title: Nitrite-derived nitric oxide protects the rat kidney against ischemia/reperfusion injury in vivo: role for xanthine oxidoreductase.
abstract: In normal conditions, nitric oxide (NO) is oxidized to the anion nitrite, but in hypoxia, this nitrite may be reduced back to NO by the nitrite reductase action of deoxygenated hemoglobin, acidic disproportionation, or xanthine oxidoreductase (XOR). Herein, is investigated the effects of topical sodium nitrite administration in a rat model of renal ischemia/reperfusion (I/R) injury. Rats were subjected to 60 min of bilateral renal ischemia and 6 h of reperfusion in the absence or presence of sodium nitrite (30 nmol) administered topically 1 min before reperfusion. Serum creatinine, serum aspartate aminotransferase, creatinine clearance, fractional excretion of Na(+), and plasma nitrite/nitrate concentrations were measured. The nitrite-derived NO-generating capacity of renal tissue was determined under acidic and hypoxic conditions by ozone chemiluminescence in homogenates of kidneys that were subjected to sham, ischemia-only, and I/R conditions. Nitrite significantly attenuated renal dysfunction and injury, an effect that was abolished by previous treatment of rats with the NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazole-1-oxyl-3-oxide (2.5 mumol intravenously 5 min before ischemia and 50 nmol topically 6 min before reperfusion). Renal tissue homogenates produced significant amounts of NO from nitrite, an effect that was attenuated significantly by the xanthine oxidoreductase inhibitor allopurinol. Taken together, these findings demonstrate that topically administered sodium nitrite protects the rat kidney against I/R injury and dysfunction in vivo via the generation, in part, of xanthine oxidoreductase-catalyzed NO production. These observations suggest that nitrite therapy might prove beneficial in protecting kidney function and integrity during periods of I/R such as those encountered in renal transplantation.
authors.affiliation: Centre for Experimental Medicine & Nephrology & Critical Care, William Harvey Research Institute, St. Bartholomew's and The Royal London School of Medicine and Dentistry, Queen Mary-University of London, Charterhouse Square, London, EC1M 6BQ, UK.
authors.forename: Pinpat
authors.initials: P
authors.lastname: Tripatara
authors.forename: Nimesh S A
authors.initials: NS
authors.lastname: Patel
authors.forename: Andrew
authors.initials: A
authors.lastname: Webb
authors.forename: Krishnaraj
authors.initials: K
authors.lastname: Rathod
authors.forename: Florence M J
authors.initials: FM
authors.lastname: Lecomte
authors.forename: Emanuela
authors.initials: E
authors.lastname: Mazzon
authors.forename: Salvatore
authors.initials: S
authors.lastname: Cuzzocrea
authors.forename: Mohammed M
authors.initials: MM
authors.lastname: Yaqoob
authors.forename: Amrita
authors.initials: A
authors.lastname: Ahluwalia
authors.forename: Christoph
authors.initials: C
authors.lastname: Thiemermann
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D007668:Kidney / Q000187:drug effects / Q000473:pathology / Q000503:physiopathology*; D008297:Male; D009566:Nitrates / Q000008:administration & dosage / Q000627:therapeutic use; D052248:Nitric Oxide Synthase Type I / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D009573:Nitrites / Q000008:administration & dosage / Q000627:therapeutic use*; D051381:Rats; D017208:Rats, Wistar; D012079:Renal Circulation / Q000187:drug effects*; D015427:Reperfusion Injury / Q000473:pathology / Q000503:physiopathology / Q000517:prevention & control*; D014443:Tyrosine / Q000031:analogs & derivatives / Q000378:metabolism; D014968:Xanthine Dehydrogenase / Q000378:metabolism*
chemical_list: D009566:Nitrates; D009573:Nitrites; C002744:3-nitrotyrosine; D014443:Tyrosine; D052248:Nitric Oxide Synthase Type I; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; D014968:Xanthine Dehydrogenase