Protective Effect And Mechanism Of Glycyrrhizin On HAART Drugs Myocardial Injury In Rats

Section I The Preparation of Experimental Model of HAART Drugs on Myocardial Injury and Glycyrrhizin Intervention in RatsObjective:The preparation and evaluation of HAART drugs injury on myocardium in rats and glycyrrhizin intervention experimental models.Method:30 male Sprague-Dawley rats, weighing 200±10g, were randomly divided into five groups(n=6): normal group(CON), HAART qd, HAART bid, GL qd and GL bid. CON group rats were intragastric administrated with nomal saline(NS, 10ml/kg), one time at 8am and the other at 6pm each day; HAART qd group rats with the same volume of HAART drugs containing(AZT 62.5 mg/kg+3TC 31.25 mg/kg+LPV/r 83.33/20.83mg/kg) at 8am, and the same volume of NS at 6pm; HAART bid group rats with the same volume of HARRT drugs containing AZT 31.25 mg/kg,3TC 15.63 mg/kg, LPV/r 41.67/10.42 mg/ kg at 8am and 6pm; GL qd group rats with the same volume of HAART drugs(as HAART qd group) and glycyrrhizin(200mg/kg) at 8am, and same volume of NS at 6pm; GL bid group rats with same volume of HAART drugs(as HAART bid group) and glycyrrhizin(100mg/kg) at 8am and 6pm. Each rat was weighed before intragastric administration and fed for 4 weeks. After the last administration, the rats were fasted for 12 h and measured ECG, left ventricle hemodynamic parameters(HR, LVSP, LVEDP, LVP ± dp/dtmax) to evaluate heart function.Results:Compared with the CON group, the weight gain in HAART rats was less; and the weight gain of HAART qd rats was less than HAART bid rats. Compared with HAART qd group, GL qd failed to increased rats weight gain. Compared with HAART bid group, GL bid increased rats weight. Compared with the CON group, LVSP, LVP+dp/dtmax and LVP-dp/dtmax in the HAART rats were decreased, LVEDP increased, showed that HAART rats heart systolic and diastolic dysfunction; compared with HAART qd group, GL qd group had no improvement rats heart function; compared with HAART bid group, GL bid group improved heart function.Conclusion:Rats were damage after intragastric administration HAART drugs for 28 days, showed less weight gain and heart systolic and diastolic dysfunction; The damages in HARRT bid rats(HAART drugs fed twice a day) were less than once a day(HARRT qd).Taking glycyrrhizin(200mg/kg) once a day failed to reduce the damage of HAART qd group, while glycyrrhizin(100mg/kg) twice a day reduced the damage caused by HAART bid.Section II The Protective Effect and Mechanism of Glycyrrhizin on HAART drugs Myocardial Injury in RatsObjective:To investigate protective effect and mechanism of different dose of Glycyrrhizin on HAART drugs myocardial injury in rats.Method:60 males Sprague-Dawley rats, eight-weeks old, were randomly divided into five groups(n=12): control group(CON), model group(HAART) and low, medium and high doses of glycyrrhizin protection group(GL 50, GL100, GL200). CON group intragastric administrated with saline(NS, 10ml/ kg) at 8 am and 6pm each day; HAART group with same volume of HAART drugs containing(AZT 31.25 mg/kg +3TC 15.63 mg/kg + LPV/r 41.67/10.42 mg/kg); GL 50, GL100, GL200 group with HAART drugs and glycyrrhizin(25,50,100mg/kg) respectively. Each rat was weighed before intragastric administration and fed for 4 weeks. After the last administration, the rats were fasted for 12 h and measured ECG, left ventricle hemodynamic parameters (HR, LVSP, LVEDP, LVP ± dp/dtmax) to evaluate heart function; taken carotid artery blood for measurement hemoglobin, lipids(TG, CHOL, LDL-C, HDL-C), aspartate aminotransferase(AST), creatine kinase(CK), creatine kinase-isozyme(CK-MB), lactate dehydrogenase(LDH) and cardiac troponin I(c Tn I); taken red blood cells, cardiac tissue and mitochondrial homogenates to measure Na+-K+-ATP enzyme; taken plasma and cardiac tissue and mitochondrial homogenates to measure malondialdehyde(MDA), superoxide dismutase(SOD), glutathione peroxidase(GSH-PX), reduced glutathione(GSH); HE staining of myocardial histology; Masson staining of myocardial tissue fibers; TEM examination of myocardial cell ultrastructure; immunoblot protein expression detected the heart myocardium bcl-2,bax and c Tn I.Result:Compared with the CON group, the weight gain in HAART rats was less, ST segment depressed, heart rate decreased, left ventricular systolic and diastolic dysfunction, blood lipids TG and CHOL increased, HDL-C decreased, serum myocardial enzymes raised, red blood cells, cardiac tissue and cardiac mitochondrial Na+-K+-ATP activity decreased, plasma lipid peroxidation products MDA increased, antioxidant SOD, GSH-PX and GSH decreased, myocardial tissue and mitochondrial MDA increased, SOD, GSH-PX and GSH reduced, HE staining showed myocardial histology structural damage, Masson staining of myocardial fibrosis, myocardial cell ultrastructure TEM examination showed cardiomyocytes myofibrils and mitochondrial structural abnormalities, Western blotting analysis showed that the myocardial tissue c Tn I and bcl-2 protein expression decreased, and bax protein expression increased.Compared with the HAART group, GL intervention group rats body weight increased; the depressed ST segment recovered to normal, left ventricular systolic and diastolic function improved; TG, CHOL and LDL-C decreased, HDL-C increased; serum AST, LDH,CK and CK-MB, c Tn I decreased; erythrocyte Na+-K+-ATP activity,myocardial tissue and mitochondrial Na+-K+-ATP activity increased; plasma SOD, GSH-PX and GSH activity increased, MDA decreased; myocardial tissue and mitochondrial MDA decreased, SOD, GSH-PX and GSH increased; HE staining showed histological structure of myocardial damage mitigation, Masson staining showed myocardial fibrosis reduction, myocardial ultrastructure TEM examination displayed cardiomyocytes myofibrils, mitochondria structure recovered to normal, Western blotting analysis showed that bcl-2 protein expression in cardiac tissue and c Tn I increased, the expression of bax decreased.Conclusion:HAART drugs intragastric administrated for 4 weeks, resulting rats injury and myocardial function and metabolism and structural abnormalities. Appropriate dose of glycyrrhizin can protect rats, increase weight gain, maintain normal cardiac function, metabolism and structure. The protective mechanisms of glycyrrhizin relatived to improve lipid metabolism, protect red blood cells and cardiac tissue and mitochondrial energy metabolism, and enhance antioxidant capacity, reduce the production of free radicals and reduce cardiac apoptosis.