Study On The Effect And Mechanism Of Ginsenoside Rg1 Against Nafld In Mice

ObjectiveNonalcoholic fatty liver disease has become the most common chronic liver disease worldwide.But there is no effective drug in the treatment of NAFLD.Ginsenoside Rgl is the active ingredient extracted from ginseng.Studies have confirmed that it has the effect of anti-inflammatory,antioxidant,regulating central nervous and so on.However,the effects of Rgl on NAFLD have been not reported.This study used high-fat diet to feed C57/BL to establish the NAFLD model of mice.Drug intervention was performed with Rg1,while metformin was used as a positive control drug.To explore the effect of Rg1 on the improvement of NAFLD in mice induced by high-fat diet and the possible mechanism for the new exploration of drugs.Methods1.Healthy female C57BL/6 mice were transferred at 6-8 weeks of age to the laboratory animal facilities where they were maintained at a 12-h light/dark cycle and a constant temperature of 26℃.After 1 week of acclimatization,they were randomly allocated to five experimental groups of eight mice per group.These were control,high-fat diet,Rgl low-dose,Rgl high-dose,and metformin groups.The control group was fed with a normal diet.The other groups were fed with a high-fat diet.All groups had free access to water and food.After 16 weeks of feeding,the control group and high-fat diet group were given by gavage daily with 0.9%saline(20 mg/kg).The Rgl low-dose group and Rgl high-dose group through administration by gavage daily with 20 mg/kg and 40 mg/kg Rg1 respectively.The metformin group animals were given by gavage daily with metformin(150 mg/kg).2.Each group was treated for 1 month.The mice were fasted for 12 h with no water restriction after the completion of treatment.All mice were sacrificed,with blood and liver samples collected for further analysis to observe the morphology of the liver tissue pathology,serum transaminase,lipid levels,the content of malondialdehyde(MDA),superoxide dismutase(SOD),free fatty acids(FFA)and expression of endoplasmic reticulum stress related proteins and inflammasome activation.3.SPSS 20.0 software was used for statistical analysis.Results were expressed as means ± standard deviation(SD).Multiple comparisons were performed by one-way analysis of variance.P<0.05 was considered statistically significant.Results1.Rgl regulates body weight and reduces the Level of serum transaminase and blood lipid in mice:The body weight of mice in each group continued to increase during model establishment,and after 16 weeks the mice fed with a HFD were significantly heavier than controls.After 4 weeks of drug treatment,the body weight of mice given Rgl was significantly less than that of mice in the HFD group.Serum ALT,AST,and TG were significantly decreased by Rgl treatment,whereas decreases of serum TC,HDL-C,LDL-C after Rg1 treatment did not reach significance.2.Rgl attenuates liver hepatic adipose infiltration:HE staining showed that the liver cells in the control group were normal,without obvious degeneration and necrosis,and no obvious inflammatory cell or fibrous tissue hyperplasia was observed.The liver tissue of the model group was replaced by the fat vacuolar,and the hepatic cell was denaturated,with inflammatory cells infiltrating in the zone and no proliferation of fibrous tissue.In Rgl treatment group,fat vacuoles dispersed in liver tissues,and no obvious inflammatory cells or fibrous tissue hyperplasia were observed.The fat variation in the model group was significantly higher than that in the control group(P<0.05).The fat variation in the Rgl treatment group were significantly less than the model group(P<0.05).3.Rgl protects liver by regulating oxidative stress and ameliorating lipid peroxidation:Compared with the control group,SOD activity in the liver tissues of the model group was significantly reduced,and the content of MDA FFA was significantly increased(P<0.05).Compared with the model group,the activity of SOD in the liver tissues of Rgl treatment group increased and the content of MDA and FFA decreased(P<0.05).PPARa expression,a key gene involved in β-oxidation of fatty acids,was decreased by the HFD,but the decrease was smaller in the mice given Rg1.4.Effects of Rgl on mRNA and protein expression of endoplasmic reticulum(ER)stress:the expression of GRP78,Caspase 12 and CHOP,three genes that code for proteins associated with in ER stress,were assayed with qPCR and western blotting.All three were increased in HFD mice,and the increase was inhibited by Rgl treatment.5.Effect of ginsenoside Rgl on the expression of inflammatory cytokines in NAFLD mice:The expression of serum IL-18 concentrations,NLRP3,IL-1β,and cleaved IL-1β proteins were all upregulated in the HFD group and the changes were all decreased by Rg1 treatment.Conclusion1.Rgl can control the body mass and liver wet weight of mice,reduce serum transaminase and TG level,reduce liver fat degeneration,and improve the role of non-alcoholic fatty liver.2.Rgl can promote SOD activity of liver tissue,decrease the content of FFA and MDA,activate PPAR alpha protein,and have the effect of anti-oxidation and inhibiting lipid peroxidation.3.Rgl alleviates liver inflammation and improves endoplasmic reticulum stress by inhibiting the activation of ER stress and inflammatory.