Search Results (1,726)

Muscle fibers exhibit high plasticity: both the fast-twitch fiber type and slow-twitch fiber type can mutually transform under the regulation of phosphorylation. In this study, we characterized the muscle fiber profiles and phosphoproteomes of the m. extensor digitorum longus (EDL) and m. soleus (SOL) in slow-growing Xueshan chickens and fast-growing Ross 308 broilers. Fiber-type distribution was quantified by immunohistochemistry and RT-qPCR of MYH7B, MYH1A and MYH1B. TMT-based phosphoproteomics, combined with bioinformatic analysis, was used to identify differentially expressed phosphopeptides (DEPs) in two comparisons: Ross 308 SOL vs. Ross 308 EDL, and Xueshan EDL vs. Ross 308 EDL. The proportion of type I (slow-twitch) fibers in EDL was significantly higher in Xueshan chickens than in Ross 308 broilers (15.53% vs. 6.14%, p < 0.05), with no significant differences in fiber distribution or diameter between the SOL and EDL in Xueshan chickens (p > 0.05). A total of 3226 phosphopeptides corresponding to 1762 phosphoproteins were identified, with serine as the most abundant phosphorylated amino acid (73.92%). PDHA1, PHKB and PGAM1 were identified as the key DEPs common to both comparison groups. Bioinformatic analyses revealed that reversible site-specific phosphorylation regulates avian muscle fiber-type transformation mainly via the glycolysis/gluconeogenesis pathway. Full article

Skeletal muscle is vital for movement and metabolism, and its dysfunction underpins disorders like muscular dystrophy and sarcopenia, severely impacting life quality. In these diseases, various cell death pathways are pivotal, driving core pathological features such as fiber loss and chronic inflammation. This study reviews the central role of cell death in skeletal muscle diseases, and analyzes its roles and mechanisms in genetic muscle disorders such as Duchenne muscular dystrophy (DMD), glycogen storage diseases (GSD), mitochondrial myopathies, as well as acquired muscle disorders such as idiopathic inflammatory myopathy, sarcopenia, rhabdomyolysis, and myasthenia gravis (MG). We also explore the potential of cell death-related molecules as biomarkers and discuss emerging therapeutic strategies that target these pathways, aiming to provide new insights for diagnosis and treatment. Full article

Peripheral nerve injury is a leading cause of disability, which can result in partial or complete loss of motor, sensory, and autonomic function, and currently, there is no effective treatment for this incapacitating condition. It is important to identify new compounds that enable rapid and complete functional recovery. This study evaluated the effects of isorhamnetin (ISO) on functional rehabilitation in a mouse model of sciatic nerve injury. A total of 30 BALB/c mice, aged 8–10 weeks, were randomly assigned to three groups: sham, control, and treatment (n = 10/group). The mice in the ISO and Ctrl groups were operated on, whilst the animals in the sham group had their sciatic nerves exposed but left intact without crushing. The Ctrl and Sham groups received DMSO and normal saline intraperitoneally in equal volumes. In contrast, the ISO-treated group received ISO (10 mg/kg) dissolved in DMSO intraperitoneally from the day of nerve crush until the end of the study. All groups were fed regular chow and provided with sufficient water throughout the experiment. Behavioural analyses evaluated sensorimotor function recovery. Biochemical and haematological assays quantified oxidative stress markers and total blood count, while morphometric analysis determined structural recovery of muscle fibers. Nerve regeneration was indirectly evaluated by analyzing S100β protein levels and proinflammatory cytokines (IL-6 and TNF-α) expression. In the mouse model, ISO treatment resulted in substantial improvement in sensorimotor function recovery (p < 0.001). A substantial difference (p < 0.001) in blood glucose levels and oxidative stress markers was observed among all groups. The treated group displayed a remarkable improvement in the cross-sectional area of muscle fibers. At the end of the study, it was noted that ISO treatment significantly downregulated the expression of S100β, TNF-α, and IL-6, suggesting a positive impact of ISO on nerve regeneration. These findings indicate that ISO expedites the restoration of sensorimotor function following sciatic nerve injury by modulating S100β and proinflammatory cytokine expression and improving oxidative stress. Full article

