The Effect of Eight Weeks of Continuous and Interval Endurance Training on Micro-RNAs Associated with Reverse Cholesterol Transport in Elderly Wistar Rats

Aging is associated with changes in blood cholesterol and subsequent cardiovascular disease. The purpose of this study was to investigate the effect of continuous and interval endurance training on micro-RNAs associated with reverse cholesterol transport in Wistar elderly rats. 30 male Wistar rats (23-month-old) With an average weight of 441.75 gram, were randomly divided into two experiment and one control group including continuous training (n = 10), Interval training (n = 10) and the control group (n = 10). Continuous and interval exercise included 8 weeks of training on treadmill and 5 days a week which the continuous group started training with 60% maximum speed for 16 minutes in the first week and continued with 70% maximum speed for 45 minutes from the fourth week to the end of the eighth week. The interval group started exercise at 40-80% of the maximum speed from the first week and continued at 30 to 110% of the maximum speed from the fourth week to the end of the eighth week. After completing training, expression of miR-33 and miR-144 and mRNA expression of ABCA1 were measured RT-PCR. The statistical analysis was performed using ANOVA test with significance level (P <0.05). The expression of miR-33a and miR-144 decreased in both continuous and interval groups compared to control group, but this decrease was only significance for miR-33a (P <0.001). After 8 weeks of training, mRNA expression of ABCA1 gene in the continuous and interval group increased compared to control group. However, this increase was statistically significance only for the interval group (P=0.002). There was no statistically significance difference between the effect of interval and continuous exercises on miR-33a and miR-144 expression. However, there was a significance difference in the mRNA expression of ABCA1 in both continuous and interval groups (P=0.028). Considering the results, it appears that both continuous and interval endurance trainings can decrease miR-33a expression and subsequently increase mRNA expression of the ABCA1, which this increase is higher in interval training compare continuous training.