Muscle Injury Research Articles

Efficacy of Resistance Band Training on Shoulder Muscle Strength and Injury Prevention in Volleyball Athletes

Efficacy of Resistance Band Training on Shoulder Muscle Strength and Injury Prevention in Volleyball Athletes

Long-term efficacy of oblique lateral interbody fusion combined with vertebral screw fixation for the treatment of lumbar specific infection

To explore medium and long term efficacy of oblique lateral interbody fusion (OLIF) in treating lumbar specific infection. From October 2017 to January 2021, 24 patients with lumbar specific infection were treated by OLIF combined with vertebral screw internal fixation, including 15 males and 9 females, aged from 27 to 61 years old with an average of (43.0±15.0) years old;the courses of disease ranged from 6 to 24 months with an average of (14.0±7.0) months;7 patients with L2-L3, 12 patients with L3-L4 and 5 patients with L4-L5;19 patients with tuberculosis infection and 5 patients with brucella infection. The amount of intraoperative blood loss, operative time and complications were recorded, and erythrocyte sedimentation rate(ESR), C-reactive protein (CRP), visual analogue scale (VAS), Japanese Orthopaedic Association(JOA) score and American Spinal Injury Association (ASIA) rating were compared before and one month after opertaion. All patients were followed up from 9 to 24 months with an average of (13.0±6.0) months. Operative time was (132.5±21.4) min, and intraoperative blood loss was (227.3±43.1) ml. ESR and CRP were decreased from (82.34±18.62) mmol·h-1 and (53.08±21.84) mg·L-1 before operation to (33.52±17.31) mmol·h-1 and (15.48±8.36) mg·L-1 at one month after operation, respectively (P<0.05). VAS was decreased from (7.52±1.36) before opertaion to (1.74±0.87) at one month after operation (P<0.05). JOA was increased from (17.86±3.95) before operation to (24.72±3.19) at one month after operation (P<0.05). Four patients had neurological symptoms before operation, and were classified to grade D according to ASIA classification, who were recovered to grade E at 1 month after operation. One patient was suffered from psoas major muscle injury after operation, and returned to normal at 3 weeks. One patient was suffered from abdominal distension and difficulty in defecation, and relieved after gastrointestinal decompression and enema. No complications such as abdominal organ injury and poor wound healing occurred in all patients. OLIF combined with vertebral screw internal fixation is a new minimally invasive surgical method for the treatment of lumbar specific infection, especially the lesion located on the middle lumbar vertebra. It has advantages of less trauma, short operation time, less blood loss, convenient operation, complete removal of the lesion, safety and effectiveness, and has good medium-and long-term efficacy for lumbar specific infection.

Potential financial loss and risk factors for hamstring muscle injuries in elite male Brazilian soccer players: a season-long prospective cohort pilot study.

The aim of this pilot study was to analyze the potential financial loss and a range of potential risk factors for hamstring muscle injuries in elite Brazilian soccer. Thirty-four male players (age: 25 ± 6 years; stature: 180 ± 8 cm; body mass: 78 ± 9 kg; minutes played in matches: 2243 ± 1423 min) from an elite professional soccer club were monitored during a 12-month season. Muscle injury was identified by magnetic resonance imaging and the severity was defined according to the number of days away: minimal (1-3 days), mild (4-7 days), moderate (8-28 days), severe (>28 days). Potential financial loss due to the team's under achievements was determined. Dorsiflexion range of motion, eccentric knee flexor strength and isokinetic tests were performed during the pre-season. Association between dependent variables and the occurrence of injury was evaluated. Nine hamstring muscle injuries with moderate severity were found in 8 athletes. Recovery time was 22 days off the field on average. Potential financial loss was $-43.2 million USD and earnings on merit money was 21%. Previous injury, increased flexor deficit 60° /sec and increased flexor fatigue index 300°/sec were all associated with a greater chance of hamstring muscle injury. Ankle dorsiflexion range of motion was significantly lower in the injured group (35.6 ± 3° vs. 39.1 ± 4.9°; p = 0.017, effect size = -0.74). High financial burden was found in elite Brazilian soccer during one full season. Injured athletes had high hamstring fatigue index, knee flexor strength deficit, ankle range of motion restriction and previous hamstring muscle injury when compared to non-injured athletes. Therefore, preventive approaches in professional soccer players with previous hamstring injuries should be a priority.