Aging is characterized by progressive degeneration of neuromuscular junctions (NMJs), which significantly contributes to muscle weakness and the development of sarcopenia. Photobiomodulation (PBM), a non-invasive therapeutic method based on the use of low-intensity light, has shown promising results in mitigating muscle degeneration in both experimental and clinical studies. The aim of this study was to evaluate the ultrastructural effects of photobiomodulation on neuromuscular junctions and skeletal muscle fibers in the m. vastus lateralis muscle of aged rats using light and transmission electron microscopy. Male Wistar rats (18 months old, body weight 650–800 g, n = 10) were subjected to photobiomodulation of the right m. vastus lateralis muscle (650 nm, 6 J/cm², four consecutive daily sessions of 3 min each). The contralateral left limb served as an untreated control. Muscle samples were analyzed by light and transmission electron microscopy. Histological examination revealed typical age-related changes in control muscles, including variability in muscle fiber diameter, centrally located nuclei, and an increased volume of connective tissue. Ultrastructural analysis confirmed signs of skeletal muscle aging, such as myofibril fragmentation, sarcomere disorganization, lipofuscin accumulation, and tubular aggregate formation. Morphometric analysis of neuromuscular junctions after photobiomodulation showed an increase in the number of active zones on the presynaptic membrane, elongation of the postsynaptic membrane, and a reduction in the width of the synaptic cleft. In addition, mitochondrial hyperplasia was observed in presynaptic terminals, while the total number of synaptic vesicles decreased. These findings indicate a compensatory reorganization of neuromuscular junctions and suggest that photobiomodulation can enhance their functional activity in aged skeletal muscle. Full article

Skeletal muscle activity, such as exercise, enhances mitochondrial function, a process critical for ATP production through oxidative phosphorylation. Mitochondrial dysfunction, often linked to mutations in the chchd10 gene, contributes to the pathogenesis of neurodegenerative and neuromuscular diseases. Although exercise is known to improve mitochondrial performance, its regulatory influence on chchd10 remains poorly defined. In this study, zebrafish (Danio rerio) at three different ages (4, 9, and 15 months) were divided into control and exercise groups, with the latter subjected to a swimming intervention. We observed that exercised male zebrafish exhibited improved muscle morphology across all age groups, marked by increased muscle fiber cross-sectional area and reduced inter-fiber spacing. Transcriptome sequencing via RNA-seq further identified chchd10 as a differentially expressed gene in three age group comparisons. Exercise may be associated with downward regulation of expression of chchd10, which was correlated with increased methylation levels in its promoter region. These results illuminate the epigenetic mechanisms induced by exercise, revealing a novel pathway through which physical activity, potentially via modulation of chchd10, promotes muscle and mitochondrial health. Full article

In this study, we examined whether dietary ADY improves growth, digestibility of feed nutrients, meat quality, and rumen microbial ecology in lambs. This experiment enrolled 90 healthy, similarly weighted (29.0 ± 0.5 kg) four-month-old Duhan lambs, which were randomly and evenly distributed into two treatment groups: a control group fed the basal diet and an ADY group fed the basal diet supplemented with 0.3 g/d per lamb of active dry yeast. The supplementation amount was adjusted weekly according to feed intake to maintain a constant daily dose. The results showed that, compared with the control group, ADY significantly increased the lambs’ average daily gain (ADG) and enhanced the apparent digestibility of neutral detergent fiber (NDF), crude protein (CP) (p < 0.05), and significantly reduced the feed conversion ratio (F/G) (p < 0.05). These improvements were accompanied by a shift in rumen fermentation toward propionate production, evidenced by higher NH₃-N, Total volatile fatty acids (TVFAs) and propionate proportion and a lower acetate proportion and acetate-to-propionate ratio (p < 0.05). ADY also altered the rumen microbiota, increasing Proteobacteria and Succinivibrionaceae_UCG-001 while decreasing norank_o_Clostridia_UCG-014 (p < 0.05). In muscle, ADY significantly increased the proportions of C14:0 and C18:3n-3 (p < 0.05). In addition, the proportion of C13:0, C18:0 and C18:2n-6t were significantly reduced (p < 0.05). In conclusion, dietary supplementation with ADY enhanced rumen fermentation, improved rumen microbial composition, and promoted nutrient utilization in lambs, thereby improving growth performance and meat quality. In addition, certain rumen microbial taxa may be associated with the formation of specific muscle fatty acids. Full article

