Echocardiography and Histological analysis

Echocardiography was performed on the rats 4 weeks after CH under anesthesia. Echocardiography was performed using a Vevo2100 high-resolution imaging system (VisualSonics, Toronto, Ontario, Canada) with a 10 MHz imaging linear scanning probe transducer with M-mode recording. Left ventricular ejection fraction (EF), shortened fraction (FS), LV end-diastolic diameter (LVEDd), LV end-diastolic diameter (LVESd) dimensions, Left ventricular posterior wall depth (LVPWs) and left ventricular anterior wall thickness (LVAWs) were measured.

For histological analysis, the heart was fixed with 4% paraformaldehyde (pH 7.4) for 48 h. The fixed heart tissue was cut into 5 μm thick sections. Hematoxylin and eosin (H & E) staining was performed to detect or assess myocardial hypertrophy. Sections were imaged using a bright-field microscope (IX71, Olympus, Tokyo, Japan) at 200x magnification. Each observer randomly checks at least five (to eight) independent images from different (non-overlapping) regions.