Spatiotemporal Analysis of Mesenchymal Stem Cells Fate Determination by Inflammatory Niche Following Soft Tissue Injury at a Single‐Cell Level

AbstractHeterotopic ossification (HO), often arising in response to traumatic challenges, results from the aberrant osteochondral differentiation of mesenchymal stem cells (MSCs). Nevertheless, the impact of trauma‐induced inflammatory exposure on MSC fate determination remains ambiguous. In this study, the cellular diversity within inflammatory lesions is elucidated, comprising MSCs and several innate and adaptive immune cells. It is observed that quiescent MSCs transition into cycling MSCs, subsequently giving rise to chondrogenic (cMSC) and/or osteogenic (oMSC) lineages within the inflammatory microenvironment following muscle or tendon injuries, as revealed through single‐cell RNA sequencing (scRNA‐seq), spatial transcriptome and lineage tracing analysis. Moreover, these investigations demonstrate that neutrophils and natural killer (NK) cells enhance transition of quiescent MSCs into cycling MSCs, which is also controlled by M1 macrophages, a subpopulation of macrophages can also stimulate cMSC and oMSC production from cycling MSCs. Additionally, M2 macrophages, CD4+ and CD8+ T lymphocytes are found to promote chondrogenesis. Further analysis demonstrates that immune cells promotes the activation of signaling transducers and activators of transcription (STAT) pathway and phosphoinositide 3 (PI3K)/protein kinase B (AKT) pathway in MSC proliferation and osteochondral progenitors’ production, respectively. These findings highlight the dynamics of MSC fate within the inflammatory lesion and unveil the molecular landscape of osteoimmunological interactions, which holds promise for advancing HO treatment.

McArdle's Disease: A Differential Diagnosis of Metabolic Myopathies.

McArdle's disease, also known as glycogen storage disease type V or McArdle syndrome, is a pure muscle myopathy with an autosomal recessive inheritance pattern. It is caused by mutations in the gene that encodes muscle phosphorylase. Symptoms typically begin in late adolescence or early adulthood, presenting as exercise intolerance. This review focuses on the diagnosis of McArdle's disease, initially manifesting as a clinical picture of rhabdomyolysis in an 18-year-old male patient with a history of minor thalassemia who had been followed in pediatric consultation since age three for failure to thrive. After excluding common causes such as alcohol consumption, drug use, traumatic muscle compression, and other conditions, the diagnosis of McArdle's disease was considered. The diagnosis was supported by laboratory tests showing myoglobinuria and elevated creatine kinase levels, as well as the absence of increased serum lactate following ischemic exercise. Genetic testing confirmed the presence of mutations in the PYGM gene, corroborating the diagnosis. Treatment includes administering a diet rich in slow-absorbing carbohydrates, regular low-intensity physical exercise, and, in some cases, supplementation with vitamin B6 and creatine. The prognosis is generally favorable with proper disease management, although vigorous exercise should be avoided to prevent complications such as severe muscle injury and rhabdomyolysis. Although McArdle's disease is a rare condition, it is likely underdiagnosed. Ideally, it should be considered in the differential diagnosis of rhabdomyolysis in all patients with symptoms of exercise intolerance and/or recurrent myoglobinuria.