Skeletal muscle development and physiological homeostasis are profoundly influenced by environmental cues. Among these factors, ambient temperature represents a critical determinant of growth performance and metabolic adaptation in mammals. However, the effects of different ambient temperature ranges on skeletal muscle characteristics and on responses across multiple visceral tissues remain poorly understood. In this study, five ambient temperature conditions (16 °C, 20 °C, 24 °C, 28 °C, and 32 °C) were established to investigate their physiological impacts in a mouse model. Our results demonstrate that ambient temperature markedly influences growth performance and skeletal muscle phenotype. Notably, mice housed at 20 °C showed relatively preserved grip strength and a shift in myofiber cross-sectional area distribution, although these findings did not consistently indicate superior skeletal muscle development across all indices. Further analysis revealed that ambient temperature significantly modulated the expression profiles of myosin heavy chain (MyHC) isoforms in skeletal muscle. Specifically, cold exposure was associated with an upregulation of the slow-twitch-related MyHC I, whereas heat stress correlated with an elevation of the fast-twitch-related MyHC IIb. Functional assessments indicated that exposure to colder or hotter conditions was associated with impaired muscle performance, as reflected by reduced grip strength at 16 °C, 28 °C, and 32 °C, and decreased endurance capacity at 28 °C and 32 °C. Histological analyses of major visceral organs revealed no obvious structural alterations in the heart, liver, spleen, lung, or kidney across temperature conditions. However, exposure to thermal extremes (16 °C and 32 °C) significantly reduced intestinal villus height, suggesting compromised intestinal integrity under temperature stress. Collectively, these findings indicate that ambient temperature is associated with multi-tissue changes in skeletal muscle characteristics, functional performance, and intestinal morphology. This study provides new insights into how environmental temperature modulates tissue adaptation and physiological homeostasis in mammals. Full article

Background/Objective: Delaying muscle fatigue could alleviate economic and food security, and welfare concerns associated with transporting market-weight pigs to harvest. Previous research demonstrates barrow nicotinamide riboside (NR) supplementation at varying doses during the last 10 d of finishing shows to be a countermeasure to muscle fatigue by reducing muscle fiber recruitment and increasing mitochondrial DNA expression in a dose-dependent manner. Therefore, this study aims to determine if a greater NR dose further enhances barrow fatigue resistance and characterize muscle mitochondria content and efficiency. Methods: Barrows (N = 87) were assigned to one of two dietary NR supplementation doses (TRT): 0 (0NR) or 150 (150NR) mg/kg body weigh NR administered during the last 14 d of finishing. Muscle (MUS) biopsies were collected on supplementation d (DAY) 0, 7 and 14 from three hind-leg muscles for NAD+ quantification and mitochondrial DNA expression and efficiency. On days 15 and 16, barrows were subjected to a performance test until they were subjectively exhausted. Electromyography data collection during the performance test were divided into five periods (PER) and included normalized root mean square (nRMS) from the same muscles. Results: There were no three-way interaction for nRMS (p > 0.83), but there were MUS × TRT and PER × TRT interactions (p < 0.05). During performance testing, 150NR had greater nRMS than 0NR in the bicep femoris (BF) and tensor fasciae latae (TFL; p < 0.01), but there were no differences in the semitendinosus (ST; p = 0.77). Treatments did not differ during PER 1 and 2 (p > 0.14) but 150NR had greater nRMS than 0NR during PER 3, 4 and 5 (p < 0.01) across all muscles. There was no three-way interaction for normalized (nNAD+; p = 0.14), but there was a DAY × TRT interaction (p < 0.05). There were no differences between 0NR and 150NR at d 0 (p = 0.95); however, by d 7 and 14, 150NR muscles had greater nNAD+ than 0NR muscles (p < 0.01). There tended to be a three-way interaction for mitochondrial DNA expression (p = 0.09). At supplementation d 14, all 150NR muscles had greater mitochondrial DNA expression and electron transport chain complex I and II activities (p < 0.01). When normalized to citrate synthase activity, electron transport chain complex I and II activity did not differ (p > 0.05). Conclusions: Large-dose NR supplementation appears to support sustained muscle fiber recruitment during prolonged activity and enhance fatigue resilience, primarily through increased NAD+ and mitochondrial biomarkers abundance and not through mitochondrial efficiency. Full article

