Molecular Phenotypes In Physiological Cardiac Hypertrophy Induced By Different Exercise Modes In Rats

Physiological cardiac hypertrophy is characterized by normal or enhanced cardiac function and myocardial metabolism, and induces concentric and eccentric hypertrophy by different exercise modes. Several studies have revealed that the molecular marker of pathologic cardiac hypertrophy did not change in physiological eccentric cardiac hypertrophy by endurance training. However, the gene expression pattern of the molecular marker of pathologic cardiac hypertrophy in different exercise modes-induced cardiac hypertrophy remains unclear. PURPOSE: The purpose of this study was to investigate the gene expression patterns of the molecular marker of pathologic cardiac hypertrophy in different exercise modes-induced cardiac hypertrophy, including aerobic training (AT), resistance training (RT), and high intensity interval training (HIIT). METHODS: Forty male 10-week-old Sprague-Dawley (SD) rats were divided into four groups; sedentary control (CON, n = 10), AT (treadmill running, 60 min at 30 m/min, 5 days/wk for 8 wk, n = 10), RT (ladder climbing, 8-10 sets/day, 3 d/wk for 8 wk, n = 10), HIIT (14 repeats of 20-s swimming session with 10-s pause between sessions, 4 d/wk for 6 wk from 12-wk-old, n = 10) groups. The mRNA expression levels of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), angiotensin-converting enzyme (ACE), and endothelin (ET)-1 in rat hearts were analyzed by real-time quantitative RT-PCR with TaqMan probe. RESULTS: Each trained heart developed cardiac hypertrophy as evidenced by increase in cardiac mass and cross-sectional area of cardiomyocytes. Moreover, the enzyme activity of oxidative phosphorylation in the skeletal muscle was promoted in the AT group, the oxidative phosphorylation and glycolytic enzyme activities were promoted in the HIIT group, and muscle hypertrophy occurred in the RT group (each p < 0.05). Levels of ANP, BNP, ACE, and ET-1 mRNA expression did not significantly increase in AT, HIIT, and RT groups as compared to the CON group. CONCLUSIONS: These findings suggest that the molecular marker of pathologic cardiac hypertrophy did not change in physiological cardiac hypertrophy by different exercise modes including AT, HIIT, and RT. Supported by: Grant-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science, and Technology of Japan [KAKENHI: 23 K24744 to M. Iemitsu]