title: Reduced secretion of the inflammatory cytokine IL-1β by stimulated peritoneal macrophages of radiosensitive Balb/c mice after exposure to 0.5 or 0.7 Gy of ionizing radiation.
abstract: Since the beginning of the 20th century, low dose radiotherapy (LD-RT) has been practiced and established as therapy of inflammatory diseases. Several clinical studies already have proven the anti-inflammatory effect of low doses of ionizing irradiation (LDR). However, further research is inevitable to reveal the underlying immune-biological mechanisms. Focus has been set on the modulation of activated macrophages by LDR, since they participate in both, initiation and resolution of inflammation. Here we examined with an ex vivo peritoneal mouse macrophage model how LDR modulates the secretion of the inflammatory cytokines IL-1β and TNF-α by activated macrophages and whether the basal radiosensitivity of the immune cells has influence on it. Peritoneal macrophages of Balb/c mice responded to exposure of 0.5 or 0.7 Gy of ionizing irradiation (X-ray) with significant decreased release of IL-1β and slightly, but not significantly, reduced release of TNF-α. Macrophages of the less radiosensitive C57BL/6 mice did not show this anti-inflammatory reaction. This was observed in both wild type and human TNF-α transgenic animals with C57BL/6 background. We conclude that only the inflammatory phenotype of more radiosensitive macrophages is reduced by LDR and that ex vivo and in vivo models with primary cells should be applied to examine how the immune system is modulated by LDR.
authors.affiliation: Department of Radiation Oncology University, Hospital Erlangen, Friedrich-Alexander Universität Erlangen-Nürnberg, Germany.
authors.forename: Birgit
authors.initials: B
authors.lastname: Frischholz
authors.forename: Roland
authors.initials: R
authors.lastname: Wunderlich
authors.forename: Paul-Friedrich
authors.initials: PF
authors.lastname: Rühle
authors.forename: Christine
authors.initials: C
authors.lastname: Schorn
authors.forename: Franz
authors.initials: F
authors.lastname: Rödel
authors.forename: Ludwig
authors.initials: L
authors.lastname: Keilholz
authors.forename: Rainer
authors.initials: R
authors.lastname: Fietkau
authors.forename: Udo S
authors.initials: US
authors.lastname: Gaipl
authors.forename: Benjamin
authors.initials: B
authors.lastname: Frey
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D015536:Down-Regulation / Q000276:immunology* / Q000528:radiation effects; D006801:Humans; D018836:Inflammation Mediators / Q000037:antagonists & inhibitors* / Q000378:metabolism; D053583:Interleukin-1beta / Q000037:antagonists & inhibitors* / Q000378:metabolism; D008262:Macrophage Activation / Q000276:immunology* / Q000528:radiation effects; D017737:Macrophages, Peritoneal / Q000276:immunology* / Q000378:metabolism* / Q000528:radiation effects; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D014965:X-Rays
chemical_list: D018836:Inflammation Mediators; D053583:Interleukin-1beta