Radiation Crossing Resistance of Erythrocyte Micronucleus in Mice Induced by ~(147)Pm Internal Radiation

Objective To explore whether low dose internal radiation of 147 Pm could act against subsequent high dose 60 Co γ radiation induced genetic damage in mice erythrocytes.Methods Counts of red blood cell(RBC),counts of reticulocytes(RC),micronucleated normochromatic erythrocytes(mn NCE) and micronucleated polychromatic erythrocytes(mn PCE)were measured and assayed in peripheral blood to observe the radiation crossing resistance of micronucleus mutation in mice erythrocyte induced by low dose 147 Pm internal radiation.Results A dose of 2 0 Gy 60 Co γ external radiation could lead to significant erythrocyte system injury.Compared with the control group,counts of RBC and RC decreased significantly(P0 01)with significant increase of mn NCE and mn PCE(P0 01).However,when treated with 0 37,3 7 and 37 Bq/g body weight of 147 Pm internal radiation beforehand,and 3 days later followed by 2 0 Gy 60 Co γ external radiation,compared with 60 Co external γ ray radiation only,counts of RBC and RC increased significantly with significant decrease of mn NCE and mn PCE(P0 05,or P0 01).Some indices even showed no significant difference compared with the control group with any radiation at all(P0 05).It suggested that prior treatment with 147 Pm internal radiation could improve the resistance of micronucleus mutation in erythrocytes at different mature stage induced by subsequent 60 Co γ external radiation.There existed a dose range for inducing the radiation crossing resistance by low dose 147 Pm internal radiation.Conclusions Genetic mutation in peripheral blood erythrocytes with characteristics of simple,quick and suitable for continuous observation might be one of the biological indexes for low dose radiation effect.