Study On The Mechanism Of Intervention Of Total Flavonoids Of Vine Tea On Hepatic Gluconeogenesis In ZDF Diabetic Rats

ObjectiveBy observing the effect of different doses of total flavonoids of Ampelopsis grossedentata on the intervention of glucose and lipid metabolism in type 2 diabetic ZDF(Zucker diabetic fatty)rats,and exploring the molecular mechanism of total flavonoids of Ampelopsis grossedentata in regulating liver glucose metabolism from the perspective of liver gluconeogenesis related protein pathway,to provide scientific experimental basis for clinical application of Ampelopsis grossedentataMethodsIn this experiment,a randomized control design method was used to select 30 spontaneous type 2 diabetic male ZDF rats that were modeled(The fasting venous blood glucose was? 7.8 mmol/L measured twice on different days).After 1 week of adaptive feeding,according to the blood glucose and body weight,the rats were randomLy divided into 5 groups with 6 rats in each group:model group(MOD),high-dose group of total flavonoids of Ampelopsis grossedentata(AGH),middle-dose group of total flavonoids of Ampelopsis grossedentata(AGH),low-dose group of total flavonoids from Ampelopsis grossedentata(AGL)and metformin treatment group(MET).Six male ZL(Zucker lean normoglycemic,+/FA)rats of the same age were used as normal control group(NC).Each treatment group was given intragastric administration of total flavonoids suspension and metformin solution prepared with deionized water every day.The dosages of each group were determined as follows:400 mg/kg/d,200 mg/kg/d,100 mg/kg,and metformin,0.135 g/kg,respectively.As a positive control and normal control,the rats in the model group and normal group were given intragastric administration of deionized water,intragastric administration of 1 mL/100 g body weight for 6 weeks.During the experiment,the general condition of rats was observed,fasting blood glucose,body weight and food intake of rats were recorded every week.Oral glucose tolerance and insulin tolerance tests were carried out at the sixth week of administration.After the end of the sixth week of experiment,blood was taken under anesthesia,and serum was separated for detection of glucose and lipid metabolism related indicators.The whole liver tissue was weighed and liver weight index(liver weight/body weight)was calculated.Part of the liver tissue was fixed for morphological observation,and the rest was frozen for Western Blot to detect the expression of Glyconeogenesis related signaling pathway proteinsResults1.General condition:The weight of all rats except the normal group began to decrease slowly from the fourth week.After 6 weeks of administration,compared with the normal group,the rats in the model group showed obvious obesity,depressed,slow in action,slow in response,and decreased in coat color and luster.The average food intake,body weight,liver weight,liver weight/body weight were significantly increased(P<0.001).Compared with the model group,the general condition of each dose treatment group of Ampelopsis grossedentata was significantly improved.High dose of Ampelopsis grossedentata and metformin can reduce body weight and liver weight/body weight(P<0.05).The high-dose and medium dose groups of Ampelopsis grossedentata could significantly reduce the liver weight(P<0.01),but the intervention of Ampelopsis grossedentata had no significant effect on reducing the average food intake(P>0.05)2.Related indexes of glucose metabolism:before treatment,fasting blood glucose of model group was significantly higher than that of normal group(P<0.01).The high-dose group of total flavonoids of Ampelopsis grossedentata could significantly reduce blood glucose(P<0.01),while the middle and low-dose groups of total flavonoids of Ampelopsis grossedentata and metformin were lower than those of model group(P<0.05).Compared with the normal group,the blood glucose level and AUC at each time point of OGTT were significantly increased in the model group(P<0.001);compared with the model group,the blood glucose level and AUC at each time point of OGTT were significantly decreased in the total flavonoids of Ampelopsis grossedentata groups and metformin groups(P<0.05,P<0.01,P<0.001);Compared with the normal group,the blood glucose level and AUC at each time point of ITT in the model group were significantly increased(P<0.001);Compared with the model group,the total flavonoids of Ampelopsis grossedentata could significantly reduce the ITT-AUC(P<0.01),but there was no significant difference in blood glucose at each time point(P>0.05).3.Liver histomorphology:compared with the normal group,the liver lobule structure of the model group was unclear,the hepatic cord structure disappeared,the cells arranged disorderly,the purplish red glycogen granules decreased obviously and the color became lighter.After 6 weeks of treatment,the structure of hepatic lobule in each treatment group was more complete,the arrangement of liver cord was more normal,the purplish red glycogen granules were significantly increased,and the color was obviously deepened.4.Lipid metabolism related indicators:Compared with the normal group,the levels of TC,TG,LDL-C and HDL-C increased significantly(P<0.001);after 6 weeks of administration,each dose group of Ampelopsis grossedentata can reduce TC,TG and LDLC,increase HDL-C significantly(P<0.05,P<0.01).5.Expression level of glycogen related proteins:the total flavonoids of Ampelopsis grossedentata treatment group significantly inhibited the expression of PGC-1?,PEPCK,G6Pase and CREB phosphorylation by inhibiting CREB-PGC-1?-PEPCK/G6Pase signaling pathway,thereby inhibiting liver gluconeogenesis and reducing blood glucose level.Conclusion1.Total flavonoids of Ampelopsis grossedentata can significantly improve the glucose metabolism disorder of ZDF rats in a dose-dependent manner.The hypoglycemic effect is similar to that of metformin.2.Total flavonoids of Ampelopsis grossedentata can significantly improve the disorder of lipid metabolism in ZDF rats,improve liver fat lesions,reduce body weight,and liver weight/body weight.It can significantly improve the morphological structure of liver cells,reduce liver fat deposition,and promote liver glycogen synthesis.3.Total flavonoids from Ampelopsis grossedentata can improve the disorder of glucose metabolism in ZDF rats,which may be mediated by inhibiting the expression of PGC-1a and the phosphorylation of CREB,thereby inhibiting the expression of downstream PEPCK and G6Pase proteins,thereby reducing blood glucose and regulating the balance of glucose metabolism.