Oxidative Stress In Skeletal Muscle Research Articles

Role of Magnesium in Skeletal Muscle Health and Neuromuscular Diseases: A Scoping Review

Magnesium (Mg) is a vital element for various metabolic and physiological functions in the human body, including its crucial role in skeletal muscle health. Hypomagnesaemia is frequently reported in many muscle diseases, and it also seems to contribute to the pathogenesis of skeletal muscle impairment in patients with neuromuscular diseases. The aim of this scoping review is to analyze the role of Mg in skeletal muscle, particularly its biological effects on muscle tissue in neuromuscular diseases (NMDs) in terms of biological effects and clinical implications. This scoping review followed the PRISMA-ScR (Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews) guidelines. From the 305 studies identified, 20 studies were included: 4 preclinical and 16 clinical studies. Preclinical research has demonstrated that Mg plays a critical role in modulating pathways affecting skeletal muscle homeostasis and oxidative stress in muscles. Clinical studies have shown that Mg supplementation can improve muscle mass, respiratory muscle strength, and exercise recovery and reduce muscle soreness and inflammation in athletes and patients with various conditions. Despite the significant role of Mg in muscle health, there is a lack of research on Mg supplementation in NMDs. Given the potential similarities in pathogenic mechanisms between NMDs and Mg deficiency, further studies on the effects of Mg supplementation in NMDs are warranted. Overall, maintaining optimal Mg levels through dietary intake or supplementation may have important implications for improving muscle health and function, particularly in conditions associated with muscle weakness and atrophy.

Sinapine suppresses ROS-induced C2C12 myoblast cell death through MAPK and autophagy pathways.

Oxidative stress in skeletal muscle can lead to muscle atrophy through reactive oxygen species (ROS)-induced damage and cell death. tert-Butyl hydroperoxide (TBHP), an exogenous ROS generator, induces oxidative stress and cell death in various cells. Sinapine from cruciferous plants possesses beneficial effects, but its role in protecting skeletal muscle cells against ROS-induced cell death remains unclear. This study demonstrates that sinapine pretreatment significantly reduced TBHP-induced cell death and ROS accumulation in a dose-dependent manner. TBHP activated mitogen-activated protein kinase (MAPK) pathways including Akt, p38, and JNK, and triggered autophagy. Sinapine suppressed the phosphorylation of Akt, MEK3/6, p38, MEK4, and JNK, and modulated key autophagy markers. Notably, the co-treatment of MAPK inhibitors attenuated TBHP-induced cell death and LC3B-II accumulation. These findings suggest that sinapine is a promising phytochemical for mitigating oxidative stress-mediated muscle injury, offering potential therapeutic strategies for maintaining skeletal muscle homeostasis and addressing muscle-related pathologies.

PSVI-14 Effects of poor maternal nutrition during gestation on first generation offspring oxidative status in skeletal muscle

Abstract Poor maternal nutrition (restricted- and over-nutrition) during gestation negatively impacts offspring pre- and post-natal growth. Previous work has identified decreased muscle mass and increased adiposity, leading to poor quantity and quality of animal protein products. Alterations in oxidative status, such as the imbalance of antioxidant activity and the production of free radicals, can result in oxidative stress damaging lipid membranes, proteins, and DNA. Changes in oxidative status may contribute to the poor growth outcomes observed in offspring from poorly nourished dams. Therefore, the objective of this research was to determine the effects of poor maternal nutrition during gestation on the oxidative status in offspring skeletal muscle in sheep. We hypothesized that offspring of restricted- and over-fed ewes would have decreased antioxidant activity and increased products of oxidative stress in skeletal muscle. To test this hypothesis, multiparous Dorset ewes (n = 46) pregnant with twins were fed 100% (CON), 60% (RES), or 140% (OVER) of total nutrient requirements (NRC) from d 30 of gestation until parturition. Following parturition, ewes were fed a control diet throughout lactation. At d 282 of age semitendinosus (STN) samples were collected from rams at necropsy, and at d 284 of age muscle biopsies from STN were collected from ewes. Data were analyzed in SAS using PROC MIXED with fixed effects of maternal diet and offspring sex. Data were considered significant at P ≤ 0.05. The activity of the endogenous antioxidant superoxide dismutase (SOD) was decreased by 45% and 33% in RES and OVER offspring, respectively, compared with CON (P ≤ 0.01). Offspring sex did not alter STN SOD activity (P = 0.35). Muscle glutathione peroxidase (GPx) activity was decreased in RES offspring by 20% compared with CON (P ≤ 0.04), but neither differed from OVER offspring (P ≥ 0.24). Ewes had 34% greater GPx activity compared with rams (P < 0.0001). Offspring from RES and OVER ewes had 77% and 87% greater concentrations of malondialdehyde (MDA), a marker of lipid peroxidation, when compared with CON (P < 0.0001). Ewes had 29% greater MDA concentrations compared with rams (P = 0.05). Protein carbonyl (PC), a marker of protein oxidation, concentrations were 36% and 38% greater in RES and OVER offspring, respectively, compared with CON (P ≤ 0.01). The decrease in antioxidant activities and increase in products of protein and lipid oxidation in offspring from poorly nourished dams suggests dysregulation in skeletal muscle oxidative status that may contribute to the negative consequences observed in offspring. Future work should focus on determining the mechanistic role of skeletal muscle oxidative stress in the decreased quantity and quality of animal protein products and identifying potential strategies to mitigate alterations in oxidative status as a result of poor maternal nutrition during gestation.

