人参皂苷Rb1预处理对糖尿病大鼠心肌缺血再灌注损伤的保护作用

Protective Effect of Ginsenoside Rb1 Pre-conditioning on Myocardium Against Ischemia-reperfusion Injury In Diabetic Rats

目的:观察人参皂苷Rb1预处理对糖尿病大鼠心肌缺血/再灌注损伤的保护作用及其对心肌丙二醛(MDA)和超氧化物岐化酶(SOD)的影响。方法:糖尿病模型制备成功的健康雄性SD大鼠30只,喂养8周后,随机分为3组(n=10):假手术组(Sham组)、缺血再灌注组(I/R组)、人参皂苷Rb1治疗组(Rb1组)。I/R组、Rb1组均采用结扎-开放左冠状动脉前降支(LAD)法建立心肌缺血/再灌注模型,Sham组只穿线包绕不结扎;Rb1组缺血前10min静脉输注人参皂苷Rb1 40mg/kg,Sham组和I/R组静脉输注等容量的晶体和胶体液(晶胶比3:1)。大鼠心肌缺血30min,再灌注120min后处死,术中监测心率(HR)、平均动脉压(MAP)并计算心率收缩压乘积(RPP)。术后计算左心室心肌梗死面积(IS/AAR)、缺血区面积(AAR/LV),光镜下观察心肌组织病理变化;测定血清乳酸脱氢酶(LDH)、肌酸激酶(CK)及心肌组织丙二醛(MDA)、超氧化物岐化酶(SOD)。评价人参皂苷Rb1预处理对糖尿病大鼠心肌缺血/再灌注损伤的保护作用。结果:术中监测血流动力学指标(HR、MAP、RPP)无统计学差异。(1)与Sham组比较,I/R组、Rb1组心肌梗死面积增加,血清LDH、CK值升高,心肌组织MDA值升高,SOD值减小(P<0.05);(2)与I/R组比较,Rb1组心肌梗死面积减少,血清LDH、CK值降低,心肌组织MDA值减小、SOD值升高,Rb1组心肌组织病理损伤程度明显轻于I/R组。结论:人参皂苷Rb1预处理可减轻糖尿病大鼠的心肌缺血/再灌注损伤,其机制可能与减少氧自由基损伤和氧化应激有关。

Objectlve：To investigate the effect of Ginsenoside Rbt pre-conditioning on myocardial MDA,SOD during ischemia- reperfusion（l/R）of myocardium in diabetic rats.Methods＇Thirty healthy adult male SD rats weighing 220-280g were used in this study.Type I diabetes mellims was induced by intraperitoneal streptozotocin 65mg.kg-1and confirmed by fasting blood glucose〉16.7mmol·L-1.The animals were randomly divided into 3 groups（n=10 each）：sham-operated,ischemia--reperfusion（l/R）,ginsenoside Rbl＋ I/R.Ischemia-reperfusion was produced by occlusion of the anterior descending branch of left coronary artery（LAD）for 30rain.The occlusion of LAD was released for repcrfusion 120rain.In Sham operation group,LAD was exposed but not occluded.In group Rbl ginsenoside Rbl 40mg.kg-1was injected into internal femoral vein J Omin before occlusion.ln group sham and group I/R,the mixture of balanced solution and polygeline（rate 3： 1 ）was injected.HR,MAP were recorded 10min before ischemia（T l,baseline）,at 15rain of ischemia（T2）,reperfusion 30min,60mim 120min（T3-T5）. The rate pressure prodnct（RPP）was calculated as the product of the heart rate and the peak mean arterial pressure.The concentration of total superoxide dismutase（T-SOD）and malonyl-dialdehyde（Ml）A）in myocardial tissue were determined.Infarct size was assessed by triphenyltetraz oliumchloride（TTC）staining.Plasma creatine kinases （CK）,lactate dehydrogenase（LDH）were also measured.Results：There was no statistically significant difference in ttR, MAP, RPP.（I）Compared with Sham group,the activity of CK, LDH in the blood plasma and the level of MDA were higher, while the activity of SOD were lower.The myocardial infract size was also increased in group l/R（P〈O.O5）.（2）Compared with 1/R group,the activity of CK, LDH in the blood plasma and the level of MDA were lower, white the activity of SOD were higher.The myocardial infract size was also decreased in Rbl group（P〈O.O5）.（3）The myocardium tissue histological damage was attenuated by ginsenoside RbI（P〈0.05,Rbl group vs I/R group）.Conclusion：The results suggest that Ginsenoside Rb/ protects the diabetic rats myocardium against ischemia/reperfusion injury via a mechanism related to decreasing the oxidative stress and reduction of free radical caused injury.