Skeletal aging is characterized by progressive bone loss and impaired bone formation, largely driven by mitochondrial dysfunction and disturbed proteostasis in osteoblast-lineage cells. Plant-derived extracellular vesicles have emerged as a promising class of natural nanotherapeutics with favorable biocompatibility and bioactivity. However, whether sea buckthorn-derived extracellular vesicles (SAEVs) can alleviate skeletal aging and the underlying molecular mechanisms remain unclear. In this study, we demonstrated that SAEVs significantly ameliorated D-galactose-induced aging-like skeletal phenotypes. Mechanistically, SAEVs restored mitochondrial homeostasis and bioenergetic function in senescent mesenchymal stromal cells (MSCs). Further analyses revealed that SAEVs reduced SIRT3 SUMOylation, which was accompanied by improved mitochondrial proteostasis. As a consequence, mitochondrial respiration and ATP production were markedly improved. These findings suggest that modulation of the SIRT3 SUMOylation axis may contribute to the protective effects of SAEVs. Our findings demonstrate that SAEVs exert protective effects against senescence-associated skeletal phenotypes and interrelated MSC senescence, potentially through modulation of SIRT3 SUMOylation and mitochondrial function. This study highlights the therapeutic potential of plant-derived extracellular vesicles as a natural nanoplatform for the prevention and treatment of age-related skeletal degeneration.

Frozen shoulder (adhesive capsulitis) is characterized by progressive fibrotic remodeling of the shoulder joint capsule. To investigate the cellular programs underlying the fibrotic process, we integrate spatial transcriptomics, pseudotime inference, and in situ validation to comprehensively resolve fibroblast heterogeneity in human shoulder joint capsules. We identify three transcriptionally and spatially distinct fibroblast states: homeostatic, immediate-early gene (IEG)-activated, and pro-fibrotic. Notably, frozen shoulder exhibits a profound loss of homeostatic fibroblasts and a striking expansion of a FOS+JUN+EGR1+ IEG-activated fibroblast subset that is rare in normal capsules. Trajectory analysis positions these cells as a stress-responsive transitional state linking homeostasis to fibrosis. Spatial mapping and immunostaining confirm the widespread emergence of IEG-activated fibroblasts in diseased capsules. Together, our findings identify an IEG-activated fibroblast state associated with fibrotic remodeling in frozen shoulder and highlight fibroblast state plasticity as a key contributor to disease pathogenesis.

OBJECTIVE:To explore the role of bone marrow mesenchymal stem cell-derived exosomes (BMSCs-Exos) in promoting the motility and functional enhancement of tendon-derived stem cells (TDSCs) and assess their potential in tendon regeneration and repair. METHODS:In vitro experiments involved the isolation and characterization of BMSCs-Exos from cultured bone marrow mesenchymal stem cells. The exosomes were analyzed for their size, morphology, and protein content using nanoparticle tracking analysis (NTA) and western blotting for exosomal markers. Tendon stem cell (TDSC) migration was assessed using a scratch assay. For in vivo analysis, a rat tendon injury model was used to evaluate the therapeutic effects of BMSCs-Exos on tendon healing and tissue regeneration. Rats were injected with BMSCs-Exos at varying doses, and the healing process was monitored through histological analysis and assessment of angiogenesis and collagen deposition. RESULTS:The results demonstrated successful extraction of BMSCs-Exosomes, confirmed by positive expression of exosomal markers (CD9, CD63, and ALIX) and the absence of cellular contaminants via western blot and uniform particle size (median 134.8 nm, concentration 8.7 × 1011 particles/mL). Immunofluorescence showed a time-dependent uptake of purified PKH26-labeled Exosomes by TDSCs. While no significant difference in proliferation or survival was observed, Exosomes promoted scratch closure (p < 0.05) and osteogenic differentiation, as evidenced by increased ALP activity, calcium deposition (ARS), and upregulation of Runx-2/COL-1 expression. In vivo, Exosomes promoted collagen synthesis (COL-1) and angiogenesis (CD31), improving tendon structural integrity (H&E staining). CONCLUSION:BMSCs-Exos demonstrate therapeutic potential for tendon repair by orchestrating key regenerative processes, including tendon stem cell motility and differentiation.