Dihydromyricetin Inhibits Ferroptosis to Attenuate Cisplatin-Induced Muscle Atrophy.

Cisplatin is a widely used chemotherapy drug for the treatment of various cancers. However, although cisplatin is effective in targeting cancer cells, it has severe side effects including skeletal muscle atrophy. In this study, we aimed to characterize the role of Dihydromyricetin in cisplatin-induced muscle atrophy in mice. 5-week-old male C57BL/6 mice were treated with Dihydromyricetin for 14 days orally followed by in intraperitoneally cisplatin administration for 6 days. Gastrocnemius muscles were isolated for the following experiments. Antioxidative stress were determined by peroxidative product malondialdehyde (MDA) and antioxidants superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities. Quadriceps muscle mass and grip strength were significantly restored by Dihydromyricetin in a dose-dependent manner. Moreover, muscle fibers were improved in Dihydromyricetin treated group. Excessive skeletal muscle E3 ubiquitin-protein ligases in cisplatin group were significantly repressed by Dihydromyricetin treatment. Dihydromyricetin significantly reduced oxidative stress induced by cisplatin by decreasing MDA level and restored SOD and GPx activities. In addition, ferroptosis was significantly reduced by Dihydromyricetin characterized by reduced iron level and ferritin heavy chain 1 and improved Gpx4 level. The present study demonstrated that Dihydromyricetin attenuated cisplatin-induced muscle atrophy by reducing skeletal muscle E3 ubiquitin-protein ligases, oxidative stress, and ferroptosis.

Protective properties of melanin from lichen Lobaria pulmonaria (L.) HOFFM. In models of oxidative stress in skeletal muscle

Melanin is a dark pigment from the group of phenolic or indole polymers with inherent biocompatibility and antioxidant capacity. In extremophilic lichen Lobaria pulmonaria, melanin is responsible for protective properties against hostile environments. Herein, the ability of melanin extracted from L. pulmonaria to counteract oxidative stress and related damages was studied in the mouse diaphragm, the main respiratory muscle. Initial in vitro experiments demonstrated ultraviolet (UV)-absorbing, antioxidant and metal chelating activities of melanin. This melanin can form nanoparticles and stabile colloidal system at concentration of 5 μg/ml. Pretreatment of the muscle with melanin (5 μg/ml) markedly reduced UV-induced increase in intracellular and extracellular reactive oxygen species (ROS) as well as antimycin A-mediated enhancement in mitochondrial ROS production accompanied by lipid peroxidation and membrane asymmetry loss. In addition, melanin attenuated suppression of neuromuscular transmission and alterations of contractile responses provoked by hydrogen peroxide. Thus, this study shed the light on the perspectives of the application of a lichen melanin as a protective component for treatment of skeletal muscle disorders, which are accompanied with an increased ROS production.

Biological sex impacts oxidative stress in skeletal muscle in a porcine heat stress model.

