ABSTRACT
AIM: To study urinary concentration of aquaporin-2 water channel protein(AQP2) at different stages of chronic heart failure(CHF) rats and its relation to hyponatremia. METHODS: Male Sprague-Dawley rats(200～250 g) underwent either a left coronary artery ligation (a model of CHF) or a sham-operation. At different stage after surgery, urinary AQP2 concentration was measured by Western blot. 24-hours urine volume, serum sodium and urine osmolality were measured at the same time. RESULTS: There were two peaks of urinary excretion of AQP2 in severe heart failure rats model: one was the third day after operation, the other was the 9th week. Serum sodium and urine osmolality were significantly different in CHF rats as compared with sham-operated rats. Seven weeks after surgery, urinary AQP2 concentration was increased significantly insevere CHF rats compared with the mild ones and the control ones(365%?103% vs 179%?81% and 99%?48%, P