en تخصصي Special پژوهشي Research Objective: High-intensity interval training (HIIT) and continues aerobic training (CT) have cardio-protective effects in diabetic rats. The functional role of microRNA in heart was studied. Only miR-29a levels were found to correlate with cardiac fibrosis, This study tests the hypothesis that applying HIIT and CT cases miR-29a increasing is associated with a reduction of connective tissue growth factor (CTGF)&nbsp; induced cardiac fibrosis.<br> Materials and Methods: In this randomized controlled trial, 18 male diabetic rats were included. They were divided into 3 groups called as HIIT, CT and control. Exercise protocol was performed 5 days/week for 5 weeks. The miR-29a and CTGF synthesis were compared between the groups by real time- PCR.<br> Results: Our results demonstrated that elevation of miR-29a using HIIT (2.67 , P=0.010,) or CT (1.79 , P=0.002) are effective in inhibiting CTGF (HIIT:0.17 P=0.000-CT:0.39 -induced cardiac fibrosis, suggesting that these types training would be selected as a new adjunctive therapy in the heart fibrosis- derived diabetic.<br> Discussion: The HIIT and CT showed increased levels of miR-29a compared CT group which is shown to decrease CTGF level resulting into lowered fibrosis of heart tissue in diabetic patients.<br> <br> &nbsp; miR-29a, CTGF Gene, High intensity interval training, Heart, Diabetes mellitus 142 150 http://ijdo.ssu.ac.ir/browse.php?a_code=A-10-30-151&slc_lang=en&sid=1 Mania Roozbayani No Ph.D. Department of Exercise Physiology, Islamic Azad University, Central Tehran Branch, Iran Maghsoud Peeri Yes Professor of Exercise Physiology, Department of Exercise Physiology, Central Tehran Branch, Islamic Azad University, Tehran, Iran. Hamid Agha-Alinejad No Associate Professor of Exercise Physiology, Department of Exercise Physiology, Central Tehran Branch, Islamic Azad University, Tehran, Iran. Mohammad Ali Azarbayjani No Professor of Exercise Physiology, Department of Exercise Physiology, Central Tehran Branch, Islamic Azad University, Tehran, Iran.