The effects of valsartan on changes of Pyk2 expression and activation in myocardium of renovascular hypertensive rats

Objective To study the effects of valsartan on ventricular hypertrophy and the expression of Proline-rich tyrosine kinase 2(Pyk2) in myocardium of renovascular hypertensive rats(RHR).Methods Two-kidney and one-clip(2K1C) renal hypertensive model was established in Sprague-Dawley rats by chronic partial occlusion of left renal artery.Rats were randomly divided into model-operation group,sham-operation group and valsartan group.Rats in valsartan group received valsartan 30 mg·kg-1·d-1.Left ventricular mass to body mass ratio was measured to assay the degree of myocardial hypertrophy.Expression of Pyk2 protein and tyrosine-phosphorylated Pyk2(p-Pyk2) were detected by immunohistochemisry.Results Blood pressure(BP),left ventricular mass to body mass ratio,Pyk2 activity in myocardium of RHR were increased gradually.Valsartan could reverse the high BP level of the model,also the myocardial hypertrophy(P0.01).Pyk2 levels and the amount of p-Pyk2 were measured by Western-Blotting,they were evidently increased in the model-operation group than that of the sham-operation group(1week P0.05,4 to 12 weeks P0.01).Pyk2 and p-Pyk2 levels were significantly dicreased in valsartan group than that of their time-matched model-operation groups(P0.01).Conclusion Increased expression of Pyk2 and p-Pyk2 in the left ventricle of RHR is probably associated with the progress of the left ventricular hypertrophy(LVH).The preventive mechanism of valsartan cardiac hypertrophy in RHR is related to the decrease of Pyk2 expression and its activity in cardiac tissue.