Effects of intermittent exposure to hypobaric hypoxia and cold on skeletal muscle regeneration: Mitochondrial dynamics, protein oxidation and turnover

Muscle injuries and the subsequent regeneration events compromise muscle homeostasis at morphological, functional and molecular levels. Among the molecular alterations, those derived from the mitochondrial function are especially relevant. We analysed the mitochondrial dynamics, the redox balance, the protein oxidation and the main protein repairing mechanisms after 9 days of injury in the rat gastrocnemius muscle. During the recovery rats were exposed to intermittent cold exposure (ICE), intermittent hypobaric hypoxia (IHH), and both simultaneous combined stimuli. Non-injured contralateral legs were also analysed to evaluate the specific effects of the three environmental exposures. Our results showed that ICE enhanced mitochondrial adaptation by improving the electron transport chain efficiency during muscle recovery, decreased the expression of regulatory subunit of proteasome and accumulated oxidized proteins. Exposure to IHH did not show mitochondrial compensation or increased protein turnover mechanisms; however, no accumulation of oxidized proteins was observed. Both ICE and IHH, when applied separately, elicited an increased expression of eNOS, which could have played an important role in accelerating muscle recovery. The combined effect of ICE and IHH led to a complex response that could potentially impede optimal mitochondrial function and enhanced the accumulation of protein oxidation. These findings underscore the nuanced role of environmental stressors in the muscle healing process and their implications for optimizing recovery strategies.

Fibroblast activation protein inhibitor positron emission tomography imaging in muscles of patients with idiopathic inflammatory myopathy.

Mesenchymal stromal cells in muscles participate in regeneration following muscle injury. This study explored the potential of [18F]fibroblast activation protein inhibitor (FAPI)-42 positron emission tomography (PET) targeting mesenchymal stromal cells to evaluate disease activity of idiopathic inflammatory myopathy (IIM). Patients with IIM (n = 26) were prospectively included and underwent [18F]FAPI-42 PET/CT and whole-body MRI between January 2023 and July 2023. Patients with malignancies were retrospectively included in the control group and only underwent [18F]FAPI-42 PET/CT (n = 28). [18F]FAPI-42 PET/CT images were evaluated using for avid-FAPI uptake and the target-to-background ratio (TBR). Whole-body MRI was evaluated for oedema, fatty infiltration, and atrophy in 42 muscles in the IIM group. The global FAPI- and MRI-derived parameters were calculated for each. . Clinical assessment of disease activity and muscle strength were collected. Patients with IIM had significantly higher global FAPI-avid muscle ratios (0.68 [interquartile range (IQR): 0.45, 0.79] vs 0.06 [IQR: 0, 0.11], p< 0.001) and global muscle TBR (2.26 [IQR: 1.71, 2.75] vs 1.23 [IQR: 1.02, 1.52], p< 0.001) compared with controls. In the IIM group, the median TBR was higher in muscles with oedema than in those without (2.44 [IQR: 1.46, 3.27] vs 1.31 [IQR: 0.95, 1.99], p< 0.001). Global FAPI-avid muscle ratios significantly correlated with global oedema score (r = 0.833), muscle strength (r=-0.649), serum creatine kinase (r = 0.456), and disease activity index (r = 0.495-0.621). Increased [18F]FAPI-42 uptake was associated with muscle oedema in IIM. FAPI-derived parameters correlated with IIM disease activity. [18F]FAPI-42 is a promising PET tracer for evaluating IIM disease activity.

Dietary supplementation with N-acetylcysteine confers a protective effect on muscle and liver in lipopolysaccharide-challenged piglets.

N-acetylcysteine (NAC) is a well-established antioxidant that offers exciting opportunities for intestinal health in weaned piglets, while the effects of NAC on muscle and liver has not been fully characterized. Therefore, the present study was performed to investigate the effects of dietary supplementation with NAC on muscle and liver in weaned piglets challenged with lipopolysaccharide (LPS). Twenty-four piglets (24-day-old) were randomly assigned to three treatment groups, the piglets in the control (CTR) and LPS- challenged (LPS) groups were fed the basal diet and those in the LPS+ NAC group was fed the basal diet supplemented with 500 mg/kg NAC. The animal trial lasted for 21 days. At the end of the trial, piglets in the LPS and LPS+ NAC groups were injected intraperitoneally with LPS (100 μg/kg body weight) and piglets in the CTR group were administrated with an equal volume of normal saline. 3 h later, the blood was collected and tissue samples were obtained after 6 h of LPS or normal saline treatment. The results showed that the level of IL-1β, and the mRNA levels of C-X-C motif chemokine receptor 3 (CXCR3) and interferon-γ (IFN-γ) in the liver were up-regulated, and the mRNA levels of insulin-like growth factor 1 (IGF-1), total glutathione (T-GSH), and the ratio of total protein to DNA in the liver were decreased under LPS challenge (P < 0.05). At the same time, LPS increased the level of H2O2 and decreased the content of T-GSH and DNA in the longissimus dorsi and gastrocnemius muscles (P < 0.05). In addition, the percentage of monocytes and the level of epidermal growth factor (EGF) were down-regulated in the LPS treatment (P < 0.05). Interestingly, dietary NAC supplementation reversed the above changes induced by LPS (P < 0.05). Furthermore, NAC might alleviate the muscle and liver injury in LPS-challenged piglets by regulating the expression of genes related to the type I interferon signaling pathway, as well as hypoxia inducible factor 1 (HIF1) and nuclear factor erythroid-2 related factor 2 (Nrf-2). Our findings suggested that dietary supplementation with NAC could benefit the health of muscle and liver in LPS-challenged weaned piglets.