Oxidative stress contributes to heat stress (HS)-mediated alterations in skeletal muscle; however, the extent to which biological sex mediates oxidative stress during HS remains unknown. We hypothesized muscle from males would be more resistant to oxidative stress caused by HS than muscle from females. To address this, male and female pigs were housed in thermoneutral conditions (TN; 20.8 ± 1.6°C; 62.0 ± 4.7% relative humidity; n = 8/sex) or subjected to HS (39.4 ± 0.6°C; 33.7 ± 6.3% relative humidity) for 1 (HS1; n = 8/sex) or 7 days (HS7; n = 8/sex) followed by collection of the oxidative portion of the semitendinosus. Although HS increased muscle temperature, by 7 days, muscle from heat-stressed females was cooler than muscle from heat-stressed males (0.3°C; P < 0.05). Relative protein abundance of 4-hydroxynonenal (4-HNE)-modified proteins increased in HS1 females compared with TN (P = 0.05). Furthermore, malondialdehyde (MDA)-modified proteins and 8-hydroxy-2'-deoxyguanosine (8-OHdG) concentration, a DNA damage marker, was increased in HS7 females compared with TN females (P = 0.05). Enzymatic activities of catalase and superoxide dismutase (SOD) remained similar between groups; however, glutathione peroxidase (GPX) activity decreased in HS7 females compared with TN and HS1 females (P ≤ 0.03) and HS7 males (P = 0.02). Notably, HS increased skeletal muscle Ca2+ deposition (P = 0.05) and was greater in HS1 females compared with TN females (P < 0.05). Heat stress increased sarco(endo)plasmic reticulum Ca2+ ATPase (SERCA)2a protein abundance (P < 0.01); however, Ca2+ ATPase activity remained similar between groups. Overall, despite having lower muscle temperature, muscle from heat-stressed females had increased markers of oxidative stress and calcium deposition than muscle from males following identical environmental exposure.NEW & NOTEWORTHY Heat stress is a global threat to human health and agricultural production. We demonstrated that following 7 days of heat stress, skeletal muscle from females was more susceptible to oxidative stress than muscle from males in a porcine model, despite cooler muscle temperatures. The vulnerability to heat stress-induced oxidative stress in females may be driven, at least in part, by decreased antioxidant capacity and calcium dysregulation.

Benzoylaconine Protects Skeletal Muscle Against Ischemia-Reperfusion Injury Through Activation of IF1-Dependent AMPK/Nrf2 Axis.

Aconitum carmichaelii (Fuzi) has been conventionally used to cure a variety of ailments, such as pain, cold sensations, and numbness of limb muscles (Bi Zheng) in China. Our prior investigations identified Benzoylaconine (BAC) as a bioactive alkaloid derived from Aconitum carmichaelii, with other studies also demonstrating its significant pharmacological potential. This study aimed to explore the potential of BAC as a protective agent against skeletal muscle ischemia-reperfusion (I/R) injury and to elucidate the underlying mechanisms. In vivo models involved subjecting Sprague-Dawley rats to I/R through femoral artery ligation followed by reperfusion, while in vitro models utilized C2C12 cells subjected to hypoxia/reoxygenation (H/R). CCK-8 assay was used to assess cell viability. TUNEL staining and flow cytometric analysis were used to measure cell apoptosis. Biochemical assay was used to assess skeletal muscle injury and oxidative stress. Immunofluorescence and Western blot were performed to determine protein levels. BAC effectively protected muscle tissue from I/R injury, enhancing cell viability (p<0.01), elevating SOD levels (p<0.05), and reducing CK (p<0.01), LDH (p<0.01), ROS (p<0.01), MDA (p<0.01), and apoptosis-related molecules in vivo and in vitro (p<0.05, p<0.01). Mechanistically, BAC increased the expression of IF1, phosphorylated AMPK, facilitated the translocation of nuclear Nrf2, and induced the expression of HO-1 (p<0.01). Notably, AMPK inhibitor Compound C significantly hindered the ability of BAC to ameliorate H/R-induced cell injury (p<0.05), oxidative stress(p<0.01), and apoptosis (p<0.05), as well as promote Nrf2 nuclear translocation (p<0.01). Moreover, silencing of IF1 with siRNA abolished BAC-induced activation of AMPK/Nrf2 axis (p<0.01). Our study provides novel evidence supporting the potential of BAC as a myocyte-protective agent against I/R injury, and we establish a previously unknown mechanism involving the activation of the IF1-dependent AMPK/Nrf2 axis in mediating the protective effects of BAC.

Targeting Mitochondrial Dynamics during Lower-Limb Ischemia Reperfusion in Young and Old Mice: Effect of Mitochondrial Fission Inhibitor-1 (mDivi-1).

