Regulation of PI3K and Hand2 gene on physiological hypertrophy of heart following high-intensity interval, and endurance training

BACKGROUND: Physical training signals cardiac hypertrophy through PI3K as an upstream and Hand2 gene as a downstream agent. The present study aimed to find the role of PI3K and Hand2 gene in myocardial hypertrophy following interval and endurance training (ET). MATERIALS AND METHODS: Twenty-four adult Wistar male rats (210–250 g) randomly divided into control, sham, high-intensity interval training (HIIT), and ET group. Swimming time in ET increased incrementally 30–75 min, whereas in HIIT, load/body weight, and time/rest ratio increased within 12 weeks. Heart morphometry, including left ventricle end systolic (LVESV) and Diastolic (LVEDV) volume, LV posterior wall (LVPW), stroke volume (SV), ejection fraction (EF), fraction shortening (%FS), pure heart weight (HW) and left ventricle weight (LVW), and PI3K and Hand2 gene expression were measured. RESULTS: HW and LVW were significantly more than control after ET (P < 0.05) and HIIT (P < 0.05). Both of the training groups demonstrated significantly thicker LVPW (P < 0.05), SV (P < 0.05), and %FS (P < 0.05). Furthermore, PI3K concentration and Hand2 expression significantly increased in ET (P < 0.001; P < 0.001, respectively) and HIIT (P < 0.05; P < 0.001, respectively) compared to control. CONCLUSION: It can be concluded that this training protocol caused physiological hypertrophy in both of ET and HIIT groups, whereas HIIT can be more beneficial because of shorter training time.