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Journal of Toxicology
Volume 2011, Article ID 973172, 11 pages
Research Article

Estimation of the Postmortem Duration of Mouse Tissue by Electron Spin Resonance Spectroscopy

1I.T.O. Provitamin Research Center, 1-6-7-3F Nakamachi, Musashino, Tokyo, Japan
2Faculty of Pharmacy, Keio University, 1-5-30 Shibakoen, Minato-ku, Tokyo 105-8512, Japan
3Department of Pharmacology and Experimental Neuroscience, College of Medicine, University of Nebraska at Omaha, Omaha, NE 68182, USA
4Department of Occupational Therapy, Faculty of Regional Health Therapy, Teikyo Heisei University, 4-1 Uruido-minami, Ichihara, Chiba, Japan

Received 14 January 2011; Revised 29 March 2011; Accepted 12 April 2011

Academic Editor: Lucio Guido Costa

Copyright © 2011 Shinobu Ito et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Electron spin resonance (ESR) method is a simple method for detecting various free radicals simultaneously and directly. However, ESR spin trap method is unsuited to analyze weak ESR signals in organs because of water-induced dielectric loss (WIDL). To minimize WIDL occurring in biotissues and to improve detection sensitivity to free radicals in tissues, ESR cuvette was modified and used with 5,5-dimethtyl-1-pyrroline N-oxide (DMPO). The tissue samples were mouse brain, hart, lung, liver, kidney, pancreas, muscle, skin, and whole blood, where various ESR spin adduct signals including DMPO-ascorbyl radical (AsA), DMPO-superoxide anion radical (OOH), and DMPO-hydrogen radical (H) signal were detected. Postmortem changes in DMPO-AsA and DMPO-OOH were observed in various tissues of mouse. The signal peak of spin adduct was monitored until the 205th day postmortem. DMPO-AsA in liver ( log (day), , , ) was found to linearly decrease with the logarithm of postmortem duration days. Therefore, DMPO-AsA signal may be suitable for detecting an oxidation stress tracer from tissue in comparison with other spin adduct signal on ESR spin trap method.