The Protective Effect And Mechanism Of G-Rb On Myocardial Ischemia-Reperfusion Injury In Rats

Ischemic heart disease has become main disease hurthuman healthy in whole world. To search safe andeffective drugs preventing and curing ischemic heartdisease is an important task of medicine research.Ginsenoside-Rb(G-Rb)was separated from total saponinsderived from leaves and root of Panax quinquefolium Linn.Main component of G-Rb is Ginsenside-Rb1, -Rb2 and–Rb3. The protective effect and mechanism of G-Rb onmyocardial ischemia-reperfusion injury in rats were reported inthis paper. The rats were randomizied to five groups:group of sham operation(ig normal saline 2m1/kg.d×7dafter sham ligation), group of model (ig normal saline2m1/kg.d×7d after ligation),and three dose groups ofG-Rb (in a dosage of 25mg/kg, 50mg/kg and 100mg/kg.dip×7d after ligation). myocardial ischemia-reperfusion injury(MIRI)model was established as follows:After anesthetised with ether, rats were face upwardfixed on the operating table. the chest was openedbetween the left third and fourth rib,and the heart wasexposed. A nylon suture attached to a fine needle wasplaced under the left anterior descending coronary arteryand ligated coronary artery immediately. The heart wasreturn into the chest, the blood and water were squeezedout and swiftly close the chest. The time opening thechest is no more than 30 seconds. sham surgical groupplaced the suture only but not ligate coronary artery.myocardial ischemia-reperfusion injury model was induced by 30min left anterior descending coronary occulusion and 24 hoursreperfusion in rats. After 24 hours of ischemia-reperfusion, ratswere anesthetized. Blood was collected through groinaorta. The activities of serum creatinephosphokinase (CK) , Aspartate aminotransferase(AST)and lactate ehydrogenase(LDH) were tested withCOBAS-FARA automatic biochemical analyser. Thehearts were taken out and perfused with 0.9% sodiumchloride through aorta. After cutting off atrium tissue andfat, myocardium of left ventricle was cut into four or fiveslices and immersed into the N-BT phosphate buffer inwater bath at 37℃. Take them out after dying completely.Normal tissues were dyed while ischemic tissues not.Myocardial infarct size(MIS) was expressed as the ratioof ischemic myocardium weight to left ventricle wetweight. The content of lipid peroxidation (LPO),and theactivities of super oxide dismutase(SOD) and glutathioneperoxidase(GSH-Px) in serum and the levels of endothelin(ET),angiotensiⅡ(AⅡ), Prostacycline(PGI2) and thromboxaneA2 (TXA2) in plasma, the content of free fatty acid(FFA)in myocardial infarct and noninfarct areas and the ratio ofPGI2/TXA2 were determined. Blood was collect todetermine low shearing specific viscosity,middle shearingspecific viscosity, high shearing specific viscosity,plasmaspecific viscosity. Inspect the function of G-Rb on theindexes mentioned above.It was found that the MIS, the contents of LPO, andthe activities of AST, CK, LDH, SOD and GSH-Px in...