Figure 4.

rhIL-1Ra induced transient and reversible HS/PC quiescence in vivo. A–C) BALB/c mice received daily injections of either PBS or IL-1Ra (3 mg/kg) over 5 d. BMCs were harvested and analyzed at d 3 and 5. Levels of Ki67 and Hoechst 33342 staining were measured in LSK cells by flow cytometry. Representative dot plots (A) and mean percentages (B) of the LSK cells in G₀, G₁, and S/G₂/M phases and the numbers of total BM, LK, and LSK cells per leg (C) are shown. D–F) The mice were treated with PBS or rhIL-1Ra as above and injected with BrdU (100 mg/kg) before euthanasia. BrdU incorporation was measured in LK and LSK cells by flow cytometry. Representative histograms (D) and mean percentages (E, F) of BrdU⁺ LK (E) and LSK (F) cells are shown. G–I) BALB/c mice received daily injections of either PBS or IL-1Ra (3 mg/kg) for 5 d. BMCs were harvested and analyzed at d 1 and 3 after the final injections (1 or 3 d recovery). Levels of Ki67 and Hoechst 33342 staining were measured in the LSK cells by flow cytometry. Representative dot plots (G) and mean percentages (H) of the LSK cells in G₀, G₁, and S/G₂/M phases and the numbers of total BM, LK, and LSK cells per leg (I) are shown. All data are expressed as means ± sem (n = 3–6 mice/group at each time point). Statistical significance of the differences between groups was assessed with Student’s t test. *P < 0.05, **P < 0.01, ***P < 0.001.