Cardioprotective Effects And Mechanical Study Of Total Saponin From Panax Japonicus C.A.Mey On Acute Myocardial In Farction In Rats

Objective Through establishing of acute myocardial infarction rats induced by ligating of the left anterior descending branch (LAD), our aims were to investigate the cardioprotective effects and its mechanism, To study the effect of total saponin from Panax japonicus C. A. Mey on oxidative stress-induced injuries of H9c2myocardial cells and its mechanism. On the basis of this investigations in vitro and in vivo, the possible mechanism of total saponin from Panax japonicus C. A. Mey on acute myocardial infarction was elucidated.Methods Experimental one:After the experimental rats were ligated the left anterior descending branch, survival rats were randomly divided into four groups:sham-operated, model group and low-dose、high-dose group of total saponin of Panax japonicus C. A. Mey. Twelve-four hours after ligation, treatment was begun, and physiological saline was givern to the sham-operated and model groups once a day for7days. Seven days after ligation, the rats were anaesthetized with urethane, and blood pressure, haemodynamics, infarct size, histomorphology and ultrastructural observation were assessed; the serum levels of lactate dehydrogenase (LDH), malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) were also measured. Real-time polymerase chain reaction was applied to detect the mRNA expressions of hemeoxygenasel (HO-1), thioredoxin-1(Txn-1), thioredoxin reductase-1(Txnrd-1), glutamate cysteine ligase catalytic (GCLc) and nuclear factor erythroid2-related factor2(Nrf2). Experimental two:Culturing H9c2myocardial cells, H2O2was used to induce oxidative stress injury in H9c2myocardial cells. Cells were divided into normal group, model group(H2O2) and low-dose(H2O2+50μg/mL)、high-dose(H2O2+100μg/mL) group of total saponin of Panax japonicus C. A. Mey. Cell viability was detected by MTT assay; The levels of LDH、MDA and the activities of SOD,CAT,GSH-Px in culture medium were also measured after treated by total saponin from Panax japonicus C. A. Mey for24hours; Cell apoptosis rate and reactive oxygen species (ROS) content were detected by flow cytometry, the apoptosis cells morphous were observed by hoechst33258through fluorescence microscope; Real-time polymerase chain reaction was applied to detect the mRNA expressions of Caspase3, Bcl-2and Bax apoptosis-related genes, and calculate ratios of Bcl-2to Bax.Results Experimental one:In comparison with the model group, low-dose and high-dose of total saponin from Panax japonicus C. A. Mey improved cardiac function significantly in acute myocardial infarction rats. Expressed as LVEDP reduced, SBP, DBP, MAP, LV+dp/dtmax, LV-dp/dtmax and LVSP Increased; Low-dose and high-dose of total saponin from Panax japonicus C. A. Mey significantly released the content of LDH and MDA, improved the active of SOD, CAT and GSH-Px markly; From HE staining, low-dose and high-dose groups obviously decreased infarct size (P<0.05and P<0.01, respectively), improved infiltration of inflammatory and the muscle fibers arranged in neat. Also, low-dose and high-dose groups improved mitochondrial morphology. From real-time PCR analysis, low-dose and high-dose of total saponin from Panax japonicus C. A. Mey increased the expression of HO-1、Txn-1、Txnrd-1、GCLc and Nrf2. Experimental two: Low-dose and high-dose groups increased cell viability significantly, and the contents of LDH, MDA in culture medium were remarkably decreased, and activities of SOD, CAT and GSH-Px were significantly increased (P<0.05and P<0.01, respectively); From Hoechst33342staining, low-dose and high-dose groups improved the apoptotic morphology significantly; Low-dose and high-dose groups weakened the fluorescence intensity of intracellular ROS by fluorescence microscopy remarkly; The low-dose and high-dose of total saponin from Panax japonicus C. A. Mey reduced the apoptosis rate of the myocardium cells (P<0.05and P<0.01, respectively). From the real-time quantitative PCR analysis, low-dose and high-dose of total saponin from Panax japonicus C. A. Mey released the expression of Caspase-3, and increased the ratio of Bcl-2/Bax (P<0.05and P<0.01, respectively).Conclusion Total saponin from Panax japonicus C. A. Mey exerted beneficially cardioprotective effects on acute myocardial infarction and oxidative stress injury induced by H2O2in H9c2myocardial cells. The mechanism may be related to activating Nrf2-ARE pathwayl, scavenging of ROS, regulating the Caspase-3, Bcl-2and Bax expression levels.