Radioprotection by Antioxidantsa



    Corresponding author
    1. Office of International Health Programs, U.S. Department of Energy, EH-63/270CC, 19901 Germantown Road, Germantown, Maryland 20874, USA
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    1. Radiation Casualty Management Team, Armed Forces Radiobiology Research Institute, Bethesda, Maryland 20889, USA
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    Views presented in this paper are those of the authors. Many of the reviewed animal studies were done at the Armed Forces Radiobiology Research Institute (AFRRI), Bethesda, Maryland, and were conducted according to the principles enunciated in the Guide for the Care and Use of Laboratory Animals prepared by the Institute of Laboratory Animal Resources, National Research Council. The contributions of the AFRRI staff, who participated in these studies, are gratefully acknowledged.

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Abstract: The role of reactive oxygen species in ionizing radiation injury and the potential of antioxidants to reduce these deleterious effects have been studied in animal models for more than 50 years. This review focuses on the radioprotective efficacy and the toxicity in mice of phosphorothioates such as WR-2721 and WR-151327, other thiols, and examples of radioprotective antioxidants from other classes of agents. Naturally occurring antioxidants, such as vitamin E and selenium, are less effective radioprotectors than synthetic thiols but may provide a longer window of protection against lethality and other effects of low dose, low-dose rate exposures. Many natural antioxidants have antimutagenic properties that need further examination with respect to long-term radiation effects. Modulation of endogenous antioxidants, such as superoxide dismutase, may be useful in specific radiotherapy protocols. Other drugs, such as nimodipine, propranolol, and methylxanthines, have antioxidant properties in addition to their primary pharmacological activity and may have utility as radioprotectors when administered alone or in combination with phosphorothioates.