Two-Stage Portal Vein Ligation Facilitates Liver Regeneration Safely in Rats with Liver Cirrhosis

Abstract

Background Portal vein (PV) embolization is performed prior to extended hepatectomy for the damaged liver to increase future remnant liver volume and prevent postoperative liver failure. This study examined whether two-stage PV ligation (PVL) increased regeneration and hypertrophy of the future remnant liver compared to conventional PVL, and whether two-stage PVL was safe for damaged liver. Method We produced a cirrhotic liver rat model with perioperatively maintained fibrosis. Rats were divided into: Group A (70%PVL), ligation of left branch of PV; Group B (90%PVL), ligation of right and left branches of PV; and Group C (two-stage 90%PVL), two-stage PVL with left branch ligation of PV followed by right branch ligation 7 days later. To evaluate liver regeneration, liver weight ratios, proliferating cell nuclear antigen (PCNA) labeling index (LI), mitotic index (MI), and TdT-mediated dUTP-biotin nick end labeling (TUNEL) LI in the non-ligated caudate lobe were measured. Results Fourteen-day survival rate was 20% in Group B but 100% in Group C. TUNEL LI differed significantly between Groups A and B at 2 and 7 days postoperatively. Weight ratios were significantly higher in Group C than in Groups A and B at 14 days postoperatively. PCNA LI and MI in the non-ligated caudate lobe decreased to preoperative levels by 7 days postoperatively in Groups A and B, but remained elevated until 14 days postoperatively in Group C. Conclusion In cirrhotic liver rats, two-stage PVL avoided the lethal liver failure seen with one-stage PVL, and significantly facilitated liver regeneration more than one-stage PVL.