Objective:To investigate the role of CD155 in hepatocyte apoptosis and liver fibrosis in mice infected with Echinococcus multilocularis. Methods:Thirty-six female C57BL/6 mice were randomly divided into a sham surgery group and a model group, with 18 mice in each group. Mice in the model group were injected with protoscolex via the portal vein to create an animal model of E. multilocularis infection. Mice in the sham surgery group were injected with the same amount of saline. The mice were sacrificed at 1 month, 3 months, and 6 months after modeling, and liver samples were collected. Hepatic pathological changes were observed by hematoxylin-eosin staining. Liver fibrosis was detected by Sirius red staining, and expression of Caspase-3 and CD155 in hepatocytes was detected by immunohistochemical staining. The correlation between CD155 expression in hepatocytes and Caspase-3 and liver fibrosis levels were analyzed by Person. Results:There were obvious lesions in the liver of the model group accompanied by severe liver fibrosis. Compared with the sham surgery group, the expression of CD155 and Caspase-3 in mouse hepatocytes at different stages in the model group was significantly increased, and the differences were statistically significant ( P<0.05). The model group's liver fibrosis level was significantly higher at different stages than the sham surgery group, with statistical significance ( P<0.05). In addition, correlation analysis showed that expression of CD155 in hepatocytes was positively correlated with the expression of Caspase-3 ( r=0.956 8; P<0.001; 95% CI: 0.885 5-0.984 1) and that expression of CD155 in hepatocytes was positively correlated with the degree of liver fibrosis( r=0.853 9; P<0.001; 95% CI: 0.643 7-0.944 3). Conclusions:CD155 expression was significantly up-regulated in mouse hepatocytes infected with E. multilocularis at different stages, which was positively correlated with the degree of hepatocyte apoptosis and liver fibrosis, suggesting that CD155 may be involved in the process of hepatocyte apoptosis and liver fibrosis caused by E. multilocularis infection.