STUDIES ON EXPERIMENTAL GALLBLADDER CARCINOMA WITH N-ETHYL-N'-NITRO-N-NITROSOGUANIDINE IN GOLDEN HAMSTERS

Abstract

Carcinoma and intestinal metaplasia were induced by insertion of paraffin pellet containing N-ethyl-N'-nitro-N-nitrosoguanidine (ENNG) in the gallbladder of hamsters. One hundred of male hamsters were divided into three groups. Group-I; Seventy hamsters were operatively inserted 5 mg of paraffin pellet with 1.2mg ENNG into their gallbladder. Group-II; Twenty of animals received insertion of 5mg paraffin pellet without ENNG. Group-III; Ten were shamoperated. All animals were sacrificed and autopsied at 6 months after the treatment. The gallbladder histologically showed hyperplasia, intestinal metaplasia, papilloma, and carcinoma. Adenocarcinoma was classified into 3 types, papillary, infiltrative, and mixed type according to Edmondson's classification.
Twenty one (38%) out of 55 in Group-I developed carcinoma; 9 papillary, 7 infiltrative, 5 mixed type. Seven out of 9 papillary carcinoma were associated with intestinal metaplasia, whereas only one in infiltrative carcinoma showed intestinal metaplasia. In Group-II, hyperplasia, intestinal metaplasia and papilloma were encountered, but no developement of carcinoma was confirmed. Moreover, no above mentioned changes were observed in Group-III.
These results suggest that papillary carcinoma might be caused from papilloma with intestinal metaplasia and that infiltrative carcinoma might develop sudddenly from intact and hyperplastic epithelium.