title: Dose-related changes of oxidative stress and cell proliferation in kidneys of male and female F344 rats exposed to potassium bromate.
abstract: It is still of importance to investigate renal carcinogenesis by potassium bromate (KBrO3), a by-product of water disinfection by ozonation, for assessment of the risk to man. Five female F344 rats in each group were given KBrO3 at a dose of 300 mg/kg by single i.g. intubation or at a dose of 80 mg/kg by single i.p. injection, and were killed 48 h after the administration for measurements of thiobarbituric acid-reactive substances (TBARS) and 8-oxodeoxyguanosine (8-oxodG) levels in the kidney. Both levels in the treated animals were significantly elevated as compared with the control values. In a second experiment, 5 male and female F344 rats in each group were administered KBrO3 at concentrations of 0, 15, 30, 60, 125, 250 and 500 ppm in the drinking water for 4 weeks. KBrO3 in the drinking water did not elevate TBARS in either sex at any of the doses examined, but 8-oxodG formation in both sexes at 250 ppm and above was significantly higher than in the controls. Additionally, the bromodeoxyuridine-labeling index for proximal convoluted tubules was significantly increased at 30 ppm and above in the males, and at 250 ppm and above in the females. Alpha2u-globulin accumulation in the kidneys of male rats was increased with statistical significance at 125 ppm and above. These findings suggest that DNA oxidation induced by KBrO3 may occur independently of lipid peroxidation and more than 250 ppm KBrO3 in the drinking water can exert a carcinogenic effect by way of oxidative stress.
authors.affiliation: Division of Pathology, Environmental Health and Medical Safety Science, National Institute of Health Sciences, Setagaya-ku, Tokyo 158-8501, Japan. umemura@nihs.go.jp
authors.forename: Takashi
authors.initials: T
authors.lastname: Umemura
authors.forename: Yasuki
authors.initials: Y
authors.lastname: Kitamura
authors.forename: Keita
authors.initials: K
authors.lastname: Kanki
authors.forename: Satoshi
authors.initials: S
authors.lastname: Maruyama
authors.forename: Kazushi
authors.initials: K
authors.lastname: Okazaki
authors.forename: Takayoshi
authors.initials: T
authors.lastname: Imazawa
authors.forename: Tetsuji
authors.initials: T
authors.lastname: Nishimura
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Hasegawa
authors.forename: Akiyoshi
authors.initials: A
authors.lastname: Nishikawa
authors.forename: Masao
authors.initials: M
authors.lastname: Hirose
mesh_terms: D000284:Administration, Oral; D000818:Animals; D001959:Bromates / Q000008:administration & dosage / Q000633:toxicity*; D002273:Carcinogens / Q000008:administration & dosage / Q000633:toxicity*; D002455:Cell Division / Q000187:drug effects*; D004249:DNA Damage; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D007668:Kidney / Q000166:cytology* / Q000473:pathology*; D007680:Kidney Neoplasms / Q000139:chemically induced*; D015227:Lipid Peroxidation; D008297:Male; D018384:Oxidative Stress; D051381:Rats; D011916:Rats, Inbred F344; D018508:Water Purification
chemical_list: D001959:Bromates; D002273:Carcinogens; C019536:potassium bromate