title: Effect of hypoxia on proximal tubules isolated from nitric oxide synthase knockout mice.
abstract: Nitric oxide (NO) has been shown to be a mediator of hypoxic injury in rat renal proximal tubules (PT). However, the role of NO in hypoxic injury to mouse. PT has not been examined. The aim of the present study was to determine the effect of knockout of nitric oxide synthase (NOS) isoforms on hypoxic injury in mouse PT. Mouse PTs were isolated by collagenase digestion and Percoll centrifugation. The nonselective NOS inhibitor, N-nitro-L-arginine methyl ester (L-NAME, 10 mM), but not its inactive stereoisomer D-NAME, protected against hypoxic injury as assessed by LDH release. Carboxy-imidazolineoxyl N-oxide (carboxy-PTIO, 100 microM), a stable NO scavenger, also afforded cytoprotection against hypoxic injury. To determine the role of the different NOS isoforms in the hypoxic injury, we examined the effect of hypoxia on PT isolated from knockout mice in which either the inducible NOS (iNOS) endothelial NOS (eNOS) or neuronal NOS (nNOS) gene was lacking. PT isolated from iNOS knockout mice were resistant to hypoxic injury compared to wild-type controls. In contrast, PT isolated from both nNOS and eNOS knockout mice were not protected against hypoxic injury. In conclusion, the present study demonstrates that NO is a mediator of hypoxic PT injury in the mouse and that knockout of the iNOS gene is cytoprotective against this hypoxic PT injury.
authors.affiliation: Department of Medicine, University of Colorado Health Sciences Center, Denver, USA.
authors.forename: H
authors.initials: H
authors.lastname: Ling
authors.forename: P E
authors.initials: PE
authors.lastname: Gengaro
authors.forename: C L
authors.initials: CL
authors.lastname: Edelstein
authors.forename: P Y
authors.initials: PY
authors.lastname: Martin
authors.forename: A
authors.initials: A
authors.lastname: Wangsiripaisan
authors.forename: R
authors.initials: R
authors.lastname: Nemenoff
authors.forename: R W
authors.initials: RW
authors.lastname: Schrier
mesh_terms: D000818:Animals; D001565:Benzoates / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D017353:Gene Deletion; D000860:Hypoxia / Q000378:metabolism*; D007093:Imidazoles / Q000494:pharmacology; D066298:In Vitro Techniques; D007687:Kidney Tubules, Proximal / Q000378:metabolism*; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout / Q000235:genetics* / Q000378:metabolism*; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000235:genetics*; D052248:Nitric Oxide Synthase Type I; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III
chemical_list: D001565:Benzoates; D004791:Enzyme Inhibitors; D007093:Imidazoles; C079393:1,3-dihydroxy-4,4,5,5-tetramethyl-2-(4-carboxyphenyl)tetrahydroimidazole; D007770:L-Lactate Dehydrogenase; D019001:Nitric Oxide Synthase; D052248:Nitric Oxide Synthase Type I; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; C496321:Nos1 protein, mouse; C496317:Nos2 protein, mouse; C496315:Nos3 protein, mouse; D019331:NG-Nitroarginine Methyl Ester