Consequences of gamma-irradiation on inflammatory cytokine regulation in human monocytes/macrophages

Inflammation is a frequent result of radiation damage, especially after therapeutic irradiation. Monocytes and macrophages play an important role in inflammatory cytokine secretion. However, knowledge of monocytel macrophage involvement in the pathogenesis of inflammation is still incomplete. In this study, we investigated the inflammatory cytokine regulation after in vitro gamma-irradiation of monocytes/macrophages. Semiquantitative RT-PCR after irradiation revealed no significant induction of interleukin 1 beta or tumour necrosis factor-alpha mRNA expression. When induction was observed, for only two donors out of seven, only interleukin 6 gene expression was affected by irradiation, with a 5-14-fold increase in level according to the donor, 2h after irradiation compared with sham-irradiated cells. For only one of seven donors tested, monocytes/macrophages responded to 10-Gy gamma-rays by releasing inflammatory cytokines.