Nishiyama Akira, Yao Li, Nagai Yukiko, Miyata Kayoko, Yoshizumi Masanori, Kagami Shoji, Kondo Shuji, Kiyomoto Hideyasu, Shokoji Takatomi, Kimura Shoji, Kohno Masakazu, Abe Youichi
Department of Pharmacology, Kagawa Medical University, Kagawa, Japan.
Hypertension. 2004 Apr;43(4):841-8. doi: 10.1161/01.HYP.0000118519.66430.22. Epub 2004 Feb 9.
Studies were performed to test the hypothesis that reactive oxygen species (ROS) and mitogen-activated protein kinase (MAPK) contribute to the pathogenesis of aldosterone/salt-induced renal injury. Rats were given 1% NaCl to drink and were treated with one of the following combinations for 6 weeks: vehicle (0.5% ethanol, SC, n=6); aldosterone (0.75 microg/H, SC, n=8); aldosterone plus a selective mineralocorticoid receptor antagonist; eplerenone (0.125% in chow, n=8); aldosterone plus an antioxidant; and tempol (3 mmol/L in drinking solution, n=8). The activities of MAPKs, including extracellular signal-regulated kinases (ERK)1/2, c-Jun-NH2-terminal kinases (JNK), p38MAPK, and big-MAPK-1 (BMK1) in renal cortical tissues were measured by Western blot analysis. Aldosterone-infused rats showed higher systolic blood pressure (165+/-5 mm Hg) and urinary excretion of protein (106+/-24 mg/d) than vehicle-infused rats (118+/-3 mm Hg and 10+/-3 mg/d). Renal cortical mRNA expression of p22phox, Nox-4, and gp91phox, measured by real-time polymerase chain reaction, was increased in aldosterone-infused rats by 2.3, 4.3, and 3.0-fold, respectively. Thiobarbituric acid-reactive substances (TBARS) content in renal cortex was also higher in aldosterone (0.23+/-0.02) than vehicle-infused rats (0.09+/-0.01 nmol/mg protein). ERK1/2, JNK, and BMK1 activities were significantly elevated in aldosterone-infused rats by 3.3, 2.3, and 3.0-fold, respectively, whereas p38MAPK activity was not changed. Concurrent administration of eplerenone or tempol to aldosterone-infused rats prevented the development of hypertension (127+/-2 and 125+/-5 mm Hg), and the elevations of urinary excretion of protein (10+/-2 and 9+/-2 mg/day) or TBARS contents (0.08+/-0.01 and 0.11+/-0.01 nmol/mg protein). Furthermore, eplerenone and tempol treatments normalized the activities of ERK1/2, JNK, and BMK1. These data suggest that ROS and MAPK play a role in the progression of renal injury induced by chronic elevations in aldosterone.
活性氧（ROS）和丝裂原活化蛋白激酶（MAPK）在醛固酮/盐诱导的肾损伤发病机制中发挥作用。给大鼠饮用1%氯化钠溶液，并采用以下组合之一进行处理，持续6周：溶剂（0.5%乙醇，皮下注射，n = 6）；醛固酮（0.75微克/小时，皮下注射，n = 8）；醛固酮加选择性盐皮质激素受体拮抗剂依普利酮（饲料中含0.125%，n = 8）；醛固酮加抗氧化剂替莫泊尔（饮水中含3毫摩尔/升，n = 8）。通过蛋白质印迹分析测定肾皮质组织中MAPK的活性，包括细胞外信号调节激酶（ERK）1/2、c-Jun氨基末端激酶（JNK）、p38MAPK和大MAPK-1（BMK1）。注射醛固酮的大鼠收缩压（165±5毫米汞柱）和尿蛋白排泄量（106±24毫克/天）高于注射溶剂的大鼠（118±3毫米汞柱和10±3毫克/天）。通过实时聚合酶链反应测定，注射醛固酮的大鼠肾皮质中p22phox、Nox-4和gp91phox的mRNA表达分别增加了2.3倍、4.3倍和3.0倍。醛固酮组（0.23±0.02）肾皮质中的硫代巴比妥酸反应性物质（TBARS）含量也高于注射溶剂的大鼠（0.09±0.01纳摩尔/毫克蛋白）。注射醛固酮的大鼠中ERK1/2、JNK和BMK1的活性分别显著升高了3.3倍、2.3倍和3.0倍，而p38MAPK活性未改变。给注射醛固酮的大鼠同时给予依普利酮或替莫泊尔可预防高血压的发生（127±2和125±5毫米汞柱），以及尿蛋白排泄量（10±2和9±2毫克/天）或TBARS含量的升高（0.08±0.01和0.11±0.01纳摩尔/毫克蛋白）。此外，依普利酮和替莫泊尔治疗使ERK1/2、JNK和BMK1的活性恢复正常。这些数据表明，ROS和MAPK在醛固酮长期升高诱导的肾损伤进展中起作用。
