Formation and the Decay of <i>p</i>-H2AX Foci, Inflammatory and Oxidative DNA damage Responses.

<p>(<b>A</b>) Diagrammatic representation of the experimental design to evaluate the effect of a single low-dose full body exposure to 50 cGy, 1 GeV ¹H and 15 cGy, 1 GeV/n ⁵⁶Fe ions on the formation and disappearance of <i>p</i>-H2AX foci, inflammation (CD68 staining), and oxidative DNA damage (8-oxo-deoxy-Guanosine ELISA) in the hearts of 8–10 months old (at the time of initial IR) C57BL/6NT mice over 28 days post-IR. CD68 staining and 8-oxo-dG ELISA were also performed at 2 and 3 months; (<b>B</b>) Graphic representation of mean <i>p</i>-H2AX foci/cell (cells with >1 foci) in non-EC (<i>p</i>-H2AX plus/ISB4 minus) cells and ECs (<i>p</i>-H2AX plus/ISB4 plus) in the heart tissue isolated from mice of sham-irradiated, ¹H-IR and ⁵⁶Fe-IR up to 28 days. In figures <b>B</b> and C the time points on the X-axis are represented in Log² scale. Dotted line represents the maximum <i>p</i>-H2AX foci/cell for non-ECs and dashed line represents maximum <i>p</i>-H2AX for ECs. *<i>P</i><0.05 for ¹H vs. ⁵⁶Fe. (<b>C</b>) Graphic representation of % change in CD68 positive (+) cells in the heart tissue of non-IR, ¹H-IR and ⁵⁶Fe-IR mice within hours and up to 12 weeks post-IR. CD68 (+) cells in control hearts was set at 100% (dash-dotted line). *<i>P</i><0.01 and **<i>P</i><0.001 for ¹H vs. ⁵⁶Fe. (<b>D</b>) Graphic representation of percent change in IR-induced 8-oxo-dG levels, quantified by ELISA in heart tissue isolated from sham-irradiated, ¹H-IR and ⁵⁶Fe-IR mice up to 12 weeks. The level of 8-oxo-dG in control hearts was set at 100% (dash-dotted line). *<i>P</i><0.005 for ¹H vs. ⁵⁶Fe All results are presented as mean ± SEM; <i>n</i> = 6–8 animals per time point/group for sham controls, ¹H-IR (solid blue line) and ⁵⁶Fe-IR (solid red line) groups. Statistical significance was assigned when <i>P</i><0.05.