Increased 8-hydroxyguanine levels in DNA and its repair activity in rat kidney after administration of a renal carcinogen, ferric nitrilotriacetate.
The renal carcinogen, ferric nitrilotriacetate (Fe-NTA), is known to induce oxidative stress and the subsequent formation of a type of oxidative DNA damage, 8-hydroxyguanine (8-OH-Gua), in the rat kidney (Umemura et al., 1990). Using an improved DNA isolation method (Nakae et al., 1995), which reduces the background level of 8-OH-Gua, we found a five-fold increase in the 8-OH-Gua level in kidney DNA after a single i.p. injection of Fe-NTA. On the basis of the report that 8-OH-Gua repair activity is enhanced after cells are exposed to oxidative stress due to ionizing radiation (Bases et al., 1992), the measurement of 8-OH-Gua repair activity will also be useful to assess cellular oxidative stress. The 8-OH-Gua repair enzyme activity was determined with an endonuclease assay using a 22 mer DNA that contains 8-OH-Gua at a specific position. A five-fold increase in the 8-OH-Gua repair activity as compared with the control, was observed in the target organ, the rat kidney, 120 h after Fe-NTA administration. In the non-target organ, the liver, the increase was not as large (two-fold). This simple assay of oxidative DNA damage repair will be useful for evaluating the carcinogenicity of oxygen radical forming chemicals, in addition to chemical analyses of oxidative DNA damage.
Yamaguchi
R
R
Department of Environmental Oncology, University of Occupational and Environmental Health, Kitakyushu, Japan.
Hirano
T
T
Asami
S
S
Chung
M H
MH
Sugita
A
A
Kasai
H
H
D000818:Animals; D002273:Carcinogens / Q000633:toxicity*; D004247:DNA / Q000187:drug effects / Q000378:metabolism*; D004249:DNA Damage; D004260:DNA Repair; D005290:Ferric Compounds / Q000633:toxicity*; D006147:Guanine / Q000031:analogs & derivatives* / Q000378:metabolism; D007668:Kidney / Q000187:drug effects* / Q000378:metabolism*; D007680:Kidney Neoplasms / Q000139:chemically induced; D008297:Male; D009571:Nitrilotriacetic Acid / Q000031:analogs & derivatives* / Q000633:toxicity; D018384:Oxidative Stress / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar
D002273:Carcinogens; D005290:Ferric Compounds; C024829:8-hydroxyguanine; D006147:Guanine; D004247:DNA; D009571:Nitrilotriacetic Acid; C020326:ferric nitrilotriacetate