RÉSUMÉ
<p><b>OBJECTIVE</b>To explore the effect of Yixintai Granule (YG) on mRNA and protein expression levels of AQP2 in renal medulla of chronic heart failure (CHF) rabbits.</p><p><b>METHODS</b>CHF rat model was established by ear marginal vein injection of adriamycin. Successfully modeled rabbits were divided into the model group, the high (8.4 g/kg), middle (4.2 g/kg), and low dose (2.1 g/kg) YG group, and the Furosemide group (2 mg/kg). Besides, a normal control group was set up. Equal volume of physiological saline was administered to rabbits of the model group and the normal control group by gastrogavage. YG at different doses was administered to rabbits of the 3 YG groups by gastrogavage. The intervention lasted for 4 weeks, once per day. After treatment the urine volume and pathomorphological changes of renal medulla tissue were observed. mRNA and its protein expression levels of AQP2 were detected.</p><p><b>RESULTS</b>Compared with the normal control group, the urine volume decreased significantly, mRNA and protein expression levels of renal medulla AQP2 increased significantly in the model group (all P < 0.01). Compared with the model group, the urine volume increased significantly, and mRNA and protein expression levels of renal medulla AQP2 decreased significantly in all medicated groups (all P < 0.01). Compared with the low dose YG group, the urine volume significantly increased and the mRNA expression level of renal medulla AQP2 significantly decreased in the middle and high dose YG groups (all P < 0.01). The expression level of AQP2 protein significantly decreased in the high dose YG group (P < 0.01). Pathological changes of the renal medulla was the most obviously seen in the model group. But they were alleviated to various degrees in all medicated groups. They were more obviously attenuated in the middle and high dose YG groups.</p><p><b>CONCLUSION</b>YG could improve CHF possibly through down-regulating mRNA and protein expression levels of AQP2 in renal medulla, and elevating the urine volume.</p>