Fig. 4

Engraftment kinetics and long-term repopulating capability of HPCs mobilized by HF51116+G-CSF. a Early engraftment strategy. G-SCF (100 μg/kg, every 12 h for 4 days) was subcutaneously injected into CD45.2⁺ mice. At 12 h post-final G-CSF injection, saline, 5 mg/kg HF51116, or 5 mg/kg AMD3100 was subcutaneously injected into the CD45.2⁺ mice. Light-density mononuclear cells (LDMNCs) were collected in PB at 0, 30, and 60 min post-injection of each of these agents. Lethally irradiated CD45.1⁺ recipients received a graft of LDMNCs. The control group was healthy mice with no radiation. The recoveries of neutrophils (b) and platelets (c) were monitored every 2 days for 40 days (mean ± SEM of n = 10 mice/group). d Competitive repopulation assay strategy using CD45 congenic mice. G-CSF, G-CSF+HF51116, or G-CSF+AMD3100 were injected into CD45.2 mice. Drug administration strategy was the same as used in a. BM cells from CD45.1 mice and LDMNCs from CD45.2 mice were isolated. The competitor cell number (CD45.1⁺ cells) was 0.5 × 10⁶, and the donor cell number (CD45.2⁺ cells) was 1.0 × 10⁶. Cell suspension containing donor and competitor cells (1.5 × 10⁶ cells) was intravenously injected into lethally irradiated (11 Gy, 5.5 Gy split dose, 2 h apart, radiation rate 1.05 Gy/min) CD45.1/CD45.2 recipients. e The percentages of CD45.2⁺ cells were checked for 6 months (mean ± SEM of n = 7 mice). f The secondary repopulation in a noncompetitive assay. At 6 months post-injection, lethally secondary irradiated CD45.1/CD45.2 mice received the BM cells of every group of recipients (e) in a noncompetitive assay. The percentage of CD45.2⁺ was checked every month (mean ± SEM of n = 7 mice). ****P < 0.0001, ***P < 0.001, **P < 0.01, *P < 0.05; ns, not significant