Antioxidants and Biological Radiation Protection

Abstract

Antioxidants and antioxidant enzymes, by combatting oxygen radical-mediated radiation-induced oxidative stress, may prevent the accumulation of damage involved in tumor initiation, promotion and progression, and thus serve to protect us against ionizing radiation. We are testing the possible role of dietary antioxidants, and other biological response modifiers, in determining individual radiation response. These experiments use the fluorescent protein beta-phycoerythrin as a target and biomolecular marker for radiation-induced oxidative stress. Antioxidants are ranked according to their radioprotectiveness by their ability to compete with beta- phycoerythrin for radiolytic oxygen radicals. Samples of blood serum from cancer patients have been analyzed using this technique. There is a trend towards decreasing antioxidant levels with increasing donor age, and this is consistent with data showing an increasing radiosensitivity with age. We are presently monitoring antioxidant and antioxidant enzyme levels in atomic radiation workers and the general public, in order to assess whether they influence individual radiosensitivity. Knowledge of this source of biological response modification will be useful in applying radiation protection practices to those individuals or groups most at risk, and for estimating individual risks associated with radiation exposure.