Adenosine A2B receptor activation regulates the balance between T helper 17 cells and regulatory T cells, and inhibits regulatory T cells exhaustion in experimental autoimmune myositis.

Idiopathic inflammatory myopathy (IIM) is a systemic autoimmune disease characterized by skeletal muscle involvement. This study aimed to investigate the role of adenosine receptor signalling pathways in the development of experimental autoimmune myositis (EAM). An ecto-5'-nucleotidase (CD73) inhibitor, adenosine receptor agonists, a hypoxia-inducible factor-1α (HIF-1α) inhibitor or a vehicle were administered to control and EAM mice. Murine splenic CD4+ or regulatory T cells (Tregs) were isolated using magnetic beads and subsequently stimulated with an adenosine A2B receptor agonist, a HIF-1α inhibitor, or vehicle in vitro. In cross-sectional studies, we collected 64 serum samples (69% female, 49±9years), 63 peripheral blood samples (70% female, 50±11years), and 34 skeletal muscle samples (71% female, 63±6years) from patients with IIM. Additionally, 35 serum samples and 30 peripheral blood samples were obtained from age- and sex-matched healthy controls, and six quadriceps muscle samples were collected from patients with osteoarthritis to serve as the normal group. Patients with IIM exhibited increased CD73 [dermatomyositis (DM), polymyositis (PM): P<0.01; immune-mediated necrotizing myopathy (IMNM): P<0.0001] and adenosine deaminase (ADA) expression (DM: P<0.001; PM, IMNM: P<0.0001) in the skeletal muscles, and serum ADA levels [56.7 (95% CI: 53.7, 58.7) vs. 198.8 (95% CI: 186.2, 237.3) ng/μL, P<0.0001]. Intervention with a CD73 inhibitor exacerbated (P=0.0461), whereas adenosine receptor agonists (A1: P=0.0009; A2B: P<0.0001; A3: P=0.0001) and the HIF-1α inhibitor (P=0.0044) alleviated skeletal muscle injury in EAM mice. Elevated expression of programmed cell death protein-1 (PD1: P=0.0023) and T-cell immunoglobulin and mucin-domain containing-3 (TIM3: P<0.0001) in skeletal muscles of patients with IIM were correlated with creatine kinase levels (PD1, r=0.7072, P<0.0001; TIM3, r=0.4808, P=0.0046). PD1+CD4+ (r=0.3243, P=0.0115) and PD1+CD8+ (r=0.3959, P=0.0017) T cells were correlated with Myositis Disease Activity Assessment Visual Analogue Scale scores (muscle) in IIM. The exhausted Tregs were identified in the skeletal muscles of patients with IIM. Activation of the A2B adenosine receptor downregulated HIF-1α (protein or mRNA level, P<0.01), resulting in decreased T helper cell 17 (Th17) (13.58% vs. 5.43%, P=0.0201) and phosphorylated-signal transducer and activator of transcription 3 (p-STAT3)+ Th17 (16.32% vs. 6.73%, P=0.0029), decreased exhausted Tregs (PD1+ Tregs: 53.55% vs. 40.28%, P=0.0005; TIM3+ Tregs: 3.93% vs. 3.11%, P=0.0029), and increased Tregs (0.45% vs. 2.89%, P=0.0006) in EAM mice. The exhausted T cells may be pathogenic in IIM,andthe activation of adenosine A2B receptor signalling pathway can regulate Th17/Treg balance and inhibit Tregsexhaustion, thereby slowing EAM disease progression.

