| Background Myocardial ischemia-reperfusion injury(MIRI)refers to pathological phenomena about aggravating myocardial damage when the flow regains after flow blockage resulting from coronary artery occlusion.The pathogenesis mechanisms of acute MIRI is various and complicated.Some study showed that lipid peroxidation induced by oxy radical is one of important causes of acute MIRI.How to reduce peroxidation and improve the compensatory ability for peroxidation is one of the hot spots in myocardial preservation of MIRI.Medicine preconditioning is frequently-used research techniques about the study of MIRI protection mechanism.There are astragalus polysaccharides,astragalus flavone and astragalus saponin in astragalus,These constituents can strong heart,antioxygenation,and improve the body’s immune function.So we choose astragalus injection as preconditioning medicine,to evaluate the effect of astragalus injection on acute MIRI.Objective Take rats with myocardial ischemia-reperfusion injury as experimental animal,to explore the effects of astragalus injection on MIRI in through observe the electrocardiogram(ECG),cardiac muscle cells ultramicrostructure,the contents of malondialdehyde(MDA),the contents and activity of superoxidedismutase(SOD)and the contents and activity of Na~+-K~+-ATPase in cardiac muscle tissue.Methods Totally 30 adult SD rats were divided into 3 groups at random:astragalus group,MIRI group and control group.The astragalus group rats were given astragalus injection40mg·kg-1 every day by intraperitoneal injection for 6 days.Those rats of MIRI group and control group were given normal saline 40mg·kg-1 every day by intraperitoneal injection for 6 days.7th day,all rats were operated.Model of acute MIRI were developed in astragalus group rats in vivo through ligatured and revascularize the left anterior descending artery of rats astragalus group and MIRI group,but there are not these operation for control group rats.Reperfusion 180 minutes,all rats were killed.measure withⅡleads electrocardiogram by electrocardiograph,test cardiac muscle cells` ultrastructure by transmission electron microscopy,test the content of MDA in cardiac muscle tissue by thiobarbituric acid reactive substance assay,test the content of SOD and Na~+-K~+-ATPase in cardiac muscle tissue by enzyme linked immunosorbent assays(ELISA),test the activity of SOD in cardiac muscle tissue by xanthinoxidase method,test the activity of Na~+-K~+-ATPase in cardiac muscle tissue by Inorganic phosphorus method,and test the level of m RNA of Mn-SOD and Na~+-K~+-ATPase gene-α1 in cardiac muscle tissue by reverse transcription-polymerase chain reaction.All datas were retained and analysed through SPSS 17.0 statistical software(P<0.05).Result1.The ECG of rats astragalus group and MIRI group were normal before ischemia,ischemia 30 min,ECG of these two group rats displayed high pointed T wave and elevated S-T segment,and there are difference about date of S-T inthese two groups.Reperfusion120 min,ECG of these two group rats displayed drops highly S-T segment,and the degree of drops highly S-T segment of astragalus group rats was greater than that of MIRI rats.Reperfusion 120 min,ECG of these two group rats displayed elevated S-T segment once more,and the degree of elevated S-T segment of astragalus group rats was less than that of MIRI rats.The ECG of control group rats was always normal.2.The ultrastructure of cardiac muscle cells of astragalus group rats displayed cellular swelling,mitochondria cristae swelling,mitochondria membrane structures still be intact.The ultrastructure of cardiac muscle cells of MIRI group rats displayed cellular swelling or rupture,mitochondria cristae rupture or disappeared,mitochondria membrane structures rupture.The ultrastructure of cardiac muscle cells of control group rats displayed normal.3.In cardiac muscle tissue,the content of MDA of astragalus group rats was less than that of MIRI group rats;the content of SOD and Na~+-K~+-ATPase of astragalus group rats were more than these of MIRI group rats;the activity of SOD and Na~+-K~+-ATPase of astragalus group rats were higher than these of MIRI group rats.4.In cardiac muscle tissue,he level of m RNA of Mn-SOD and Na~+-K~+-ATPase gene-α1 of astragalus group rats was higher than these of MIRI group rats.Conclusion1.Astragalus injection can attenuate the injury of myocardium ultrastructure,increase the content and activity of SOD,decrease the content of acute MDA,increase the content and activity of Na~+-K~+-ATPase in acute MIRI cardiac muscle tissue.2.Astragalus injection preconditioning can alleviate myocardial structure damage and protect cardiac function. |
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