Effects of different intensity exercise training on apoptosis-related microRNAs and the targeted proteins in cardiomyocytes

Abstract

To detect the levels of miR-1, miR-21 and their targeted proteins in hearts of mice after different exercise training, and discuss potential molecular mechanism. Male C57BL/6 mice were randomly divided to 3 groups:sedentary (SE), exercise training 1(ET1) and exercise training 2 (ET2). SE did not do any exercise; ET1 undertook swimming training for 8 weeks, once a day, 5 days/week. Swimming 30 min in the 1st week, and the duration was increased 10 min per week to 90 min and maintained in the 7th and 8th week. ET2 performed the same work as ET1 and switched to twice a day by the end of the 5th week. TUNEL assay was applied to test myocardial apoptosis. Western blot and RT-PCR were used to detect proteins and miRs levels respectively. Compared with SE, in ET1, myocardial apoptosis and miR-1 level did not change, but its targeted protein Bcl-2 increased significantly(P<0.01). miR-21 and its targeted protein PDCD4 did not change significantly. In ET2, myocardial apoptosis and miR-1 level were decreased significantly(P<0.05). Bcl-2 was increased significantly(P<0.01). miR-21 also increased significantly (P<0.05), but PDCD4 did not decrease significantly. Exercise training in ET2 other than ET1 could down-regulate myocardial apoptosis. Alterations of miR-1 and Bcl-2 may be responsible for this cardioprotection. PDCD4 is not sensitive to exercise training, it is likely that miR-21 and other targeted proteins participate in exercise-regulative apoptosis.