Ethics code: IR.PNU.REC.1398.059
Barzegari A, Mirzaaghaee S, Delfanihosseiny S N, Soltani Dehkordi M, Jafari S. Alteration of expression of cyclic adenosine monophosphate in the liver tissue of male wistar rats following different intensities of interval training. RJMS 2021; 28 (4) :24-33
URL:
http://rjms.iums.ac.ir/article-1-6440-en.html
Payame Noor University, Tehran, Iran , ali_barzegari@pnu.ac.ir
Abstract: (2108 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. While athletes use a variety of training methods to increase their aerobic and anaerobic fitness, one of the most recent training activity protocols that training physiologists are considering is interval training (HIT, HIIT, MIT). Among cellular changes in the body following training, cAMP is a type of intracellular secondary messenger and is produced in response to various extracellular stimuli such as hormones or neurotransmitters. The cAMP is synthesized from ATP by the enzyme Adenylin Cyclase and degraded to AMP by Phosphodiesterases. The cAMP is involved in a variety of cellular processes, such as cell differentiation, cell cycle progression, and apoptosis, and performs these functions both in a protein-dependent and protein A-independent manner. cAMP (cyclic adenosine monophosphate) is a purine nucleoside that has broad and important effects on biological processes such as smooth muscle contraction, neurotransmission, secretion of endogenous and exogenous hormones, immune responses, inflammation, cardiac pain, and platelet aggregation. Effective training programs, such as intense intermittent training, seem to not only save time but also increase physiological capabilities such as aerobic capacity and anaerobic capacity, giving sufficient time to improve other essential skills such as related technical and tactical skills. Provided with different sports.
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% VO2 max 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% VO2 max 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 of one-way analysis of variance showed that there was a statistically significant difference in cAMP gene expression in the liver tissue of rats in the study groups (p<0.001). The results of the Tukey post hoc test also showed that there was a significant decrease in cAMP gene expression as a result of training compared to the control group (p=0.001), so that in the HIIT group there was a significant decrease in the control group compared to the control group. There was cAMP expression (p=0.001), so that in the HIIT group it decreased by 0.0006 units compared to the control group and in the MIT group by 0.00059 units compared to the control group and in the HIT group by Decreased by 0.00053 units. However, the findings showed that there was no significant difference between the three groups of HIT, MIT, and HIIT (p>0.05).
Conclusion: Based on the findings of our study, it was found that there is no significant difference in the expression of cAMP gene in the liver tissue of male Wistar rats between MIT and HIT groups compared to HIIT group. While there was a significant difference between HIIT and control groups, no significant difference was observed between HIT and MIT groups. Examination of post hoc test in training groups showed that there was a significant difference in cAMP gene expression between MIT and HIT training groups compared to the control group. Due to age, apoptosis and necrosis increase and training is the best way to reduce apoptosis in old age. One of the limitations of the present study is the lack of control over the calorie intake of rats and the lack of control over physical activity outside the animal research program. However, the research background on the effect of the present training protocols on cAMP in liver tissue is very limited and needs further investigation.
Type of Study:
Research |
Subject:
Exercise Physiology