Peripheral arterial disease (PAD) strikes more than 200 million people worldwide and has a severe prognosis by potentially leading to limb amputation and/or death, particularly in older patients. Skeletal muscle mitochondrial dysfunctions and oxidative stress play major roles in this disease in relation with ischemia-reperfusion (IR) cycles. Mitochondrial dynamics through impairment of fission-fusion balance may contribute to skeletal muscle pathophysiology, but no data were reported in the setting of lower-limb IR despite the need for new therapeutic options. We, therefore, investigated the potential protective effect of mitochondrial division inhibitor-1 (mDivi-1; 50 mg/kg) in young (23 weeks) and old (83 weeks) mice submitted to two-hour ischemia followed by two-hour reperfusion on systemic lactate, muscle mitochondrial respiration and calcium retention capacity, and on transcripts specific for oxidative stress and mitochondrial dynamics. At the systemic levels, an IR-related increase in circulating lactate was still major despite mDivi-1 use (+305.9% p < 0.0001, and +269.4% p < 0.0001 in young and old mice, respectively). Further, IR-induced skeletal muscle mitochondrial dysfunctions (more severely impaired mitochondrial respiration in old mice (OXPHOS CI state, -68.2% p < 0.0001 and -84.9% p < 0.0001 in 23- and 83-week mice) and reduced calcium retention capacity (-46.1% p < 0.001 and -48.2% p = 0.09, respectively) were not corrected by mDivi-1 preconditioning, whatever the age. Further, mDivi-1 treatment did not oppose superoxide anion production (+71.4% p < 0.0001 and +37.5% p < 0.05, respectively). At the transcript level, markers of antioxidant enzymes (SOD 1, SOD 2, catalase, and GPx) and fission markers (Drp1, Fis) remained unchanged or tended to be decreased in the ischemic leg. Fusion markers such as mitofusin 1 or 2 decreased significantly after IR in both groups. In conclusion, aging enhanced the deleterious effects or IR on muscle mitochondrial respiration, and in this setting of lower-limb IR, mDivi-1 failed to protect the skeletal muscle both in young and old mice.

Monascus pigment prevent the oxidative cytotoxicity in myotube derived hydrogen peroxide.

The amounts of Reactive oxygen species (ROS) become higher by strenuous exercises which consume larger amounts of oxygen in active muscles. Since these ROS directly injured muscles, the high ROS concentration involves muscle fatigue. Thus, an immediate ROS scavenging system in the muscle is desired. Since Monascus pigment (MP) involves physiologically active substances which scavenge ROS, it may be a clue to save the muscle injury. However, there are no reports examining MP effects on oxidative stress in skeletal muscle. In this study, we investigated the effect and mechanism of MP on skeletal muscle cells damaged by oxidative stress. The ability to directly eliminate ROS was evaluated by mixing MP solutions with •OH and O2 •-, a type of ROS. The effect of peroxidation in C2C12 cells was evaluated by cell viability assay and Western blotting. MP scavenges •OH and O2 •-. MP treatment increases the survival rate under oxidative stress. At that time, the expression of catalase was increased: the enzyme change H2O2 into H2O to rescue the cells under oxidative stress. We conclude that monascus pigment suppressed myotube damage under oxidative stress by both non-enzymatic ROS scavenging and up-regulation of catalase expression.

Genistein in combination with Chlorogenic acid ameliorates insulin resistance and oxidative stress in skeletal muscle of high-fat diet fed mice

Objectives: Increasing evidence has demonstrated that oxidative stress plays a significant role in the pathogenesis of muscle insulin resistance. The beneficial impacts of genistein (GEN) and chlorogenic acid (CGA) on insulin resistance have already been revealed. However, their combined effects on skeletal muscle oxidative stress and insulin resistance have not been completely understood. The aim of the present study was to determine the effect of GEN in combination with CGA on skeletal muscle insulin resistance in high-fat diet (HFD) fed C57BL/6 mice.&#x0D; Methods: C57BL/6 male mice were fed an HFD for 15 weeks. The mice were then divided into five groups: standard chow diet (SCD), HFD, HFD + GEN, HFD + CGA, and HFD + GEN + CGA for 10 weeks.&#x0D; Results: The findings indicated that single treatment with GEN or CGA, and with a stronger effect of GEN+CGA combined treatment, decreased body weight gain and improved glucose intolerance. Moreover, following treatment with GEN and CGA alone or in combination with further effect, the level of plasma and muscle triglyceride (TG) were reduced. Furthermore, the combination therapy of GEN and CGA with greater efficacy than the single treatments, could decrease several oxidative stress markers in the skeletal muscle. Treatment with GEN and CGA alone or in combination could increase the expression of NF-E2–related factor 2 (Nrf2), heme oxygenase-1 (HO-1), and NAD(P): Quinone Oxidoreductase 1 (NQO1).&#x0D; Conclusion: The data of this study suggest that the combination of GEN and CGA might ameliorate insulin resistance and reduce oxidative stress in the skeletal muscle of mice fed HFD.

