title: Histopathological evaluation of rat urinary bladders from the IRDC two-generation bioassay of sodium saccharin.
abstract: Bladder tissues from rats treated with sodium saccharin in a two-generation dose-response study, in which 1.0% in the diet had been identified as the no-effect level for primary bladder cancer, were re-examined without knowledge of the test groups or the previous histopathological findings. Compound-related increases in the incidences of hyperplasia were found at the 6.25 and 7.5% saccharin levels (the highest dietary levels tested). There were also compound-related increased in the incidence of transitional-cell papillomas and/or carcinomas at the 4.0, 5.0, 6.25 and 7.5% levels. There was a slight increase in the incidence of transitional-cell carcinomas at the 3.0% level, but this was not statistically significant (P = 0.25). No compound-related effects were evident at the 1.0% level. All tumours were well to moderately differentiated and there was no increase in mean grades of severity or anaplasia for any proliferative lesion.
mesh_terms: D000818:Animals; D001681:Biological Assay; D006965:Hyperplasia; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012439:Saccharin / Q000633:toxicity*; D001743:Urinary Bladder / Q000187:drug effects* / Q000473:pathology; D001749:Urinary Bladder Neoplasms / Q000139:chemically induced / Q000473:pathology
chemical_list: D012439:Saccharin