Experimental Study Of Anti-Oxidative Stress Action Of DAA-I With Danshensu On Myocardial Ischemia Injury In Rats

Objective:Through continuous subcutaneous injection with isoprenaline hydrochloride(ISO) to induce rodent model of myocardial ischemic injury in rat, we observed the level of both superoxide dismutase(SOD) and Malondialdehyde(MDA) during ischemic injury process, explored the possible action and mechanism of Des-Aspartate-angiotensin-I(DAA-I) in oxidative stress injury, and also attempted to evaluate therapeutic effectiveness for DAA-I on the treatment of ischemic heart disease by pre-clinical animal experiments.Methods:Sprague-Dawley rats were randomly selected and categorized into control group, model group, DAA-I prevention group, DAA-I treatment group, DAA-I+Danshensu group, Danshensu treatment group and valsartan treatment group. Myocardial ischemia was induced by using ISO with repeated s.c. method. The first dose at 4mg/kg and the second dose at 2mg/kg and the control group was injected with 0.9%NS i.p. From the 6th day onwards, control group and model group were injected with 0.9%NS i.p.; DAA-I treatment group, DAA-I+Danshensu group and Danshensu group were injected with DAA-I(1013pmol/kg/d) and Danshensu(50mg/kg/d) respectively; valsartan group was treated with valsartan(30mg/kg/d) by gastric irrigation. DAA-I prevention group was injected with DAA-I(1013/pmol/kg/d) continuously for 12 days. Animal model of myocardial ischemia injury were induced through subcutaneous injection with ISO for twice continuously on Sprague-Dawley rats. Related medications were administrated for 7 days and all rats were executed after 13 days of model building. Part of left ventricular myocardium was dissected for tissue homogenate and colorimetry was applied to detect the SOD activity as well as MDA content; the left part of ventricular myocardium was used to make histopathological slices and observe the injury extent of myocardial tissue under optical microscope after conventional chemical fixation.Results:1.SOD activity comparison:model group had the SOD activity reduced by 55.66±8.09 (U/mgprot) when compared with control group. The SOD activity of myocardial tissue homogenate in the model group was significantly lower than that in the control group(P<0.01). DAA-Ⅰprevention group and Danshensu group had higher SOD activity when compared with model group(P<0.05). DAA-Ⅰtreatment group and DAA-Ⅰ+Danshensu group had activity levels of 91.21±19.13 and 98.96±21.30 (U/mgprot) respectively. Valsartan group had activity level at 71.34±20.90 (U/mgprot). Comparison between treatment groups show that DAA-Ⅰ+Danshensu group had a higher SOD activity than valsartan group.2.MDA content comparison:the content of lipid peroxidation product MDA in the model group was significantly higher than that in the control group(P<0.01); compared with the model group, each treatment group was indicated an increase in the activity of SOD and a decrease in the content of MDA with statistical significance(P<0.01/P<0.05), particularly the DAA-I+Danshensu group was of the most obvious.3.HE stain results:the cardiac muscle fiber structure of rats'left ventricular in the control group was distinct, regularly arranged, uniform nuclear staining, and cardiomyocytic gap was close without edema or fibrosis alteration; while myocardium of rats in the model group can be seen clearly hydropic degeneration, cell edema, dark stained nucleus with vascular bleeding, inflammatory cell infiltration, myocardial fiber atrophy, disordered arrangement and cardiomyocytic gap widened; compared with the model group, DAA-Ⅰprevention group, DAA-Ⅰtreatment group, DAA-Ⅰ+Danshensu group, valsartan group and Danshensu group all have ameliorated in various degree.Conclusions:1.Early preventative treatment and conventional treatment using DAA-Ⅰhas a significant effect in improving cardiac cell metabolism and anti-myocardial oxidative stress injury.2.DAA-Ⅰcould reduce tissue MDA content and raise SOD activity against myocardial ischemic injury.3.Danshensu and valsartan both have positive effects on arteries while a combination of DAA-Ⅰ+Danshensu would yield better results.4.Use a combination of DAA-Ⅰwith Chinese drugs could play a protective role in myocardial ischemia and improve the prognosis of ischemic heart disease, the integrated prevention and treatment in IHD will have a broad application prospect.