In vivo singlet-oxygen generation in blood of chromium(VI)-treated mice
- 70 Downloads
Although it is assumed from in vitro experiments that the generation of reactive oxygen species such as the singlet oxygen (1O2), the hydroxyl radical, and the superoxide anion are responsible for chromium(VI) toxicity/carcinogenicity, no electron spin resonance (ESR) evidence for the generation of 1O2 in vivo has been reported. In this study, we have employed an ESR spin-trapping technique with 2,2,6,6-tetramethyl-4-piperidone (TMPD), a specific 1O2 trap, to detect 1O2 in blood. The ESR spectrum of the spin adduct observed in the blood of mice given 4.8 mmol Cr(VI)/kg body weight exhibited the 1 : 1 : 1 intensity pattern of three lines with a hyperfine coupling constant A N=16.08 G and a g-value=2.0066. The concentration of spin adduct detected in the blood was 1.46 µM (0.1% of total Cr concentration). The adduct production was inhibited by the addition of specific 1O2 scavengers such as 1,4-diazabicyclo[2.2.2]octane and sodium azide to the blood. The results indicate that the spin adduct is nitroxide produced by the reaction of 1O2 with TMPD. This is the first report of ESR evidence for the in vivo generation of 1O2 in mammals by Cr(VI).
Index EntriesChromium(VI) singlet oxygen blood in vivo mice ESR spin-trapping 2,2,6,6-tetramethyl-4-piperidone
Unable to display preview. Download preview PDF.
- 10.Y. Lion, E. Gandin, and A. Van de Vorst, On the production of nitroxide radicals by singlet oxygen reaction: an EPR study, Photochem. Photobiol. 31, 305–309 (1980).Google Scholar
- 12.C. S. Foote, Detection of singlet oxygen in complex systems: a critique, in Biochemical and Clinical Aspects of Oxygen, W. S. Caughey, ed., Academic, New York, pp. 603–626 (1979).Google Scholar
- 13.J. D. Tan, S. E. Hudson, S. J. Brown, M. M. Olmstead, and P. K. Mascharak, Syntheses, structures, and reactivities of synthetic analogues of the three forms of Co(III)-bleomycin: proposed mode of light-induced DNA damage by the Co(III) chelate of the drug, J. Am. Chem. Soc. 114, 3841–3853 (1992).CrossRefGoogle Scholar
- 14.C. Veillon and K. Y. Patterson, Method 23: determination of chromium in human tissues by atomic absorption spectrometry, in Environmental Carcinogens—Selected Methods of Analysis. Some Metals: As, Be, Cd, Cr, Ni, Pb, Se, and Zn, vol. 8, IARC Scientific Publ. No. 71, I. K. O’Neil, P. Schyller, and L. Fishbein, eds., Oxford University Press, New York, pp. 433–440 (1986).Google Scholar
- 15.P. J. Thornalley, Theory and biological applications of the electron spin resonance technique of spin trapping, Life Chem. Rep. 4, 57–112 (1986).Google Scholar
- 16.G. R. Buettner, Spin trapping: ESR parameters of spin adducts, Free Radical Biol. Med. 3, 259–303 (1987).Google Scholar
- 18.K. Yamamoto and S. Kawanishi, Hydroxyl free radical is not the main active species in site-specific DNA damage induced by copper(II) ion and hydrogen peroxide, J. Biol. Chem. 264, 15,435–15,440 (1989).Google Scholar
- 24.A. Kortenkamp, M. Casadevall, S. P. Faux, A. Jenner, R. O. J. Shayer, N. Woodbridge, and P. O’Brien, A role for molecular oxygen in the formation of DNA damage during the reduction of the carcinogen chromium(VI) by glutathione, Arch. Biochem. Biophys. 329, 199–207 (1996).PubMedCrossRefGoogle Scholar