Combination therapy of metformin and morin attenuates insulin resistance, inflammation, and oxidative stress in skeletal muscle of high-fat diet-fed mice.

Lipid accumulation, inflammation, and oxidative stress are the most important causes of muscle insulin resistance. The aim of this study was to investigate the single and combined treatment effects of metformin (MET) and morin (MOR) on lipid accumulation, inflammation, and oxidative stress in the skeletal muscle of mice fed a high-fat diet. The mice were supplemented with MET (230 mg/kg diet), MOR (100 mg/kg diet), and MET + MOR for 9 weeks. Our results revealed that single treatment with MET or MOR, and with a stronger effect of MET + MOR combined treatment, reduced body weight gain, improved glucose intolerance and enhanced Akt phosphorylation in the muscle tissue. In addition, plasma and muscle triglyceride levels were decreased after treatment with MET and MOR. The expression of genes involved in macrophage infiltration and polarization and pro-inflammatory cytokines showed that MET + MOR combined treatment, significantly reduced inflammation in the muscle. Furthermore, combined treatment of MET + MOR with greater efficacy than the single treatment improved several oxidative stress markers in the muscle. Importantly, combined treatment of MET and MOR could increase the expression of nuclear factor erythroid 2-related factor 2, the master regulator of the antioxidant response. These findings suggest that combination of MET with MOR might ameliorate insulin resistance, inflammation, and oxidative stress in the skeletal muscle of mice fed high-fat diet.

Isoliquiritigenin inhibits apoptosis and ameliorates oxidative stress in rheumatoid arthritis chondrocytes through the Nrf2/HO-1-mediated pathway

Rheumatoid arthritis (RA) is a chronic inflammatory condition known for its irreversible destructive impact on the joints. Chondrocytes play a pivotal role in the production and maintenance of the cartilage matrix. However, the presence of inflammatory cytokines can hinder chondrocyte proliferation and promote apoptosis. Isoliquiritigenin (ISL), a flavonoid, potentially exerts protective effects against various inflammatory diseases. However, its specific role in regulating the nuclear factor E2-associated factor 2 (Nrf2)/heme oxygenase-1 (HO-1) pathway in chondrocytes in RA remains unclear. To investigate this, this study used human chondrocytes and Sprague-Dawley rats to construct in vitro and in vivo RA models, respectively. The study findings reveal that cytokines markedly induced oxidative stress, the activation of matrix metalloproteinases, and apoptosis both in vitro and in vivo. Notably, ISL treatment significantly mitigated these effects. Moreover, Nrf2 or HO-1 inhibitors reversed the protective effects of ISL, attenuated the expression of Nrf2/HO-1 and peroxisome proliferator-activated receptor gamma-coactivator-1α, and promoted chondrocyte apoptosis. This finding indicates that ISL primarily targets the Nrf2/HO-1 pathway in RA chondrocytes. Moreover, ISL treatment led to improved behavior scores, reduced paw thickness, and mitigated joint damage as well as ameliorated oxidative stress in skeletal muscles in an RA rat model. In conclusion, this study highlights the pivotal role of the Nrf2/HO-1 pathway in the protective effects of ISL and demonstrates the potential of ISL as a treatment option for RA.

Metabolomic Analysis of Trehalose Alleviating Oxidative Stress in Myoblasts.

Trehalose, a naturally occurring non-toxic disaccharide, has attracted considerable attention for its potential in alleviating oxidative stress in skeletal muscle. In this study, our aim was to elucidate the metabolic mechanisms underlying the protective effects of trehalose against hydrogen peroxide (H2O2)-induced oxidative stress in C2C12 myoblasts. Our results show that both trehalose treatment and pretreatment effectively alleviate the H2O2-induced decrease in cell viability, reduce intracellular reactive oxygen species (ROS), and attenuate lipid peroxidation. Furthermore, using NMR-based metabolomics analysis, we observed that trehalose treatment and pretreatment modulate the metabolic profile of myoblasts, specifically regulating oxidant metabolism and amino acid metabolism, contributing to their protective effects against oxidative stress. Importantly, our results reveal that trehalose treatment and pretreatment upregulate the expression levels of P62 and Nrf2 proteins, thereby activating the Nrf2-NQO1 axis and effectively reducing oxidative stress. These significant findings highlight the potential of trehalose supplementation as a promising and effective strategy for alleviating oxidative stress in skeletal muscle and provide valuable insights into its potential therapeutic applications.

