title: Early renal ischemia, with or without reperfusion, activates NFkappaB and increases TNF-alpha bioactivity in the kidney.
abstract: OBJECTIVE
  Acute tubular necrosis (ATN) and the ensuing renal failure induced by ischemia and reperfusion injury (I/R) remain a major cause of morbidity and mortality among patients in the intensive care unit. Although it is well established that exogenous tumor necrosis factor-alpha (TNF) induces renal injury, it remains unknown whether ischemia and/or reperfusion activates the signaling mechanisms required for renal TNF production. We hypothesized that ischemia and/or reperfusion would activate the oxidant sensitive TNF transcription factor, nuclear factor kappa B (NFkappaB), and thereby lead to renal TNF production.
  
  
  METHODS
  Male Sprague-Dawley rats were anesthetized with sodium pentobarbital, after which various periods of renal ischemia, with or without reperfusion, were induced in rats. At different time intervals, kidneys were harvested and NFkappaB activation (electrophoretic mobility shift assay), TNF mRNA content (RT-PCR), and TNF bioactivity (WEHI-164 cell clone cytotoxicity assay) were determined.
  
  
  RESULTS
  Results indicate that 15 minutes of ischemia alone activates NFkappaB, whereas peak activation occurred at 30 minutes of ischemia alone. NFkappaB remained activated through 60 minutes reperfusion. Thirty minutes of ischemia is required to induce renal TNF mRNA production; however, renal TNF protein expression and bioactivity peaked following 1 hour of ischemia and 2 hours reperfusion.
  
  
  CONCLUSIONS
  These results are the initial demonstration that renal ischemia, with or without reperfusion, activates the TNF transcription factor NFkappaB and increases TNF bioactivity in the kidney.
authors.affiliation: Department of Urology, Indiana University Medical Center, Indianapolis 46202, USA.
authors.forename: K K
authors.initials: KK
authors.lastname: Donnahoo
authors.forename: D R
authors.initials: DR
authors.lastname: Meldrum
authors.forename: R
authors.initials: R
authors.lastname: Shenkar
authors.forename: C S
authors.initials: CS
authors.lastname: Chung
authors.forename: E
authors.initials: E
authors.lastname: Abraham
authors.forename: A H
authors.initials: AH
authors.lastname: Harken
mesh_terms: D000818:Animals; D007511:Ischemia / Q000276:immunology*; D007668:Kidney / Q000098:blood supply* / Q000276:immunology*; D008297:Male; D016328:NF-kappa B / Q000096:biosynthesis* / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D015427:Reperfusion Injury; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D016328:NF-kappa B; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha