ObjectiveTo evaluate the effect of heparin binding epidermal growth factor-like growth factor (HB-EGF) on liver regeneration after partial orthotopic liver transplantation. MethodsFourty SD rats were used to establish the model of partial orthotopic liver transplantation with ameliorated two-cuff technique. Then all the rats were divided into 2 groups: experiment group and control group. Twenty rats of experiment group were administered 500 μg/kg HBEGF via vena caudalis immediately after operation twice a day, while the same volume of saline was administered to the rats in control group. Five rats in each group were selected randomly and killed at the 6th hour, day 2, 4 and 7 after operation, respectively. The serum levels of albumin (Alb) and alanine aminotransferase (ALT) in the blood sample were detected. Every liver was removed and weighed. The expression of Ki67 was detected by using immunohistochemistry assay. The regeneration activity of hepatocytes was evaluated by flow cytometry. ResultsThe wet weights of liver in experiment group were all significantly higher than that in control group at the 6th hour, day 2 and 4 after transplantation (P＜0.05). The serum levels of ALT were significantly lower in experiment group than those in control group at the 6th hour, day 2， 4, 7 after operation (P＜0.05), while the levels of Alb were significantly higher on day 4 and 7. The proliferating index and Ki-67 labeling index of graft in experiment group were higher than those in control group on day 2 and 4 after transplantation （2 d: P＜0.01; 4 d: P＜0.05）. ConclusionHBEGF could promote the regeneration of rat hepatocytes after partial liver transplantation.