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. 2021 Jul 3;20(7):e13419. doi: 10.1111/acel.13419

FIGURE 2.

FIGURE 2

SIRT1 and SIRT3 are critical to maintaining the contractile properties of cardiomyocytes and heart in aging. (a) The representative cardiomyocyte contractility from young (4–6 months)/aged (24–26 months) WT, SIRT1 f/f /icSIRT1−/− (4–6 months), SIRT3 f/f /cSIRT3−/− (4–6 months) hearts. (b) The contractile properties of the isolated cardiomyocytes from young/aged WT, SIRT1 f/f /icSIRT1−/−, and SIRT3 f/f /cSIRT3−/− hearts under normoxia and H/R stress conditions. Values are mean ± SEM. N ≥ 30 cardiomyocytes collected from 5 male mice for each group, *p < 0.05 vs. young, SIRT1 f/f , SIRT3 f/f , respectively: † p < 0.05 vs. normoxia, respectively. (c) The representative traces of transient calcium signal young/aged WT, SIRT1 f/f /icSIRT1−/−, and SIRT3 f/f /cSIRT3−/− hearts. (d) The transient calcium signal response of the isolated cardiomyocytes from young/aged WT, SIRT1 f/f /icSIRT1−/−, and SIRT3 f/f /cSIRT3−/−hearts under normoxia and H/R stress conditions. Values are mean ± SEM. N ≥ 30 cardiomyocytes collected from 5 male mice for each group, *p < 0.05 vs. young, SIRT1 f/f , SIRT3 f/f , respectively: † p < 0.05 vs. normoxia, respectively. (e) The relationship loop between sarcomere length and calcium signal of the isolated cardiomyocytes from young/aged WT, SIRT1 f/f /icSIRT1−/−, and SIRT3 f/f /cSIRT3−/− hearts under normoxia and H/R stress conditions. (f) Echocardiography showed that aged vs. young WT, icSIRT1−/− vs. SIRT1 f/f and cSIRT3−/− vs. SIRT3 f/f mice were more vulnerable to I/R stress as shown by ejection fraction (EF) and fractional shortening (FS). Upper: Reprehensive images of M‐mode echocardiography for systolic function and doppler of diastolic function. The yellow arrows and lines are the analysis method performed on Vevo Image software to obtain the parameters for systolic function and diastolic function analysis. Lower: Quantification of echocardiography measurements for EF, FS and E/A ratio. N ≥ 5, values are means ± SEM. *p < 0.05 vs. young, SIRT1 f/f , SIRT3 f/f , respectively; † p < 0.05 vs. sham, respectively