Urinary excretion of aquaporin-2 water channel protein in chronic heart failure rats

Objective To study the urinary excretion of aquaporin-2 (AQP2) water channel protein, and the relationship between urine AQP2 concentration and renal AQP2 gene expression in chronic heart failure (CHF) rats. Methods Male Sprague-Dawley rats (200 g-250 g) underwent either a left coronary artery ligation, a model of CHF, or a sham-operation. Nine weeks after surgery, urinary AQP2 concentrations and renal AQP2 protein levels were measured by Western blot.Results The urinary concentration of AQP2 water channel protein increased significantly in CHF rats as compared with sham-operated rats (365.6%±102.9% vs 98.5%±47.6%, P<0.01). There was positive correlation between urinary AQP2 concentration and renal AQP2 protein expression (r=0.89, P<0.01). Conclusion The urinary concentration of AQP2 water channel protein increases significantly in chronic heart failure rats.