Meniscus injuries present dual challenges, including limited regenerative capacity due to avascularity and a persistent inflammatory microenvironment following injury. Herein, we reported a decellularized meniscus extracellular matrix (dmECM) scaffold functionalized with a hyaluronic acid (HA) and celecoxib (CLX) grafted (dmECM-HC) through carbodiimide chemistry. This design integrates acute immunomodulation with long-term regenerative support. The dmECM scaffold recapitulated the ECM architecture of the native meniscus, while the HA-CLX enhanced its elasticity and immunomodulatory capacity. The dmECM-HC scaffold exhibited superior mechanical performance retention during 1000 cyclic compression cycles and demonstrated sustained release of CLX for up to 7 weeks in vitro. It promoted M2 polarization of lipopolysaccharide (LPS)-stimulated macrophages and effectively modulated acute inflammation through Toll-like receptor, tumor necrosis factor (TNF), and Nuclear factor kappa-B (NF-κB) signaling pathways. Together with its robust antioxidant capacity, the dmECM-HC scaffold provided a pro-regenerative microenvironment. Furthermore, it significantly facilitated stem cell recruitment and ECM deposition. In a rabbit meniscus defect model, the dmECM-HC scaffold promoted tissue repair by activating NF-κB and calcium signaling pathways. At 12 weeks, it significantly enhanced tissue maturation and collagen arrangement in the defect area and mitigated cartilage degeneration. This strategy guides meniscus healing with a dual function by modulating the inflammatory environment while providing biomimetic structural support.

The assessment of motor function recovery in spinal cord injury (SCI) mouse models traditionally relies on semi-quantitative methods like the Basso Mouse Scale (BMS), which are prone to inter-observer variability and are labor-intensive. To address these limitations, this study aimed to develop and validate novel, objective kinematic metrics for a more precise and automated evaluation of motor function. Using the DeepLabCut software package to analyze locomotion videos of SCI mice, we applied Permutation Feature Importance (PFI) to identify key joints associated with motor recovery. Based on this data-driven approach, we engineered four new indicators: max horizon-hip-hindpaw angular velocity to quantify hindlimb movement speed and range, average horizon-hindpaw-hindpaw tip angle to assess foot posture (dorsal versus plantar contact), neck swing times to evaluate trunk stability at later recovery stages, and step difference to measure forelimb-hindlimb coordination. Our results demonstrate that these novel metrics exhibit strong correlations with manual BMS scores and capture distinct aspects of motor recovery. Furthermore, integrating these indicators into a Random Forest regression model improved the sensitivity of automatic assessment of BMS compared with models using only previously established metrics. In conclusion, these novel kinematic indicators provide a more objective, sensitive, and efficient framework for assessing motor function in SCI mice, thereby enhancing experimental reproducibility and offering a powerful tool for preclinical research.

Following spinal cord injury (SCI), neuroinflammation driven by lipid-laden macrophage foam cells is a key pathology, yet how these cells manage their lipid homeostasis is unclear. We delineate a neuroprotective axis in which macrophages deploy apolipoprotein E (APOE) to transfer intracellular lipids to neighboring cells, especially fibroblasts. Genetic ablation of Apoe disrupts this intercellular lipid transport, culminating in pathological lipid retention that activates the Hippo signalling cascade and transcriptionally induces complement component C1q. This excess C1q aberrantly tags intact synapses for excessive microglial pruning, leading to significant synaptic loss and impaired locomotor function recovery. Direct blockade of C1q using neutralizing antibodies recapitulated these neuroprotective effects, confirming C1q as the critical mediator. Crucially, macrophage-specific APOE re-expression reverses this entire cascade, preserving synapses and restoring locomotor function (BMS score: 4.81 ± 0.21 (Apoe) vs. 1.75 ± 1.28 (NC); Incline plane: 69.24° ± 2.33° (Apoe) vs. 51.66° ± 5.14° (NC) in Apoe−/− mice). These findings identify the APOE-Hippo-C1q pathway in macrophages as a novel therapeutic target for SCI.

