Promoting effects of bile acid load on the occurrence of cholangiocarcinoma induced by diisopropanolnitrosamine in hamsters.

This study was performed to clarify the promoting effects of primary or secondary bile acid load on the occurrence of cholangiocarcinoma, using Syrian golden hamsters. These hamsters received subcutaneously diisopropanolnitrosamine (DIPN) once weekly for 10 weeks, and simultaneously were given a standard pellet diet (control group) containing taurocholic acid (TCA group) or deoxycholic acid (DCA group). The rates of cholangiocarcinoma at 20 weeks were 23% in the control group, 60% in the TCA group and 59% in the DCA group. There were significant differences between the control and the TCA or DCA groups (p < 0.05). The rates of proliferation of bile ductules or hyperplasia of the bile duct epithelium and the bromodeoxyuridine labeling indices of bile duct epithelial cells were high in both groups treated with bile acids, compared with those in the control group. Regarding the composition of bile acids in the intraductal bile, the TCA and DCA groups revealed a decrease in primary bile acids and an increase in DCA. These results suggest that both TCA and DCA given orally promote the occurrence of DIPN-induced cholangiocarcinoma.