Eight-week-old male wild-type (WT) 129S1/SvImJ mice and SIRT3-knockout (SIRT3-KO) mice were injected intraperitoneally daily with STZ (60 mg/kg, DM group) or sodium citrate buffer (control group) for 5 days. a, b The level of fasting blood glucose (FBG) was detected at different time points. c After 12 weeks, typical two-dimensional M-mode echocardiography and pulse Doppler ultrasound measurements were recorded. d Ejection fraction (EF) and fractional shortening (FS) were calculated. e The ratio of the early diastolic peak (E) to the late diastolic peak (A) of mitral valve blood flow was measured. Significance was determined by one-way ANOVA. Data are presented as the means ± SEM. *P < 0.05, **P < 0.01 vs the control group of the same genotype; ##P < 0.01 vs the DM group of WT mice, n = 8.