| Objective:To explore the improvement effect on myocardial dysfunction and fibrosis by aqueous extract of Lycopus Lycidus Turcz(ALT)in diabetic rat models of cardiomyopathy mediated by AMPK/TGF-α signaling pathway.Methods:50 SD male rats weighted 200±20 g were randomly divided into 5groups:normal group(Control);diabetic model group(DM);metformin group(MET);high-dose treatment group of ALT(ALTH);low-dose treatment group of ALT(ALTL).According to the requirement of model building,60 mg/kg streptozotocin(STZ)was injected intraperitoneally once.After 72 hours,the fasting blood glucose of rats was measured to be more than 11.1 mmol/L,this is a marker of successful modelling of diabetes mellitus.The normal group was given the disposable intraperitoneal injection of the isopyknic sodium citrate buffer(calculated according to the weight of STZ injection).The changes of blood glucose and body weight were monitored by stationary-phase every week.After 4 weeks of normal feeding,each group was given intragastric administration.Dosage and route of administration:Control group and DM group were given intragastric administration of the isopyknic physiological saline,which was calculated according to the weight of other groups;MET group,was given intragastric administration of 200 mg/kg/d;ALTL group was treated with 300 mg/kg/d intragastric administration;ALTH group,was given intragastric administration of 600 mg/kg/d.All groups were treated by intragastric administration for 8 weeks,and blood glucose and body weight were monitored by weekly stationary phase.After intragastric administration,all rats were weighed,anesthetized and fixed in proper order.The left ventricular hemodynamic changes were measured by PV-loop intubation,and the blood was taken,and the heart weight was recorded.Hemodynamic test:blood glucose,body weight and heart weight were measured.The maximum increase and decrease rate of left ventricular pressure(± dp/dt max),left ventricular systolic pressure(LVSP),left ventricular end-diastolic pressure(LVEDP);the changes of TNF-α,IL-6,ROS,SOD,MDA and GHbA1c in serum were measured by ELISA kit;HE staining was observed the pathological changes of myocardium;IHC was used to detect the changes of protein expression of Collagen-Ⅰ,Collagen-Ⅲand TGF-β antibodies in diabetic cardiomyopathy rat hearts;Masson staining was used to evaluate myocardial fibrosis;Western blotting was observed the changes of protein expression of AMPK,p-AMPK,GLUT4,TGF-β,Smad2/3,p-Smad2/3,Collagen-Ⅰ,Collagen-Ⅲ and GAPDH in cardiomyocytes.Result:After 8 weeks of intragastric administration,compared with DM group,the changes of blood glucose,heart weight and heart-body ratio in the aqueous extract of Lycopus Lycidus Turcz treatment groups were decreased significantly(P<0.01),and± dp/dt max was increased significantly(P<0.05).LVSP is not obvious,LVEDP decreased significantly(P<0.05).After gastric administration of drugs,ELISA showed that compared with DM group,the serological indexes of TNF-α,IL-6,ROS,MDA and HbAlc in the ALT treatment groups were decreased significantly,while the serological indexes of SOD was increased significantly(P<0.05).HE staining showed that ALT treatment groups could improve the morphological changes of cardiomyocyte structure disorder and gap enlargement in diabetic cardiomyopathy rats,especially,the improvement of ALTH group was more obvious.Masson staining and CVF(collagen volume fraction)quantitative analysis showed that compared with DM group,ALT treatment group could reverse the original increase of blue collagen fibers and CVF value,and reduce the severity of myocardial fibrosis,especially in ALTH group(P<0.01).IHC showed that the change of expression of Collagen-I,Collagen-III and TGF-β in the ALT treatment groups were significantly decreased,compared with those in DM group(P<0.05).Western blotting showed that compared with diabetic model group,the protein levels of p-AMPK/AMPK and GLUT4 in the ALT treatment groups were increased significantly,while the levels of TGF-β and its downstream p-Smad2/3/Smad2/3 decreased significantly,and the protein expressions of Collagen-I and Collagen-Ⅲ decreased significantly(P<0.01).Conclusion:ALT had protective effect on cardiac dysfunction and myocardial fibrosis in diabetic rat model of cardiomyopathy and it might be associated with AMPK/TGF-β signaling pathway. |
PDF Full Text Request