Hematopoietic toxicity of RUX in normal CByB6F1 mice. (A) Normal 7- to 8-week-old CByB6F1 female mice were fed with Con-chow (Lab Diet 5002, CON, n = 10) or Rux-chow (2 g/kg ruxolitinib in Lab Diet 5002, RUX, n = 10). (B) Animals were bled and euthanized at day 14 to measure NEUs, RBCs, and PLTs. (C) BM cells were extracted from bilateral tibiae and femurs to estimate total BM cell recovery; spleens (SP) were also extracted to calculate SP cell recovery. (D) BM cells were stained with cell surface markers to define CLP (CD127⁺Lin⁻Kit⁺Sca-1⁺). (E) MP (Lin⁻Sca-1⁻CD117⁺), KSL cells (Lin⁻Sca-1⁺CD117⁺), and their subset populations in the BM are shown as representative dot plots. Recovery of total MP and its subset populations including granulocyte-macrophage progenitors (GMP, Lin⁻Sca-1⁻CD117⁺CD34⁺CD16/32⁺), common myeloid progenitors (CMP, Lin⁻Sca-1⁻CD117⁺CD34⁺CD16/32⁻), and megakaryocyte-erythrocyte progenitors (MEP, Lin⁻Sca-1⁻CD117⁺CD34⁻CD16/32⁻), as well as KSL and its subset population including short-term hematopoietic stem cell (ST-HSC, Lin⁻Sca-1⁺CD117⁺CD34⁺CD135⁻), long-term HSC (LT-HSC, Lin⁻Sca-1⁺CD117⁺CD34⁻CD135⁻), and multipotent progenitor (MPP, Lin⁻Sca-1⁺CD117⁺CD34⁺CD135⁺) cells per mouse at 2 weeks were calculated accordingly. ∗P < .05; ∗∗P < .01; ∗∗∗P < .001; ∗∗∗∗P < .0001.