FIGURE 8.

miR-9 inhibits cardiac hypertrophy in the animal model. A, Iso induces a reduction of miR-9 levels in the hearts. Adult male C57BL/6 mice (8 weeks old) were infused with Iso (30 mg/kg). The expression levels of miR-9 were determined with qRT-PCR. *, p < 0.05 versus control. B–E, miR-9 mimic inhibits cardiac hypertrophy. Adult male C57BL/6 mice (8 weeks old) were infused with Iso (30 mg/kg/day), along with miR-9 mimic or the mimic negative control (mimic-NC) (30 mg/kg) as described under “Experimental Procedures.” B, histological sections of hearts, gross hearts (top row; bar, 2 mm), heart sections stained with hematoxylin and eosin in the middle row (bar, 2 mm) and bottom row (bar, 20 μm). C, cross-sectional areas analyzed by staining with fluorescein isothiocyanate-conjugated wheat germ agglutinin. *, p < 0.05 versus Iso alone. D, the protein levels of myocardin in the hearts (top panels) and the ratio of heart/body weight (bottom panel). *, p < 0.05 versus Iso alone. E, the expression levels of atrial natriuretic peptide and β-MHC. *, p < 0.05 versus Iso alone. F, echocardiographic assessment of cardiac dimensions and function. Echocardiography was performed as described under “Experimental Procedures.” The mice were treated as described for B. Diastolic interventricular septal thickness (IVSd), diastolic posterior wall thickness (PWd), systolic left ventricular internal diameters (LVIDs), and fractional shortening of left ventricular diameter (FS). *, p < 0.05 versus Iso alone. The values represent means ± S.E. (n = 5–6). Con, control.