance when compared with either monotherapy(P<0.05).(2)Compared with the model group,each treatment group had different degrees of improvement.After 10 weeks,the expression of m RNA and proteins related to the AMPK and SIRT1 in rat liver tissue markedly increased as a result of LBP combined with AE,and the levels of lipid synthesis-related genes ACC and FAS were significantly reduced(P<0.05).Compared with the modelgroup,each treatment group had different degrees of improvement.The expression of m RNA or protein levels of PGC-1α,PPARα,CPT-1A,UCP2,SIRT3 and Mn SOD showed an upward trend,and the protein and m RNA expressions of CYP2E1 was suppressed(P<0.05).Moreover,after the intervention of LBP and aerobic exercise,the serum MDA level of NASH in rats was significantly reduced,and the SOD and GSH levels were significantly increased when compared with the model group(P<0.05).(3)Significant decreases in TNF-α,IL-6 and MCP-1 were observed in the LPB group,AE and LBP combined with AE groups compared with the model group(P<0.05).The levels of TLR4,p38 MAPK and NF-κB protein expressions and m RNA were significantly lower than the model group(P<0.05).Conclusions LBP combined with AE activated the AMPK/SIRT1 pathway to reduce fatty acid chain synthesis,increased lipolysis and β-oxidation in hepatocytes.At the same time,the progression of NASH disease was slowly declines by Inhibition of hepatitis factor.