RIBE affect HSPC cell-cycle entry and increases apoptosis and senescence in vivo. (A) Experimental diagram of in vivo RIBE model for analysis. (B) The proportion of BrdU⁺ cells of human CD34⁺ cells from irradiated and nonirradiated mice. BrdU was injected simultaneously with human CD34⁺ cells. (C) Frequency of early apoptotic cells (Annexin V⁺7AAD⁻) and late apoptotic cells (Annexin V⁺7AAD⁺) in the homed human CD34⁺ cells from irradiated and nonirradiated mice. (D) Homed human CD34⁺ cells from irradiated and nonirradiated mice were sorted and cultured in vitro for 3 days to detect SA-β-gal activity. 5-dodecanoylaminofluorescein di-β-d-galactopyranoside (C₁₂FDG) was used as a substrate. Bars represent fold change C₁₂FDG MFI compared with that in the control (Ctrl) group. (E-F) Flow cytometric analysis of fold change of ROS levels by DCF-DA (E) and dihydroethidium staining (F) in homed human CD34⁺ cells. (G) Fold change of mitochondrial ROS levels in homed human CD34⁺ cells were detected by MitoSOX staining. (H-I) Fold change of mitochondrial membrane potential of homed human CD34⁺ cells from irradiated or nonirradiated NOG mice were determined with tetramethylrhodamine methyl ester (TMRE) (H) and DilC1(5) staining (I) (n = 4 mice per group, *P < .05; **P < .01; ***P < .001).