Prenatal transportation stress does not impact resting skeletal muscle mitochondrial function or antioxidant activity in Brahman calves

In cattle, prenatal transportation stress has been associated with differential methylation of genes related to metabolism, but the effects of prenatal transportation stress on skeletal muscle mitochondria and oxidative stress have not been investigated. We tested the hypothesis that prenatally stressed calves would exhibit increased skeletal muscle mitochondrial function resulting in greater oxidative stress than calves from non-stressed dams. Serum and longissimus thoracis muscle samples were collected from yearling Brahman calves whose mothers were stressed by transportation at five time points during gestation [i.e., prenatally stressed (PNS); eight bulls and six heifers] and control calves (CON; four bulls and six heifers). Serum was evaluated for concentration of the stress hormone, cortisol and for a marker of muscle perturbation, creatine kinase activity. Muscle samples were analyzed for concentration of a by-product of lipid peroxidation, malondialdehyde, and activity of the antioxidants, superoxide dismutase and glutathione peroxidase. Additionally, muscle mitochondrial volume density and function were estimated by citrate synthase and cytochrome c oxidase activities, respectively. Data were analyzed using mixed linear models with sex, treatment, and the sex × treatment interaction as fixed effects. No investigated variable differed between CON and PNS calves (p ≥ 0.3). These data suggest that prenatal transportation stress does not have an impact on skeletal muscle mitochondrial metabolism or markers of stress or muscle damage in Brahman yearling calves at rest. However, previously reported negative impacts of prenatal stress on inflammatory responses suggest that PNS calves may be differentially equipped to handle an acute stressor. Future research should investigate the energetic and inflammatory implications of acute stressors in animals subjected to prenatal stress.

N-acetylcysteine alleviates oxidative stress and apoptosis and prevents skeletal muscle atrophy in type 1 diabetes mellitus through the NRF2/HO-1 pathway

AimsType 1 diabetes mellitus (T1DM) has been linked to the occurrence of skeletal muscle atrophy. Insulin monotherapy may lead to excessive blood glucose fluctuations. N-acetylcysteine (NAC), a clinically employed antioxidant, possesses cytoprotective, anti-inflammatory, and antioxidant properties. The objective of our study was to evaluate the viability of NAC as a supplementary treatment for T1DM, specifically regarding its therapeutic and preventative impacts on skeletal muscle. Main methodsHere, we used beagles as T1DM model for 120d to explore the mechanism of NRF2/HO-1-mediated skeletal muscle oxidative stress and apoptosis and the therapeutic effects of NAC. Oxidative stress and apoptosis related factors were analyzed by immunohistochemistry, immunofluorescence, western blotting, and RT-qPCR assay. Key findingsThe findings indicated that the co-administration of NAC and insulin led to a reduction in creatine kinase levels, preventing weight loss and skeletal muscle atrophy. Improvement in the reduction of muscle fiber cross-sectional area. The expression of Atrogin-1, MuRF-1 and MyoD1 was downregulated, while Myh2 and MyoG were upregulated. In addition, CAT and GSH-Px levels were increased, MDA levels were decreased, and redox was maintained at a steady state. The decreased of key factors in the NRF2/HO-1 pathway, including NRF2, HO-1, NQO1, and SOD1, while KEAP1 increased. In addition, the apoptosis key factors Caspase-3, Bax, and Bak1 were found to be downregulated, while Bcl-2, Bcl-2/Bax, and CytC were upregulated. SignificanceOur findings demonstrated that NAC and insulin mitigate oxidative stress and apoptosis in T1DM skeletal muscle and prevent skeletal muscle atrophy by activating the NRF2/HO-1 pathway.

Bacillus coagulans T4 and Lactobacillus paracasei TD3 Ameliorate Skeletal Muscle Oxidative Stress and Inflammation in High-Fat Diet-Fed C57BL/6J Mice.

