Liver regeneration is dependent on the extent of hepatectomy

BackgroundThe 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.Materials and methodsA 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.ResultsLiver 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.ConclusionsWe show that liver RR and the number of proliferating hepatocytes increase, whereas the initial hepatic synthetic capacity decreases with increasing hepatectomy size.