Objective To explore the pathological features of rejection reaction and whether it accord with antibody-mediated rejection (AMR) in the liver transplantation model of allo-sensitized rat. Methods Twelve male Lewis rats as the recipient, 250–290 g; 6 male Brown Norway (BN) rats as the donor, 250–280 g. Twelve Lewis recipient rats were randomly divided into 4 groups by random number method (n=3): Lewis control group (LC group, without any treatment), direct transplantation group (T group, livers from BN rats were directly transplanted into Lewis rats), sensitized group (S group, spleen lymphocytes from BN rats were injected into Lewis rats), and sensitized transplantation group (TS group, splenic lymphocytes from BN rats were injected into Lewis rats for 2 weeks before liver transplantation). On the 14th day after liver transplantation, 3–4 mL of recipient non-lethal blood was collected to detect serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), total bilirubin (TB), alkaline phosphatase (ALP) and creatinine (CRE) levels, and detect the expression of donor-specific alloantibody (DSA) and complement C4d in recipients. Hematoxylin-eosin (HE) staining and Masson staining were used to evaluate the morphological indexes of rat liver tissue, and CK-19, C4d and CD20 immunohistochemical staining methods were used to evaluate the degree of liver rejection and rejection activity index (RAI) score was performed. ResultsCompared with the T group, the serum AST, TB, and ALP levels, as well as the positive rates of DSA (IgG1, IgG2a, IgG2b, IgG2c) and C4d expression in Lewis rats in the TS group increased. Compared with the LC group, rats in the T group showed partial bile duct edema and lymphocyte infiltration, but no obvious damage of capillary structure was observed. Compared with the T group, a large number of lymphocytes or monocytes were infiltrated and capillaries were severely damaged in the anterior bile duct of rats in the TS group. The RAI and C4d scores of the TS group were higher than those of the T group. Conclusions More severe acute rejection and liver dysfunction occurred after liver transplantation in sensitized rats, and the acute rejection in sensitized rats was consistent with the characteristics of AMR. However, due to the small sample size in this study, further exploration of AMR model remains to be done.