Fig. 2

IL-33 signaling mediates HSC regeneration in vivo. a Left, representative H&E-stained femurs from irradiated mice treated with either PBS or IL-33 for 7 days. Scale bar, 100 μm. Right, bone marrow cell counts. Data are mean ± SEM (n = 6 in each group). *P < 0.05 compared to untreated controls. b Representative FACS analysis of bone marrow c-Kit⁺Sca-1⁺ cells within the Lin⁻ gate (KSL) from nonirradiated (Nonirrad) mice and at day 7 from irradiated mice treated with either PBS or IL-33. The numbers shown indicate the percentage of c-Kit⁺Sca-1⁺ cells within the Lin⁻ population. c Bone marrow KSL cells, CFCs, and CFU-S12 at day 7 in irradiated mice treated with either PBS or IL-33. Data are mean ± SEM (n = 6 in each group). *P < 0.05 compared to untreated controls. d Survival rates of lethally irradiated mice that were adoptively transferred with 5 × 10⁵ BM cells from irradiated mice treated with or without IL-33. Data are pooled from three experiments, n = 6 mice per group per experiment. *P < 0.05 compared to untreated controls. e KSL cells in the BM of recipient mice at 10 weeks after transplantation of 5 × 10⁵ bone marrow cells from irradiated and PBS-treated or irradiated and IL-33-treated donor mice. Data are mean ± SEM (n = 6 in each group). *P < 0.05 compared to untreated controls