Fig. 3

Hyperplasia contributes to increased heart size in pregnancy. a Hearts harvested from not pregnant (NP) and pregnant female mice, at the indicated stages of embryonic development (E12 and E18). b Quantification of weight of the heart in not pregnant (NP, circles) and pregnant female mice, at the indicated stages of embryonic development (E12, squares and E18, tip up triangles) and at the day of the delivery (P0, tip down triangles). c Quantification of circulating Tregs in the peripheral blood of DEREG mice, expressed as the percentage of EGFP⁺ cells over the total number of CD4⁺ cells at the same time points as in (b). d Quantification of the CM cross-sectional area (CSA) in heart sections of mice at different stages of pregnancy, as in (b, c). e Sections of the heart of pregnant mice at E12, showing a relatively high level of EdU incorporation (stained red) in the nuclei of CMs (stained green) compared to a control, not pregnant (NP) female heart. Scale bar, 100 μm. f Quantification of EdU incorporation (% of total CM nuclei) in CMs of not pregnant (NP) and pregnant female mice, at the indicated stages of embryonic development (E12 and E18) and at the day of the delivery (P0). g Sections of the heart of pregnant mice at E12 showing Aurora B localization in midbodies (stained red) of CMs (stained green by anti-α-actinin antibodies). Nuclei are stained blue with DAPI. No Aurora-B signal is present in control, not pregnant (NP) female heart. Scale bar, 100 μm. h Quantification of the AuroraB⁺ (% of total CM nuclei) in CMs of not pregnant (NP) and pregnant female mice, at the indicated stages of embryonic development (E12 and E18) and at the day of the delivery (P0). All values are mean ± s.e.m., each dot indicates a biological replicate. One-way analysis of variance and Bonferroni/Dunn’s post hoc tests were used to compare multiple groups. *P < 0.05, **P < 0.01, ***P < 0.001 relative to NP