| Objective To observe the protective effect and the expression of Connexin43(Cx43) of astragaloside IV (AST Ⅳ) on isoproterenol-induced myocardial infarction,and investigate its possible mechanism.Methods The50healthy male Sprague-Dawley rats were randomly divided into five groups:normal control group, model group, Astragaloside Ⅳ group A (5mg/kg), Astragaloside Ⅳ B group (10mg/kg), Astragaloside IV group C (20mg/kg). Myocardial infarction model of rats were induced by subcutaneous injection of large dose of isoproterenol(ISO).The change of electrocardiogram(ECG) was observed.The levels of lactate dehydrogenase(LDH), creatine kinase isoenzyme(CK-MB) in blood plasma, the activities of superoxide dismutase(SOD), and the content of malondialdehyde(MDA) in mycardial tissue were measured. The expressions of connexin43(Cx43)in myocardium were detected by immunohistochemistry method and was semi-quantitatively analyzed.Results Compared with the model group, Astragaloside Ⅳ could fight against ST-segment elevation in myocardial infarction of rats(P<0.01), could significantly improve the indexes on hemodynamics in myocardial infarction of rats(P<0.05or P＜0.01), significantly decrease the levels of surum LDH and CK-MB(P<0.01), notably increase the activities of SOD in mycardial tissue and decrease the content of MDA in myocardial tissue(P＜0.01).The density of Cx43was increased(P<0.01), the inhomogeneity in Cx43distribution significantly reduced.Conclusion:Astragaloside Ⅳ has a protective effect on acute myocardial infarction induced by isoproterenol in rats, has a reversal effect on the expession reduced and distribution disordered of Cx43, has anti-arrhythmic effect, the protective mechanisms of astragaloside Ⅳ may be related to anti-oxidation. |
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