An analysis of the global expression of microRNAs in an experimental model of physiological left ventricular hypertrophy.

BACKGROUND: MicroRNAs (miRs) are a class of small non-coding RNAs that regulate gene expression. Studies of transgenic mouse models have indicated that deregulation of a single miR can induce pathological cardiac hypertrophy and cardiac failure. The roles of miRs in the genesis of physiological left ventricular hypertrophy (LVH), however, are not well understood. OBJECTIVE: To evaluate the global miR expression in an experimental model of exercise-induced LVH. METHODS: Male Balb/c mice were divided into sedentary (SED) and exercise (EXE) groups. Voluntary exercise was performed on an odometer-monitored metal wheels for 35 days. Various tests were performed after 7 and 35 days of training, including a transthoracic echocardiography, a maximal exercise test, a miR microarray (miRBase v.16) and qRT-PCR analysis. RESULTS: The ratio between the left ventricular weight and body weight was increased by 7% in the EXE group at day 7 (p