1992 Volume 83 Issue 1 Pages 16-22
Bladder tumors were induced in rats by the oral administration of 0.025% N-butyl-N-(hydroxybutyl) nitrosamine (BBN). In order to study the suppressive effects of rat interferon-α (IFN-α) on induction of carcinogenesis in vivo, rats were treated with IFN-α i. m. twice a week. The treatment began at 5th week of BBN administration. The bladder mucosa was observed macroscopically and microscopically, and NK activity was examined. The results were as follows.
1) There was no significant difference in the bladder to body weight ratio between the BBN+IFN-α and BBN groups in during stage A (10th-14th week when changes in the mucous membrance such as hypertrophy in the bladder wall or vascular formation are observed). This ratio in the BBN+IFN-α group was less than that in the BBN group in during stages B and C (15th-19th week and 20th-30th week respectively when tumors are visually recognizable).
2) The rate of carcinogenesis in the BBN+INF-α group was less than that in the BBN group in stages A and C.
3) The pathological grade and stage of the bladder cancer in the BBN+IFN-α group were lower than those in the BBN group in stages B and C.
4) There was no significant difference in NK activity between the two groups in stage A, but NK activity of the BBN+IFN-α group was higher than that of the BBN group in stage B.
5) These findings substantiated the hypothesis that IFN-α can suppress tumor-growth in BBN induced bladder carcinoma.
