Clonorchis sinensis infection contributes to hepatocellular carcinoma progression in rat

Clonorchis sinensis (C. sinensis) infection is a risk factor for cholangiocarcinoma. Whether it also contributes to the development of hepatocellular carcinoma (HCC) is still unclear. This study explored the potential relationship between C. sinensis infection and HCC. A total of 110 Sprague-Dawley rats were divided into four treatment groups, the negative control group (NC) received intragastric (i.g.) administration of saline, while the clonorchiasis group (CS) received i.g. administration of 150 C. sinensis metacercariae. The diethylnitrosamine-induced group (DEN) received intraperitoneal (i.p.) administration of DEN. The clonorchiasis DEN-induced group (CSDEN) received i.g. administration of 150 C. sinensis metacercariae followed by i.p. administration of DEN. Hematoxylin and eosin staining, immunohistochemistry, and Masson's trichrome staining were performed for histopathological analysis of the isolated tissues. RNA-seq technology and RT-PCR were employed for gene expression. In the DEN group, 15 rats survived, of which 9 developed liver cirrhosis and 7 developed HCC. In the CSDEN group, all of the 17 surviving rats developed cirrhosis, and 15 showed development of HCC. The incidence of liver cirrhosis and HCC was significantly higher in the CSDEN group than in the DEN group. KEGG pathway analysis of the differentially expressed genes suggested significant upregulation in inflammation-associated pathways. Immunohistochemistry and RT-PCR results showed significant upregulation of hepatic progenitor cell markers (CK19, SOX9, EpCAM) in the CS group compared to the NC group, as well as in the CSDEN group compared to the DEN group. Our study suggests that C. sinensis infection increases risk of HCC in a rat model by stimulating proliferation of hepatic progenitor cells.