[Protective effect of Ophiopogonis polysaccharide MDG-1 on experimental myocardial ischemic rats]

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.

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.

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.

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.