Investigation of expression of myocardial miR-126, miR-29a and miR-222 as a potential marker in STZ- induced diabetic rats following interval and continuous exercise training

Purpose Cardiac miRNAs are the recently discovered key modulators of gene expression in the heart which have been shown to contribute to both transcriptional and post-transcriptional regulation in diabetic cardiomyopathy. The aim of this study was to evaluate the protective effects of interval and continuous aerobic training on diabetic hearts by examining the expression of myocardial miR-126, miR-222 and miR-29a genes. Methods Thirty male wistar rats (200 +/- 20 g) were randomly divided into six groups of healthy control (HC), diabetes control (DC), continuous training (CT), interval training (IT), continuous training with diabetes (CTD), and interval training with diabetes (ITD). Nicotinamide and Streptozotocin (STZ) were injected to induce type 2 diabetes. CT was performed with a speed of 10 to 22 m/min and 20 to 30 min and IT was performed with 10 to 39 m/min and total time of 15 min, five sessions per week for 6 weeks. Muscle expression of miR-126, miR-29a and miR-222 was determined by the RT-PCR method. Results The results show that gene expression of miR-126 was higher in IT (p < 0.01) compare to other groups. Also expression of miR-126 was higher in the CT compare to DC (p < 0.05) group. Gene expression of miR-222 was higher in aerobic groups than other groups (p < 0.01). Also expression of miR-222 was higher in ITD compare to the DC and CTD (p < 0.01) groups. Expression of miR-29a gene was higher in the aerobic groups compare to other groups. Also miR-29a was higher in the IT compare to CT (p < 0.01) group. Conclusion Diabetes decreased the expression of genes associated with the development of cardiac function. It seems that IT played a more effective role in cardiac protection than CT through higher miR-126, miR-222 and miR-29a gene expression.