This study aims to investigate the effects of Bacillus coagulans T4 and Lactobacillus paracasei TD3 probiotics on skeletal muscle inflammation and oxidative stress in C57BL/6J mice fed a high-fat diet (HFD). Probiotics B. coagulans T4, and L. paracasei TD3 were administered to male C57BL/6J mice fed with HFD. The gene expression of macrophage infiltration markers, inflammatory cytokines, and oxidative stress indicators in the muscle tissue was investigated. Treatment with B. coagulans T4 and L. paracasei TD3 reduced macrophage infiltration, accompanied by a decrease in the expression of monocyte chemoattractant protein-1 (MCP-1) and an increase in the expression of interleukin (IL)-10. On the other hand, L. paracasei TD3 decreased malondialdehyde (MDA) while B. coagulans T4 decreased carbonyl and increased catalase activity. Treatment with probiotics B. coagulans T4 and L. paracasei TD3 partially ameliorated obesity-induced skeletal muscle inflammation in HFD-fed mice.

Cordycepin inhibits myogenesis via activating the ERK1/2 MAPK signalling pathway in C2C12 cells

Cordycepin (with a molecular formula of C10H13N5O3), a natural adenosine isolated from Cordyceps militaris, has an important regulatory effect on skeletal muscle remodelling and quality maintenance. The aim of this study was to investigate the effect of cordycepin on myoblast differentiation and explore the underlying molecular mechanisms of this effect. Our results showed that cordycepin inhibited myogenesis by downregulating myogenic differentiation (MyoD) and myogenin (MyoG), preserved undifferentiated reserve cell pools by upregulating myogenic factor 5 (Myf5) and retinoblastoma-like protein p130 (p130), and enhanced energy reserves by decreasing intracellular reactive oxygen species (ROS) and enhancing mitochondrial membrane potential, mitochondrial mass, and ATP content. The effect of cordycepin on myogenesis was associated with increased phosphorylation of extracellular signal-regulated kinase 1/2 (p-ERK1/2). PD98059 (a specific inhibitor of p-ERK1/2) attenuated the inhibitory effect of cordycepin on C2C12 differentiation. The present study reveals that cordycepin inhibits myogenesis through ERK1/2 MAPK signalling activation accompanied by an increase in skeletal muscle energy reserves and improving skeletal muscle oxidative stress, which may have implications for its further application for the prevention and treatment of degenerative muscle diseases caused by the depletion of depleted muscle stem cells.

1644-P: Exercise and Caloric Restriction Exert Different Benefits on Metabolism and Mechanical Function of Skeletal Muscle in Aging Condition

Exercise and caloric restriction improve skeletal muscle metabolism. However, the benefits of exercise and caloric restriction on metabolism and mechanical function of skeletal muscle in aging condition have never been compared. Seven-week-old male Wistar rats (n = 24) were divided into 4 groups (n = 6 per group) to receive subcutaneous injection with either 1) normal saline solution as a vehicle for 28 weeks, 2) 150 mg/kg/day of D-galactose [D-gal] for 28 weeks to induce premature aging, 3) D-gal for 28 weeks and exercise for 16 weeks (week 13-28), and 4) D-gal for 28 weeks and 30% caloric restriction for 16 weeks (week 13-28). The 17-month-old male Wistar rats (n = 6) were subcutaneously injected with the vehicle for 28 weeks as the naturally aged control. At the end of week 28, whole-body substrate oxidation during vigorous physical activity, total walking distance, and fitness level were determined. Then, all rats were sacrificed to collect the tibialis anterior muscle for protein expression analyses and mass spectrometry-based metabolomics study. We found that skeletal muscle of D-gal successfully mimicked that of natural aging. Exercise and caloric restriction equally improved whole-body carbohydrate oxidation during vigorous physical activity, myogenesis, and amino acid metabolism in skeletal muscle. However, exercise was superior to caloric restriction in terms of improving fatty acid oxidation, oxidative phosphorylation, and mechanical function of skeletal muscle. Interestingly, caloric restriction decreased oxidative stress, whereas exercise increased oxidative stress in skeletal muscle. These findings suggested that the benefits of exercise and caloric restriction on metabolism and mechanical function of skeletal muscle in aging were different. Hence, either combined exercise and caloric restriction, exercise with antioxidant supplement, or caloric restriction with fatty acid oxidation enhancement is highly recommended. Disclosure C.Thonusin: None. P.Pantiya: None. W.Nawara: None. B.Arunsak: None. S.Sriwichaiin: None. N.Chattipakorn: None. S.C.Chattipakorn: None.

