Fig. 4

Cell morphology, mitochondria and metabolism in rat myocardial slices cultured for 24 h. a Representative images of the morphology of rat myocardial slices cultured for 24 h. Scale bar = 50 μm. b Average cardiomyocyte area (0 h, SL = 1.8 and 2.2 N = 90/6, unloaded N = 76/6, SL = 2.0 N = 135/6 and SL = 2.4 N = 75/6). c Cardiomyocyte length-to-width ratio of rat myocardial slices cultured for 24 h (0 h, SL = 1.8–2.2 N = 90/6, unloaded N = 76/6 and SL = 2.4 N = 75/6). d Representative images of cardiac fibroblasts on the surface of rat myocardial slices cultured for 24 h. Scale bar = 250 μm. e Quantification of stromal cell proliferation on rat myocardial slices cultured for 24 h (values are expressed as normalised vimentin + area of rat myocardial slices cultured for 24 h) (N = 18/6, except SL = 2.4 N = 15/6). f Expression of genes associated with cardiac fibroblasts and myofibroblasts (N = 3). g Top—representative image of a rat myocardial slice stained with TOM20 (mitochondria) and α-actinin (sarcomeric apparatus). Scale bar = 5 μm. Bottom—profile plot of dual staining. h TOM20 density of rat myocardial slices cultured for 24 h (N = 9, except unloaded N = 6). i Concentration of adenosine triphosphate (ATP) of rat myocardial slices cultured for 24 h (N = 7). j) ATP:ADP ratio of rat myocardial slices cultured for 24 h (N = 7). Gene expression data from rat myocardial slices cultured for 24 h and expressed relative to 0 h rat myocardial slice gene expression. N = number of myocardial slices. For cardiomyocyte morphology analysis, N = number of cardiomyocytes analysed/number of myocardial slices. Black dots represent individual data points. Mean ± standard error is shown on graphs. One-way analysis of variance (ANOVA) was used to determine whether there were any statistically significant differences between the means of groups. $, $$, $$$ = p value < 0.05, 0.01 and 0.001, respectively, compared with 0 h. *, **, *** = p value < 0.05, 0.01 and 0.001, respectively, between the two groups highlighted by a bar. Source data are provided as a Source Data file