Currently, a new approach to the concept of “inflammation” has been formed. Increasing evidence indicates that cellular and molecular mediators of inflammation are involved in a wide range of biological processes, including tissue remodeling, metabolism, thermogenesis, and nervous system function. Given the diversity of biological processes involving inflammatory signals and cells, the traditional view of inflammation as a response to infection or tissue damage is incomplete, since inflammation can occur in the absence of these triggers. The review examines the effects caused by myokines produced during physical activity. It can be argued that these proteins are involved in ensuring adaptive changes, pro- and anti-inflammatory reactions to maintain homeostasis, and their overall effect can be characterized as physiological inflammation. At the same time, the mechanisms of transcription activation of many myokines differ significantly from similar mechanisms in cells of the immune system. This suggests that myokines can be considered as factors of physiological inflammation, which is not a pathological process, but ensures normal physiological reactions during physical activity. A hypothesis has been formulated about the role of myokines as factors stimulating the development of physiological inflammation. The effects caused by myokines produced during physical activity are involved in ensuring adaptive changes, anti-inflammatory reactions and maintaining homeostasis. Physiological inflammation can be considered as, in some way, an antagonist of pathological inflammation; it is due to this antagonism that many positive effects of physical activity, including metabolic disorders, can be realized.

Aim. To study the effect of forced treadmill exercise on lipid and carbohydrate metabolism parameters in liver and skeletal muscle tissues of mice with a model of type 2 diabetes mellitus, taking into account age and biological rhythm characteristics.Materials and methods. To create a model of type 2 diabetes mellitus (T2DM), a high-fat diet was used. Physical activity in the form of forced treadmill exercise was carried out for 4 weeks. Parameters of lipid and carbohydrate metabolism in muscle and liver tissues were determined by Western blotting.Results. A decrease in glycogen content in the muscles in T2DM was associated with activation of its breakdown rather than with its reduced synthesis. Significant and multidirectional changes were recorded in the content of glycogen phosphorylase in the liver and skeletal muscle tissues. These changes were significantly influenced by both the nature of diet and physical activity. The development of T2DM in mice was accompanied by a decrease in high-density lipoprotein (HDL) content in the liver along with an increase in low-density lipoprotein (LDL) and very-low-density lipoprotein (VLDL) levels. It is worth noting that physical activity provided partial normalization of the ratio of lipid fractions, despite the fact that the exercises were performed in the context of a high-fat diet. In the T2DM group, metabolic changes caused by both T2DM modeling and physical exercises were not only quantitative, but in some cases also qualitative. The effects of physical exercises performed at different times of the day on metabolic processes in the liver and muscle tissues varied significantly.Conclusion. Physical activity can help prevent not only metabolic disorders (obesity and insulin resistance), but also associated complications on the part of the liver and cardiovascular system.

Aim. To study the effect of forced exercises on the content and parameters of oxidative phosphorylation in brown adipose tissue of mice with type II diabetes mellitus.Materials and methods. To model the disease, we used a high-fat diet and physical exercises in the form of forced treadmill running for 4 weeks. The content of oxidative phosphorylation enzymes in brown adipose tissue was determined by Western blotting.Results. Modeling diabetes in experimental animals was accompanied by expansion of adipose tissue. However, in brown adipose tissue, the content of all oxidative phosphorylation components decreases. Apparently, during type II diabetes mellitus modeling in mice, there is a decrease in the “energy efficiency” in brown adipose tissue, which is partially offset by an increase in its content in the body. Regular physical activity in mice with type II diabetes mellitus, in contrast to healthy animals, contributes to a decrease in the content of brown adipose tissue. At the same time, the content of most oxidative phosphorylation components in brown adipose tissue increases, in some casesб it even exceeds the baseline values. The latter is typical of a variable load mode – when the execution time of exercises periodically changes.Conclusion. The obtained results suggest that metabolic rearrangements in brown adipose tissue may serve as some of the mechanisms of preventive and projective effects of physical activity in type 2 diabetes mellitus.

