Impact of head-only iron ion radiation on the peripheral LPS response

Although there is a large body of evidence indicating that radiation can have a dramatic impact on both immune and brain function, there is very little known about its effect on communication between these critical two systems. In this study, mice were exposed to head-localized irradiation with 5 Gy (56)Fe(26+) ions and assessed for immune function. Mice were inoculated with lipopolysaccharide 37-38 days post-irradiation. Subsets of mice were euthanized 1, 7, or 14 days later. Radiation significantly impacted the response to an immune challenge in terms of splenic and circulating leukocyte counts and lymphocyte distributions; the effect was especially pronounced on granulocytes and B-cells (p<0.05). However, there were no interactions in spontaneous or mitogen-induced blastogenesis of activated T-cell proportions, brain interleukin-1β, or circulating corticosterone levels. These data demonstrate that head-localized iron ion radiation modified the peripheral response to a potent bacterial component associated with septic shock.