Comparison of interleukin-1 alpha gene expression and protein levels in the murine spleen after lethal and sublethal total-body irradiation.

To understand the effects of ionizing radiation on the production of IL-1 alpha in vivo within a hematopoietic organ, we evaluated acute changes in splenic IL-1 alpha mRNA and IL-1 alpha protein after exposing B6D2F1 mice to lethal and sublethal 60Co radiation. Results suggest that in vivo, ionizing radiation induces a time- and dose-dependent accumulation of IL-1 alpha mRNA in the mouse spleen after exposure to gamma radiation. Time-dependent increases in the level of IL-1 alpha protein were also observed, although the magnitude of increased protein expression did not complement the magnitude of the accumulation of the message. Selective concentration of cells producing IL-1 alpha does not appear to account completely for the increase in splenic IL-1 alpha mRNA observed in this in vivo system.