Gata4G295Ski/wt mice exhibit progressive valve disease in the postnatal period. (A-D) Histological sections through aortic valve stained with Russell-Movat's Pentachrome show thickened leaflets with ECM disorganization and proteoglycan enrichment (blue) in Gata4G295Ski/wt valves (C,D) when compared with wild-type littermates at P21 (A,B). B and D are high magnification images of the boxed areas in A and C, respectively. (E-H) At P10, Gata4G295Ski/wt aortic valves (G-H) stained with Russell-Movat's Pentachrome are dysmorphic with abnormal ECM when compared with wild-type (E-F). F and H are high magnification images of the boxed areas in E and G, respectively. For P21 mice: n=4 for Gata4G295Ski/wt, n=3 for wild type; for P10 mice: n=5 for Gata4G295Ski/wt, n=3 for wild type. For Russell-Movat's Pentachrome stains, yellow indicates elastin and blue indicates proteoglycans. Scale bars: 100 μm.