title: Quantitative histological assessment of hepatic ischemia-reperfusion injuries following ischemic pre- and post-conditioning in the rat liver.
abstract: BACKGROUND
  Ischemic preconditioning (IPC) has been shown to protect the liver against ischemia-reperfusion (I/R) injuries. However, ischemic post-conditioning has received little attention. The aim of the present study was to quantify and compare the hepato-protective properties of IPC and IPO, for the first time, using unbiased design-based stereological methods.
  
  
  METHODS
  We divided 67 rats into four groups: sham, liver ischemia (LI), IPC, and IPO. Rats were subjected to 60 min LI, followed by 4- or 24-h reperfusion. We performed quantification of (NVR) and apoptotic cell profile number.
  
  
  RESULTS
  We observed no significant differences in NVR between ischemic groups after 4 h. After 24-h reperfusion, NVR had increased to 70% in the LI group, compared with 51% (P = 0.02) and 49% (P = 0.01) in the IPC and IPO groups, respectively. After 4-h reperfusion, the apoptotic cell number was significantly higher in all ischemic groups than in the sham group; we detected no difference between ischemic groups. After 24-h reperfusion, we detected a significantly lower number of apoptotic cell profiles in the IPC group than in the LI group (P = 0.02). The mean number of apoptotic cell profiles decreased insignificantly in the IPO group (P = 0.06). Liver parameters were at all time comparable between groups.
  
  
  CONCLUSIONS
  After I/R, IPC and IPO reduce the degree of hepatocellular injury. Both methods are equally efficient at preventing hepatocellular necrosis. Furthermore, apoptosis is significantly lower after IPC.
authors.affiliation: Department of Surgical Gastroenterology L, Aarhus University Hospital, Aarhus, Denmark. auknudsen@gmail.com
authors.forename: Anders R
authors.initials: AR
authors.lastname: Knudsen
authors.forename: Anne-Sofie
authors.initials: AS
authors.lastname: Kannerup
authors.forename: Henning
authors.initials: H
authors.lastname: Grønbæk
authors.forename: Stephen H
authors.initials: SH
authors.lastname: Dutoit
authors.forename: Jens R
authors.initials: JR
authors.lastname: Nyengaard
authors.forename: Peter
authors.initials: P
authors.lastname: Funch-Jensen
authors.forename: Frank V
authors.initials: FV
authors.lastname: Mortensen
mesh_terms: D000818:Animals; D017209:Apoptosis; D015850:Interleukin-6 / Q000097:blood; D057775:Ischemic Postconditioning; D019194:Ischemic Preconditioning; D008099:Liver / Q000098:blood supply* / Q000473:pathology; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D015427:Reperfusion Injury / Q000473:pathology*; D014409:Tumor Necrosis Factor-alpha / Q000097:blood; D000511:alpha-Macroglobulins / Q000032:analysis
chemical_list: D015850:Interleukin-6; D014409:Tumor Necrosis Factor-alpha; D000511:alpha-Macroglobulins