Journal of Exercise & Organ Cross Talk

Abstract Aging is associated with mitochondrial dysfunction, which leads to decreased cellular function and the development of age-related diseases. Exercise training is considered one of the most effective strategies for improving muscle cell function. The aim of the present study was to investigate the effect of six-week combined exercise on mitochondrial dynamics and biogenesis markers (MFN1, DRP1) as well as oxidative stress markers (MDA and SOD) in fast- and slow-twitch muscles of aged rats. In this study, 16 male Wistar rats (463.2 ± 9.3 g) were randomly divided into two groups (n=8 per group): control and resistance-endurance training. The training group underwent combined resistance-endurance training, 6 days a week for 6 weeks (3 resistance days, 3 endurance days). Forty-eight hours after the last training session, animals were sacrificed and fast-twitch (gastrocnemius) and slow-twitch (soleus) muscle tissues were collected. Gene expression levels of mitofusin 1 (MFN1), dynamin-related protein 1 (DRP1) were measured by real-time PCR (RT-PCR). In slow-twitch muscle, exercise training significantly increased mRNA expression levels of SOD genes, and significantly decreased mRNA expression of DRP1 and the concentration of MDA compared to the control group (p<0.05). Similarly, in fast-twitch muscle, six weeks of combined training significantly increased SOD gene expressions and decreased DRP1 mRNA and MDA levels compared to controls (p<0.05). Combined exercise training positively modulates mitochondrial biogenesis and dynamics markers (decreased DRP1 mRNA) and enhances antioxidant capacity (increased SOD gene expression and enzyme activity, decreased MDA levels) in both fast- and slow-twitch muscles of aged rats, highlighting its significant role in mitigating age-associated mitochondrial dysfunction. These findings reflect improvements in markers of mitochondrial quality control and oxidative stress rather than direct measurements of mitochondrial function.

Abstract Most of the intracellular and extracellular factors that play a vital role in regulating energy metabolism and determining cell fate converge in the mitochondria. To promote or hinder cell survival through regulating the function and maintaining the mitochondrial structure. The decline of mitochondrial function and homeostasis with aging is the basis of the pathogenesis of aging-related diseases, especially in skeletal muscles. One of the important components of mitochondrial quality control that helps maintain the homeostasis of myocytes is autophagy, which is an important biological and evolutionary process, and its vital function is the removal of defective organelles. Although it has been proven that regular sports activities act as autophagy stimulators and play a role in maintaining the cellular homeostasis of skeletal muscle fibers and regulating intracellular metabolism. However, cellular autophagic responses to exercise in skeletal muscle appear to be different in different exercise protocols and disease models. How exercise activity modulates autophagy in skeletal muscle and how the effect of exercise is regulated by the autophagy signaling pathway are still poorly understood. The importance of understanding the obscure angles of this process can be an important goal in preventing the pathology of age-related diseases in skeletal muscle.

Abstract Primary objective of this study was to examine the interplay between grip strength, a functional marker of hypertrophy, and its connection to the Firmicutes to Bacteroidetes ratio in the gut microbiome. Twenty-five male Wistar rats were divided into five groups using a computerized randomizer: old and young control groups (OC, YC), old resistance training group (OR), old supplement group (OS), and old resistance training combined with supplement group (ORS). Rats in the OR and ORS cohorts underwent eight weeks of ladder-climbing resistance training three times a week, while those in the OS group were given supplements 5 times per week after the intervention. Muscle samples were collected from all rats two days’ post-intervention. FOXO1, BAX, and cytochrome C, were assessed using PCR-real time. Analysis of the data was carried out using one-way ANOVA and post-hoc Tukey testing. The results revealed a decrease in FOXO1 and apoptotic gene expression post-intervention, with a more pronounced reduction observed in the ORS group compared to the other groups (p<0.05). Notably, supplementation alone did not impact FOXO1 expression, akin to the effect of exercise on cytochrome C. A moderate negative correlation was documented between the F/B ratio and grip strength (p= 0.003; r= -0.54). Additionally, positive and moderate correlations were observed between FOXO1, BAX, cytochrome C, and the F/B ratio (p<0.05). These findings emphasize a functional association between the gut microbiome and muscle through their metabolites, indicating mutual regulation. Furthermore, it is suggested that exercise and supplements may further enhance these interconnected mechanisms.

