Liu Changxuan, Song Yi, Qu Lei, Tang Jiawei, Meng Liqiang, Wang Yu
Renal Division, Department of Medicine, Peking University First Hospital and Institute of Nephrology, Peking University, Key Laboratory of Renal Disease, Ministry of Health of China, Key Laboratory of Chronic Kidney Disease Prevention and Treatment, Ministry of Education, Beijing, China.
Nephron. 2015;130(1):66-76. doi: 10.1159/000381858. Epub 2015 May 14.
BACKGROUND/AIMS: Renal tubular expression of Na/K-ATPase has been reported to be rapidly reduced in kidneys after unilateral ureteral obstruction (UUO), contributing to compromised sodium regulation. In this study, apocynin was utilized to test the hypothesis that the renal nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) system is involved in the regulation of Na/K-ATPase expression in early UUO.
Eighty Wistar rats underwent UUO or sham surgery, and half of each group was administered 100 mg/kg apocynin by oral gavage after surgery. Renal tissue samples were collected on day 1 and day 3 after surgery and the distribution of NOX2, NOX4 and Na/K-ATPase was assessed by immunofluorescence and immunohistochemical staining. The Heme oxygenase-1 (HO-1), NOX2, NOX4, osteopontin, Na/K-ATPase and aquaporin-1 (AQP-1) content of renal homogenates was assessed by immunoblotting, and malondialdehyde (MDA), nitric oxide (NO) content was assessed by biochemical analyses. Activity of inducible NO synthase (iNOS) and antioxidant enzymes was assessed by enzymatic assay.
Kidney Na/K-ATPase and AQP-1 content was decreased, and MDA and NOX4, NOX2 and HO-1 content were increased in the obstructed kidneys of UUO rats. Apocynin attenuated these changes and partially, but significantly, reversed the downregulation of Na/K-ATPase and AQP-1 in UUO rats. However, apocynin did not alter iNOS activity and NO production, osteopontin expression or the activity of antioxidant enzymes.
Activation of the NOX system and subsequent production of ROS are likely responsible for the downregulation of renal tubular Na/K-ATPase expression in early UUO.
背景/目的：据报道，单侧输尿管梗阻（UUO）后肾脏中钠钾ATP酶的肾小管表达迅速降低，这导致钠调节受损。在本研究中，使用阿扑辛来检验肾烟酰胺腺嘌呤二核苷酸磷酸（NADPH）氧化酶（NOX）系统参与早期UUO中钠钾ATP酶表达调节的假说。
80只Wistar大鼠接受UUO手术或假手术，每组中一半大鼠在术后通过灌胃给予100mg/kg阿扑辛。在术后第1天和第3天收集肾组织样本，通过免疫荧光和免疫组织化学染色评估NOX2、NOX4和钠钾ATP酶的分布。通过免疫印迹评估肾匀浆中血红素加氧酶-1（HO-1）、NOX2、NOX4、骨桥蛋白、钠钾ATP酶和水通道蛋白-1（AQP-1）的含量，通过生化分析评估丙二醛（MDA）、一氧化氮（NO）的含量。通过酶促测定评估诱导型一氧化氮合酶（iNOS）和抗氧化酶的活性。
UUO大鼠梗阻肾脏中肾钠钾ATP酶和AQP-1含量降低，MDA以及NOX4、NOX2和HO-1含量增加。阿扑辛减轻了这些变化，并部分但显著地逆转了UUO大鼠中钠钾ATP酶和AQP-1的下调。然而，阿扑辛并未改变iNOS活性和NO生成、骨桥蛋白表达或抗氧化酶的活性。
NOX系统的激活及随后活性氧的产生可能是早期UUO中肾小管钠钾ATP酶表达下调的原因。
