Figure 3. Effect of cardiac dSir2 knockdown on young hearts. (A) Cardiac dSir2 expression level. (B) Cardiac Foxo expression. (C) Cardiac SOD activity level. (D) Cardiac MDA level. (E) Cardiac TAG level. (F) Cardiac bmm expression. (G) Heart period. (H) Heart systolic period. (I) Heart diastolic period. (J) Heart diastolic dysfunction index. The diastolic dysfunction index is diastolic interval standard deviation/diastolic interval median). (K) Fractional shortening. (L) Diastolic diameter. (M) Systolic diameter. (N) Microscopic image of cardiac function from M-mode trace. 1: hand-Gal4>w11118 flies; 2: hand-Gal4>UAS-dSir2RNAi flies; 3: 7-week-old hand-Gal4>w11118 flies; 4: 7-week-old hand-Gal4>UAS-dSir2-RNAi flies. It can be observed from 1 and 2 that the cardiac dSir2 knockdown could reduce heart period and fractional shortening, and increase diastolic dysfunction. Independent-sample t tests were used to assess differences between the hand-Gal4>w11118 and hand-Gal4>UAS-dSir2RNAi flies to explore the effects of cardiac dSir2 knockdown on the heart. Data are represented as means ± SEM. *P<0.05; **P <0.01. Sample size was the same as in our previous experiments.