Ouabain induces cardiac remodeling in rats independent of blood pressure

<正> Aim:To investigate the ouabain's effects on cardiac remodeling in rats.Methods:Male Sprague-Dawley rats were treated with ouabain.Systolic blood pressure(SBP)was recorded weekly.After 4 and 6 weeks,echocardiography were performed,hemodynamic parameters were measured by invasive cardiac catheterization,changes in cardiac ultrastructure were analyzed using transmission electronmicroscopy,the collagen fraction of the left ventricle was assessed with Picrosiriusred stain,and RT-PCR was applied to evaluate the mRNA level of myosin heavychain-αand-βin the left ventricle.Results:Having been treated with ouabain for4 weeks,there was no significant difference in the mean SBP of the two groups.However,left ventricular hypertrophy,myocardial ultrastructure deterioration,and extracellular matrix remodeling were induced by ouabain treatment;meanwhile,cardiac systolic and diastolic performance were both worsened.Moreover,thecardiac MHC-β mRNA was upregulated by ouabain treatment,whereas MHC-αmRNA was downregulated.After 4 weeks,the mean SBP in the ouabain groupbegan to increase and was significantly higher than that in control group after 6weeks(P<0.01);the rats' cardiac structure and function were worsened.Conclusion:These results suggested that ouabain induces alterations in cardiacstructure and function,and the effects happened before the increase of bloodpressure.The results indicated that ouabain induced cardiac remodeling in ratsindependent of blood pressure.