Fig. 4
The effect of HSI, exercise, and FOXO-RNAi on heart function, physiology, and structure in 5-week-old flies. A Heart systolic period. B Heart diastolic period. C Heart period. D Systolic diameter. E Diastolic diameter. F Fractional shortening. G Systolic image and diastolic image. SD, systolic diameter; DD, diastolic diameter. H Heart relative FOXO expression. I Heart relative PGC-1α expression. J Heart succinodehydrogenase (SDH) protein level. K Heart SOD activity levels. L Transmission electron microscopy of hearts (scale: the black line represents 1 micron). The red arrows indicate the myofibrillary and Z line. The white arrows indicate the mitochondria. FOXO-RNAi and HSI could damage myofibrils and mitochondria, and FOXO-RNAi could block the protective effect of exercise on myofibrils and mitochondria. FOXO-OE and exercise could protect myofibrils and mitochondria from HSI damage. For heart function, the sample size was 22 hearts for each group. For heart failure, the sample size was 30 hearts for each group. For RT-PCR and ELISA, the sample size was 80 flies’ hearts for each group, and measurements were taken 3 times. The 1-way analysis of variance (ANOVA) with least significant difference (LSD) tests was used to identify differences among the groups. Data are represented as means ± SEM. *P < 0.05; **P < 0.01; ns means no significant differences