DAPA protects heart function in response to Dox treatment. Representative Western blot images (A) and densitometric analysis of phospho-Smad3 (B), BNP (C), α-SMA (D), and phospho-p38 (E) in control (CON) group, Dox only group, and combination treatment of Dox and DAPA (Dox + DAPA) group were shown. (F) Left ventricular internal dimension at end-diastole (LVIDd), (G) left ventricular internal dimension at end-systole (LVIDs), (H) ejection fraction (EF), and (I) fractional shortening (FS) of the heart were measured using echocardiography. Results are shown as means ± SD of three independent experiments. Statistical analysis was performed using one-way ANOVA with a Bonferroni post hoc test. [* p < 0.05 compared to the control group; # p < 0.05 compared to the Dox-only group].