Effects of preactivation by portal vein ligation on liver regeneration following massive hepatectomy in rats

Background/Aims: We performed a long-term assessment of liver regeneration with or without PVL after massive hepatectomy in similar sized remnant livers to evaluate effects of regenerating livers preactivated by PVL following massive hepatectomy. Methodology: Rats were randomly divided into two groups, PVL-88%Hx and sham 88%Hx. As the initial operation, PVL or sham operation was performed by ligation of the portal vein of the left and median lobes or a similar manipulation without ligation, respectively. Four days after PVL, the volume of the posterior caudate lobe (5%) increased approximately two-fold (12%) and was the same size as the whole caudate lobe (12%) in the sham animals. Subsequently, 88%Hx was performed in the two groups. Results: Survival rates were not significantly different between the two groups. Relative liver weight in PVL-88%Hx group was significantly higher up to 24hr, but after 48hr no significant difference was evident between the two groups. PCNA LI in sham-89%Hx group was significantly higher than that in PVL-88%Hx group after 48hr. The mRNA expression levels of activin A and ActRIIA were significantly higher in PVL-88%Hx group than in sham-88% group at 72hr. Conclusions: The regenerating liver preactivated by PVL is restricted late-phase liver regeneration after massive hepatectomy.