Protective Effect And Mechanism Of Isoliquiritigenin On Diabetic Cardiomyopathy Rats

Part One: Preparation and Evaluation of Diabetic Cardiomyopathy Model by StreptozotocinObjective: Preparation and evaluation of experimental Diabetic cardiomyopathy mellitus model by streptozotocin.Methods: 60 Sprague-Dawley rats, weighing 200±10g,all males. were randomly divided into 2 groups(n=30). Normal control group(CON), diabetic mellitus model group(DM). Normal control group were injected with citric acid- sodium citrate buffer(p H4.2, 5ml/kg), model group were injected with streptozotocin(STZ, 60mg/ kg), a total of 1 times. Acid- sodium citrate buffer is solvent of STZ, test blood sugar after 72 h, random 3 times a week, blood glucose ? 16.7mmol / L was selected in the model group. Control and DM group orally with 1,2- propanediol(5ml / kg.d), each divided into 3 groups(n=10): gavage 10 d, 30 d, 60d; Before the experiment,fasting the rats 12 h, Surface electrocardiogram(ECG) tracings; measurements of Left Ventricular hemodynamics indexes(HR, LVSP, LVDP, ± dp / dtmax) by Left Ventricular Intubation;Results: 10 d, 30 d, 60 d DM group than Control group the blood glucose significantly growth(P <0.05); the HR,LVDP, LVP± dp / dtmax, body weight, significantly decreased(P <0.05).Conclusion:Large injected with streptozotocin can prepared Diabetic cardiomyopathy mellitus model, blood glucose significantly growth, induce myocardial injury in rats and left ventricular function.Part two: Protective Effect and Mechanism of Isoliquiritigenin on Diabetic Cardiomyopathy RatsObjective: To explore the protective effect and mechanism of isoliquiritigenin on experimental Diabetic cardiomyopathy mellitus rats.Methods: 50 Sprague-Dawley rats, weighing 200±10g,all males. were randomly divided into 5 groups. After diabetic cardiomyopathy mellitus model group establish. Model group were randomly divided into four groups(n = 9 ~ 10): the model group(DM), isoliquiritigenin(ISO) treatment groups(ISO50, ISO100 and ISO200): Control and DM group orally with 1,2- propanediol(5ml / kg ? d), isoliquiritigenin treatment groups treated with different doses of ISO(50mg/kg ? d, 100mg/kg ? d, 200mg/kg ? d),all gavage 60 d. 1,2- propanediol is solvent of ISO. Before the experiment,fasting the rats 12 h, Surface electrocardiogram(ECG) tracings; measurements of Left Ventricular hemodynamics indexes(HR, LVSP, LVDP, ± dp / dtmax) by Left Ventricular Intubation; Abdominal aortic blood measured the levels or activity of four lipids(TG, TC, LDL-C, HDL-C), aspartate aminotransferase(AST), take measurements of erythrocyte Na +-K +-ATP enzyme, measured in plasma and the myocardial tissue malondialdehyde(MDA), superoxide dismutase(SOD), glutathione peroxidase(GSH-PX), reduced glutathione(GSH) and catalase(CAT);HE staining of myocardial histology; Masson staining of myocardial fibrosis; western-blot detection of myocardial GLUT-1, GLUT-4, TNF-?,IGF-1, AKT, and p AKT protein expression.Results: Left ventricular blood flow in DM rats dynamics indicators(HR, LVSP, LVDP and LVP ± dp / dtmax) was significantly lower than the CON group(P <0.05); lipids TG and LDL-C was significantly higher than CON group(P <0.05), lipids TCH on the rise compared to the CON group; plasma indicators CAT, SOD, tissue GSH, GSH-PX, erythrocyte Na +-K +-ATP enzyme significantly lower(P <0.05) than the CON group; plasma AST, GSH-PX, tissue MDA, CAT rise compared with CON group(P <0.05); immunoblotting detected, compared with the CON group, the myocardial tissue DM group p AKT and TNF-? protein expression increased(P <0.05), AKT ?GLUT-4 and GLUT-1 protein expression reduction(P <0.05). HE staining DM model group, myocyte disarray, dissolved state cytoplasm, the cell gap widened, myocardial fibrosis obvious. Isoliquiritigenin treated ventricular hemodynamics ± dp/dtmax compared with DM group, +dp/dtmax was significantly increased compared with DM group(P <0.05), low-dose ISO(50mg/kg · d) treatment group(ISO50 group)-dp/dtmax significantly increased compared with DM group(P <0.05); in the high-dose ISO(100mg/kg · d, 200mg/kg · d) treatment group(ISO100, ISO200 group) lipids(TG, LDL-C) compared with DM significantly increased group(P <0.01), ISO5 O, ISO200 group lipids(TCH) was significantly reduced(P <0.05) compared with DM group; erythrocyte Na +-K +-ATP enzyme compared with DM group on the rise, and the ISO200 group erythrocyte Na +-K +- ATP enzyme increased significantly compared with DM group(P <0.05); plasma SOD upward trend compared with DM group and DM group than ISO100 significantly increased(P <0.05); plasma GSH-PX, ISO200 group than in the DM group decreased(P < 0.05); isoliquiritigenin myocardial tissue MDA treatment group was significantly lower than the DM group(P <0.01); tissue GSH, ISO50 group compared with an increase of DM group(P <0.05); myocardial tissue CAT, ISO200 group than in the DM group decreased(P < 0.05); immunoblot detection of myocardial ISO treated group compared with the DM group, p AKT, TNF-? protein expression was decreased(P <0.05); GLUT-4, ISO100 and ISO200 groups histone expression increased(P <0.05). HE staining ISO treated cardiac histological structure recovery trend, and restore near-normal high-dose group; Masson staining ISO treated to reduce myocardial fibrosis; transmission electron microscope observation showed that ISO group improved trend, and ISO100 group recovery normal.Conclusion: Large doses of diabetic cardiomyopathy model STZ prepared diastolic left ventricular systolic function decreased myocardial injury, increased myocardial fibrosis, myocardial metabolism. ISO for the Diabetic cardiomyopathy has a protective effect; improve myocardial contractility in rat diabetic cardiomyopathy and diastolic function and reduce myocardial injury and fibrosis. Its protection mechanism isoliquiritigenin inhibit myocardial oxidative stress, improve myocardial cell metabolism, may reduction p AKT and TNF-? protein expression; increase GLUT-4 protein expression.