The diversity of mitochondria ultrastructure in human aging striated muscles is presented in relation to the complexity and variability of the cristae architecture and in relation to the environment of mitochondrial occurrence in the muscle fiber on the example of the orbicularis oculi. Ultrastructure analysis of mitochondria in muscles was performed using a transmission electron microscope. The studies revealed the presence of mitochondria of various sizes and unexpected shapes, and also modifications of the cristae architecture which included the occurrence of different configurations of membranes. In some mitochondria, instead of cristae, crystalline inclusion bodies and granules resembling calcium deposits were found. The range of diversity of the studied morphotypes of mitochondria exceeds the algorithms for the morphology of these organelles presented in the literature to date. This diversity of mitochondria should probably be viewed as a manifestation of evolution from the classical cristae architecture to a wide range of forms of mitochondria corresponding to the current environmental conditions of the muscle fiber. Full article

Compound sugars (Cs) and creatine (Cr) have the potential to enhance exercise endurance; however, the mechanisms underlying their effects and the stability of their formulations still require further investigation. This study investigated the effects of Cs and Cr supplementation on exercise performance in C57BL/6 mice, as well as the processing properties of Cs and Cr powder. The exhaustion time, serum fatigue indices, creatine contents, the morphology of muscle tissue in mice were determined. The results demonstrated that combined supplementation of sugar and creatine (Cs-Cr, Cs 6.2 mg/g + Cr 1.0 mg/g) could significantly increase exhaustion time and forelimb grip strength and reduce the levels of lactate and blood urea nitrogen by 22.3% and 25.86%, respectively. In addition, Cs-Cr supplementation increased muscle mass and muscle fiber density in exercise-trained mice and thus alleviated muscle damage caused by exercise. However, Cs-Cr powder exhibits poor stability during processing. Xanthan gum and locust bean gum (m/m = 6:4) has been demonstrated to increase the stability and viscosity of Cs-Cr beverages. Moreover, the addition of 1.5% CaSiO₃ also reduced the caking of the powder and increased the stability of the product. This study provides a theoretical basis for the application of Cs-Cr in a functional solid beverage. Full article

