Figure 1.

E-MPP and L-MPP cell numbers are downregulated by ⁵⁶Fe- and ¹H-IR but recover to control levels by 40 weeks post-IR. Effect of full-body single dose of proton (¹H) at 0.5 Gy, 1 GeV and iron (⁵⁶Fe) at 0.15 Gy, 1 GeV/nucleon of ionizing radiation (IR) on survival of multipotent progenitor cell populations was examined. The survival of (A) E-MPPs and (B) L-MPPs in the BM after particle IR in C57BL/6NT mice were determined at 1, 2, 4, 8, 12, 28, and 40 weeks post-IR. Total BM-derived mononuclear cells were triple-stained with FITC-labeled RAM34 antibody (that consists of CD34, c-kit, and Sca1 antibodies), PE-Cy7-AC133, and PE-hematopoietic lineage cocktail (CD3e, Ly-6G/Ly-6C, CD11b, CD45R/B220, TER-119), then sorted by FASC for (A) E-MPPs (CD34⁺/c-kit⁺/Sca-1⁺/AC133⁺/Lin⁻) and (B) L-MPPs (CD34⁺/c-kit⁺/Sca-1⁺/AC133⁻/Lin⁻). Percentage changes in cell numbers were calculated relative to control sham irradiated mice, which was set to 100% for each time point. Solid lines represent mean ± SEM (n = 6/group) for ¹H-IR (solid blue lines) and ⁵⁶Fe-IR (solid red lines). “*” represents statistically significant differences compared to control with p < 0.05.