Hypoglycemic Effect Of Eugenol On Type 2 Diabetic Mice And Regulation Of Signal Transduction Pathway Of Glucose And Lipid Metabolism In Liver

Objective: To investigate the hypoglycemic effect of eugenol(EU)on type 2diabetes(T2DM)mice,the effect of eugenol on liver glucose and lipid metabolism and its mechanism,so as to provide a theoretical basis for eugenol to improve the disorder of liver glucose and lipid metabolism and reduce the blood glucose level of type 2 diabetes.Methods: Forty 5-6-week-old SPF healthy male C57BL/6J mice were selected for adaptive feeding for 1 week,then they were randomly divided into normal feed group(RD,n=10)and experimental group(n=30).The mice in the experimental group were fed with high fat diet(HFD)for 8 weeks to prepare type2 diabetes mice model.Thirty mice in the experimental group with FBG≥ 7.0mmol/L were included in the experimental objects and further randomly divided into four groups.Group 1(n = 10): ordinary diet(RD)group;Group 2(n = 10):high fat diet(HFD)group;Group 3(n = 10): high fat diet plus metformin hydrochloride(HFD + MET200)group;Group 4(n = 10): high fat diet plus eugenol(HFD + E40)group.Group 3 and group 4 were given eugenol(EU40mg/kg)and metformin hydrochloride(MET200mg/kg)by gavage every day.Group 1 and group 2 were given the same amount of normal saline by gavage every day.The blood glucose and body mass were measured once a week.After 6weeks of continuous administration,the liver tissues of mice in each group were taken and the liver weight and body mass of mice were weighed;The indexes of liver index,liver tissue lipid metabolism and liver function were measured;Oral glucose tolerance test;The levels of blood glucose,insulin,triglyceride,cholesterol,resistin,leptin,ghrelin,glucagon and plasminogen activator inhibitor-1 in serum were measured;HE staining was used to observe the pathological changes of liver tissue;The protein expressions of SHP,pfoxo1,p CREB,PEPCK and G6 Pase in liver were detected by Western bolt.Results:1.Modeling results: compared with the mice in the normal diet(RD)group,the mice fed with high-fat diet had significantly increased body mass(P < 0.001),bloated body shape,increased liver weight,increased liver volume,steatosis,light red liver surface,and fasting blood glucose ≥ 7.0 mmol/L.The modeling was successful.2.Results of liver biochemical indexes: compared with RD group,liver weight,liver index,liver lipid content,triglyceride(TG),alanine aminotransferase(ALT)and aspartate aminotransferase(AST)in HFD group increased significantly(P < 0.001,P < 0.01,P < 0.001,P < 0.001,P < 0.001,P < 0.001,P < 0.05);Compared with HFD group,the liver weight,liver index,liver lipid content,triglyceride,alanine aminotransferase(ALT)and aspartate aminotransferase(AST)of E40 group decreased significantly(P < 0.01,P < 0.05,P < 0.001,P < 0.001,P< 0.001,P < 0.05).3.Results of oral glucose tolerance test(OGTT): compared with RD group,the blood glucose values of HFD group mice increased significantly at 30 min,60min,90 min and 120min(P < 0.001),and the area under the curve increased by1.8 times(P < 0.001);Compared with HFD group,the blood glucose value of E40 group decreased at 30 min and 90min(P <0.05),the blood glucose value decreased significantly at 60min(P < 0.01),the blood glucose value decreased at 120 min,there was no statistical significance,and the area under the curve decreased(P <0.05).4.Results of serum biochemical indexes: compared with RD group,the levels of blood glucose,insulin,cholesterol,resistin,leptin,glucagon and plasminogen activator inhibitor-1(PAI-1)in HFD group increased(P < 0.001,P <0.001,P < 0.001,P < 0.01,P < 0.001,P < 0.001,P < 0.001),and the levels of triglyceride and adiponectin decreased(P < 0.01,P < 0.01);Compared with HFD group,the levels of serum glucose,insulin,resistin,leptin,glucagon and PAI-1 in E40 group decreased(P < 0.05,P < 0.01,P < 0.05,P < 0.05,P < 0.01,P < 0.001).5.HE staining results: compared with RD group,hepatocytes in HFD group showed obvious swelling,steatosis,lipid droplet vacuoles and balloon like changes in cytoplasm,disorder of hepatic cord,disappearance of hepatic lobules and even disappearance of hepatic sinus stenosis;Compared with HFD group,the cells of E40 group were arranged orderly,the structure of hepatic lobules was complete,and the steatosis and inflammatory infiltration of hepatocytes were significantly reduced.6.Western blot results: compared with RD group,the expression of SHP protein in liver tissue of HFD group was down-regulated(P < 0.05),and the expression of PEPCK and G6 Pase protein were significantly up-regulated(P <0.01).Compared with HFD group,the expression of SHP,pfoxo1 and p CREB protein in E40 group was up-regulated(P < 0.05),and the expression of PEPCK and G6 Pase protein was significantly down regulated(P < 0.01).Conclusion: Eugenol may up regulate the protein expression of SHP and its downstream targets Fox O1 and CREB phosphorylation in liver tissue,inhibit the protein expression of PEPCK and G6 Pase,and then regulate gluconeogenesis and lipid metabolism in liver,inhibit insulin resistance,and improve the blood glucose level and hepatic glucose and lipid metabolism disorder in type 2 diabetes.