Long-term detraining reverses the improvement of lifelong exercise on skeletal muscle ferroptosis and inflammation in aging rats: fiber-type dependence of the Keap1/Nrf2 pathway.

We investigated the effects of lifelong aerobic exercise and 8months of detraining after 10months of aerobic training on circulation, skeletal muscle oxidative stress, and inflammation in aging rats. Sprague-Dawley rats were randomly assigned to the control (CON), detraining (DET), and lifelong aerobic training (LAT) groups. The DET and LAT groups began aerobic treadmill exercise at the age of 8months and stopped training at the 18th and 26th month, respectively; all rats were sacrificed when aged 26months. Compared with CON, LAT remarkably decreased serum and aged skeletal muscle 4-hydroxynonenal (4-HNE) and 8-hydroxy-2-deoxyguanosine (8-OHdG) levels. Superoxide dismutase 2(SOD2) levels were higher in the LAT group than in the CON group in skeletal muscle. However, DET remarkably decreased SOD2 protein expression and content in the skeletal muscle and increased malondialdehyde (MDA) level compared with LAT. Compared with LAT, DET remarkably downregulated adiponectin and upregulated tumor necrosis factor alpha (TNF-α) expression, while phosphoinositide 3-kinase (PI3K), protein kinase B (AKT), and 70-kDa ribosomal protein S6 kinase (P70S6K) protein expression decreased, and that of FoxO1 and muscle atrophy F-box (MAFbX) proteins increased in the quadriceps femoris. Adiponectin and TNF-α expression in the soleus muscle did not change between groups, whereas that of AKT, mammalian target of rapamycin (mTOR), and P70S6K was lower in the soleus in the DET group than in that in the LAT group. Compared with that in the LAT group, sestrin1 (SES1) and nuclear factor erythroid 2-related factor 2 (Nrf2) protein expression in the DET group was lower, whereas Keap1 mRNA expression was remarkably upregulated in the quadriceps femoris. Interestingly, the protein and mRNA levels of SES1, Nrf2, and Keap1 in soleus muscle did not differ between groups. LAT remarkably upregulated ferritin heavy polypeptide 1(FTH), glutathione peroxidase 4(GPX4), and solute carrier family 7member 11 (SLC7A11) protein expression in the quadriceps femoris and soleus muscles, compared with CON. However, compared with LAT, DET downregulated FTH, GPX4, and SLC7A11 protein expression in the quadriceps femoris and soleus muscles. Long-term detraining during the aging phase reverses the improvement effect of lifelong exercise on oxidative stress, inflammation, ferroptosis, and muscle atrophy in aging skeletal muscle. The quadriceps femoris is more evident than the soleus, which may be related to the different changes in the Keap1/Nrf2 pathway in different skeletal muscles.

The Effect of the Microbiota Metabolite – Butyric Acid on Motor Coordination, Muscle Strength and the Level of Oxidative Stress in Skeletal Muscles in Mice with Dysbiosis

According to modern concepts, the composition and diversity of the intestinal microbiota play an essential role in maintaining immunity, homeostasis, and, in general, the physiological functions of the host organism. Recently the positive role of the microbiota and its metabolites especially short-chain fatty acids, in the metabolism and functional activity of skeletal muscles was reported. The aim of our work was to analyze muscle strength and motor coordination in mice after injection of broad–spectrum antibiotics with simultaneous administration of a microbiota metabolite – one of the representatives of short-chain fatty acids – butyric acid. In addition, we determined the level of malondialdehyde, the concentration of total glutathione and the activity of glutathione peroxidases in the muscles of the hind limbs in mice with administration of antibiotics and butyric acid. The administration of antibiotics to adolescent mice for two weeks induced higher mortality and decrease of weight, and also caused significant changes in motor behavior, including an increase in horizontal motor activity, decrease in vertical motor activity, muscle strength, and motor coordination. A higher level of oxidative stress was found in the muscle tissues of the hind limbs of mice treated with antibiotics. At the same time, oral administration of butyric acid prevented the observed changes and improved not only behavioral disorders, but also partially reduced the level of oxidative stress. In conclusion, metabolite of normal microbiota has a positive effect on the functional and biochemical parameters of skeletal muscles in dysbiosis, which can be used to prevent loss of muscle function in various pathological conditions.