Abstract The purpose of this research is to survey the effect of eight weeks of sub-maximal training on the C-Reactive Protein (CRP) in elderly males. The subjects of the research consisted of 21 elderly males between 50-80 years old, divided into two groups (one experimental group and one control group), with VO_2Peak values of 51.14±2.7, 51.92±3.17, and 43.61±1.85 (based on the 1-mile (1609 meters) Track Jog test). The experimental group carried out Balke-Ware sub-maximal aerobic exercise 5 sessions a week for 8 weeks, while the control group did not participate in the training program. The results of the research showed that the average CRP levels decreased in the experimental group, while they increased in the control group. However, these differences were not statistically significant according to the paired sample T-Test results. On the other hand, a significant difference in Vo2 Peak was observed between the two groups (p<0.039 and p<0.001), with the experimental group showing higher values compared to the control group. Additionally, there was no statistically significant difference in HS-CRP levels between the subjects (experimental group 1, experimental group 2, and control group) before and after the training period. In general, it seems that a longer duration is required to observe better markers of inflammatory and cardiovascular effects of these variables. The pre-study hypothesis of cardiorespiratory fitness on CRP response confirms that assessing control and inflammatory markers of cardiorespiratory fitness in the elderly requires more time.

Abstract The immune system is one of the main defenders of human health. The immune system can fight off viruses in the body and kill them. Therefore, keeping the components of the immune system healthy is very important. With age, the immune system ages, and its function decreases. This decline in immune function can easily lead to viral infections in the elderly. Evidence is accumulated that the best solution to maintain and enhance the immune system in the elderly is physical activity. Regular physical activity can lead to healthy aging of the immune system. Therefore, in this review study, we have discussed the changes in the immune system during aging and physical activity suggestions for healthy aging of the immune system. Finally, future research needs are reported.

Abstract Understanding the cellular and molecular mechanisms that regulate aging reduces the possibility of dependence on age-related diseases. Exercise treatment strategies reduce the burden of aging-related illness, disability, and premature death in the elderly. The aim of this study was to evaluate the effect of high-intensity interval swimming training on ULK and TSC1/2 proteins of hippocampus tissue in elderly rats. In this experimental study, 16 elderly male Sprague Dawley rats (20 months old and mean weight 300-450 g) were divided into two groups of control and high-intensity interval swimming training. High-intensity interval swimming training consisted of 14 bouts 20-second swimming sessions with 10 seconds of rest between each session for six weeks (three days a week). The content of ULK and TSC1/2 proteins in hippocampal tissue was measured by Western blotting. Data were analyzed using independent t-test at the P<0.05. The results showed that high-intensity interval swimming training caused significant increase in content of ULK protein of hippocampus tissue in elderly rats (P=0.010). Also, high-intensity interval swimming training caused significant decrease in content of TSC1/2 protein of hippocampus tissue in elderly rats (P=0.010). According to the results, it seems that high-intensity interval swimming training can help improve the homeostasis regulatory pathways in hippocampal neurons in the elderly animal model.

Abstract Sarcopenia, an age-associated phenomenon, is characterized by the reduced skeletal muscle mass and function. Research studies indicate that a wide range of factors can play a key role in the onset of muscle atrophy and its progression, especially during old age. However, the pathophysiology of this event is not well understood and there are many unresolved issues yet. Performing different training methods (aerobic, resistance, and concurrent) is among the strategies that may be beneficial for the prevention and improvement of sarcopenia by affecting the signaling pathways of muscle cells. On the other hand, the way in which this type of training affects the signaling pathways involved in sarcopenia has not been well understood. Even the previous research has been incapable of well introducing an effective training method for the elderly at risk for sarcopenia. Generally, in this review article, we investigate and summarize the important and key mechanisms that may contribute to sarcopenia. In the following, we have examined the effect of regular physical activity on cellular signaling pathways involved in sarcopenia, as well as the usefulness of aerobic, resistance, and concurrent activities in adaptation and prevention of the pathology of sarcopenia in the elderly.