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

Figure 10

The effect of cfDNAox on the survival of cells and formation of γH2AX foci after exposure to radiation (2 Gy). haMSCs were grown for 3 h in presence of cfDNAox and then irradiated with 2 Gy and grown in fresh media for 48 h more before GG assay. Ai (0), Ai (2 Gy)—absorbance of MTT derivative as normalized to the number of assayed cells in control and irradiated cell populations after preconditioning. The differences are significant at . (b) (1) Fluorescence-activated cell sorting (FACS) analysis was used to assess the accumulation of gH2AX foci in haMSCs. The plot of FL1 (gH2AX) versus FL2 (DNA content, PI) is shown as drawn for the control cells. The Gate R denotes the fraction of haMSCs, with type 2 nuclei and large number of gH2AX foci. (b) (2) Mean relative fluorescence of the main population of haMSCs (b) after subtraction of the background. Means for the three experiments and SD are shown. The difference from the control is statistically significant ().

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