Aortic valve defects in P0 Rac1
SHF hearts. More than 30% (9 of 28) of P0 Rac1
SHF hearts exhibited thick aortic valve leaflets (B) compared with the thin, remodeled valves of controls (A). Toluidine blue staining showed that GAG (light purple color) occupies the acellular space of Rac1
SHF and littermate valve leaflets (C and D). Masson's trichrome staining in Rac1
f/f aortic valves showed collagen in the commissure of valve leaflets (E, arrows), which was absent in Rac1
SHF aortic valves (F, arrows). The GAG‐positive area (light purple color) in each valve leaflet (C and D) was quantified in (G). **P<0.01 by Mann–Whitney test, n=5 to 6 hearts per group. Scale bars: 100 μm (A through D), 10 μm (E and F). Ao indicates aorta; GAG, glycosaminoglycans; LCC, left coronary cusp; NCC, noncoronary cusp; RCC, right coronary cusp; SHF, second heart field.