Experimental Study Of The Protective Effect Of Pharmacological Precondition Induced By GSTT On Isolated Rat Myocardium

Precondition Induced by GSTT on Isolated Rat Myocardium Objective: To investigate the protective effect of Gross Saponins from Tribulus terrestris L.(GSTT) preconditioning against ischemic-reperfusion injury on isolated rat heart between eleutherosid preconditioning and the myocardium protection.Methods: Isolated Wistar rat hearts were divided into 7 groups at random: Normal group: hearts were perfused by K-H perfusate for 90 minutes; Ischemia/Reperfusion (I/R)group: hearts suffered from 40-minute global ischemia/ 30-minute reperfusion; Ischemia precondition(IP) group: hearts were preconditioned by three times 5-minute global ischemia/5-minute reperfusion before it suffered from 40-minute global ischemia/30-minute reperfusion; Adenosine(Ado) group: previously hearts were perfused with K-H perfusate administered with 2.76mg/L Ado then subjected to 40-minute global ischemia/30 minute reperfusion; GSTT200mg/L(GSTT200) group: previously hearts were perfused with K-H perfusate administered with 200mg/L GSTT then subjected to 40-minute global ischemia/30 minute reperfusion; GSTT100mg/L(GSTT100) group: previously hearts were perfused with K-H perfusate administered with 100mg/L GSTT then subjected to 40-minute global ischemia/30 minute reperfusion; GSTT50mg/L(GSTT50) group: previously hearts were perfused with K-H perfusate administered with 50mg/L GSTT then subjected to 40-minute global ischemia/30 minute reperfusion. Hemodynamic parameters and coronary effluents were recorded before ischemia, at 5th min,10th min,15th min, 20th min,30th min during reperfusion. At the end of reperfusion,coronary effluents were collected in order to analyze Lactate Dehydrogenase(LDH),creatine kinase(CK),aspartate transcarbamoylase(AST) activity as an index of cellular damage induced by ischemic-reperfusion. The left ventricle was homogenized and tissue content of malonyldialdehyde(MDA), superoxide dismutase(SOD)activity and ATPase activity were analyzed.Results:â‘ The LVSP decreased,CF were increased by the perfusion of GSTT precondition.Compared with normal control, difference is notable ( P<0.01 ,P<0.05),showed that GSTT could decrease cardiac contractility and expande coronary in a dose-dependent manner.â‘¡GSTT200,100 decreased the release of LDH,CK,AST and GSTT had protective effects on ischemia-reperfusion injury myocardium. Respectively, GSTT200,100 increased myocardial SOD activity and decrease MDA level. GSTT also increased coronary effluents.â‘¢Alleviated calcium overload in myocardial cell; lessened the incidence and severity of ventricular arrhythmias; furthered activity of ATPase in myocardium.Conelusions:â‘ Gross Saponins from Tribulus terrestris L.(GSTT) can increase the coronary flow by dilating coronary artery.â‘¡GSTT exerts negative inotropic effects on myocardium and leads to a decrease of oxygen consumption.â‘¢GSTT precondition can resist toxieity of free radical and Ca²⁺-overload;lessened the incidence and severity of ventricular arrhythmias; furthered activity of ATPase in myocardium.â‘£The ischemia/reperfusion injury can be reduced by GSTT. Mechanism of the protective effect of the GSTT may be related to the increase of SOD, the decrease of MDA and the dilation of coronary artery.⑤The protective effect of GSTT preconditioning against ischemic-reperfusion injury on isolated rat heart.