Fig. 4

Confocal imaging of cardiomyocyte T-tubule networks. a Representative images of cardiomyocytes from each study group labeled with di-8-ANEPPS captured on a Leica LSM using a 63x objective. Scale bar = 10 um. b AutoTT quantitative analysis of di-8-ANEPPS images showing tubule densities as percent total number of pixels of skeletalized transverse-oriented tubules (TE%) or longitudinal-oriented tubules (LE%) divided by the total number of pixels of the region of interest (ROI). Each dot represents averaged values from one animal. Box-and-whisker plots show median value, box fences at 25th /75th percentiles, and whiskers at max/min values. c TT power analysis of di-8-ANEPPS images. Each dot is the average TT power value of 6–8 z-stacks captured per cell of ~ 10 cells per heart. Box-and-whisker plots as described in (b); n = 4–5 rats/group. d Representative images of cardiomyocytes labeled with AlexaFluor-488 conjugated wheat germ agglutinin (WGA-488) and images captured using Nikon C2 LSC microscope with 63x oil immersion objective. Scale bar, 10 um. e TT power quantitative analysis of WGA images. Each dot is the average TT power value of ~ 12 z-stacks captured per cell of 15–20 cells per heart. Box-and-whisker plots as described above; n = 6–7 rats/group. One-way ANOVA, with post-hoc Tukey analysis, p-values between groups are indicated