Study On Protective Mechanism Of Flavonoids From Glycyrrhiza Uralensis On Non-alcoholic Fatty Liver Disease In Rats

Objective: To study the protective effect and mechanism of licorice flavonoids(LF) on non-alcoholic fatty liver disease in ratsMethods: Using the model of non-alcoholic fatty liver disease rats induced by high-fat diet.120 male SD rats were feed by a week to adapt to the environment.Then divided them into 2 groups randomly according to the weight. Control group,20,feed by the ordinary maintain diet(protein 20%,carbohydrate 70%,fat 10%);High-fat diet group,100, feed by the high-fat diet(protein 20%,carbohydrate 35%,fat 45%). Control group and high-fat diet group were feed by 13 weeks.After 13 weeks, sorting the high-fat group according to the weight.We eliminate the 30 rats that were not sensitive to the high-fat diet,the remaining 70 rats were saw as sensitive to the high-fat feed.Then divided the 70 rats into 6 groups according to the weight randomly.Model group,LF group(50,150,400mg· kg-1),Metformin group(300 mg·kg-1) and Fenofibrate group(40 mg· kg-1).From 14 th week,intervented by drugs. Drug intervention for 6 weeks,in addition to the control group,the other 5 groups were keep feeding by the high-fat diet.During the experimenting, monitoring the weight and food intake of each group.After the drug intervention,using the urethane(1.4 g/kg i.p) to anesthesia the rats.Taking blood from the femoral artery.The serum was used to detect the lipid, liver function and serum antioxidant indicators.Remove the fat and liver tissue quickly.The liver tissue were used to immunohistochemistry and Western Blot experiments.Results: The flavonoids extracted parts from Glycyrrhiza uralensis showed the significant difference in pharmacodynamics index(including body weight,fat index)(P<0.05 or P<0.01). In the serum lipid profile, the flavonoids can improved the high level of blood lipid in the NAFLD rats obviously(P<0.05 or P<0.01). Also, the flavonoids can reduce the high level of ALT/AST of serum in the NAFLD rats.From the HE and Oil Red O stains, the results showed the flavonoids extracted parts from Glycyrrhiza uralensis can reduce the lipid drops in the liver of NAFLD rats.The immunohistochemistry results:(1) Compared with the control group, AMPK protein expression in the liver were significantly heightened in the flavonoids treated rats(P<0. 05 or P <0.01).(2)Compared with thecontrol group, p-AMPK α expression in the liver were significantly heightened in the flavonoids treated rats(P<0. 05 or P <0.01).The Western blot results: Compared with the control group, High doses of the flavonoids and the positive control drug metformin can improve the level of AMPK α and p-AMPK αprotein expression in the liver of NAFLD rats(P <0.05 or P <0.01).Conclusion: The flavonoids extracted parts from Glycyrrhiza uralensis may produce the protective effect in non-alcholic fatty liver disease rats, and its relevant mechanisms may be associated with the increasing AMPK signal transduction pathway.