Meat quality serves as a pivotal determinant of consumer purchasing behavior and of the economic viability of the livestock industry; as such, research into its regulatory mechanisms is of critical significance for the development of modern agriculture. Traditional investigations into meat quality have predominantly centered on sensory and physicochemical assessments of ultimate phenotypic traits, thereby facing inherent limitations in systematically deciphering the intricate molecular regulatory networks underlying meat quality formation. By contrast, an integrated analysis of the transcriptome and metabolome effectively connects the cascade of “gene transcription—metabolic regulation—phenotypic determination,” which has emerged as a core methodological paradigm in contemporary research on the molecular mechanisms governing meat quality. This review systematically delineates the evolutionary trajectory and principal technological frameworks of meat quality evaluation systems, with a focused synthesis of recent advances achieved through combined transcriptomic and metabolomic analyses in the field of meat quality regulation. The scope of this review encompasses core transcriptional regulatory networks associated with meat quality attributes, pivotal metabolic pathways, signal transduction mechanisms, and protein degradation dynamics. Furthermore, the regulatory impacts exerted by genetic variation among breeds, nutritional modulation, rearing environments, and stress responses on meat quality characteristics are comprehensively elucidated. Integrative analysis reveals that combined transcriptome–metabolome approaches transcend the inherent limitations of single-omics investigations, systematically unraveling the hierarchical regulatory mechanisms governing fundamental meat quality traits, such as muscle fiber type differentiation, postmortem glycolytic progression, intramuscular fat deposition, and flavor compound accumulation. Such integrative strategies have facilitated the identification of functional genes and metabolic biomarkers with potential utility for the early prediction of meat quality outcomes. Concurrently, this review acknowledges persistent challenges confronting the field, including the absence of standardized protocols for multi-omics data integration, insufficient functional causal validation, and a discernible disconnect between research discoveries and practical industrial implementation. Building upon this comprehensive assessment, prospective directions for future multi-omics research in meat quality are proposed, accompanied by the formulation of an integrated end-to-end improvement framework spanning fundamental research, technological innovation, and industrial application. Collectively, this review provides a systematic theoretical foundation for the in-depth elucidation of mechanisms that determine meat quality and the precision-oriented regulation of quality-determining traits in livestock production practices, thereby offering substantial scientific guidance for quality improvement initiatives within the animal husbandry sector. Full article

This study investigated the synergistic effects of liquid fermentation of rapeseed meal (RSM) on feed microbiota, growth performance, and muscle development in growing pigs. RSM was fermented using four compound probiotics and eleven enzyme preparations, and microbial changes were analyzed using 16S rRNA sequencing. Seventy-two Duroc × Jingfen White pigs were randomly assigned to three groups: soybean meal (Ctrl), RSM, and fermented RSM (FRSM). FRSM showed higher trichloroacetic acid-soluble protein (TCA-sp) content and significantly lower neutral detergent fiber (NDF), acid detergent fiber (ADF), anti-nutritional factors (ANFs), and toxins (TS) (p < 0.01). Fermentation increased microbial diversity, with higher abundances of Lactobacillus and Pediococcus. Compared with Ctrl and RSM, the feed-to-gain ratio (F/G) decreased in the FRSM group (p < 0.01). FRSM also improved serum antioxidant capacity, enhanced intestinal villus height (VH)and villus height/crypt depth ratio (VH/CD), and upregulated the expression of tight junction proteins (ZO-1, occludin) and the anti-inflammatory factor IL-10 (p < 0.01). FRSM group also increased myofiber diameter and cross-sectional area in the longissimus dorsi and elevated MyoD, MyoG and Myf5 expression (p < 0.01). RNA-seq revealed 2094 differentially expressed genes enriched in metabolic pathways. Overall, FRSM improved growth performance, intestinal health, and muscle development in growing pigs, which may guide the development of protein resource utilization technologies. Full article

