Low-Dose Ionizing Radiation Affects Mesenchymal Stem Cells via Extracellular Oxidized Cell-Free DNA: A Possible Mediator of Bystander Effect and Adaptive Response

Figure 6

Low-dose radiation and cfDNAox and cfDNAoxR fragments cause DNA breaks and γH2AX foci in nuclear DNA. (a) (1) Flow cytometry detection of DSB in cells exposed to cfDNAox and cfDNAoxR fragments. Cells were processed for immunofluorescence staining with anti γH2AX antibody-DyLight488 (FL1). Gate R encircles the fraction of cells with elevated values of FL1-γH2AX. (2) Distribution of γH2AX fluorescence intensities with varying DSB levels. (b) Median signal intensity of FL1 (mean value for three independent experiments). (c, d) DSB in irradiated cells (10 cGy, 15 min and 2 h after exposure) and cells exposed to cfDNAox and cfDNAoxR (50 ng/ml, 15 min and 2 h, fluorescence microscopy). Cells stained with anti γH2AX antibodies (c) and DAPI (d), .

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