Protective effect of Suxiao jiuxin pill, a traditional Chinese medicine, against acute myocardial ischemia in dogs

Background: The purpose of this study was to investigate the effect of Suxiao Jiuxin Pill (SX), a traditional Chinese medicine, on acute myocardial ischemia induced by coronary occlusion in anesthetized dogs. Methods: Acute myocardial ischemia model was established by ligating the left anterior descending artery to reduce flow by 90 %. Adult mongrel dogs were randomly divided into six groups: model, SX high dose, SX middle dose, SX low dose, Isosorbide dinitrate (ISD) and Sham groups. Adult mongrel dogs were anesthetized and instrumented for measurements of heart rate (HR), mean arterial pressure (MAP), left ventricular systolic pressure (LVSP), left ventricular dP/dt, coronary blood flow (CBF), myocardial blood flow (MBF), coronary vascular resistance (CVR), and epicardial electrocardiogram (EECG). After administration with SX, changes in hemodynamics were recorded. Serum enzymes and blood gas analysis were also detected. Results: SX has a dose-dependent effect on the reduction of infarct size. Besides, SX exerted a notable inhibition on the elevation of serum creatine kinase MB (CK-MB), lactate dehydrogenase (LDH), malondialdehyde (MDA), and elevation in the superoxide dismutase (SOD) activity. SX also showed a capacity to recover myocardial function by significantly reducing MAP, CVR, LVSP, left ventricular systolic pressure (LVEDP), systolic blood pressure (SBP), diastolic blood pressure (SDP), and increasing CBF and myocardial blood flow (MBF). In addition, SX high dose group markedly reduced total mV of ST segment elevation (Sigma-ST), total number of sites with this degree of ST segment elevation (N-ST) and oxygen extraction ratio (O-2 Extr). Conclusion: SX can improve hemodynamic and myocardial oxygen metabolism, reduce the degree and scope of myocardial ischemia, and hence exert notable anti-anginal ischaemic effect.