RESUMO
Objective To investigate the expression of renal aquaporin 2 (AQP2), epithelial sodium channel (ENaC) and kidney specific Na-K-2Cl cotransporter (rBSC1) in the thick ascending limb of Henle in different kinds of congestive heart failure rats. Methods To establish different congestive heart failure animal models with abdominal aortocaval shunts (1 pore and 3 pores) and ligature of the left coronary artery respectively in SD rats. Cardiac function was tested with Doppler echocardiography. The amount of renal AQP2, ENaC and rBSC1 mRNA was measured using semi-quantitative RT-PCR. Results Cardiac function of aortocaval shunt rat deteriorated to a lesser extent. While cardiac function of ligation rats was severely decompensated. AQP2 mRNA was enhanced only in renal cortex in ligation group. While rBSC1 was up-regulated significantly both in aortocaval shunt rat and ligation rat. In renal cortex, the amount of ENaC increased remarkably in all three congestive heart failure groups, while in medulla, the significant increasing in ENaC expression was only found in ligation rat. Conclusions Renal AQP2, ENaC and rBSCl mRNA enhance to different extent in different kinds of congestive heart failure animal models. There is probably a correlationship between the upregulation of rBSC1 mRNA and impaired renal sodium excretion in early phase of cardiac lesion.
