Study On The Mechanism Of Balsam Pear Alcohol Extract Regulating Liver Glucose And Lipid Metabolism In ZDF Rats

ObjectiveBy observing the regulatory effects of different doses of Momordica charantia alcohol extract on glucose and lipid metabolism in spontaneous type 2 diabetic ZDF rats,the molecular mechanism of Momordica charantia alcohol extract regulating liver glucose and lipid metabolism was explored from liver insulin signal transduction pathway proteins and their downstream target genes.MethodUsing the method of randomized controlled design,28 ZDF rats(fa/fa),an animal model of spontaneous type 2 diabetes mellitus,were selected.After one week of adaptive feeding,the rats were selected into the experiment according to the level of blood glucose,and were randomly divided into model group(DM),high-dose Momordica charantia alcohol extract group(MCH),middle-dose Momordica charantia alcohol extract group(MCM)and low-dose Momordica charantia alcohol extract group(MCL).At the same time,7 ZL rats(fa/+)of the same week were selected as normal control group(NC).The rats in each treatment group were given intragastric administration of deionized water with suspension of Momordica charantia alcohol extract every day.The high,middle and low doses of Momordica charantia alcohol extract were 800mg/kg/d,400mg/kg/d and 200mg/kg/d,respectively,and the gastric perfusion volume was lml/100g body weight.The rats in the model group and normal group were given the same amount of deionized water for 6 weeks.During the intervention,the general condition of rats was observed,and the fasting blood glucose,body weight and food intake of rats were monitored every week.After the intervention,the rats were anesthetized to take blood,and the serum was used to detect the related indexes of glucose and lipid metabolism,fat factors and so on.Liver tissue was used to detect the index of oxidative stress,histomorphology,and the protein expression of insulin signal transduction pathway and the transcriptional level of downstream target genes in liver were detected by Western Blot and Real-time PCRResults1.General condition monitoring:compared with the normal group,the rats in the model group showed obvious polydipsia,polyuria,slow movement,dark yellow fur,fasting blood glucose,average food intake,liver weight and liver weight/body weight(P<0.01).There was no statistical difference since the fourth week of intervention.Compared with the model group,Momordica charantia treatment groups significantly improved the general condition of ZDF rats,significantly decreased fasting blood glucose,liver weight,liver weight/body weight,average food intake and body weight,but there was no statistical difference2.Serum test:①Glucose and lipid metabolism and insulin resistance:in the normal group,the glucose and lipid metabolism was normal and there was no insulin resistance.Compared with the normal group,FINS,HOMA-IR,TC,TG,LDL,HDL and FFA in the model group were significantly increased(P<0.01),blood glucose level and AUC in OGTT were significantly increased(P<0.01),and FINS,HOMA-IR,TC,TG,LDL and FFA,in each treatment group were significantly lower than those in the model group(P<0.01 or P<0.05).HDL,significantly decreased blood glucose level and AUC in OGTT at each time point(P<0.01).②In the aspect of improving fat factor and oxidative stress:compared with the normal group,RES and MDA in the model group significantly increased(P<0.01),while ADP,SOD and CAT decreased significantly(P<0.01).Compared with the model group,Momordica charantia treatment group significantly decreased RES,MDA(P<0.01 or P<0.05),significantly increased ADP,SOD,CAT(P<0.01 or P<0.05).3.Histomorphological detection of liver:HE staining showed that Momordica charantia treatment group significantly improved liver steatosis,hepatocyte morphology and structure improved,inflammatory infiltration decreased;glycogen(PAS)staining showed that Momordica charantia treatment group promoted liver glycogen synthesis;oil red O staining showed that Momordica charantia treatment group reduced liver fat deposition 4.Western Blot and Real-time PCR:Momordica charantia treatment group can promote PI3K-AKT-FoxO1 signal transduction,enhance the protein expression of PI3K,p-AKT and p-FoxO1(P<0.01 or P<0.05),inhibit the protein expression of FoxOl(P<0.01),and then inhibit the transcriptional level of target genes G6P,PEPCK,SCD1,ACC and FAS(P<0.01 or P<0.05),and increase the transcriptional level of PFK(P<0.01 or P<0.05),thus improving the metabolism of glucose and lipids in the liver.Conclusion1.The alcohol extract of Momordica charantia can significantly improve the disorder of glucose and lipid metabolism and insulin resistance in ZDF rats.2.The alcohol extract of Momordica charantia can significantly improve the hepatic steatosis and reduce the liver weight and liver weight/body weight in ZDF rats.It can significantly improve the morphology and structure of hepatocytes,reduce inflammatory infiltration,promote hepatic glycogen synthesis and reduce liver fat deposition3.The mechanism of the alcohol extract of Momordica charantia in improving the disorder of glucose and lipid metabolism may be through promoting insulin signal transduction,enhancing the protein expression of PI3K and p-AKT,promoting the phosphorylation of FoxO1 protein,and inhibiting the protein expression of FoxO1,thus reducing the transcriptional level of its downstream target genes G6P,PEPCK,SCD1,FAS and ACC,increasing the transcriptional level of PFK,inhibiting hepatic gluconeogenesis,promoting glycolysis and inhibiting fatty acid synthesis.At the same time,increase the expression of ADP and liver SOD,CAT,inhibit the expression of RES and liver MDA play the role of anti-inflammation and anti-oxidation.