Qili
qiangxin capsule (QL), a traditional Chinese herbal compound, has been proved to be effective and safe for the treatment of chronic
heart failure (CHF). Upregulation of
aquaporin-2 (AQP2) accounts for the water retention in CHF. The aim of the present study was to evaluate the effects of QL on the expression of AQP2 in rats with CHF induced by acute
myocardial infarction and to investigate the underlying mechanisms. The urine output of all rats was quantified and collected every day at the first week and the 4th week after administration of QL or
Valsartan. The expression of AQP2,
vasopressin type 2 receptor (V2R), and
angiotensin II type 1 receptor (AT1R) were examined
after treatment for 4 weeks. Urinary output increased significantly after administration of QL. Importantly, the
protein expression of AQP2 and AQP2 phosphorylated at
serine 256 (pS256-AQP2) was downregulated after administration of QL and
Valsartan to CHF rats. Furthermore, QL reduced plasma
arginine vasopressin (AVP) and
angiotensin II (AngII) level and downregulated V2R and AT1R
protein expression. Thus, QL exerts its
diuretic effect and improves cardiac function in CHF rats by reversing the increases in both AQP2 and pS256-AQP2 expression. The possible mechanisms may involve inhibition of V2R and AT1R.