Figure 9.

Layer-specific analysis. (a) Layer separation technique: atrial and ventricular sides are shown. The atrialis is separated from the fibrosa as shown in the image. (b) Layer-specific analysis: Movat-stained sections of MVAL samples after layer separation. From left to right: intact anterior leaflet sample with all four layers, leaflet with the atrialis removed, leaflet with both ventricularis and atrialis removed. A, atrialis; S, spongiosa; F, fibrosa; V, ventricularis. Scale bar: 100 µm. (c) Acid–pepsin soluble collagen content (microgram per milligram wet weight) in the separated atrialis, fibrosa, and ventricularis quantified for the post-mortem, 10% and 30% samples. Data are mean ± SEM, n = 3 samples, *p < 0.05. A significant soluble collagen content increase is observed at the hyper-physiological strain level (30%) in both the atrialis and fibrosa layers. (d) Collagen content relative to the fibrosa for the post-mortem, 10%, and 30% groups. (e) Measured NAR for both non-pregnant (NP) and pregnant (P) bovine specimens (post-mortem), highlighting an initial increase in NAR in early pregnancy (EP) followed by a gradual recovery to the pre-pregnancy value. These data underscore the relevance of our experimental work by linking it to the physiological phenomenon of pregnancy. Adapted with permission from [46]. (f) Previous layer-specific findings of growth and remodelling during pregnancy from [44,45]. (Online version in colour.)