石榴多酚对心肌缺血/再灌注损伤大鼠心功能的保护作用

目的观察石榴多酚对心肌缺血/再灌注损伤(I/R)大鼠的心功能的影响,并初步探讨其可能机制。方法采用阻断大鼠左冠状动脉前降支45 min,再灌注180 min心肌缺血/再灌注损伤模型。50只雄性SD大鼠随机分为伪结扎组(Sham)、缺血/再灌注组(I/R)和石榴多酚(150、300、600 mg/kg)组。连续监测心功能变化,实验结束后检测血浆乳酸脱氢酶(LDH)、磷酸肌酸激酶(CK)、丙二醛(MDA)含量及超氧化物歧化酶(SOD)活性,TTC染色法检测心肌梗死面积。结果与伪结扎组相比,缺血/再灌后各组大鼠的心功能指标中,左室收缩压(LVSP)、左室内压最大上升/下降速率(±dp/dtmax)明显降低(P<0.01),左室最大舒张压(LVEDP)明显升高(P<0.01);与缺血再灌模型组相比,石榴多酚(150、300、600 mg/kg)组缺血再灌大鼠的心脏收缩和舒张功能(LVSP、LVEDP及±dp/dtmax)显著改善(P<0.05);LDH、CK和MDA含量降低(P<0.01),SOD活性增加(P<0.01),心肌梗死程度减轻(P<0.01)。结论石榴多酚对缺血/再灌注损伤大鼠的心功能有显著的保护作用,其机制可能与石榴多酚提高氧自由基清除能力、降低脂质过氧化损伤,减轻心肌梗死程度有关。

Protective effects of pomegranate polyphenols on cardiac function in rats with myocardial ischemia/reperfusion injury

Objective To determine the protective effect of pomegranate polyphenols on cardiac function in rats with myocardial ischemia/reperfusion(I/R) injury and explore the possible mechanism.Methods Fifty SD rats were randomized into 5 equal groups,including a sham-operated group,an I/R model group,and 3 pomegranate polyphenol dose groups(150,300,and 600 mg/kg).The rats were subject to a 45-min left main coronary artery occlusion followed by a 180-min reperfusion to induce myocardial I/R injury except for the rats those in the sham-operated group.The cardiac functions were monitored continuously during the experiment.At the end of the reperfusion,arterial blood samples were obtained to measure plasma contents of lactate dehydrogenase(LDH),creatine kinase(CK),malondialdehyde(MDA) and the activities of superoxide dismutase(SOD).Triphenyltetrazolium chloride(TTC) staining was used to evaluate the infarct size.Results Compared with the sham-operated group,all the rats with I/R showed significantly decreased left ventricular systolic pressure(LVSP),maximal rates of increase/decrease of the left ventricular pressure(±dp/dtmax)(P<0.01) and significantly increased left ventricular end-diastolic pressure(LVEDP)(P<0.01).Compared with the I/R model group,all the 3 pomegranate polyphenol groups had significantly improved cardiac function(P<0.05),decreased plasma contents of CK,LDH and MDA(P<0.01),increased SOD activities(P<0.01),and obviously reduced infarct size(P<0.01).Conclusion Pomegranate polyphenols can protect the cardiac function of rats with I/R injury probably in association with their actions in enhancing oxygen free radical scavenging activity and decreasing lipid peroxidative damage of the myocardial tissues.