Histopathologic Changes of the Bile Duct in Mice Experimentally Infected with Clonorchis sinensis

The objective of this sutdy was to obtain further information on the relationship between oncogenesis of cholangiocellular carcinoma of the liver and the infection with a liver fluke, Clonorchis sinensis in the earlier stage of the infection. A group of 24 BALB/C male mice were used. Approximately 500 metacercariae were given orally to each mouse. Three mice were killed on the scheduled day, 3rd, 5th, 7th, 10th, 15th, 20th, 25th and 28th day after infection, respectively and histopathologic changes of the bile ducts were examined using hematoxylin and eosin stain method. The histopathologic findings observed were summarized as follows ; 1) Mice killed on the 3rd day showed a mild epithelial hyperplasia with the formation of papillae and adenomatous tissue proliferation. Bile ducts were dilated and the stroma was infiltrated by inflammatory cells, mainly eosinophils and polymorphonuclear leucocytes. Occasionally mitotic figures and atypia of epithelial cells were seen. Worms were found in the distal peripheral smaller branches of the bile duct. 2) Mice killed on the 7th day gave a mild connective tissue proliferation in addition to more striking pictures in the bile ducts. Chronic mononuclear leucocytes appeared in the stroma. 3) Bile duct chagnges including epithelial hyperplasia, adenomatous tissue formation, connective tissue proliferation and inflammatory cell infiltration were greater in the degrees in mice killed on the 10th day after infection. Mucinous cell metaplasia and collagen fiber proliferation were also observed. 4) From the 15th day throughout the 28th day after infection, mice showed the most striking pictures of peithelial hyperplasia, adenomatous tissue formation and mucinous cell metaplasia. The stroma demonstrated the excessive eosinophil and chronic mononuclear leucocyte infiltrations, while polymorphonuclear leucocytes were decreased.