充血性心力衰竭时肾脏水通道蛋白mRNA表达的改变及意义

目的 研究在不同程度的充血性心功能衰竭（心衰）时肾脏水通道蛋白2（AQP2），上皮性钠通道（ENaC)和髓襻升支粗段的Na-K-2Cl转运子（rBSC1)表达的情况。方法 将SD大鼠通过腹主动脉－下腔静脉穿刺造瘘和冠状动脉结扎的方法建成不同的心衰模型，设正常对照组，穿刺造瘘1孔组，穿刺造瘘3孔组和冠脉结扎组。用Doppler超声心动图及心脏秤重的方法比较其心功能的各项参数，并用RT－PCR的方法检测肾脏AQP，ENaCα亚单位和rBSC1mRNA表达。结果 穿刺造瘘大鼠心功能损害较轻，而冠脉结扎大鼠心功能严重失代偿。AQP2仅在冠脉结扎大鼠肾皮质表达增高，而rBSC1在造瘘1孔，3孔和结扎大鼠的肾髓质表达均显著上调。肾皮质αENaC含量3组心衰大鼠都显著增高，而在肾髓质仅冠脉结扎大鼠明显升高，造瘘大鼠虽有上升趋势，但差异无显著性意义。结论 在不同类型的充血性心力衰竭大鼠模型中存在着肾脏AQP，rBSC1和ENaC mRNA表达的上调，其中rBSC1增高可能和心脏受累早期肾脏排钠障碍有一定关系。

Expression of channel protein mRNA in kidney of congestive heart failure and its significance

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.