Change and significance of urinary excretion of aquaporin-2 detected by enzyme linked immunosorbent assay in rat models of heart failure / 中国组织工程研究

ABSTRACT

AIM: To detect the change of urinary concentration of aquaporin-2 (AQP-2) by enzyme linked immunosorbent assay in rat models of different degrees of heart failure and make a comparison with sham-operation group.METHODS: This experiment was carried out between January 2000 and January 2002 in the animal laboratory of Nanfang Hospital of Southern Medical University. Forty-two male adult Sprague-Dawley rats were involved. Twenty-six rat models of chronic heart failure were prepared by ligation of left coronary artery. When left ventricle infarct area was≥20%, the rat models of congestive heart failure were successful (heart failure group, n =13); When left ventricle infarct area was＜20%, the rat models of congestive heart failure were unsuccessful (compensation group, n =13). The other 16 rats were not ligated at coronary rtery (control group). Serum sodium concentration was determined with BeckmanC×3 equipment and urine osmole by cryoscopic method. Urine volume of 24 hours was monitored. Urinary concentration ofAQP-2 level of rats was determined by double antibodies sandwich enzyme linked immunosorbent assay (DABs-ELISA).RESULTS: Forty-two rats were involved in the result analysis. The 24-hour urine volume and serum sodium concentration in the heart failure group and compensation group were significantly lower than those in the control group (P＜0.05-0.01), while urine osmole in two groups was significantly higher than that in the control group (P＜0.05-0.01).②At postoperative 4 and 6 weeks, urinary concentration of AQP-2 level of rats in the control group was significantly lower than that in the other two groups (P＜0.05-0.01), and urinary concentration of AQP-2 level of rats in the compensation group was significantly lower than that in the heart failure group (P＜0.05, 0.01).In the compensation group and heart failure group, urinary concentration of AQP-2 level of rats was significantly higher at postoperative 6 weeks than at postoperative 4weeks (P＜0.05).CONCLUSION:①AQP-2 is the key target protein of water retention and hyponatremia at heart failure.②Detection of urinary concentration of AQP-2 by ELISA can effectively reflect water retention and hyponatremia when heart failure occurs.