Study On The Efficacy And Mechanism Of Aqueous Extract Of Siraitia Grosvenorii And Mogroside V In Non-alcoholic Steatohepatitis (NASH)

OBJECTIVE: To explore the pharmacological effects and biological mechanisms of Luohanguo(Siraitia grosvenorii)on Nonalcoholic steatohepatitis(NASH),I detected the liver lipid,transaminase,liver coefficient,signal pathways and fatty acid synthesis-related genes expression in NASH.This study may provide new ideas and methods for the treatment of NASH.Methods: The experiment was divided into in vivo experiment and in vitro experiment.C57BL/6 mice were randomly divided into the following six groups and received the corresponding treatment for 12 days:(1)mice fed with MCS(methionine-and cholinesupplemented)diet;(2)mice fed with MCD(Methionine-choline-deficient)diet;(3)-(5)mice fed with MCD diet supplemented with 50,100,500 mg/kg/day aqueous extract of Siraitia grosvenorii,(6)mice fed with MCD diet supplemented with 100mg/kg/day fenofibrate respectively.Each group has 10 mice.The mice were sacrificed.Then serum,liver tissue and fecal samples of mice were collected for the analysis of aspartate aminotransferase(AST),alanine aminotransferase(ALT)in serum,triglyceride(TG),lipid peroxides(MDA)and total cholesterol(CHO)content in liver tissues.Some parts of liver tissue samples were fixed with methanol for pathological section.The total RNA and protein were extracted from liver samples.Proteins of ERS,MAPK and NF-κB signaling pathways were detected by Western Blotting.The genes related with fat synthesis and inflammation were detected with RT-PCR.The effect of aqueous extract of Siraitia grosvenorii intestinal microflora in feces of NASH mice model was also detected.Experimental NASH cell model was induced by incubating a normal mice liver cell line AML-12 with methionine-choline deficiency(MCD)medium for 24 hours.This model was treated with different concentrations aqueous extract of Siraitia grosvenorii and mogroside V,respectively.The intracellular triglyceride(TG)contents,MDA and SOD were measured using the enzymatic kits.ERS,NF-κB,MAPK signaling pathways as well as lipid synthesis and inflammation related genes were detected for exploration of the mechanism.Results: The analysis of hepatic index showed lower toxicity of aqueous extract of Siraitia grosvenorii compared with the control group,while positive drug Fenofibrate group coefficients were significantly higher(p<0.01).The analysis of pathology showed that aqueous extract of aqueous extract of Siraitia grosvenorii can reduce lipid accumulation and inflammatory infiltration in the liver tissues induced by MCD diet.Compared with the MCD group,the ratio of Bacteroides and Firmicutes in aqueous extract of Siraitia grosvenorii groups increased significantly.And the Akkermansia muciniphilia of the warts microbacteria was significantly higher than that of the control group.Compared with those of mice fed with MCD diet,AST,ALT contents in serum of mice fed with medium,high dose of aqueous extract of Siraitia Grosvenorii reduced.The medium,high dose of aqueous extract of aqueous extract of Siraitia grosvenorii decreased the liver TG and MDA contents in a dose-dependent manner.The proteins expressions of the endoplasmic reticulum stress NF-κB,and MAPK signaling pathways BIP,p-PERK,IRE-1,ATF-6,SREBP-1,p-JNK,p-p38,IKKα,IKKβ,p-p65 in cytoplasm and nuclear were up-regulated in the NASH model and down-regulated after aqueous extract of Siraitia Grosvenorii treatment.Moreover,the proteins expressions of IκBα were down-regulated in the NASH model and up-regulated after aqueous extract of Siraitia Grosvenorii treatment.The RT-PCR revealed that treatment with MCD diet up-regulated the expression of lipid synthesis related genes FAS,SCD1,GPAT,ACC,inflammation related genes TNF-α,IL-1β,IL-6.While aqueous extract of Siraitia grosvenorii treatment downregulated these genes expression.The NASH cell model was successfully established in mice AML-12 cells.The aqueous extract of Siraitia grosvenorii and Mogroside V treatment decreased the intracellular TG contents and lipid peroxidation.And the changes of proteins and genes after aqueous extract of Siraitia grosvenorii and Mogroside V treatment were similar to the results of in-vivo experiment.Conclusion: The aqueous extract of Siraitia grosvenorii and Mogroside V show therapeutic effect in animal model and cell model of NASH.They can decrease transaminase,reduce fat accumulation and lipid peroxidation.The aqueous extract of Siraitia grosvenorii and Mogroside V can reduce proteins expression of ER,MAPK and NF-κB pathway,decrease fatty acid synthesis-related genes expression of ACC,FAS,SCD1,GPAT and inflammation-related genes expression of TNF-α,IL-1β,IL-6.In short,Siraitia grosvenorii can be applied in NASH treatment by reducing hepatic lipid accumulation,alleviating inflammation.