[Experimental induction of biliary tract carcinoma associated with proliferative cholangitis in Syrian hamster]

The biliary tract carcinogenesis related to proliferative cholangitis was investigated using Hamster. Proliferative cholangitis was induced by inserting a nylon thread into the papilla followed by ad libitum oral intake of the water including 70 ppm N-nitrosobis (2-oxopropyl) amine (BOP). The respective 12 animals were sacrificed 4, 8 and 12 weeks after the procedure to evaluate histologic features of the bile ducts and to determine the incidence of carcinoma. The treated specimens showed papillary proliferation of the epithelium, fibrous thickening of the wall and hypertrophy of the peribiliary gland at fourth week; and they appeared to resemble the features observed in the human proliferative cholangitis. This analogy was also confirmed by means of mucin-double staining with PAS-AB. In the extrahepatic bile ducts, the incidence of carcinoma was 41.7% twelve weeks after the treatment. The results of BrdU-staining indicated that the hyperplastic peribiliary glands could presumably be its preceding lesions. In the intrahepatic bile ducts, the minimal carcinoma arose even in 25.0% of the animals treated with BOP administration alone after 12 weeks. However, the incidence of the present model was at higher rate; it was 50.0% and 91.7% at 8 and 12 weeks postprocedure, respectively. The induced carcinomas were also relatively advanced and consisted of different histologic types. The results of BrdU Labeling Index suggested that hyperplasia and dysplasia might be precancerous lesion. In conclusion, this hamster model is easily established and would provide us valuable informations concerning the proliferative cholangitis related carcinogenesis of the bile ducts.