Tubular aggregate myopathy (TAM) is a rare inherited muscle disorder characterized by the abnormal accumulation of tubular aggregates (TAs) within skeletal muscle fibers. These aggregates, composed of compacted sarcoplasmic reticulum (SR) tubules, are strongly linked to disturbances in calcium (Ca²⁺) homeostasis. Clinically, TAM manifests with slowly progressive proximal muscle weakness, exercise intolerance, cramps, and myalgia, frequently beginning in childhood and often present with elevated serum creatine kinase levels. These symptoms can also be associated with some additional disorders, such as thrombocytopathy, miosis, hypocalcemia, hyposplenism, and ichthyosis, thereby resulting in a clinical picture that overlaps with symptoms of Stormorken (STRMK) syndrome. Considerable heterogeneity exists in age of onset, severity, and extra-muscular involvement, suggesting that TAM and STRMK represent a continuum rather than distinct entities. Histopathological hallmarks include TAs staining positive for SR proteins and displaying a honeycomb-like ultrastructure, consistent with aberrant SR remodeling. Mutations in genes encoding key regulators of store-operated calcium entry (SOCE), including STIM1 and ORAI1 have been identified as major contributors to TAM and its broader clinical spectrum, which encompasses STRMK syndrome, whereas mutations in CASQ1 and RYR1, have been described in only a minority of patients. Despite advances in delineating the genetic and molecular basis of TAM, key questions remain regarding the mechanisms that drive TAs formation and translate Ca²⁺ dysregulation into muscle dysfunction and multisystem disease. Understanding the molecular mechanisms underlying TAM and STRMK syndrome is crucial for developing targeted therapies. Moreover, further research is needed to elucidate additional pathways involved in disease progression and to refine genotype–phenotype correlations. This review summarizes current knowledge on the genetics, pathophysiology, clinical features, and diagnostic hallmarks of TAM, with particular emphasis on the role of Ca²⁺ homeostasis. Full article

This study evaluated the efficacy of ammonia-nitrogen-reducing biofilms (aquatic nitrifying bacteria biofilm media, a fixed-bed biofilm capable of simultaneous nitrification and denitrification) in mitigating water quality deterioration and transport-induced physiological stress in live-transported Crucian carp (Carassius auratus). In a simulated bag transport system, the application of the biofilm significantly decreased ammonia-nitrogen concentrations through enhanced nitrification, stabilized pH and dissolved oxygen dynamics, and suppressed nitrite accumulation. Correspondingly, biofilm-treated fish exhibited significantly reduced systemic stress responses, as evidenced by reduced serum cortisol, glucose, and lactate dehydrogenase concentrations, along with diminished histopathological changes in gill and liver tissues and preserved muscle fiber integrity. Regarding post-transport muscle quality, biofilm treatment delayed glycogen catabolism and lactate accumulation, maintained elevated muscle pH and water-holding capacity, reduced shear force decline, decelerated ATP hydrolysis and freshness degradation (K-value), and simultaneously suppressed lipid peroxidation and myonuclear apoptosis. These findings demonstrate that ammonia-nitrogen-reducing biofilms represent a viable biotechnological approach for maintaining water quality, mitigating stress-induced physiological disturbances, and preserving flesh quality during live fish transportation. This approach has significant potential for improving post-harvest outcomes in aquaculture logistics. Full article

Different types of skeletal muscle fibers display marked heterogeneity in metabolic, mechanical, and regenerative properties. However, their role in chronic musculoskeletal pain remains insufficiently integrated into clinical models. Chronic pain is associated with altered neuromuscular control, prolonged low-level activation, and reduced recruitment of high-threshold motor units. These factors may promote fiber type-specific remodeling. This narrative review critically synthesizes current evidence on the relationship between musculoskeletal pain and muscle fiber types. The focus was on metabolic vulnerability, mechanical susceptibility, and regenerative capacity. A structured literature search was conducted in PubMed, Scopus, and Web of Science, focused on human studies and key translational models. Chronic musculoskeletal pain is characterized by acquired fiber type-specific adaptations rather than a fixed unfavorable profile. In chronic pain scenarios, Type I fibers present features of chronic overload, including hypertrophy with insufficient capillarization and increased satellite cell activity. Type II fibers exhibit relative disuse, atrophy, and reduced satellite cell content, resembling accelerated muscle aging. Symptom duration, neuromuscular control strategies, and task-specific loading patterns modulate these adaptations, with interindividual variation. Muscle dysfunction in chronic pain reflects maladaptive but potentially reversible neuromuscular and histological plasticity. These findings indicate that rehabilitation strategies should be individualized, involving context-specific exercise strategies to restore muscle structure, function, and regenerative potential in chronic musculoskeletal conditions. Full article