Effect And Mechanism Of Different Intervention Methods On Nonalcoholic Fatty Liver In Rats

Objective To study the effect and mechanism of lycium barbarum polysaccharides(LBP),aerobic exercise and their combination on nonalcoholic fatty liver disease(NAFLD),NAFLD model was induced by high fat diet(HFD)in SD rats,which were to provide a theoretical basis for clinical treatments of NAFLD.Methods The SPF male SD rats(n=54)was randomly divided into two groups: control group and HFD group,which were respectively given normal diet and high-fat diet for 10 weeks.After successful modeling,the NAFLD rats were randomly divided into 4 groups according to body weight,namely HFD group,LBP group(LBP 50mg/kg),aerobic exercise intervention group(33.3cm/s,60min/d),and combined intervention group(LBP 50mg/kg + 33.3cm/s 60min/d)with ten in each.After intervening 8 weeks,fasting for 12 h,fasting blood glucose level and the weight were measured.Blood samples and liver tissues were collected.The liver index was calculated.The appearance of the liver was observed,and the accumulation of liver fatty was observed with pathological sectioning.Total serum cholesterol(TC),triacylglycerol(TG),low density lipoprotein(LDL),high density lipoprotein(HDL),alanine aminotransferase(ALT),aspartate aminotransferase(AST),superoxide dismutase(SOD),malondialdehyde(MDA),insulin and plasma irisin levels in rats were measured with the corresponding kits.The expressions of p38 MAPK,PGC-1?,FNDC5 genes and proteins in liver were detected by RT-PCR and Western blot,respectively.The content of LBP was measured by the phenol–sulfuric acid method.The composition of LBP was determined as heteropolysaccharides(HPLC).Results 1.LBP is a heteropolysaccharide composed of galacturonic acid,mannose,rhamnose: glucose,galactose,and arabinose in a molar ratio of0.66:1:0.93:12.55:0.31:0.53;2.Compared with the HFD group,Liver lipid accumulation in three different intervention groups were alleviated,and their body weight was also decreased(P<0.05).3.Compared with the HFD group,the serum TC and AST/ALT ratio levels of the three intervention groups were reduced(P<0.05).Serum TG was decreased in exercise group and combined intervention group(P<0.05).HDL level was increased in LBP group(P<0.05).LDL level in aerobic exercise group was decreased(P<0.05).TC and TG in liver were decreased(P<0.05).4.Compared with HFD group,serum and liver SOD levels in three intervention groups were increased(P<0.05);The serum and liver MDA levels were also reduced(P<0.05).5.Compared with the HFD group,the plasma irisin level was significantly increased(P<0.05),and the insulin resistance index was decreased(P<0.05);6.Compared with the HFD group,the expression levels of p38 MAPK genes were decreased the three different intervention groups(P<0.05),and the proteins were decreased theaerobic exercise group and the combined intervention group(P<0.05),and the expression levels of PGC-1? and FNDC5 genes and proteins in the LBP group,aerobic exercise group and combined intervention group were increased(P<0.05).Colclusion Lycium barbarum polysaccharides and aerobic exercise can improve lipid metabolism disorders,increase antioxidant capacity,reduce liver lipid deposition,and reduce body weight in nonalcoholic fatty liver disease rats,which may be related to down-regulated liver p38 MAPK expression andup-regulated liver PGC-1?/FNDC5 expression,and to increase plasma irisin levels.