MO delays terminal maturation in mouse embryonic erythrocyte. (A-D) Flow cytometry analysis of fetal peripheral blood at E13.5, identifying EryA, EryB, and EryC populations based on FSC-A and Ter119 expression. (E) Representative peripheral blood smears stained with new methylene blue at E13.5. The top panels were imaged at 100× magnification and the bottom panels at 400× magnification. (F) Proportional analysis of erythroid cells in peripheral blood at E13.5. (G-H) Representative images of new methylene blue–stained liver blood cells at E17.5 (G, 400× magnification), with corresponding quantification (H). (I-J) Representative images of new methylene blue staining in peripheral blood cells at E17.5 (I, 400× magnification), and quantification of the staining (J). (K-L) Representative images of Giemsa-stained neonatal peripheral blood cells at P0 (K, 400× magnification), with corresponding quantification (L). Data are presented as mean ± SEM; each dot represents an individual embryo. For all experiments, embryos from 3 to 6 pregnancies per group were used. For flow cytometry, one embryo was selected from each pregnancy, and fetal blood from these embryos was pooled within each group (CT or MO) to generate a single sample for analysis. Statistical significance was determined by unpaired 2-tailed t test. ∗P < .05. Colored arrows in the representative images indicate typical erythrocytes at different developmental stages. BasoE, basophilic erythroblast; PolyE, polychromatic erythroblast; OrthoE, orthochromatic erythroblast; Retic, reticulocyte.