The effect of forced running for 1 hour daily for 4 weeks on the content of Na + /K + -ATPase isoforms and monovalent cations in the skeletal muscles of mice with a model of type II diabetes mellitus (DM-II) was studied. To form a model of the disease, a high-fat diet was used, and physical activity in the form of forced running was carried out for 4 weeks. The content of Na + /K + -ATPase isoforms and Na + and K + ions in muscle tissue of m.gastrocnemius was determined by Western blotting and atomic absorption spectrophotomery, respectively. It has been shown that the formation of DM-II in mice is accompanied by changes in the content of Na + /K + -ATPase alpha 1 and 2 isoforms in muscle tissue. The effect of forced running loads on the content of Na + /K + -ATPase in muscle tissue is significant and primarily differs in age groups. One can also note a certain dependence of the influence of forced running loads on the content of this enzyme on the time of their use. In young animals, changes in the concentrations of monovalent sodium and potassium cations after forced running loads were less pronounced. In aged mice, against the background of forced loads, an increase in the content of sodium and decrease in the content of potassium in muscle tissue was observed. The detected changes in monovalent cations content in the muscle tissue of mice with diabetes mellitus II under the influence of forced running loads may play a role in the implementation of the metabolic effects of physical activity.

Introduction . The problems of studying the molecular mechanisms of pathogenesis, insulin resistance and finding new ways to correct them are still relevant. Aim : To study the effect of electrical stimulation on the amount of pAkt in a cell culture of C2C12 mouse myoblasts cultivated under hyperglycemic conditions. Material and Methods . We studied the effect of electrical stimulation on the amount of pAkt in a cell culture of C2C12 mouse myoblasts cultivated under hyperglycemic conditions. Cells were cultured in a medium containing 25 mM glucose and subjected to electrical impulse stimulation for 2, 6, and 24 hours. Results . It has been shown that the cultivation of C2C12 myoblasts in a medium with excess glucose is accompanied by a decrease in the amount of pAkt in cells, while pulsed electrical stimulation from 2 to 6 hours increases the concentration of this enzyme and restores the sensitivity of its phosphorylation pathways to insulin. Conclusions . The results obtained suggest that the contractile activity of muscle cells contributes to the restoration of cell sensitivity to insulin and the ability to absorb glucose, using the same regulatory and transport pathways that are affected i the development of type 2 diabetes.

Type 2 diabetes mellitus accounts for about 90% of cases of diabetes and is considered one of the most important problems of our time. Despite a significant number of studies on glucose metabolism, the molecular mechanisms of its regulation in health and disease remain insufficiently studied. That is why non-drug treatment of metabolic disorders is of great relevance, including physical activity. Metabolic changes under the influence of physical activity are very complex and are still difficult to understand. This study aims to deepen the understanding of the effect of physical exercise on metabolic changes in mice with diabetes mellitus. We studied the effect of forced treadmill running on body weight and metabolic parameters in mice with metabolic disorders. We developed a high-fat-diet-induced diabetic model of metabolic disorders. We exposed mice to forced treadmill running for 4 weeks. We determined glucose and insulin levels in the blood plasma biochemically and analyzed Glut-4 and citrate synthase in M. gastrocnemius muscle tissue using Western blotting. The research results show that daily treadmill running has different effects on different age groups of mice with metabolic disorders. In young-age animals, forced running has a more pronounced effect on body weight. At week 12, young obese mice had a 17% decrease in body weight. Body weight did not change in old mice. Moreover, at weeks 14 and 16, the decrease in body weight was more significant in the young mice (by 17%) compared to the old mice (by 6%) (p < 0.05). In older animals, it influences the rate of glucose uptake. At 60 min, the blood glucose in the exercised older mice decreased to 14.46 mmol/L, while the glucose concentration in the non-exercised group remained at 17 mmol/L. By 120 min, in mice subjected to exercise, the blood glucose approached the initial value (6.92 mmol/L) and amounted to 8.35 mmol/L. In the non-exercised group, this difference was 45%. The effects of physical activity depend on the time of day. The greater effect is observed when performing shift training or exercise during the time when animals are passive (light phase). In young mice, light phase training had a significant effect on increasing the content of Glut-4 in muscle tissue (84.3 ± 11.3%, p < 0.05 with control group—59.3 ± 7.8%). In aged mice, shift training caused an increase in the level of Glut-4 in muscle tissue (71.3 ± 4.1%, p < 0.05 with control group—56.4 ± 10,9%). In the group of aged mice, a lower CS level was noticed in all groups in comparison with young mice. It should also be noted that we observed that CS increased during exercise in the group of young mice, especially during light phase training. The CS content in the light phase subgroup (135.8 ± 7.0%) was higher than in the dark phase subgroup (113.3 ± 7.7%) (p = 0.0006). The CS decreased in aged chow-fed mice and increased in the high-fat-fed group. The CS content in the chow diet group (58.2 ± 5.0%) was 38% lower than in the HFD group (94.9 ± 8.8%).

