OXYGEN-CONSUMPTION AND OXIDANT STRESS IN SURVIVING NEPHRONS
OXYGEN-CONSUMPTION AND OXIDANT STRESS IN SURVIVING NEPHRONS
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DOI：
10.1152/ajprenal.1990.258.5.f1354
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发表时间：
1990-05-01
影响因子：
--
通讯作者：
HOSTETTER, TH
中科院分区：
文献类型：
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作者：
NATH, KA;CROATT, AJ;HOSTETTER, TH
我们研究了肾质量减少对存活肾单位氧消耗率、钠转运率和氧化应激指数的影响。在标准蛋白质摄入量的大鼠中，存活肾单位的耗氧率比完整肾单位的耗氧率升高两倍以上。存活肾单位钠重吸收（TNa）的绝对速率随TNa与耗氧量的比率降低而增加。为了确定氧化应激，我们测量了肾脏和尿液中的丙二醛（MDA）和肾脏组织中的谷胱甘肽氧化还原比。在肾次全切除模型中，每个肾单位的MDA增加，并伴有MDA的绝对和部分尿排泄增加，但每毫克蛋白质的肾脏MDA增加。谷胱甘肽的氧化还原率相似。由于增加膳食蛋白质摄入会导致肾损伤，我们研究了膳食蛋白质操作（30%对6%）对耗氧量、MDA水平和谷胱甘肽氧化还原比的影响。维持30%蛋白质饮食的肾次全切除动物的肾脏表现出增加的耗氧率。增加饮食中蛋白质的摄入导致增加MDA/肾单位，增加尿中的MDA排泄量，并增加MDA每毫克蛋白质在次全肾切除动物，并显着增加谷胱甘肽氧化还原比。我们的结论是，尽管增加耗氧量，存活的肾单位与完整的肾单位在大鼠的标准蛋白质摄入量相比，没有证据表明氧化应激。尿中MDA清除率的增加可能提供了一种防止脂质过氧化的机制。使残余肾单位经受增加的蛋白质增加氧消耗并施加氧化应激。（250字处删节）
We investigated the effects of reduction of renal mass on rates of oxygen consumption, sodium transport, and indexes of oxidant stress in surviving nephrons. Rates of oxygen consumption in surviving nephrons were elevated by more than twofold compared with nephrons in intact kidneys in rats on standard protein intakes. Absolute rates of sodium reabsorption (TNa) in the surviving nephrons were increased with a lower ratio of TNa to oxygen consumption. To determine oxidant stress, we measured malondialdehyde (MDA) in the kidney and urine and the glutathione redox ratio in kidney tissue. MDA per nephron was increased in the subtotally nephrectomized model and was accompanied by increased absolute and fractional urinary excretion of MDA but not by an increase in kidney MDA per milligram protein. The glutathione redox ratios were similar. Since increased dietary protein intake worsens renal injury, we studied the effects of dietary protein manipulation (30 vs. 6%) on oxygen consumption, MDA levels, and the glutathione redox ratio. The kidneys of subtotally nephrectomized animals maintained on 30% protein diets exhibited increased rates of oxygen consumption. Increased dietary protein intake led to increased MDA per nephron, increased urinary excretion of MDA, and increased MDA per milligram protein in subtotally nephrectomized animals, and markedly increased the glutathione redox ratio. We conclude that, despite increased oxygen consumption, surviving nephrons compared with intact nephrons in rats on standard protein intake demonstrate no evidence of oxidant stress. Increased urinary clearance of MDA may provide a mechanism that prevents the buildup of lipid peroxidation. Subjecting the remnant nephron to increased protein increases oxygen consumption and imposes oxidant stress.(ABSTRACT TRUNCATED AT 250 WORDS)