TY - JOUR
T1 - Xanthine oxidase produces O2/-· in posthypoxic injury of renal epithelial cells
AU - Greene, E. L.
AU - Paller, M. S.
PY - 1992/1/1
Y1 - 1992/1/1
N2 - 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.
AB - 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.
KW - allopurinol
KW - oxygen free radical
KW - superoxide
KW - tungsten
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U2 - 10.1152/ajprenal.1992.263.2.f251
DO - 10.1152/ajprenal.1992.263.2.f251
M3 - Article
C2 - 1324607
AN - SCOPUS:0026675501
VL - 263
SP - F251-F255
JO - American Journal of Physiology - Renal Fluid and Electrolyte Physiology
JF - American Journal of Physiology - Renal Fluid and Electrolyte Physiology
SN - 0002-9513
IS - 2 32-2
ER -