Fig. 4

Histological analysis of cardiomyocyte cross-sectional diameter and collagen content in LV myocardium. a represents cardiomyocyte cross-sectional diameter in subsequent stages of heart failure (mild, moderate, and severe HF), separately in male (black columns) and female animals (white columns). Values are presented as means ± SEM. *p < 0.05 vs. the control group; ^# p < 0.05 female vs. male pigs (in particular study group). Representative photomicrograph of van Gieson-stained sections of LV demonstrating interstitial collagen content and myocyte cross-sectional diameter in controls (sham-operated, b female, c male) and in subsequent stages of heart failure in females (d mild, f moderate, and h severe HF) and in males (e mild, g moderate, and i severe HF). Original magnification ×200; scale bar—100 μm). Note that collagenous network (red) surrounding muscle bundles (yellow) is similar in all shown sections