ObjectiveTo investigate the expression of Lgr5 protein in regeneration tissue of remnant liver after associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) and its significance.MethodsA total of 120 male SD rats (200–240 g) were randomly equally divided into sham operation (SO) group, portal vein ligation (PVL) group, and ALPPS group using random number table method. The liver regeneration rate (LRR), liver function (AST and ALT), and the expressions of Ki-67 and Lgr5 in the right middle lobe of the liver were observed at day 1, 2, 4, and 7 after surgery.ResultsCompared with SO group, the LRRs and the Ki-67 protein expression positive rates and Lgr5 related protein expression levels in the right middle lobe of liver tissue were increased in the PVL group and ALPPS group at day 1, 2, and 4 after surgery (P<0.05), and the LRR was still increased at day 7 after surgery (P<0.05). The LRRs at day 4 and 7 after surgery in the ALPPS group were higher than those in the PVL group (P<0.05), the Ki-67 protein expression positive rates and Lgr5 related protein expression levels at day 2 and 4 after surgery in the ALPPS group were higher than those in the PVL group (P<0.05). The AST and ALT levels at day 1 and 2 after surgery in the ALPPS group and PVL group were higher than those in the SO group (P<0.05), which at day 1 after surgery in the ALPPS group were higher than those in the PVL group (P<0.05), but which returned to normal on day 4 after surgery.ConclusionsALPPS could promote liver regeneration better. Lgr5 is closely related to liver regeneration after ALPPS. Liver stem cells might be involved in liver regeneration after ALPPS.