Inducible nitric oxide synthase inhibitors reduce urinary markers of systemic oxidant stress in murine proliferative lupus nephritis

Chinedu J. Njoku, Kennerly S. Patrick, Philip Ruiz, Jim C. Oates

Research output: Contribution to journalArticle

24 Scopus citations

Abstract

Background: Proliferative lupus nephritis (PLN) is characterized by increased expression of inducible nitric oxide (NO) synthase (iNOS). Inhibition of iNOS with NG-monomethyl L-arginine (L-NMMA) abrogates renal disease in two models of murine PLN, but the mechanism of this effect is unknown. Reactive oxygen species have both direct and indirect pathogenic effects in inflammatory lesions and are therefore potentially an important therapeutic target in PLN. We hypothesized that inhibition of iNOS activity would reduce ROS production in murine PLN. Methods: A dose escalation of L-NMMA (0, 20, 100, and 500 mg/kg/day) was performed in New Zealand Black × New Zealand White F1 (NZB/W) mice with active renal disease. Twenty-four-hour urine nitrate + nitrite (NOX) was measured with a chemiluminescence NO analyzer. Twenty-four-hour urine 8-isoprostane F (8-iso-PGF) was measured by gas chromatography-negative ion chemical ionization mass spectrometry. MRL-MpJFASlpr (MRL/lpr) and NZB/W mice were divided into three groups and given either L-NMMA, L-N6-iminoethyl-lysine (L-NIL), or distilled water for 2 weeks. Urine NO X and 8-iso-PGF were determined after 2 weeks. Results: L-NMMA reduced both urine NOX and 8-iso-PGF levels in a dose-dependent fashion in NZB/W and MRL/lpr mice. Urine NOX and 8-iso-PGF levels were highly correlated. Both specific (L-NIL) and nonspecific (L-NMMA) iNOS inhibition reduced urine NOX and 8-iso-PGF levels in both models of murine PLN. Conclusion: These findings suggest that iNOS activity is a major source of reactive oxidant stress in these models of murine PLN. Future studies will address the pathogenic role of reactive oxygen stress in PLN.

Original languageEnglish (US)
Pages (from-to)347-352
Number of pages6
JournalJournal of Investigative Medicine
Volume53
Issue number7
StatePublished - Nov 2005

Keywords

  • Isoprostanes
  • Lupus nephritis
  • Nitric oxide synthase

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)

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