The Protective Effect Of Pretreated With Valsartan On Acute Myocardial Infarction Rat Myocardium

Valsartan is an angiotensin receptor blocker ,often used to treat hypertension .Recently scholar found that it has another kind of role which is reversal left ventricular (LV) myocardial remodeling .All these effection need patients long-term use this type drugs.However, scholar found that many patients who treatment with angiotensin receptor blocker (ARB) still can suffer from MI.And people found Valsartan not only block the binding of AngII and AT-1R,but also increase the expression of AT-2R. This study was designed to determine the impacts of the rat myocardium,which rat was pretreated with angiotensin receptor blocker on acute myocardial infarction (MI) and study its possible mechanism.Methods: Eighty healthy Wistar rats of both sexes were selected and randonly divided into 3 groups : sham-operation group,model group,treatment group. The treatment group rats were pretreated with valsartan (20 mg·kg-1·d-1) for 2 weeks. Model group and treatment group were ligated of the left main coronary artery to establish model of MI.All rats were measured infarct sizes at 24 hours after MI,collect serum for measuring CK,LDH and SOD. The AT2 receptors and OPN mRNA level were quantified by reverse transcription-polymerase chain reaction (RT-PCR) .HE staining method was used to observe myocardial pathologic changes. Results: Compared with untreated rats, in the group of pretreatment with valsartan the levels of plasma CK,LDH decreased,the content of plasma SOD increased.Compared with modle group,the infarct sizes in treatment group were reduced. The expression of AT-2R reduced, OPN mRNA increased in model group compared with sham-operation group.However, at treatment group the expression of rats' AT-2R was increased ,OPN mRNA was reduced. Conclusions: Pretreatment with valsartan before acute MI protects rats' heart, And make the expression of AT-2R mRNA increased,make the expression of OPN mRNA reduced.