Aim. This paper aims at evaluating the effect of physical activity on energy metabolism in the skeletal muscles of untrained and trained experimental mice. Materials and methods. Mature (8-12 weeks) male C57Bl/6 mice weighing 25-30 g were used as experimental animals. Groups for acute (untrained mice) and chronic (trained mice) experiments were formed for the study. We used a dynamic exercise in the form of forced floating and a static exercise in the form of hanging on a horizontal grid. The content of lactate and glycogen in skeletal muscles was determined by the colorimetric method. The de-termination of citrate synthase, total OXPHOS, and the concentration of the Na+/K+-ATPase alpha 2 isoform in muscle tissue was performed by Western blotting. Results. It is shown that dynamic and static exercises have different effects on energy metabolism in the muscles of untrained and trained experimental animals. If the effects of a single exercise of a static or dynamic nature differed not so significantly, then those of daily training activities differed significantly. Static training led to significantly more pronounced changes in the energy metabolism of muscle cells. At the same time, the effect of a single static exercise on energy metabolism in trained animals was less pronounced than that of a dynamic one. Conclusion. Modification of these mechanisms under the influence of physical activities of various nature and intensity is of considerable interest as a promising way to affect metabolic processes both at the cellular and systemic levels, which is very important for both improving sports performance and correcting metabolic disorders associated with a number of socially significant diseases.

Aim . To assess the effect of a single physical activity on the concentration of endothelial NO-synthase and plateletactivating factor in blood plasma of athletes training in cyclic and strength sports, as well as in untrained volunteers. Materials and methods . The study involved 28 men aged 18–25 years, who were relatively healthy and had no disorders of the cardiovascular system. Three groups were formed according to the sports classification. Group 1 (TFG): highly qualified athletes (Candidates for Master of Sports (CMS), Master of Sports (MS)) of cyclic sports – track and field athletics (middle-distance running, 800–1500 m), n = 10. Group 2 (WG): highly qualified athletes (CMS, MS) of strength sports – weightlifting, n = 8. Group 3 (CG): control group – untrained men with no sports category, n = 10. All volunteers were examined in the morning on an empty stomach. One day before the study, the athletes were advised to stop the training process. The blood from cubital vein was taken from all the subjects three times: before exercise (test A), immediately after performing the standard PWC 170 test on a bicycle ergometer (test B), and 60 minutes after performing the stress test (test C). Determination of the concentration of endothelial NO-synthase (eNOS) and platelet-activating factor (PAF) in plasma was performed by enzyme immunoassay. Results . It has been shown that the features of endothelial reactivity in athletes of various specializations in comparison with untrained volunteers are significantly associated with the level of eNOS production both at rest and in response to short-term physical exertion. Platelet-activating factor can also affect endothelial reactivity, but to a lesser extent, and is involved only in the mechanisms of adaptation to repetitive high-intensity physical loads.

Modulation of cytokine production by physical activity is of considerable interest, since it might be a promising strategy for correcting metabolic processes at both cellular and systemic levels. The content of IL-6, IL-8, and IL-15 in the plasma and the concentration of monovalent cations in the skeletal muscles of trained and untrained mice were studied at different periods after static and dynamic exercises. Dynamic loads caused an increase in the IL-6 content and decrease in the IL-15 content in the plasma of untrained mice, but produced no effect on the concentration of IL-8. In trained mice, the effect of a single load on the concentration of IL-6 and IL-15 in the plasma was enhanced, while the concentration of IL-8 decreased. Static loads produced a similar, but more pronounced effect on the plasma concentration of IL-6 and IL-15 compared the dynamic exercises; however, the concentration of IL-8 in response to the static exercise increased significantly. Prior training reinforced the described response for all the myokines studied. Dynamic load (swimming) increased the intracellular content of sodium but decreased the content of potassium in the mouse musculus soleus . Similar response was observed after the static load (grid hanging) in the musculus biceps ; but no correlation of this response with the prior training was found. Possible mechanisms involved in the regulation of cytokine secretion after exercise are discussed, including triggering of gene transcription in response to changes in the [Na + ] i /[K + ] I ratio.

