title: Vascular relaxation of canine visceral arteries after ischemia by means of supraceliac aortic cross-clamping followed by reperfusion.
abstract: BACKGROUND
  The supraceliac aortic cross-clamping can be an option to save patients with hipovolemic shock due to abdominal trauma. However, this maneuver is associated with ischemia/reperfusion (I/R) injury strongly related to oxidative stress and reduction of nitric oxide bioavailability. Moreover, several studies demonstrated impairment in relaxation after I/R, but the time course of I/R necessary to induce vascular dysfunction is still controversial. We investigated whether 60 minutes of ischemia followed by 30 minutes of reperfusion do not change the relaxation of visceral arteries nor the plasma and renal levels of malondialdehyde (MDA) and nitrite plus nitrate (NOx).
  
  
  METHODS
  Male mongrel dogs (n = 27) were randomly allocated in one of the three groups: sham (no clamping, n = 9), ischemia (supraceliac aortic cross-clamping for 60 minutes, n = 9), and I/R (60 minutes of ischemia followed by reperfusion for 30 minutes, n = 9). Relaxation of visceral arteries (celiac trunk, renal and superior mesenteric arteries) was studied in organ chambers. MDA and NOx concentrations were determined using a commercially available kit and an ozone-based chemiluminescence assay, respectively.
  
  
  RESULTS
  Both acetylcholine and calcium ionophore caused relaxation in endothelium-intact rings and no statistical differences were observed among the three groups. Sodium nitroprusside promoted relaxation in endothelium-denuded rings, and there were no inter-group statistical differences. Both plasma and renal concentrations of MDA and NOx showed no significant difference among the groups.
  
  
  CONCLUSIONS
  Supraceliac aortic cross-clamping for 60 minutes alone and followed by 30 minutes of reperfusion did not impair relaxation of canine visceral arteries nor evoke biochemical alterations in plasma or renal tissue.
authors.affiliation: Department of Surgery and Anatomy, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil.
authors.forename: José G
authors.initials: JG
authors.lastname: Ciscato
authors.forename: Verena K
authors.initials: VK
authors.lastname: Capellini
authors.forename: Andrea C
authors.initials: AC
authors.lastname: Celotto
authors.forename: Caroline F
authors.initials: CF
authors.lastname: Baldo
authors.forename: Edwaldo E
authors.initials: EE
authors.lastname: Joviliano
authors.forename: Paulo R B
authors.initials: PR
authors.lastname: Evora
authors.forename: Marcelo B
authors.initials: MB
authors.lastname: Dalio
authors.forename: Carlos E
authors.initials: CE
authors.lastname: Piccinato
mesh_terms: D000818:Animals; D001012:Aorta, Abdominal / Q000601:surgery*; D001158:Arteries / Q000502:physiology* / Q000601:surgery; D003250:Constriction; D004285:Dogs; D007511:Ischemia; D008297:Male; D017063:Outcome Assessment, Health Care; D011897:Random Allocation; D015424:Reperfusion; D015427:Reperfusion Injury / Q000209:etiology; D013514:Surgical Procedures, Operative; D014664:Vasodilation / Q000502:physiology*