Low-Dose Irradiation Differentially Impacts Macrophage Phenotype in Dependence of Fibroblast-Like Synoviocytes and Radiation Dose

Figure 3

Conditioned supernatants of irradiated fibroblast-like synoviocytes have an impact on the expression of phenotype characteristic surface markers of macrophages in dependence of the radiation dose. hTNF-α tg bone marrow cells were isolated and differentiated into M0 macrophages according to the experimental set-up shown in (a). Prior to macrophage generation, fibroblast-like synoviocyte cultures (FLS) were generated, phenotyped, and irradiated. Conditioned SN were collected and stored at -80°C until they were added to macrophage cultures 24 h prior to characterization of the macrophage phenotype. The M2 marker CD206 (b) was significantly reduced at doses starting from 0.5 Gy while M1 markers CD80 (c), MHCII (d), and CD86 (e) showed fewer alterations. While CD80 expression was not influenced by LD-RT, MHCII showed a slight reduction at 0.1 and 0.5 Gy, respectively. CD86 expression was significantly reduced at 2.0 Gy and already slightly downregulated at 0.5 and 1.0 Gy. Depicted is data from four independent experiments, each performed in triplicate (data points from one experiment are marked with equal symbols). Data is presented as the mean ± SEM. , , and . Representative histograms of the analyses are displayed in Supplementary Figure 4A.

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