Figure 3. miR-21 knockout (miR-21−/−) protects against angiotensin II (Ang II)-induced cardiac alterations in both young and aged mice. (A) The study design. (B) Sequential echocardiography measurements are shown in wild-type (WT) and miR-21−/− mice with or without exposure to Ang II. Echocardiographic measurements of (C) fractional shortening (FS), (D) interventricular septum (IVSd), and (E) left ventricular internal diameter in diastole (LVIDd) are shown for each group. *P < 0.05, **P < 0.01, and ***P < 0.001 for difference from each group (N = 6–8).