醛固酮及醛固酮拮抗剂依普利酮对自发性高血压大鼠足细胞CD2AP表达的影响

Effects of aldosterone and eplerenone on CD2AP expression in podocytes from spontaneously hypertensive rats

目的观察自发性高血压大鼠肾损害早期血浆与组织醛固酮水平和醛固酮受体拮抗剂对肾足细胞损伤和CD2AP表达的影响。方法 20只8周龄雄性自发性高血压大鼠(SHRs),随机分成干预组和未干预组,每组10只,10只同龄Wistar-Kyoto大鼠为对照组。每天给予干预组依普利酮悬浊液灌胃(50mg/kg,溶于2ml过滤水),未干预组和对照组用同体积过滤水灌胃。测量大鼠尾动脉收缩压、尿微量白蛋白、血浆醛固酮和肾组织醛固酮。RT-PCR和Western印迹法检测肾小球CD2AP基因和蛋白表达。透射电镜检测大鼠肾足细胞形态学变化。结果 SHRs收缩压明显高于对照组(P<0.01);未干预组的尿微量白蛋白水平高于对照组和干预组(P<0.01);未干预组血浆和肾组织醛固酮水平高于对照组(P<0.05)。透射电镜显示未干预组上皮足突节段融合,肾小管上皮细胞溶酶体中度增多,肾间质毛细血管扩张。未干预组CD2AP基因和蛋白表达水平低于对照组和干预组(P<0.01)。尿微量白蛋白水平与肾小球CD2AP蛋白表达水平呈中度负相关(r=-0.587,P<0.01)。肾小球CD2AP蛋白表达水平与血浆和肾组织醛固酮水平呈中度负相关(r=-0.552和r=-0.577,P<0.01)。结论自发性高血压大鼠肾损害早期的足细胞损伤与血浆和肾组织高醛固酮水平有关。依普利酮可以减轻足细胞损伤,改善CD2AP的表达。

Objective To observe the tissue and plasma levels of aldosterone at the early stage of renal damage in spontaneously hypertensive rats （SHRs）, and to analyze the effects of eplerenone, aldosterone receptor antagonist, on podocytes injury and CD2AP expression in podocytes. Methods Twenty male SHRs, 8-week-old, were randomly separated into two groups： intervention group and non-intervention group, with 10 in each group. Another ten age-matched Wistar-Kyoto rats were used as control group. The rats in intervention group were administrated intragastrically with eplerenone （50 mg/kg per day） dissolved in 2ml filtered water, and the rats in unintervention and control groups with the same volume of filtered water. Systolic blood pressure of caudal artery was measured by tail-cuff plethysmography. Microalbuminuria, plasma aldosterone and renal tissue aldosterone were detected respectively. RT-PCR and Western blot were performed to evaluate the gene expression and protein synthesis of CD2AP respectively. Morphology of podocytes was detected by transmission electron microscope. Results Systolic blood pressure was obviously higher in SHRs than in control group（P〈 0.01）. The rats in unintervention group presented higher microalbuminuria level than control and intervention groups （P 〈 0.01）. Aldosterone levels of plasma and renal tissue were higher in unintervention group than in control group （P 〈 0.05）. Transmission electron microgscopy showed fusion of podocytes, moderate increase in cytolysosome of tubular epithelial cells, and hyperplasia of renal interstitial microvessels in unintervention group. Gene and protein expressions of CD2AP were lower in unintervention group than in control and intervention groups （P 〈 0.01）. CD2AP protein expression had negative correlation with microalbuminuria （r =-0.587, P〈 0.01）, and with plasma and renal tissue aldosterone levels （r =-0.552, r =-0.577, P 〈 0.01） repectively. Conclusion Podocytes injury is associated with high aldosterone levels in plasma and renal tissue at early stage of renal damage in SHRs. Eplerenone alleviates podocytes injury and attenuates CD2AP expression in SHRs.