Mesenchymal Stromal Cell Transplantation Ameliorates Fibrosis and microRNA Dysregulation in Skeletal Muscle Ischaemia.

Peripheral arterial disease (PAD) is associated with lower-extremity muscle wasting. Hallmark features of PAD-associated skeletal muscle pathology include loss of skeletal muscle mass, reduced strength and physical performance, increased inflammation, fibrosis, and adipocyte infiltration. At the molecular level, skeletal muscle ischaemia has also been associated with gene and microRNA (miRNA) dysregulation. Mesenchymal stromal cells (MSCs) have been shown to enhance muscle regeneration and improve muscle function in various skeletal muscle injuries. This study aimed to evaluate the effects of intramuscularly delivered human umbilical cord-derived MSCs (hUC-MSCs) on skeletal muscle ischaemia. Herein, we report an hUC-MSC-mediated amelioration of ischaemia-induced skeletal muscle atrophy and function via enhancement of myofibre regeneration, reduction of tissue inflammation, adipocyte accumulation, and tissue fibrosis. These changes were observed in the absence of cell-mediated enhancement of blood flow recovery as measured by Laser Doppler imaging. Furthermore, reduced tissue fibrosis in the hUC-MSC-treated group was associated with upregulation of miR-1, miR-133a, and miR-29b and downregulation of targeted pro-fibrotic genes such as Col1a1 and Fn1. Our results support the use of hUC-MSCs as a novel approach to reduce fibrosis and promote skeletal muscle regeneration after ischaemic injury in patients with PAD.

Injection therapy in professional footballers.

Injection therapy offers a minimally invasive approach for symptomatic relief that allows concurrent training, limiting time loss and providing a faster recovery. However, there is a lack of scientific evidence to support it, and there are controversies about its use. The present narrative review aims to present the available scientific literature on injection therapies in professional footballers (PF), highlighting the advantages and disadvantages of its use in the most common injuries. The authors searched and reviewed contemporary literature on injection therapies in PF in electronic databases, summarizing them in a narrative review. Injection therapies such as hyaluronic acid and PRP have shown an adequate safety profile that allows their use. Current evidence suggests that hyaluronic acid injections are a valid option for managing symptomatic cartilage injuries. At the same time, PRP injections have failed to prove beneficial in treating muscle injuries and should be avoided until further evidence proves the opposite. Yet, PRP may have potential use in partial ACL injuries, anterior inferior tibiofibular ligament injuries (ankle syndesmosis), and fifth metatarsal fractures and needs further study. Due to the long-term health repercussions, other injection therapies should be preferred over corticosteroids in PF. There is a paucity of evidence on the use and benefits of injection therapies in PF despite its extensive use among physicians. Viscosupplementation may have a role in improving symptomatic cartilage injuries. In contrast, PRP injection therapy needs further high-quality clinical trials to assess its role in PF sports injuries.

Efficacy of Fat and Perifascial Areolar Tissue Graft in Refractory Esotropia: A Case Report

Purpose: This case report presents a novel approach for the management of refractory esotropia using adhesiolysis and fat and perifascial areolar tissue (PAT) transplantation.Case summary: A 62-year-old male presented with left eye strabismus fixus following iatrogenic medial rectus (MR) muscle injury and medial orbital wall fracture during endoscopic sinus surgery. One month later, he underwent MR laceration repair and orbital wall reconstruction. Despite three subsequent interventions for exotropia and its subsequent conversion to esotropia, the left eye esodeviation progressively worsened, culminating in strabismus fixus. Initial examination revealed significant left eye esotropia with fixed gaze and 5-mm enophthalmos. Surgery included implant removal, adhesiolysis between the eyeball and surrounding tissues, scar and MR recession, and placement of a fat and PAT graft on the medial aspect of the eyeball to prevent postoperative re-adhesion. Three years of follow-up demonstrated sustained orthophoria in primary gaze with improved extraocular muscle function and enophthalmos.Conclusions: Fat and PAT graft has potential in oculoplastics for preventing re-adhesion and augmenting orbital volume in patients with refractory restrictive strabismus due to multiple surgeries.

