Pragasam Viswanathan, Sakthivel Ramasamy, Kalaiselvi Periyandavan, Rajesh Nachiappa Ganesh, Varalakshmi Palaninathan
Department of Medical Biochemistry, Dr. ALM PGIBMS, University of Madras, Taramani Campus, Chennai 600 113, India.
Urol Res. 2005 Aug;33(4):301-8. doi: 10.1007/s00240-005-0477-3. Epub 2005 Jul 9.
Nitrosative stress plays a role in calcium oxalate stone formation, as nitrosated proteins have been identified in stone formers. Nitric oxide (NO(*)), the common precursor for reactive nitrogen species, is synthesized in the juxtaglomerular apparatus of the kidneys. The present study is aimed to determine the role of nitric oxide synthase (NOS) in an experimental hyperoxaluric condition by histological and biochemical techniques. Hyperoxaluria was induced by 0.75% ethylene glycol in drinking water. L-arginine (L-arg) was supplemented at a dose of 1.25 g/kg body weight orally for 28 days. Nitric oxide metabolites (NOx), protein content in the urine and lipid peroxidation in the kidney were determined at the end of the experimental period. Histopathological examination of the rat kidneys was then carried out. NADPH-diaphorase and eNOS expression studies were carried out in control and hyperoxaluric rat kidneys using histochemical and immunohistochemical techniques. Significant amounts of NOx were present in the urine of hyperoxaluric animals when compared to control rats. Histopathological examinations revealed membrane injury, tubular dilatation and edema in the hyperoxaluric rats, whereas co-supplementation of L-arg to the hyperoxaluric rats significantly reduced these changes. The results of histochemical analysis for NADPH-diaphorase staining demonstrate the role of NOS in hyperoxaluric rats. Hyperoxaluric rats showed intense staining for NADPH-diaphorase when compared to control and L-arg co-supplemented hyperoxaluric rats. Immunohistochemical demonstration confirmed that eNOS expression was markedly increased in L-arg supplemented rats, when compared to EG treated rat kidney sections. Thus, from the present study, we conclude that supplementation of L-arg to the hyperoxaluric animals minimizes the cellular injury mediated by ethylene glycol, prevents oxidative/nitrosative damage to the membranes and reduces the incidence of calcium oxalate stone formation.
亚硝化应激在草酸钙结石形成中起作用，因为在结石患者中已鉴定出亚硝化蛋白质。一氧化氮（NO(*)）是活性氮物质的常见前体，在肾脏的球旁器中合成。本研究旨在通过组织学和生化技术确定一氧化氮合酶（NOS）在实验性高草酸尿症中的作用。通过在饮用水中添加0.75%的乙二醇诱导高草酸尿症。以1.25 g/kg体重的剂量口服补充L-精氨酸（L-arg），持续28天。在实验期结束时测定一氧化氮代谢产物（NOx）、尿液中的蛋白质含量和肾脏中的脂质过氧化。然后对大鼠肾脏进行组织病理学检查。使用组织化学和免疫组织化学技术对对照和高草酸尿症大鼠肾脏进行NADPH-黄递酶和eNOS表达研究。与对照大鼠相比，高草酸尿症动物尿液中存在大量的NOx。组织病理学检查显示高草酸尿症大鼠存在膜损伤、肾小管扩张和水肿，而向高草酸尿症大鼠联合补充L-arg可显著减轻这些变化。NADPH-黄递酶染色的组织化学分析结果证明了NOS在高草酸尿症大鼠中的作用。与对照和L-arg联合补充的高草酸尿症大鼠相比，高草酸尿症大鼠显示出强烈的NADPH-黄递酶染色。免疫组织化学证实，与乙二醇处理的大鼠肾脏切片相比，L-arg补充大鼠的eNOS表达明显增加。因此，从本研究中我们得出结论，向高草酸尿症动物补充L-arg可使乙二醇介导的细胞损伤最小化，防止对膜的氧化/亚硝化损伤，并降低草酸钙结石形成的发生率。
