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.