Ethics code: IR.PNU.REC.1399.082
Barzegari A, Kazari S, Shariatzadeh Joneydi M, Satvati Niri Z, Alizadeh Mirashrafi M A. Comparison of the Effect of Different Intensities of Aerobic Exercise on the Expression of Transcription Factors E2F1 and E2F4 in Liver Tissue of Wistar Rats. RJMS 2022; 29 (1) :48-59
URL:
http://rjms.iums.ac.ir/article-1-6463-en.html
Assistant Professor, Department of physical education, Payame Noor University, Tehran, Iran , ali_barzegari@pnu.ac.ir
Abstract: (1237 Views)
Background & Aims: The liver is one of the main and major organs of the body, which with the help of various enzymes is of special importance in regulating hormonal activities and metabolism, during rest, training, and returning to the original state of sports activities. Under normal circumstances, the liver and kidneys receive 27% and 22% of circulating blood, respectively, but as a result of heavy training, the blood flow to the liver and kidneys decreases to 5% and 3%, respectively. Prolonged reduction in blood flow to the liver and kidneys may have detrimental consequences, of which fatigue observed as a result of the constant sub-maximal activity is part of it. The liver is also one of the most sensitive tissues targeted by training-induced oxidative stress. Sports science coaches and professionals are working to find ways to reduce the effects of strenuous training and increase the effectiveness of training programs over a limited period. The liver has different functions in the body and different roles are considered for it. Metabolism, control of glycolysis, glycogenesis, and lipogenesis are the main functions of liver tissue. Many factors and proteins play a role in these processes, and two factors have recently been identified called E2F1 and E2F4.
Methods: The present study was approved by the ethics committee of Payame Noor University with the code IR.PNU.REC.1398.059. In terms of purpose, it is fundamental-applied, which was implemented experimentally. In the present study, 32 8-week-old male Wistar rats with an average weight of 237 ±33 g were purchased from the Pasteur Institute. After being transferred to the animal laboratory environment, these animals are housed in transparent polycarbonate cages in an environment with a temperature of 22 ± 1.4 °C, the humidity of 45 to 55%, four heads in each cage with free access to water and closed. Foods were maintained according to a 12-hour sleep-wake cycle. Animals were randomly divided into 5 groups: control group (Co) (8 heads), moderate intensity training (MIT) (8 heads), high-intensity training (HIT) (8 heads), and high-intensity interval training (HIIT) (8 heads) were divided.
The MIT protocol was performed in such a way that in the first week, 5 minutes of warm-up, 5 minutes of cooling, and 20 minutes of the main body of the exercise, including running at 65% VO2max at a speed of 20 m/min, was added to the training time every week. In the sixth week, the training time reached 37 minutes and remained constant until the end of the eighth. Also, the training speed was unchanged from the first week to the eighth week and was equal to 20 meters per minute.
The HIT protocol in the first week included: 5 minutes of warm-up, 5 minutes of cooling, and 20 minutes of running training with 65% VO2max at a speed of 20 m/min and an increasing slope of the treadmill. The training time was increased every week, so that in the sixth week the training time reached 30 minutes and remained constant until the end of the eighth. On the other hand, the slope of the strip was 2% in the first and second weeks and 2% was added to the slope every 2 weeks to reach 8% in the seventh and eighth weeks. Also, the training speed from the first week to the eighth week was 20 meters per minute and was kept constant.
The HIIT protocol also included 10 minutes of warm-up before the workout, in the first to fourth weeks including 3 intense intermittent runs with an intensity of 90 to 100% VO2max and a speed of 30 meters per minute in 4 minutes and 3 low-intensity intermittent runs. With 50 to 60% VO2max and at a speed of 20 meters per minute in 3 minutes. From the fifth to the eighth week, it also includes 4 intense intermittent runs with an intensity of 90 to 100% VO2max at a speed of 30 meters per minute in 4 minutes and 3 low-intensity intermittent runs with 50 to 60% VO2max at a speed of 20 meters per minute. It took 3 minutes. The main body time of the exercise was 28 minutes per repetition. Mice in the control group did not participate in any exercise program but were placed on a stationary treadmill for 10 to 15 minutes per session to adapt to the environment to create the same conditions.
After in vitro analysis of the samples, descriptive statistics including standard mean and standard deviation and inferential statistics were used to quantitatively describe the data. First, the Shapirovilk test was used to determine the normality of data distribution, and the Leven test was used to determine the homogeneity of variance. Due to the normal distribution of data, parametric tests including one-way analysis of variance and Tukey's post hoc test were used at a significance level of p≥0.05.
Results: The results showed that there was a significant difference in the expression of the E2F1 gene in the liver tissue of male Wistar rats between the HIT group compared to the control group. There was also a significant difference between MIT and control groups (P = 0.003). Comparison between groups with post hoc test showed that there was no significant difference between HIT groups and MIT, HIIT, and control groups (P = 0.977, P = 0.917, P = 0.093, respectively). Post hoc tests in training groups showed that there was no significant difference in E2F4 gene expression between MIT and HIT, HIIT, and control groups (P = 0.977, P = 0.721, P = 0.202, respectively). On the other hand, a significant difference was observed between the HIIT group and the control group (P = 0.022, respectively).
Conclusion: In general, the results showed that there was no significant difference between IT MIT, HIT, and HIIT methods on E2F1 and E2F4 gene expression in liver tissue of male Wistar rats. However, there is a significant difference between training groups with control of differences.
Type of Study:
Research |
Subject:
Exercise Physiology