| Obgectives: To establish the model of myocardial ischemia in rats by hypodermic injectionwith isoprenaline(ISO) and comprehensively evaluate the medicinal function of cuscuta chinensisflavone resisted to myocardial ischemia from sides of electrocardiogram(ECG), hemodynamics, levels ofserum antioxidant enzymes, pathologic histology, and also preliminarily study on mechanism ofprotecction of cuscuta chinensis on cardiovascular, in order to provide the experimental basis for thedevelopment and clinical application of cuscuta chinensis flavone.Methods: SD rats are randomly allocated to control, model, low-dose of cuscuta chinensisflavone(10mg/kg), middle-dose of cuscuta chinensis flavone(20mg/kg) and hige-dose of cuscutachinensis flavone(40mg/kg) groups. To establish the model of myocardial ischemia in rats by using themethod of hypodermic injection with ISO, then collect ECG, the internal pressure of left ventricle andarterial pressure by rat limb â…¡ leads connected to16channel physiological recorder of PowerLab.Determine activity of superoxide dismutase (SOD) in serum by using hydroxylamine method, determineactivity of glutathione peroxidase (GSH-Px) by using colorimetric method. Make observation ofmyocardial tissue pathology changing by HE staining.Results:(1) Electrocardiogram indication: the heart rate of rats slowed down in model group(p<0.01) and make off-set value of ST segment increase(p<0.05), contrasted to control group; Thehigh-dose of cuscuta chinensis flavone can make heart rate of myocardial ischemia in rats slowdown(p<0.05or p<0.01) and make off-set value of ST segment decrease(p<0.05), contrasted to model group.(2) Intraventricular pressure: the rate of left ventricular systolic (LVSP),+dp/dtmax andcontraction index (CI) of model group reduced(p<0.01), the rate of left ventricular end diastolic pressure(LVEDP) and-dp/dtmax increased(p<0.01) by contrasting to control group; Low-dose, middle-dose andhigh-dose of medicine group can increase the rate of LVSP,+dp/dtmax and CI(p<0.05or p<0.01) afterintravenous administration in different degree, meanwhile, the rate of LVEDP and-dp/dtmaxreduced(p<0.05or p<0.01) by contrasting to model group.(3) Arterial pressure: after injecting ISO twominutes in model group, both the rate of systolic pressure (SP) and diastolic pressure (DP)reduced(p<0.01) by contrasting to control group. Contrasted to model group, low-dose, middle-dose andhigh-dose of medicine group can reduce the rate of SP and DP(p<0.05or p<0.01).(4) Anti-oxidationindication: activity of SOD and GSH-Px of rat serum in model group reduced(p<0.001); Group ofcuscuta chinensis flavone can significantly increase activity of SOD and GSH-Px (p<0.01or p<0.001).(5)Contrasted to control group, the pathological injury of cardiac muscle cell is obvious in model group, itsintercellular space has been increased, muscle fibers swellinged, structure arranged loosely, and appeareduniversally muscle fibers denaturation. High-dose of cuscuta chinensis flavone has obvious improvementof myocardial tissue.Conclusion: By analysizing the results of this study, we find that the medicine group can slowdown heart rate of myocardial ischemia in rats by hypodermic injection ISO, it can make off-set STsegment decrease. And it also can increase LVSP,+dp/dtmax and CI in the internal pressure of leftventricle, and reduce LVEDP,-dp/dtmax, arterial pressure and improve index of hemodynamics at thesame time. The medicine group can increase activity of SOD and GSH-Px in serum of ischemia in rats.High-dose of cuscuta chinensis flavone has high degree of improvement for tissue pathological injuryinduced by ischemia myocardial. So it indicates that cuscuta chinensis flavone has some protection for ischemia myocardial. |
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