The Study Of Ginsenoside Rg₁ On Angiogenesis And Anti-apoptosis In Rat AMI

ObjectiveRemedial angiogenesis would become a new treatment mode, and be of benefitto the patient in coronary artery diffuse process and unacceptable blood vessel restitution. Myocardial cell apoptosis are concerned with ventricle remodeling and functionnless after acute myocardial infarction (AMI), and exist in both infarction area and noinfarction area. After infarction myocardial cell keep on variance at quantity and qua-lity. Angiogenesis and apoptosis effect on myocardial remodeling, but research of mol-ecular biology is few yet.Generally, vascular endothelial cell renewing rate is low, and only about 0.25percent of endothelial cell present in division cycle. Under some specific physiologyand pathology circumstance, endothelial cell in blood capillary vein can enter quicklydivision cycle and participate in angiogenesis. Myocardial ischemia new vesselsimprove obviously, humoral factor play a key part in this process. Hypoxia inducingfactor-1α(HIF-1α) participate in many transcription regulation of hypoxia reactiongene in body, and is a key factor in hypoxia reaction and is important tomicrocirculatory reconstruction after tissue postischemia. HIF-1αbinding with targetgene can adjust transcription and regulation of post-transcription, so that the body canrise adjustment reaction in hypoxia and ischemic. Increasing of HIF-1αactivity couldreduce myocardial damage after ischemia. Target gene action include vascularendothelial growth factor (VEGF) and endothelin-1 (ET-1) rising, glycoclasticenhancing, nitric oxide synthase (NOS) reaction increasing, atrial natriureticpolypeptide (ANP) improving, and so on. The diversities are close to the effect of HIF-1αacting on target gene action. Among of target gene action, VEGF haverepresentation mostly, and express in different histiocyte, and promote angiogenesis toensure microcirculatory establishment in the revival process of ischemic tissue. Thestudy of medicine promoting angiogenesis in infarction area became hot spot.Myocardial apoptosis exist in many cardiovascular diseases such as acutemyocardial ischemia and myocardial infarction, and cooperate with its occurrence anddevelopment. Abbate considered that myocardial apoptosis was an important pathologyprocess in ventricle remolding and heart failure, and was concerned with many genesexpression, such as chondriosome damaged and Bcl-2/Bax balanced state. How toreduce myocardial apoptosis in both infarction area and no infarction area, becomeimportant step to improve survival rate and to raise quality of life after myocardialinfarct.It finds that the activity of ginsenoside Rg₁ resemble angiogenin, and give newtreatment to many patients without revascularizating opportunity. Ginseng is a valuablemedical material applied extensively, and is isolated to tens of compositions. Foundthat simple substance Rg₁ and Re promoted angiogenesis, but Rg₃ hasanti-angiogenesis. So, it is important to research the simple substance of ginsenoside, itcan provide rationale for those men without change getting revascularizating treatment.This studying aimed at knowing the mechanisms and influence of ginsenoside Rg₁effecting on angiogenesis, VEGF and HIF-1αIt is necessary to research a newtreatment of reducing ischemic myocardial damage. And, this study is also set up amodel of myocardial cell with hypoxia/reperfusion, and observed myocardial cellapoptosis rate and relating gene changing and anti-apoptosis action of ginsenoside Rg₁.MethodsTo establish the model of AMI in rats, 104 Wistar rats were randomly divided intonon-operation group, AMI control group, low ginsenoside Rg₁ group (1mg P kg) andhigh ginsenoside Rg₁ group (5mg P kg). Myocardial enzyme, infarct area, microvasc-ular density, VEGF and HIF-1αmRNA were detected at 3, 7, 10, 14day after opera- tion.The model of primary cultured myocardial cell with hypoxia/reperfusion were established, and were randomly divided into control group, hypoxia/reperfusion group,and ginsenoside Rg₁ treatment group. Morphology of myocardial cell apoptosis, apopt-osis rate, bcl-2 and bax mRNA were detected.Results1. Myocardial creatase observationNon-operation group was lower obviously than other groups (P＜0.01), andginsenoside Rg₁ treatment group was lower obviously than control group (P＜0.05). Itindicated that ginsenoside Rg₁ could reduce ischemic myocardial damage.2. Infarct area affectionIn low ginsenoside Rg₁ group and high ginsenoside Rg₁ group,infarct areas were decreased dramatically than in control group(P＜0.05).3. Infarction myocardial angiogenesis observationUnder light microscope, new vessels were found that it wasdistributing more in endocardium than in epicardium, and more in ischemic marginalzone than in infarct center. Infarct area angiogenesis was raised quickly aftermyocardial infarction. Microvascular density in treatment group was kept improvingstably, and was increased than control group (P＜0.01).4. The expression of VEGF protein in infarct areaThe expression of VEGF protein of infarct groups were higherthan those of no operation group, and the expression of VEGF protein of treatmentgroups in 3d, 7d and 10d were rising gradually than those of control groups(P＜0.01),but were stopping in 14d, even if were reducing at control group. The expression ofVEGF protein was significant between different dosage groups.5. The expression of VEGF and HIF-1αmRNAThe expression of VEGF and HIF-1αmRNA of infarct groupswere higher than those of no operation group, increasing gradually, rising than those of control groups(P＜0.01). But The expression of VEGF and HIF-1αmRNA werefound contradict tendency that the expression of VEGF mRNA halted or decreased andthe expression of HIF-1αmRNA continued to rise. The expression of VEGF andHIF-1αmRNA were significant between different dosage groups.6. MTT measuring myocardial cell activity.Myocardial cell activity in 1.0 mg P L treatment group was increasing comparedwith single hypoxia/reperfusion group. Myocardial cell activity in 2.5 and 5.0 mg P Lgroups were higher than in 1.0 mg P L, but there were not the significance of them.7. Morphology of myocardial cell apoptosisApoptosis cells were few in control group, and were found in hypoxia/reperfusiongroups.8. Myocardial cell apoptosis rate measuringApoptosis rates in simple hypoxia/reperfusion groups were higher than inginsenoside Rg₁ groups, and had no obviously change with reperfusion extending.Apoptosis rates were reduced with ginsenoside Rg₁ treatment that had dose-effectrelationship in some concentration range.9. Expression of bcl-2 and bax mRNA in myocardial cellObviously, the rate of bcl-2/bax in ginsenoside Rg₁ treatmentgroups (T1 and T3 groups) during 3 hours reperfusion were higher than in simplehypoxia/reperfusion groups (P＜0.05). The rate of bcl-2/ bax in ginsenoside Rg₁treatment groups (T2 and T4 groups) during 18 hours reperfusion were lower thanduring 3 hours reperfusion, but still higher to simple hypoxia/reperfusion groups during18 hours reperfusion (P＜0.05).Conclusion1. Approved that injection of ginsenoside Rg₁ could induce myocardial creataseand infarct area, increase VEGF and HIF-1αexpression, improve angiogenesis andlessen the myocardial ischemic damage.2. Ginsenoside Rg₁ could effect on myocardial cell activity with right dose-effect relationship in some concentration range, and improve hypoxia/reperfusionmyocardial cell apoptosis through increasing the rate of Bcl-2/Bax.