Aim . To assess the effect of a single physical activity on the concentration of endothelial NO-synthase and plateletactivating factor in blood plasma of athletes training in cyclic and strength sports, as well as in untrained volunteers. Materials and methods . The study involved 28 men aged 18–25 years, who were relatively healthy and had no disorders of the cardiovascular system. Three groups were formed according to the sports classification. Group 1 (TFG): highly qualified athletes (Candidates for Master of Sports (CMS), Master of Sports (MS)) of cyclic sports – track and field athletics (middle-distance running, 800–1500 m), n = 10. Group 2 (WG): highly qualified athletes (CMS, MS) of strength sports – weightlifting, n = 8. Group 3 (CG): control group – untrained men with no sports category, n = 10. All volunteers were examined in the morning on an empty stomach. One day before the study, the athletes were advised to stop the training process. The blood from cubital vein was taken from all the subjects three times: before exercise (test A), immediately after performing the standard PWC 170 test on a bicycle ergometer (test B), and 60 minutes after performing the stress test (test C). Determination of the concentration of endothelial NO-synthase (eNOS) and platelet-activating factor (PAF) in plasma was performed by enzyme immunoassay. Results . It has been shown that the features of endothelial reactivity in athletes of various specializations in comparison with untrained volunteers are significantly associated with the level of eNOS production both at rest and in response to short-term physical exertion. Platelet-activating factor can also affect endothelial reactivity, but to a lesser extent, and is involved only in the mechanisms of adaptation to repetitive high-intensity physical loads.

The effect of forced treadmill running on the level of some cytokines in skeletal muscles of mice with a model of type II diabetes mellitus was studied. The mouse model was developed using a 12-week high-fat diet; physical loading in the form of forced treadmill running was applied for 4 weeks. The concentration of myokines in m. gastrocnemius was determined by an enzyme-linked immunosorbent assay (ELISA). Diabetes formation in mice was accompanied by changes in the skeletal muscle concentration of two pro-inflammatory cytokines: an increase in IL-6 and a decrease in IL-15. Forced treadmill running loads had differential effects on the level of myokines in healthy and sick mice. In healthy animals, there was a decrease in IL-6 and IL-15 concentrations and an increase in the leukemia inhibitory factor (LIF) concentration in skeletal muscles after 4 weeks of regular forced running. At the same time, in diabetic mice, IL-6 and IL-15 concentrations increased, while the LIF concentration decreased after forced running loads. The NAP3 concentration in skeletal muscles was found to be insensitive to both the development of type II diabetes mellitus and regular forced treadmill running.

The effect of treadmill running exercise training on the content of some cytokines in the skeletal muscles of mice with a model of type II diabetes mellitus was studied. To develop a model of the disease, a high fat feeding for 12 weeks was used, physical activity in the form of forced running was carried out for 4 weeks. The concentration of myokines in the muscle tissue of m. gastrocnemius was determined by enzyme-linked immunosorbent assay (ELISA). The development of diabetes in mice is accompanied by an increase in the concentration of inflammatory cytokines IL-6 and a decrease in the concentration of IL-15 in skeletal muscle tissue. 4 weeks treadmill running exercise training has a different effect on the content of myokines in healthy and sick mice. In healthy animals, there was a decrease in IL-6 and IL-15 concentration and an increase in LIF concentration in skeletal muscle tissue after 4 weeks of regular forced running. At the same time, in diabetic mice, the concentrations of IL-6 and IL-15 increased after exercise, while LIF, on the contrary, decreased. The concentration of NAP3 in the skeletal muscle tissue of mice was insensitive to either the formation of diabetes mellitus II or to regular treadmill running exercise training.

