| Objective:Diabetes mellitus is a group of metabolic diseases caused by insulin secretion or function defects characterized by continuous increase of blood glucose level.Chronic complications of diabetes affect many tissues and organs in the body,including cardiovascular system,liver,kidney and nervous system.Nonalcoholic fatty liver disease(NAFLD)is a common complication of diabetes.NAFLD can interfere the blood glucose control of diabetes and accelerate the occurrence and development of diabetic microvascular complications.Some studies have found that insulin resistance,lipid metabolism disorder,oxidative stress and other factors play an important role in its pathogenesis.Berberine is an effective ingredient extracted from the Chinese herb rhizoma coptidis.In recent years,it has been found to be able to treat dyslipidemia,hyperglycemia,hypertension and arrhythmia.Studies on berberine on diabetes NAFLD have attracted more and more attention.In this study,the rat model of type 2 diabetes was established by intraperitoneal injection of low dose streptozotocin and high fat diet.After 20 weeks of continuous administration,the protective effect of berberine on the liver of model rats was observed and the possible mechanism of its action was discussed.Methods:1.The protective effect of berberine on liver of type 2 diabetic ratsThe rat model of type 2 diabetes was established by intraperitoneal injection of low dose streptozotocin and high fat diet.The rats were randomly divided into normal group,model group and berberine group.Berberine was given continuously for 20 weeks after successful model-making.At the end of the 20 th week,animal samples were collected and serum was collected for blood biochemical testing.Liver tissue was collected for pathological observation and mechanism study.2.Effect of berberine on lipid metabolism mediated by AMPK pathway in the liver of rats with type 2 diabetesThe expression of AMPK,ACC,FAS and CPT1 related to the fatty acid synthesis ofAMPK pathway in hepatic tissues of each group of rats was detected by Real-time PCR.The protein levels of AMPK(pAMPK),ACC(pACC),FAS and CPT1 were detected by immunohistochemistry.Protein expression levels of pAMPK,pACC,FAS and CPT1 were detected by Western Blot.3.Effects of berberberine on oxidative stress response mediated by Nrf2 pathway in liver of type 2 diabetic ratsDetermination of each rat liver tissue oxidative stress indicators: the activity of SOD,CAT and GSH-Px and MDA level,and through the Real-time PCR to detect Nrf2 signaling pathways related gene(Nrf2,Keap1,SOD,CAT,GSH-Px,NQO1 and HO1)on the expression of mRNA level.The expression of proteins related to the oxidative stress response of Nrf2,Keap1,SOD,CAT,GSH-Px,NQO1 and HO1 was detected by immunohistochemistry.Protein levels of Nrf2,Keap1,SOD,CAT,GSH-Px,NQO1 and HO1 were detected by Western Blot.Results:1.The protective effect of berberine on liver of type 2 diabetic ratsThe weight of the model group was significantly lower than that of the normal group from week 4 to week 20.There was no significant difference in body weight between berberine group and model group,but the hepatic weight index was significantly decreased(P<0.05).Blood glucose,blood lipid and liver function were also significantly increased in the model group compared with the normal group(P<0.05),and berberine significantly decreased the blood lipid and liver function in the model rats(P<0.05).HE and oil red O staining showed that berberine can effectively reduce inflammatory cell infiltration and lipid deposition in the liver of model rats,suggesting that berberine can improve liver injury in type2 diabetic rats induced by high fat diet and low-dose streptozotocin.2.Effect of berberine on lipid metabolism mediated by AMPK pathway in the liver of rats with type 2 diabetesReal-time PCR results showed that the mRNA expression levels of AMPK and CPT1 in the liver tissues of rats in the model group were significantly down-regulated compared with the normal group(P<0.01),while the mRNA expression levels of ACC and FAS were significantly increased(P<0.01).Compared with the model group,the mRNA expression of AMPK and CPT1 in the liver tissues of the berberine group increased(P<0.05),and the mRNA expression of ACC and FAS decreased significantly(P<0.05).The results of immunohistochemistry showed that compared with the normal group,the protein content of pAMPK,pACC and CPT1 in the liver tissues of the model group was relatively low(P<0.001),and FAS expression was significantly increased(P<0.001).Compared with the model group,the protein content of pAMPK,pACC and CPT1 in berberine group was significantly increased(P<0.05),while FAS was significantly decreased(P<0.001).Western Blot results showed that the protein content of pAMPK,pACC and CPT1 in the liver tissues of rats in the model group was relatively low compared with the normal group(P<0.05),while FAS was highly expressed(P<0.01).The relative contents of pAMPK,pACC and CPT1 in liver tissues in berberine group were significantly higher than those in the model group(P<0.05),and FAS expression was significantly lower(P<0.01).3.Effects of berberberine on oxidative stress response mediated by Nrf2 pathway in liver of type 2 diabetic ratsCompared with the normal group,the activity of SOD,CAT and GSH-Px in the liver homogenation of rats in the model group was significantly decreased,and the level of MDA was significantly increased(P<0.05).Compared with the model group,the activity of SOD,CAT and GSH-Px in the liver tissue of rats in the berberine group was significantly increased,and the level of MDA was significantly decreased(P<0.05).Real-time PCR results showed that the mRNA levels of the antioxidant transcription factor Nrf2 and its regulated downstream genes CAT,GSH-Px and HO1 in the model group were significantly decreased compared with the normal group(P<0.01).Compared with the model group,berberine group significantly improved the mRNA expression of Nrf2,SOD,CAT,GSH-Px and HO1 in the liver tissues of model rats(P<0.05).The results of immunohistochemistry showed that the protein contents of Nrf2,SOD,CAT,GSH-Px and HO1 in the liver tissues of rats in the model group were lower than those in the normal group(P<0.05).The relative expression levels of Nrf2,SOD,CAT,GSH-Px and HO1 in the berberine group were significantly higher than those in the model group(P<0.05).Western Blot results showed that the protein contents of Nrf2,SOD,CAT,GSH-Px,NQO1 and HO1 were low in the liver tissues of rats in the model group.Berberine can significantly increase the protein content of Nrf2,SOD,CAT,GSH-Px and HO1 in the liver tissues of model animals(P<0.05),and slow down the injury caused by oxidative stress to the liver.Conclusion:1.The study found that after 20 weeks of treatment with berberine,the ALT,AST,TC,TG and LDL-C levels of the model rats were significantly reduced,and the pathological damage of liver tissue was significantly improved,showing a good liver protection effect.2.Berberine may up-regulate the mRNA expression of AMPK and CPT1 in the liver tissues of rats with type 2 diabetes and down-regulate the mRNA expression of ACC and FAS.Up-regulated pAMPK,pACC and CPT1 proteins and down-regulated FAS proteins reduce lipid synthesis,promote fatty acid oxidation and reduce the injury of fat deposition to liver.3.Berberine may increase the mRNA and protein expression of Nrf2 and up-regulate the mRNA and protein expression of its downstream antioxidant molecules SOD,CAT,GSH-Px and HO1,so as to alleviate liver injury caused by oxidative stress and protect the liver. |
PDF Full Text Request