Transverse small incision intrathecal "loop" minimally invasive suture for treatment of acute Achilles tendon rupture

To evaluate the effectiveness and feasibility of a transverse small incision intrathecal "loop" minimally invasive suture for acute Achilles tendon rupture. The clinical data of 30 patients with acute Achilles tendon rupture treated with transverse small incision intrathecal "loop" minimally invasive suture between January 2022 and October 2023 was retrospectively analyzed. The patients were all male, aged from 29 to 51 years, with an average of 39.8 years. The cause of injury was acute sports injury, and the time from injury to operation was 1-14 days, with an average of 3.4 days. The operation time, incision length, intraoperative blood loss, intraoperative complications, wound healing, and hospital stay were recorded. Postoperative appearance and function of ankle were evaluated by American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score, Vancouver Scar Scale (VSS) score, and Arner-Lindholm score. The operation time ranged from 30 to 90 minutes, with an average of 54.2 minutes; the incision length ranged from 1.3 to 3.5 cm, with an average of 2.2 cm; the intraoperative blood loss ranged from 5 to 70 mL, with an average of 22.3 mL; and the hospital stay ranged from 2 to 6 days, with an average of 3.7 days. All incisions healed by first intention, and there was no incision infection, poor healing, and deep venous thrombosis. All patients were followed up 5.3-22.0 months (mean, 14.7 months). During the follow-up, all the 30 patients had returned to exercise, and there was no complication such as Achilles tendon re-rupture, postoperative infection, and gastrocnemius muscle injury. At last follow-up, the AOFAS ankle-hindfoot score was 82-100, with an average of 95.1; the VSS score was 1-4, with an average of 2.1; according to the Arner-Lindholm score, 24 cases were rated as excellent and 6 cases as good. Transverse small incision intrathecal "loop" minimally invasive suture for the treatment of acute Achilles tendon rupture has the advantages of simple instrument, convenient operation, small trauma, quick recovery, and satisfactory effectiveness.

Protective Role of Ovothiol-A against Muscle and Kidney Injuries in Obese Rats

Background: Obesity is a serious chronic metabolic disease impairing health damaging many organs such as kidneys and muscles. Ovothiol-A (Ovo-A) has been found to keep the redox balance normal in sea urchins indicating its antioxidant characteristics. Aim: This study aims to investigate the protective effects of Ovo-A on kidneys and muscles in obese rats. objective: Investigation of the protective effect of Ovo-A on kidneys and muscles in obese rats. Methods: In-silco studies were performed on lactate dehydrogenase (LDH) and creatine kinase (CK) with Ovo-A to compute their binding affinities. Obesity was induced by high-fat diet (HFD) for 4 weeks. Wistar rats were used in this study as 6 rats per group as control, HFD, Ovo-A (200 and 400 mg/Kg, p.o) groups. Results: Docking results have revealed that Ovo-A has affinities to bind to LDH (-8.5 kcal/mol) and CK (-17.7 kcal/mol). Ovo-A reduced the levels of uric acid, urea, creatinine, LDH, CK, malondialdehyde (MDA), and nitric oxide (NO), while increasing the levels of glutathione (GSH), catalase (CAT), and glutathione-S-transferase (GST). Histopathological investigations have revealed that Ovo-A restored the renal and muscular structure. Conclusion: The current study showed that Ovo-A has a protective effect on kidneys and muscles in obese rats. Ovo-A enhances renal and muscular functions by inhibiting LDH and CK activities and improving the antioxidant system. Ovo-A is more effective in the high dose.

Comparison of Different Animal Models in Hindlimb Functional Recovery after Acute Limb Ischemia-Reperfusion Injury.

