Improved functional reserve of hypertrophied contra lateral liver after portal vein ligation in rats

Background/Aims: We assessed the functional capacity of hypertrophied liver after portal vein ligation (PL) in a test group of rats compared to a control group (without PL) having the same size liver. Methods: The portal veins of the left and median lobes in the test group were ligated in an initial operation. Four days after the PL, the liver volume of the posterior caudate lobe (5%) increased two-fold, accounting for 10% of the liver. Then a 90% hepatectomy was performed, leaving only the hypertrophied posterior caudate lobe. Rats in a sham group underwent a 90% hepatectomy 4 days after having laparotomy, leaving the normal anterior and posterior caudate lobes (10%). Results: The survival rate for the PL group was significantly higher than for the sham group at 4 days after hepatectomy (56.3 and 26.7%, P<0.05). The regeneration ratio and the proliferating cell nuclear antigen (PCNA) labeling index in the PL group was markedly higher than in the sham group 24 h after hepatectomy. Conclusions: Hypertrophied liver at 4 days after PL still showed liver regeneration. Regenerating liver provided greater tolerance for extended hepatectomy than normal liver. This is because of the induced rapid regeneration of the remaining liver after hepatectomy.