Bone marrow MK hyperplasia and MF in Dnm2^fl/flPf4-Cre mice. (A) H&E, reticulin, and TGF-β1 staining of Dnm2^fl/fl and Dnm2^fl/flPf4-Cre femur bone marrow sections. Sections shown are representative of 5 mice for each genotype. Arrowheads in panel A (middle row) point to reticulin fibers. Bars represent 20 µm. (B) Dnm2^fl/fl and Dnm2^fl/flPf4-Cre bone marrow MK counts (mean ± SEM; n = 5 in each group; ***P < .0001). (C) Percentage of bone marrow Dnm2^fl/fl and Dnm2^fl/flPf4-Cre MK ploidy (mean ± SEM; n = 5 in each group; ***P < .001). (D) Bone marrow CFUs in Dnm2^fl/fl and Dnm2^fl/flPf4-Cre mice (mean ± SEM; n = 6 in each group; *P = .0188). (E) Bone marrow MK CFUs in Dnm2^fl/fl and Dnm2^fl/flPf4-Cre mice (mean ± SEM; n = 6 in each group; **P = .0034). (F) Bone marrow TGF-β1 levels in Dnm2^fl/fl and Dnm2^fl/flPf4-Cre mice (mean ± SEM; n = 6 in each group; **P = .0044).