Figure 4

Viability evaluation by vital staining with Dapi/Syto9 and confocal microscopy imaging. (A) Processing scheme. Z-series of images were collected at 50–150 longitudinal focal planes at the central core of both sides of the slices. Z-stacks from each side were divided into an external and an internal subset and each one compressed into a single image to evaluate the percentage of damaged cells. (B) Boxplots showing percentages of viable cells in the surface (black boxes) and in the first cell layer directly below the surface (grey boxes). i/n/N = 3/1/1 for pig tissue block, i/n/N = 4/2/2 for human papillary muscles and i/n/N = 24/12/12 for human transmural biopsies. ***p < 0.001 and n.s. non-statistically significant differences either in the comparison between external and inner layers (Wilcoxon signed rank test for paired samples) or between different tissues types (Mann–Whitney U-test for unpaired samples).