Figure 6: TT-10 Enhances Proliferation of Existing CMs, and Decreases ROS and DNA Damage After MI

(A) The percentage of mOrange-labeled clustered CMs in αMHC-MerCreMer; Rosa26rbw/+ mice. The increase from the background (MI [−]) indicates the proliferation of existing CMs (clonal expansion). Representative images of infarct border-zone myocardium are shown. Inset images were enlarged by confocal microscopy. Arrowheads indicate positive CMs; white asterisk indicates infarct area. n = 6 (MI [−]), 7 (vehicle), and 6 (TT-10). Scale bars: 100 μm; 25 μm in inset. (B) The relative mean fluorescence intensity for measuring ROS generation, detected by a mainly nuclear localized ROS-sensitive CellROX Green probe. Mean fluorescence intensity in the infarct border-zone myocardium relative to that in MI [−] mouse myocardium was shown. Representative images of infarct border-zone are shown. White asterisk indicates infarct area. n = 7 (MI [−]), 7 (vehicle), and 8 (TT-10). Scale bars: 100 μm; 50 μm in inset. (C) Quantitative analyses of γH2AX-positive CMs in the infarct border-zone 1 week after MI, with representative images. Arrowheads indicate positive CMs; white asterisk indicates infarct area. n = 10 (vehicle), and 12 (TT-10). Scale bars: 50 μm; 25 μm in inset. *p < 0.05, **p < 0.01 versus vehicle control. ##p < 0.01, ###p < 0.001 versus non-MI baseline. Abbreviations as in Figures 1, 4, and 5.