title: The natural history of liver regeneration in rats: description of an animal model for liver regeneration studies.
abstract: BACKGROUND
  Rodent models have been used to evaluate aspects of liver regeneration. The aim of the present study was to investigate the natural history of liver regeneration in healthy rats.
  
  
  METHODS
  A 70% partial hepatectomy was performed in 64 rats. The animals were randomised into 8 groups and evaluated on postoperative days one to eight. Hepatocyte proliferation was evaluated by immunohistochemistry using unbiased stereological principles.
  
  
  RESULTS
  The mean rat body weight was 238 g (211-287). The mean weight of the resected liver was 6.3 g (5.2-7.3) and the estimated mean total liver weight was 8.9 g (7.4-10.4). Both liver weight analysis and regeneration rate showed an ascending curve, with a maximum slope on postoperative days 1-4, reaching a steady state on days 5-8. Hepatocyte proliferation (positive Ki-67 cell profiles pr. mm(2)) was high (250 cell profiles/mm(2)) on postoperative days 1-3 and tapered off on day 5.
  
  
  CONCLUSIONS
  Seventy percent partial hepatectomy in healthy rats induces a rapid regenerative response and PODs 2, 4 and 8 seems optimal for assessing hepatic growth in future studies.
authors.affiliation: Department of Surgical Gastroenterology, Aarhus University Hospital, 8000 Aarhus, Denmark. Electronic address: kasperjarlheltandersen@gmail.com.
authors.forename: Kasper Jarlhelt
authors.initials: KJ
authors.lastname: Andersen
authors.forename: Anders Riegels
authors.initials: AR
authors.lastname: Knudsen
authors.forename: Anne-Sofie
authors.initials: AS
authors.lastname: Kannerup
authors.forename: Hideki
authors.initials: H
authors.lastname: Sasanuma
authors.forename: Jens Randel
authors.initials: JR
authors.lastname: Nyengaard
authors.forename: Stephen
authors.initials: S
authors.lastname: Hamilton-Dutoit
authors.forename: Erland J
authors.initials: EJ
authors.lastname: Erlandsen
authors.forename: Bo
authors.initials: B
authors.lastname: Jørgensen
authors.forename: Frank Viborg
authors.initials: FV
authors.lastname: Mortensen
mesh_terms: D000818:Animals; D001663:Bilirubin / Q000378:metabolism; D001835:Body Weight / Q000502:physiology; D048708:Cell Growth Processes / Q000502:physiology; D022781:Hepatocytes / Q000166:cytology; D015850:Interleukin-6 / Q000378:metabolism; D008099:Liver / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D008115:Liver Regeneration / Q000502:physiology*; D023421:Models, Animal; D051381:Rats; D014443:Tyrosine / Q000378:metabolism; D000511:alpha-Macroglobulins / Q000378:metabolism
chemical_list: D015850:Interleukin-6; D000511:alpha-Macroglobulins; D014443:Tyrosine; D001663:Bilirubin
keywords: BTR; Hepatocyte proliferation; Liver regeneration; Liver resection; Rats