The effect of high intensity interval training (HIIT) on cardiac hypertrophy: the role of Wnt / β-catenin signaling pathway

The aim of this study was to determine the effect of 12-week high-intensity interval training on heart mass and expression of beta-catenin and glycogen synthase kinase-3-beta genes in myocardial tissue of male rats. Thirty male Wistar rats were randomized into three groups, including sham (n = 10), control (n = 10), and HIIT (n = 10). The experimental group underwent HIIT consisting of 2 - 8 repetitions of 4-min high-intensity intervals (85% - 90% peak speed) interspersed with low-intensity intervals (45% - 50% peak speed), performed five times/week over 12 weeks. Forty-eight hours after the last training session, animals’ hearts were removed. The gene expressions of beta-catenin and glycogen synthase kinase-3-beta were analyzed by the RT-PCR method. The independent t-test was used for statistical analysis (P < 0.05). The results showed that the body weight was significantly lower in HIIT group (P = 0.029) and heart/body weight ratio were significantly higher in the intervention group than in the control group (P = 0.001). Also, beta-catenin gene expression were significantly higher in trained rats than the control group (P = 0.002). Regarding GSK3-β genes expression, although mean levels were lower in the trained group than the control, the differences were statistically insignificant (P = 0.71). HIIT training, along with considerable reduction of body weight, increase the ratio of heart to body weight and cardiac hypertrophy. Also, these exercise training trigger cardiac hypertrophic signals by stimulating the Wnt signaling pathway and significantly increasing beta-catenin gene expression.