The cardiotonic steroids (CTS), such as ouabain and marinobufagenin, are thought to be adrenocortical hormones secreted during exercise and the stress response. The catalytic α-subunit of Na,K-ATPase (NKA) is a CTS receptor, whose largest pool is located in skeletal muscles, indicating that muscles are a major target for CTS. Skeletal muscles contribute to adaptations to exercise by secreting interleukin-6 (IL-6) and plethora of other cytokines, which exert paracrine and endocrine effects in muscles and non-muscle tissues. Here, we determined whether ouabain, a prototypical CTS, modulates IL-6 signaling and secretion in the cultured human skeletal muscle cells. Ouabain (2.5-50 nM) suppressed the abundance of STAT3, a key transcription factor downstream of the IL-6 receptor, as well as its basal and IL-6-stimulated phosphorylation. Conversely, ouabain (50 nM) increased the phosphorylation of ERK1/2, Akt, p70S6K, and S6 ribosomal protein, indicating activation of the ERK1/2 and the Akt-mTOR pathways. Proteasome inhibitor MG-132 blocked the ouabain-induced suppression of the total STAT3, but did not prevent the dephosphorylation of STAT3. Ouabain (50 nM) suppressed hypoxia-inducible factor-1α (HIF-1α), a modulator of STAT3 signaling, but gene silencing of HIF-1α and/or its partner protein HIF-1β did not mimic effects of ouabain on the phosphorylation of STAT3. Ouabain (50 nM) failed to suppress the phosphorylation of STAT3 and HIF-1α in rat L6 skeletal muscle cells, which express the ouabain-resistant α1-subunit of NKA. We also found that ouabain (100 nM) promoted the secretion of IL-6, IL-8, GM-CSF, and TNF-α from the skeletal muscle cells of healthy subjects, and the secretion of GM-CSF from cells of subjects with the type 2 diabetes. Marinobufagenin (10 nM), another important CTS, did not alter the secretion of these cytokines. In conclusion, our study shows that ouabain suppresses the IL-6 signaling via STAT3, but promotes the secretion of IL-6 and other cytokines, which might represent a negative feedback in the IL-6/STAT3 pathway. Collectively, our results implicate a role for CTS and NKA in regulation of the IL-6 signaling and secretion in skeletal muscle.

An experimental model of the obesity and type II diabetes mellitus formation in C57BL/6 mice using a high fat diet was developed and tested. In the study, it was shown that mice feeding high-fat diet had a significant body weight gain during the 3rd week. By the end of the experiment, body weight has more than doubled. In mice that feed chow diet, body weight increased by 50%, by the end of the experiment It was shown that high fat diet also induced glucose tolerance, and the insulin concentration tripled. The data obtained confirm the adequacy of the experimental model of diabetes mellitus type II in mice.

Elevation of Ca-i(2+) and AMP-activated protein kinase (AMPK) are considered as major signals triggering tran-scriptomic changes in exercising skeletal muscle. Electrical pulse stimulation (EPS) of cultured myotubes is widely employed as an in vitro model of muscle contraction. This study examines the impact of Ca-i(2+)-mediated and Ca-i(2+)-independent signaling in transcriptomic changes in EPS-treated C2C12 myotubes. Electrical pulse stimulation (40 V, 1 Hz, 10 ms, 2 h) resulted in [Ca2+](i), oscillations, gain of Na-i(+), loss of K-i(+), and differential expression of 3215 transcripts. Additions of 10 mu M nicardipine abolished [Ca-i(2+)], oscillations but did not affect elevation of the [Na+](i)/[K+](i) ratio seen in EPS-treated myotubes. Differential expression of 1018 transcripts was preserved in the presence of nicardipine, indicating a Ca-i(2+)-independent mechanism of excitation-transcription coupling. Among nicardipine-resistant transcripts, we noted 113 transcripts whose expression was also affected by partial Na+,K+-ATPase inhibition with 30 mu M ouabain providing the same elevation of the [Na+](i)/[K+](i) ratio as in EPS-treated cells. Electrical pulse stimulation increased phosphorylation of CREB, ATF-1, Akt, ERK, and p38 MAPK without any impact on phosphorylation of acetyl-CoA carboxylase and Unc-51 like autophagy activating kinase-1, i.e. downstream markers of AMPK activation. Unlike CREB, ATF-1, and MAPKs, an increment in Akt phosphorylation was abolished by nicardipine. Thus, our results show that Ca-i(2+) -independent signaling plays a key role in altered expression of 30% of studied genes in EPS-treated myotubes. This signaling pathway is at least partially triggered by dissipation of transmembrane gradients of monovalent cations.

Electrical pulse stimulation (EPS)-treated cultured myotubes are widely employed as an in vitro model of muscle contraction. Here we examined time-dependent EPS action and dose-dependent ouabain action on [Na+]i and [K+]i in C2C12 myotubes. After 2 h of EPS (40 V, 1 Hz, 10 ms) [Na+]i increased by ∼150% whereas [K+]i declined by ∼20%. 3 μM ouabain had a negligible impact on [Na+]i and [K+]i in control cells but increased the [Na+]i/[K+]i ratio in EPS-treated myotubes by 85%. Thus, our results show for the first time that EPS results in dissipation of Na+ and K+ gradients in cultured myotubes and suggest that the augmented production of endogenous cardiotonic steroids may contribute to elevation of the [Na+]i/[K+]i ratio in exercising muscle.