title: Role of UCP2 expression after hepatic warm ischemia-reperfusion in the rat.
abstract: OBJECTIVE
  The role of uncoupling protein-2 (UCP2) in the liver is currently unclear. Emerging evidence suggests a relationship between UCP2 and oxidative stress. In the present study, we tested the hypothesis that UCP2 expression in the liver might change during warm ischemia-reperfusion (I/R) according to oxidative stress.
  
  
  METHODS
  Wistar rats were subjected to 40 (short ischemia) or 90 (long ischemia) minutes of partial lobar ischemia followed by 4 hours of reperfusion. UCP2 expression in the ischemic and nonischemic lobes was assessed using reverse transcription-polymerase chain reaction and immunohistochemistry. Malondialdehyde concentrations in the liver tissue were also compared.
  
  
  RESULTS
  Malondialdehyde concentrations in the ischemic lobes were significantly higher in the long ischemia group. In the ischemic lobes of the short ischemia group, UCP2 protein expression was induced in hepatocytes, which did not express the protein prior to treatment, and the expression levels were higher than in the long ischemia group. The intralobular distribution of UCP2 seemed to correlate inversely with that of the necrotic area. UCP2 expression was observed, even in nonischemic lobes with similar intralobular heterogeneity.
  
  
  CONCLUSIONS
  UCP2 was induced in hepatocytes after warm I/R. Although the primitive role of UCP2 expression may be cytoprotective in nature, its actual protective effect in hepatic I/R may be minimal.
authors.affiliation: Department of Surgery and Science, Kyushu University, Fukuoka Graduate School of Medical Sciences, Fukuoka, Japan.
authors.forename: Mizuki
authors.initials: M
authors.lastname: Ninomiya
authors.forename: Ken
authors.initials: K
authors.lastname: Shirabe
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Shimada
authors.forename: Takahiro
authors.initials: T
authors.lastname: Terashi
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Maehara