Acute limb ischemia (ALI) is a sudden lack of blood flow to a limb, primarily caused by arterial embolism and thrombosis. Various experimental animal models, including non-invasive and invasive methods, have been developed and successfully used to induce limb ischemia-reperfusion injuries (L-IRI). However, there is no consensus on the methodologies used in animal models for L-IRI, particularly regarding the assessment of functional recovery. The present study aims to compare different approaches that induce L-IRI and determine the optimal animal model to study functional limb recovery. In this study, we applied a pneumatic cuff as a non-invasive method and ligated the aorta, iliac, or femoral artery as invasive methods to induce L-IRI. We have measured grip strength, motor function, creatine kinase level, inflammatory markers such as nuclear factor NF-κB, interleukin-6 (IL-6), hypoxia markers such as hypoxia-induced factor-1α (HIF-1α), and evaluated the muscle injury with hematoxylin and eosin (H&E) staining in Sprague Dawley rats after inducing L-IRI. The pneumatic pressure cuff method significantly decreased the muscle strength of the rats, causing the loss of ability to hold the grid and inducing significant limb function impairment, while artery ligations did not. We conclude from this study that the tourniquet cuff method could be ideal for studying functional recovery after L-IRI in the rat model.

Menstrual cycle phase differences in myofiber damage and macrophage infiltration following electrical stimulation-induced muscle injury.

The purpose of this study was to examine the effects of menstrual cycle phase on myofiber injury, regenerative events and inflammation after electrical-stimulation (ES) induced myofiber damage. 28 premenopausal women (21.3 ± 2 yrs) were randomized into an early follicular (EF; N=14) or late follicular (LF; N = 14) group. After menstrual cycle tracking and phase confirmation, subjects underwent 200 electrically stimulated eccentric muscle contractions one week after providing a muscle biopsy. 7 days post-ES, subjects provided a final biopsy. Primary outcomes included: serum estradiol, indirect markers of muscle damage, direct indicators of myofiber necrosis and regeneration, satellite cell number, and macrophage infiltration. Women in the LF group had higher serum estradiol (122.1 ± 23.4 vs. 81.7 ± 30.8 pg/ml; P<0.001)compared to the EF group on the day of ES. Whereas the EF group recovered baseline maximal isometric strength by 4 days post-ES, the LF group did not. Only women in the LF group showed significant and consistent evidence of myofiber necrosis and regeneration pre- to post-ES. Despite showing more evidence of myofiber damage, women in the LF group also experienced reduced total and CD206+ macrophage infiltration relative to the EF group. Satellite cell quantity increased significantly post-ES in both groups, with no differences between groups. Collectively, the data suggest that the high estrogen LF phase may be associated with increased susceptibility to myofiber injury while also limiting the subsequent intramuscular inflammatory response.

Effects of radial extracorporeal shock wave with different frequencies on acute skeletal muscle injury in rabbits

To study the efficacy and possible mechanisms of radial extracorporeal shock wave (rESW) with different frequencies for the treatment of acute skeletal muscle injury in rabbits, 48 rabbits of acute injured biceps femoris were randomly divided into 4 groups. Except for the control group, the other groups were treated by rESW with 5 Hz, 10 Hz and 15 Hz, respectively. The injury symptom index scores (ISISs) in the rESW group were significantly lower than those in the control group, with the lowest in the 10 Hz rESW group. Histomorphological features demonstrated a decrease in mononuclear cells and an increase in new myocytes across all groups, with the rESW group showing the most significant changes. The concentrations of PGE2 and IL-1β were significantly lower in all rESW groups by ELISA compared to the control group. Additionally, the 10 Hz group had lower concentrations than the 5 Hz and 15 Hz group. Compared with the control group, MyoD of the rESW groups was significantly increased, and the expression level of the 10 Hz group was higher than that of the other groups. In conclusion, rESW with 5 Hz, 10 Hz and 15 Hz take certain curative effects on acute biceps femoris injury in rabbits, and the 10 Hz rESW takes advantage over 5 Hz and 15 Hz rESW.

