Liver regeneration is dependent on the extent of hepatectomy.
The upper limit for the size of hepatectomy is approximately 90% in rats. The aim of the study was to assess quantitatively using stereological methods the impact on liver function, regeneration rate (RR), and hepatocyte proliferation of varying hepatectomy size in a rat model.



A total of 104 male Wistar rats were subjected to 30%, 70%, or 90% partial hepatectomy, sham operation, or no operation. Euthanization and harvesting of liver tissue and blood took place at postoperative days 1, 3, and 5 (n = 8 per group). Liver-specific biochemistry and RR were evaluated. Hepatocyte proliferation was estimated by immunohistochemical staining for Ki-67 antigen using unbiased stereological principles.



Liver RR in the 90% group increased by a 6.6 fold during the 5 postoperative days compared with only a minor increase in both the 70% and 30% partial hepatectomy groups. The highest number of Ki-67-positive hepatocytes was observed in the 70% group at postoperative day 1 and for the 90% group at postoperative day 3. Prothrombin-proconvertin ratio was significantly lower in the 90% group 1 d after surgery compared with all other groups, however, nearly normalized at postoperative day 5.



We show that liver RR and the number of proliferating hepatocytes increase, whereas the initial hepatic synthetic capacity decreases with increasing hepatectomy size.
Department of Surgical Gastroenterology, Aarhus University Hospital, Aarhus, Denmark. Electronic address: michellemeiermd@gmail.com.
Michelle
M
Meier
Department of Surgical Gastroenterology, Aarhus University Hospital, Aarhus, Denmark.
Kasper Jarlhelt
KJ
Andersen
Department of Surgical Gastroenterology, Aarhus University Hospital, Aarhus, Denmark.
Anders Riegels
AR
Knudsen
Stereology & Electron Microscopy Laboratory, Centre for Stochastic Geometry and Advanced Bioimaging, Aarhus University Hospital, Aarhus, Denmark.
Jens Randel
JR
Nyengaard
Institute of Pathology, Aarhus University Hospital, Aarhus, Denmark.
Stephen
S
Hamilton-Dutoit
Department of Surgical Gastroenterology, Aarhus University Hospital, Aarhus, Denmark.
Frank Viborg
FV
Mortensen
D000818:Animals; D001835:Body Weight; D049109:Cell Proliferation; D006498:Hepatectomy; D022781:Hepatocytes / Q000502:physiology; D008115:Liver Regeneration; D008297:Male; D011897:Random Allocation; D017208:Rats, Wistar
Hepatectomy; Liver; Regeneration; Stereology; Surgery