Study On Anti-Myocardial Ischemia Effect And Its Mechanism Of Salvianolic Acid B

PurposeTo observe the effect of SalB and to explore its mechanism on myocardial ischemia/reperfusion.To provide reasonable preclinical experimental basis for the clinical use of SalB.Methods1.Twenty-four adult Sprague-Dawley rats and divided into 4 groups,control group,model group,low digoxin positive drug group and SalB,the high dose group.In addition to the sham group,the other groups of rats were established model of myocardial ischemia.After modeled,the first seven days of the first day of administration by intravenous injection of imaging agent.1h after injection,to observe on average standard uptake value(SUV mean)of rat heart Through Micro-PET scans,VOI outlined by evaluating the rate of change of myocardial infarction.2.Take coronary artery ligation in dogs,Use of epicardial potential instrument to record 1,5,10,15,30,45,60,90,120min of EECG,SAP,DAP,MAP,HR.before ligation,ligation 15min and after administration Map each point EECG ST-segment deviation statistics ∑-ST,and ST-segment elevation above the N-ST≥2mv.Each group tests blood oxygen from left ventricular arterial and coronary sinus before and after the administration of 60min,the difference to reflect myocardial oxygen.Femoral vein blood before ligation,ligation 15min and after administration 60min,test serum CK,LDH values.After the end of the experiment,immediately remove the heart,after saline wash blood,weighed heavy heart and ventricular weight,And cut cardiac ventricle into 5 plate,Placed them into 37℃ 0.5%NBT solution for 15min.Cut each piece is stained myocardial infarct zone of non,Weigh the unstained infarcted myocardium,accounted for Total infarct ventricular heart weight or weight percentage.3.Seed cell H9C2 in 96-well plates With 104/well after cell counting,Induced H9C2 In 200μmol/L H2O2.To observe H9C2 cell viability which H2O2 induced with SalB low,middle and high doses,and ROS expression levels in cells,and the effect of CK,MDA and CTSD content.4.Rats were randomized to the control group,model group,positive group,SalB high,medium and low dose group.Injection 2ml Corresponding drug by vena caudalis.After the last administration except the control group,injection of ISO 5mg,2 times a day for two days.The first three days after modeling,fasting for 12h,Tracings electrocardiogram(ECG).Test serum Creatine phosphokinase,β-glucuronidase and cathepsin D.Test the content of β-glucuronidase and cathepsin D in the 10%heart homogenate.And test the content of P-glucuronidase and cathepsin D in another lysosomal heart homogenates from heart homogenate which was centrifuged with high speed.Take heart in the part of the heart’s lower 1/3 to observe myocardial infarct size.Results:1.SalB can obviously improve the activity of myocardial by increasingly uptaking 18F-FDG、13NH3·H2O.Also SalB can reduce myocardial infarct size and increase myocardial perfusion in ischemic tissue perfusion.Above all,it proves that Micro-PET could be regard as the new method for evaluating the effects of myocardial preservation and possesses the ability of cardioprotective effects(P<0.01,P<0.05).2.Compared with the model group,the low、medium and high doses of SalB can significantly reduce myocardial oxygen consumption(P<0.05),Reduce E-ST、N-ST in coronary artery ligation-induced myocardial infarction in anesthetized dogs in part time(P<0.05,P<0.01).The three doses of SalB can also reduce the release of LDH and CK and myocardial infarct size in coronary artery ligation-induced myocardial infarction dogs.3.Compared with the normal group,cell viability significantly decreases(P<0.01)in H2O2 group.The low,medium and high doses of SalB notabely increase cell viability(P<0.01).Also,the fluorescence intensity level of ROS in H9C2 cell significantly decreases in the low、medium and high doses of SalB,compared with H2O2 group(P<0.05 or P<0.01).CK、MDA and CTSD level in H9C2 cell supernatant induced by H2O2 in SalB groups lower than H2O2 group(P<0.05 or P<0.01).4.Compared with the model group,T-wave elevation values significantly decreases(P<0.05 or P<0.01)in the period of 5min to 30min in SalB groups.In the low doses of SalB,T-wave elevation values notabely decreases(P<0.05 or P<0.01)at the time of 10min and 20min.The enzyme activities of CK and β-glucuronidase are lower in serum of SalB groups than in the model group(P<0.05 or P<0.01).The enzyme activity of Cathepsin D is lower in serum of SalB groups than in the model group(P<0.05 or P<0.01).In the tissue homogenates,The enzyme activity of Cathepsin D decreases in the medium and high doses of SalB compared with the model group.The enzyme activity of β-glucuronidase notabely increases in the lysosomal homogenates comparing SalB groups and the model group(P<0.05 or P<0.01).The content of Cathepsin D in the lysosomal homogenates significantly increases in the high dose of SalB group compared with the model group.Myocardial fibrosis and necrosis and inflammatory cell infiltration show differences between the medium doses of SalB and the model group.Conclusions:1.Taking the technology of Micro-PET,the cardioprotective effects of SalB can be observed in living conditions.2.SalB can significantly reduce the extent of myocardial ischemia in coronary artery ligation-induced myocardial infarction dogs.3.SalB can repair the cell viability in H2O2-induced H9C2 cell.The enzyme activities of ROS、CK、MDA and CTSD are suppressed by the effects of SalB in H2O2-induced H9C2 cell.4.Through the effects of SalB,the ECG is modified in myocardial ischemia rats.The enzyme activity of β-glucuronidase is suppressed in serum.The enzyme activity of Cathepsin D is suppressed in serum and heart homogenates.The enzyme activities of P-glucuronidase and Cathepsin D are incresed in heart homogenates.Also SalB can ameliorate pathology of ischemic myocardium.