Exercise for patients with neuromuscular diseases

Background: Neuromuscular diseases (NMD) vary widely with regard to their onset, progression, and symptoms, which include muscle weakness, sensory loss, pain, fatigue, and joint contractures. Owing to this diversity, creation of a unified exercise therapy approach is challenging.Current Concepts: Exercise recommendations for patients with NMD prioritize maintenance of patients’ current functional status, prevention of further decline, and provision of compensatory training. Conventionally, highintensity exercises are not recommended owing to the risks of overwork weakness and muscle injury. Recent studies indicate that tailored aerobic exercises can improve endurance, cardiovascular function, and overall health without worsening muscle injury. Flexibility exercises are essential to prevent joint contractures. Resistance training should focus on avoidance of high-intensity and eccentric exercises and on maintenance of rather than an increase in muscle strength.Discussion and Conclusion: Evidence regarding the benefits of exercise in patients with NMD is inconsistent. Aerobic exercise is usually safe and may help maintain function and increase maximal oxygen uptake; however, low-intensity exercise is preferred to avoid fatigue and muscle injury. Resistance training may help preserve muscle strength in some patients; however, high-intensity workouts are not should be avoided to mitigate the risk of muscle overload and injury. Tailored exercise programs designed according to disease characteristics are essential.. Further well-designed, large-scale studies are necessary to establish effective and safe exercise guidelines for patients with NMD.

Athlete Health Implications of Match Injuries in Portuguese Rugby Union.

Our aim was to report time-loss match injuries in Portugal's "Divisão de Honra" (Portuguese first tier) in the 2022/2023 season, focusing on injury incidence, burden, anatomical region, and type, to assess their impact on athletes' health and availability to play. A prospective cohort study was conducted monitoring injuries via an online form filled in by each team's medical department, categorizing player position, as well as injury type, location, and severity. Incidence and burden were calculated per 1000 player-match-hours. The overall injury incidence was 54.4 injuries per 1000 player-match-hours (95% CI 30.3-96.2). Forwards had higher injury incidence than backs. Lower limbs were the most affected locations-29 injuries/1000 h of exposure (95% CI 13.7-52.0). Sprain/ligaments injuries were the most common type of injury (14.4 injuries/1000 h (95% CI 3.7-30.0), followed by muscle injuries (8.1 injuries/1000 h 95% CI 4.9-11.5). Injury incidence was higher than what is reported in amateur competitions and lower than for professionals. Injury severity was similar to that in other studies. Our study suggests a lower injury burden than in other semi-professional and elite leagues. These findings highlight the need for targeted injury prevention strategies in the Portuguese Rugby Union to increase athletes' availability by decreasing injury incidence and/or burden. Further research with broader participation and training injury data is needed.

Metformin and intermittent fasting mitigate high fat-fructose diet-induced liver and skeletal muscle injury through upregulation of mitophagy genes in rats

BackgroundHigh fat-fructose diet is a proinflammatory diet that increases risk of hepatocytes and myocytes steatosis and fibrosis. Finding anti-inflammatory strategies to fight these harmful effects is paid attention to nowadays. This study compared the effects of two widely anti-inflammatory interventions—metformin and intermittent fasting on myocytes and hepatocyte injury induced by proinflammatory diet and tracking possible underlying mechanisms. In this work, rats fed high fat-fructose diet were subdivided into untreated group, treated by metformin, and/or intermittent fasting.ResultsMetformin (300 mg/kg/day) and intermittent fasting (3 days/week) specially their combination for 4 weeks showed significant improvement in insulin resistance, lipid profile, antioxidants (p < 0.05), as well as enhanced hepatocytes and myocytes repair and reduced collagen deposition through upregulation of mitophagy-related genes: PINK1, PARKIN, LAMP2, and PPAR-α (p < 0.05).ConclusionsIntermittent fasting has beneficial metabolic and molecular therapeutic effects against proinflammatory diet-induced injury. Their results are like those of metformin sparing its adverse effects. Their combination showed additional effects against diet-induced myocytes and hepatocyte injury by upregulation of mitophagy-related genes without the need of increasing the dose of metformin.Graphic abstract