The effect of moderate endurance training on cardioprotective molecule adaptations

Purpose: This study aimed to investigate the effect of moderate endurance training on cardio-protective molecule adaptations, including marker of stem cell activation in the myocardium. Materials and Methods: Twenty-four Spra-gue-Dawley rats were randomly divided into a 4-wk exercise training (4WT) group, a 4-wk sedentary control (4WC) group, an 8-wk exercise training (8WT) group, and an 8-wk sedentary control (8WC) group (n=6 respectively). The training protocol consisted of treadmill running at 20 m/ min for 30 min on a 0% grade, for 3 days/wk. Immunohistochemistry staining coupled with image analysis, as expressed by mean optical density, was used for protein quantification.Results: The results indicated that the heat shock protein (HSP70) and stem cell marker, as evaluated by c-kit, were higher in 4WT than those in the 4WC and 8WT group (p < 0.05), and the HSP70 content in the 8WT was higher than that of the 8WC group. In addition, 4WT and 8WT groups exhibited a significantly higher hepatocyte growth factor (HGF) and c-met content compared to their respective control counterparts (p <0.05).Conclusions: This study suggests that training-induced stem cell activation in the myocardium corresponds with the cardioprotective molecular markers in the early stage of training, and thenthe activated stem cells in the myocardium might subject to a withdrawal before the remodeling events have completed. Additionally, training induced upregulation of cardiomyocyte HGF/c-met signaling pathway may participate in a more long lasting mechanism of exercise training-induced cardioprotection.