RADIATION PROTECTION AND RADIATION RECOVERY WITH ESSENTIAL METALLOELEMENT CHELATES

Understanding essential metalloelement metabolism and its role in tiss ue maintenance and function, as well as the roles of essential metallo element-dependent enzymes in responding to injury, offer a new approac h to decreasing and/or treating radiation injury, This review presents the roles of some essential metalloelement-dependent enzymes in tissu e maintenance and function, and their responses to radiation injury in accounting for radiation protection and recovery effects observed for nontoxic doses of essential metalloelement compounds, Effects of bioc hemicals including water undergoing bond radiolysis and the effects of free radicals derived from diatomic oxygen account for the acute and chronic aspects of radiation injury, Recognized biochemical roles of e ssential metalloelement-dependent enzymes and the observed pharmacolog ical effects of small-molecular mass chelates predict the therapeutic usefulness of essential metalloelement complexes in decreasing and/or treatment of radiation injury, Copper chelates have radiation protecti on and radiation recovery activities and cause rapid recovery of immun ocompetency and recovery from radiation-induced histopathology, Mice t reated with Cu(II)(2)(3,5-diisopropylsalicylate)(4) [Cu(II)(2)(3,5-DIP S)(4)] had increased survival and corresponding increases in numbers o f myeloid and multipotential progenitor cells early after irradiation and earlier recovery of immune reactivity, Examination of radiation-in duced histopathology in spleen, bone marrow, thymus, and small intesti ne also revealed CU(II)(2)(3,5-DIPS)(4)-mediated rapid recovery of rad iation-induced histopathology, Most recently, Fe, Mn, and Zn complexes have also been found to prevent death in lethally irradiated mice, Th ese pharmacological effects of essential metalloelement chelates can b e understood as due to facilitation of de novo synthesis of essential metalloelement-dependent enzymes which have roles in preventing the ac cumulation of pathological concentrations of oxygen radicals or repair ing biochemical damage caused by radiation-induced bond homolysis, Ess ential metalloelement chelates offer a physiological approach to preve ntion and/or treatment of radiation injury.