Abstract
This study was carried out to clarify the influence of incomplete bile duct obstruction (IBDO) on the occurrence of cholangiocarcinoma induced by diisopropanolnitrosamine (DIPN)and to evaluate the effect of release of IBDO.
In the first experiment,320 male Syrian golden hamsters were divided into 2 groups, consisting of the simple laparotomy group and the IBDO group. These groups were administered with subcutaneous injection of 500 mg/kg body weight of DIPN weekly for 20 weeks after preliminry procedures.
In the second experiment,170 hamsters were administered with subcutaneous injection of 500 mg/kg body weight of DIPN weekly for 10 weeks. There hamsters were divided into 3 groups, consisting of the simple laparotomy group, the IBDO group and the 2 week IBDO group, in which IBDO was released at 2 weeks after procedure. In both experiments, the occurrence rates of cholangiocar cinoma at 15 and 20 weeks in the IBDO groups were significantly higher than those in other groups. The mean numbers of tumors per hamster at same weeks in the IBDO group were significantly larger than those in other groups. Besides, in the second experiment the simple laparotomy and 2 week IBDO group indicated similar coccurrence rates and numbers of tumor.
The above results suggest that IBDO has an in fluence, as promoter, on the occurrence of cholangiocarcinoma induced by DIPN, and that its promoting effect disappears caused by release of obtruction.
