title: Protective effect of intermittent clamping of the portal triad in the rat liver on liver ischemia-reperfusion injury.
abstract: BACKGROUND
  Intermittent clamping (IC) of the portal triad is an effective method of protecting the liver from ischemia-reperfusion injury (IR). In clinical practice, this method is employed during a resection, but its mechanism is still not clear.
  
  
  OBJECTIVE
  To evaluate the effect of IC on rat liver and determine its mechanisms.
  
  
  METHODS
  Wistar rats were submitted to 60-min IC (cycles of 12-min clamping followed by 4-min reperfusion), and the samples were collected after 1, 6, and 72 hrs of reperfusion. We determined the serum activity of alanine aminotransferase (ALT), and measured the concentration of TNF-α, malondialdehyde (MDA) and myeloperoxidase (MPO) in liver homogenates. The apoptosis of hepatocytes was evaluated immunohistochemically.
  
  
  RESULTS
  When compared to the IR rats, the activity of ALT decreased in the IC group in all periods of observation (the highest decrease of ~48% after 1 hr of reperfusion). When compared to the IR group, a statistically significant decrease (p < 0.05) in the TNF-α concentration (~33%) in the IC rats occurred only after 1 hr of reperfusion, and it was accompanied by a decrease in the MPO concentration after 1 and 6 hrs of reperfusion. IC reduces the effects of reactive oxygen species (ROS) activity, which has been confirmed by a statistically significant decrease in MDA concentration by 25%-35% in all studied periods. The limitation of hepatocytes apoptosis due to IC occurs in the early (~26%; p < 0.05) and late (~45%; p < 0.01) phases of reperfusion.
  
  
  CONCLUSIONS
  The use of IC in early phase of reperfusion brings about a decrease in TNF-α release, which can be related to liver injury due to neutrophil infiltration and apoptotic cell reduction. It seems that the reduction of lipid peroxidation may also limit the liver injury.
authors.affiliation: Department of Histology and Embryology, Medical University of Silesia, Zabrze, Poland.
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Helewski
authors.forename: Grazyna
authors.initials: G
authors.lastname: Kowalczyk-Ziomek
authors.forename: Eugeniusz
authors.initials: E
authors.lastname: Czecior
authors.forename: Grzegorz
authors.initials: G
authors.lastname: Wyrobiec
authors.forename: Marzena
authors.initials: M
authors.lastname: Harabin-Slowinska
authors.forename: Malgorzata
authors.initials: M
authors.lastname: Juszko-Piekut
authors.forename: Bogumila
authors.initials: B
authors.lastname: Braczkowska
authors.forename: Jadwiga
authors.initials: J
authors.lastname: Josko
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