title: Direct evidence for in vivo hydroxyl radical generation in blood of mice after acute chromium(VI) intake: electron spin resonance spin-trapping investigation.
abstract: Although it is assumed from in vitro experiments that the hydroxyl radical (*OH) may be responsible for chromium(VI) toxicity/carcinogenicity, no electron spin resonance (ESR) evidence for the generation of *OH in vivo has been reported. In this study, we have employed an ESR spin-trapping technique with 5,5-dimethylpyrroline-N-oxide (DMPO), a selective *OH trap, to detect *OH in blood. The ESR spectrum of spin adduct observed in the blood of mice given 4.8 mmol Cr(VI)/kg body weight exhibited the 1:2:2:1 intensity pattern of a quartet with a hyperfine coupling constant A(N) = A(H) = 14.81 G and g-value = 2.0067. The concentration of the spin adduct detected in the blood was 7.37 microM. The adduct production was inhibited by the addition of specific *OH scavengers such as sodium benzoate and methional to the blood. The results indicate that the spin adduct is nitroxide produced by the reaction of *OH with DMPO. This is the first report of ESR evidence for the in vivo generation of *OH in mammals by Cr(VI).
authors.affiliation: Department of Food Sciences and Nutritional Health, Kyoto Prefectural University, Shimogamo, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Hojo
authors.forename: A
authors.initials: A
authors.lastname: Okado
authors.forename: S
authors.initials: S
authors.lastname: Kawazoe
authors.forename: T
authors.initials: T
authors.lastname: Mizutani
mesh_terms: D000447:Aldehydes / Q000737:chemistry; D000818:Animals; D002857:Chromium / Q000493:pharmacokinetics*; D003497:Cyclic N-Oxides / Q000737:chemistry; D004578:Electron Spin Resonance Spectroscopy; D017665:Hydroxyl Radical / Q000097:blood* / Q000633:toxicity; D008297:Male; D051379:Mice; D020160:Sodium Benzoate / Q000737:chemistry; D013054:Spectrophotometry, Atomic; D013997:Time Factors
chemical_list: D000447:Aldehydes; D003497:Cyclic N-Oxides; C008390:methional; D002857:Chromium; D017665:Hydroxyl Radical; C017245:5,5-dimethyl-1-pyrroline-1-oxide; D020160:Sodium Benzoate