Xanthine oxidase produces O2/-· in posthypoxic injury of renal epithelial cells

E. L. Greene, M. S. Paller

Research output: Contribution to journalArticle

72 Scopus citations

Abstract

The hypothesis that posthypoxic renal injury is mediated by xanthine oxidase-derived oxygen free radical production was tested in an in vitro model of rat proximal tubule epithelial cells in primary culture subjected to 60 min of hypoxia and 30 min of reoxygenation. Hypoxia-reoxygenation-induced injury, measured as lactate dehydrogenase (LDH) release, was 54.0 ± 7.1%. Inhibition of xanthine oxidase by 10-4 M allopurinol attenuated injury (LDH release = 35.5 ± 3.7%; P < 0.01). Oxypurinol was similarly effective. Alternatively, cells were treated with 50 or 100 μM tungsten to inactivate xanthine oxidase. Tungsten prevented hypoxia-reoxygenation-induced superoxide radical production (basal = 97 ± 8, hypoxia-reoxygenation = 172 ± 12, and plus tungsten = 73 ± 8 nmol/μg protein) and attenuated hypoxia- reoxygenation-induced injury (LDH release: basal = 18.8 ± 3.0%, hypoxia- reoxygenation = 62.0 ± 4.8%, plus 50 μM tungsten = 24.8 ± 5.0%, and plus 100 μM tungsten = 6.0 ± 0.7%). In addition, hypoxia and reoxygenation increased the ratio of xanthine oxidase to total activity (xanthine oxidase + xanthine dehydrogenase) from 73 to 100%. Therefore xanthine oxidase was responsible for hypoxia-reoxygenation-induced superoxide radical formation and hypoxia-reoxygenation-induced injury. Xanthine oxidase is likely to be the major source of oxygen free radicals during renal ischemia and reperfusion.

Original languageEnglish (US)
Pages (from-to)F251-F255
JournalAmerican Journal of Physiology - Renal Fluid and Electrolyte Physiology
Volume263
Issue number2 32-2
DOIs
StatePublished - Jan 1 1992

Keywords

  • allopurinol
  • oxygen free radical
  • superoxide
  • tungsten

ASJC Scopus subject areas

  • Physiology

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