Abstract

• The main objective of the present study was to obtain further information on the histopathologic changes in the bile ducts at chronic stage of Clonorchis sinensis infection for the establishment of relationship between clonorchiasis and cholangiocarcinoma. BALB/C male mice were used. Approximately 500 metacercariae were given orally to each mouse. Three mice were sacrificed once monthly from the 10th month through the 20th month after infection. The hepatobiliary tissues were fixed in 10% formalin solution, sectioned serially, and stained with hematoxylin and eosin for histopat-hologic examination. The results obtained are summarized as follows; 1) The bile ducts showed moderate adenomatousproliferation, mucinous cell metaplasia and goblet cell metaplasia from the 10th month up to the 13th month after infection, then gradual regression. As time elapsed, scattered abortive acini were aslo regressive. 2) Most of the stromal fibrous tissues were replaced by excessive collagen fibers which persisted throughout the observation. The pictures were considered to be irreversible. 3) Polymorphonuclear leucocyte and eosinophil infiltrations was slight in the degree, while chronic mononuclear leucocyte infiltration was moderate throughout the observation. 4) Even though no any evidence of malignant change of epithelial cells was demonstrated thoughout the observation, Clonorchis infection was considered to be an impotant predisposing factor in carcinogenesis in the bile ducts.