Radioprotective action of extracellular adenosine on bone marrow cells in mice exposed to gamma rays as assayed by the micronucleus test

The frequency of micronucleated polychromatic erythrocytes (PCEs) in mouse bone marrow was assessed after administration of dipyridamole and/or adenos ine monophosphate (AMP) to nonirradiated mice or to mice irradiated 15 min later with a sublethal dose of 6.5 Gy gamma rays. In nonirradiated mice, th e administration of the drugs increased the frequency of micronucleated PCE s significantly (by 108%). In contrast, in irradiated mice, the number of r adiation-induced micronucleated PCEs was significantly decreased if the mic e had been pretreated with dipyridamole or AMP alone (by 24% after administ ration of each of the compounds) and in particular after administration of the drugs in combination (by 36%). (C) 2000 by Radiation Research Society.