Comparison of eight weeks of resistance training and high-intensity intermittent aerobic training on the expression of microRNAs associated with adipose tissue angiogenesis and antiangiogenesis in rats fed a high-fat diet

Exercise and obesity alter angiogenesis in adipose tissue, resulting in large changes in metabolic processes. The aim of this study was to compare the effect of eight weeks of resistance training and high-intensity intermittent aerobic training (HIIAT) on the expression of microRNAs associated with adipose tissue angiogenesis and antiangiogenesis in rats fed a high-fat diet.

In the experimental study, 60 six-week-old male wistar rats (mean body weight = 192.40 ± 11.35) were obtained from Pasteur Institute of Iran. The animals were randomly divided into six equal groups after transfer to the laboratory environment and one week of exposure to the new environment: 1. Normal diet (CO), 2. Normal diet + Resistance training (NRT), 3. Normal diet + HIIAT (NHT), 4. High-fat diet (HF), 5. High-fat diet + Resistance training (HFRT), 6. High-fat diet + HIIAT (HFHT) (n = 10 per group). The training groups performed their training protocol for eight weeks and five sessions per week. Resistance training included climbing a 1-meter ladder with a 90-degree slope and 46 steps. Initially, the weight attached to the rats' tails was 30% of their body weight and gradually reached about 180% of their body weight in the final week. The exercises were performed in five sets of four repetitions. High-intensity intermittent aerobic training was started on the treadmill at an initial speed of 15 meters per minute, and in each session, one to two meters per minute was added to the treadmill speed, depending on the ability of the rats. During the Pabani week, the exercise reached six stages of three minutes of running at a speed of 40 meters per minute with a slope of 15 degrees. To evaluate the effect of resistance training and high-intensity intermittent aerobic training and high-fat diet (58% of calories in the form of fat) on miR-221, miR-222, miR-329 and VEGF variables, subjects in each group were killed 48 hours after the last training session. Sampling of mesenteric adipose tissue was performed immediately after killing the animals. Data analysis was performed using independent t-test, one-way and two-way ANOVA at the significant level (P ≥ 0.05). Scheffe post hoc test was used to compare the pairwise .

The miR-221, miR-222 and VEGF in the Normal diet + Resistance training, Normal diet + HIIT and High-fat diet + Resistance training groups a significant increase was observed compared to the control group (P ≥ 0.01). However, miR-329 was significantly higher only in the high-fat diet group than in the normal diet + HIIAT group (P = 0.022).

The results showed that resistance training and HIIAT by increasing miR-221, miR-222, and decreasing miR329 led to the activation of pathways that increased VEGF protein and ultimately increased angiogenesis in rats with a high-fat and normal diets. Therefore, these exercises are an important factor in angiogenesis and mechanism in adipose tissue, which may be able to cause significant changes in adipose tissue during this process. However, in order to confirm this point and generalize it to humans, more research is needed, especially on human specimens. Also, since the effect of resistance training on miRNAs was greater than HIIAT, these exercises can be a good alternative to HIIAT.