麦冬多糖MDG-1对鼠实验性心肌缺血的保护作用

Protective Effect of Ophiopogonis Polysaccharide MDG-1 on Experimental Myocardial Ischemic Rats

目的研究麦冬多糖(MDG-1)对鼠离体心脏缺血再灌注损伤和皮下注射异丙肾上腺素致急性心肌缺血的保护作用。方法在离体实验中,采用Langendorff豚鼠离体心脏缺血再灌注模型,将豚鼠随机分为缺血再灌注损伤组(IRI)、阳性对照组(果糖二磷酸钠,FDP)和MDG-1给药组。阳性对照组和MDG-1给药组各设10^(-6)～10^(-4)g/mL 3个剂量,分别测定缺血再灌注后不同时间的心脏收缩幅度、心率、冠脉流量。在整体动物实验中,采用大鼠皮下注射异丙肾上腺素致急性心肌缺血的模型,分别给予大鼠口服MDG-1 10、20、40 mg/kg,以普奈洛尔为阳性对照,分别设置模型组和正常对照组,观察心电图ST段位移和血浆乳酸脱氢酶(LDH)的活性。结果在离体实验中,不同剂量的MDG-1可以增加离体心脏缺血再灌注后的冠脉流量(P<0.01),较快恢复心脏收缩幅度(P<0.01),抑制由缺血再灌注引起的心率加快(P<0.01)。在整体实验中,给予大鼠口服40 mg/kg MDG-1可以抑制异丙肾上腺素导致的心肌缺血大鼠血浆LDH活性的升高(P<0.05),而对心电图ST段位移无显著的影响(P>0.05)。结论MDG-1具有拮抗豚鼠离体心脏缺血再灌注损伤的作用,口服MDG-1对异丙肾上腺素所致大鼠心肌缺血损伤具有一定的保护作用。

Objective To investigate the protective effect of Ophiopogonis polysaccharide （MDG-1） on isolated myocardium ischemia/reperfusion injury （IRI） and subcutaneous injection of isoprenaline induced acute myocardial ischemia. Methods In ex vivo heart experiment： Langendorff guinea pigs were randomly divided into the IRI group, the fructose sodium diphosphate （FDP） group, treated with FDP 10^-6 -- 10^-4 g/mL for positive control and the MDG groups treated with MDG-1 10^-6 -- 10^-4 g/mL. The amplitude and frequency of cardiac contraction, coronary blood flow at different time points after ischemia reperfusion were measured. In integral animal experiments： acute myocardium ischemia model rats established by subcutaneous injection of isoprenaline were used, they were administered with MDG-1 in dosage of 10, 20 and 40 mg/kg respectively, and controlled with propranolol. Besides, a normal control group and an untreated model group for control were set up. The ST segment shift in ECG and lactate dehydrogenase （LDH） activity in serum were observed. Results Ex vivo heart experiment showed that different doses of MDG-1 can increase IRI caused abnormal coronary blood flow, quickly resume the heart contraction and restrain the quickened heart rate （all P 〈 0.01）. The integral animal experiment showed that oral administration of 40 mg/kg can reduce the increased activity of LDH in serum （P 〈 0.05） induced by isoprenaline, but almost had no effect on ST-segment shift in ECG. Conclusion MDG-1 can alleviate IRI isolated myocardium of guinea pigs, and oral administration of MDG-1 showed a definite protection on isoprenaline caused rats＇ myocardial ischemia damage.