Controversy still exists regarding whether the sinus tarsi approach can effectively manage the Sanders type III fractures. The objective of this retrospective study was to describe and evaluate the clinical applications of the limited sinus tarsi approach and the extended lateral approach for treating Sanders type III calcaneal fractures. Between January 2020 and February 2023, 35 patients with calcaneal fractures (Sanders type III) treated in our trauma center were enrolled in this retrospective study. Surgeries were performed after improvement of soft tissue conditions. Either limited ORIF via sinus tarsi approach (limited sinus tarsi approach group, ST group) or ORIF via extended lateral approach (extended lateral approach group, EL group) was performed on these patients. Clinical evaluation indicators including time to surgery, time for surgery, complications, subtalar joint stiffness, traumatic arthritis, SF-36, VAS, AOFAS score, Böhler’s angle as well as Gissane's angle were recorded and compared between these two groups. The waiting time before surgery in ST group was significantly shorter than that in the EL group. The mean operative time was significantly higher than that in the EL group. No significant difference with respect to the AOFAS score, VAS score and SF-36 score between the groups was manifested. Subtalar stiffness occurred in 3 cases in the ST group while 7 cases in the EL group. 2 cases in EL group and one case in the ST group presented with subtalar traumatic arthritis and the symptoms subsided after treatment. The difference regarding the Böhler angle and Gissane angle between groups were not statistically significant. With the lower incidence of soft tissue complications and subtalar joint stiffness, treatment of calcaneal Sanders III fracture through the sinus tarsal incision can be performed as one of the routine options.

Age-related sarcopenia is a degenerative condition characterized by loss of muscle mass and strength. Satellite cells (SCs), the stem cells of skeletal muscle, decline in number and function with age, contributing to sarcopenia. Enhancing SC function represents a promising therapeutic strategy. Neuromuscular electrical stimulation (NMES) induces passive muscle contraction and improves SC activity, partly through calcium-dependent mechanisms. Calcium signaling is essential not only for excitation-contraction coupling but also for SC proliferation and differentiation. This review summarizes age-related changes in SCs, current sarcopenia treatments, and the therapeutic potential of NMES. We propose a novel combined strategy integrating NMES with calcium signaling modulation to synergistically enhance SC function. This approach offers a promising avenue for treating age-related sarcopenia and warrants further investigation.

Infected wounds remain a significant clinical challenge due to bacterial resistance and impaired healing. Therefore, developing effective antibacterial agents and precise delivery systems is crucial for rapid wound repair. To address this, we constructed zeolitic imidazolate framework-8 (ZIF-8) nanoparticles loaded with the host defense peptide-mimicking glycine-poly(2-oxazoline) (Gly-POX) and incorporated them into methacrylated gelatin (GelMA) to prepare the Gel-P@Z nanocomposite hydrogel. The hydrogel integrates the following core design elements: the pH-responsive degradation of ZIF-8 enables targeted drug release within the infected microenvironment; Gly-POX, mimicking the structure of host defense peptides, exerts membrane-disruptive antibacterial activity against MRSA, which possesses a negatively charged cell membrane, through its positively charged side chains; and the GelMA hydrogel provides a three-dimensional extracellular matrix-like scaffold that supports cell adhesion and proliferation. Gel-P@Z exhibited a slow and sustained release of Gly-POX and achieved >99% antibacterial efficacy against drug-resistant bacteria without toxicity. Moreover, Gel-P@Z promoted macrophage polarization from M1 to M2 phenotype and enhanced efferocytosis, while also facilitating fibroblast migration and inducing contraction in ex vivo fascia explants. In a murine full-thickness MRSA-infected wound model, Gel-P@Z effectively cleared bacteria, modulated the inflammatory microenvironment, and promoted both angiogenesis and collagen deposition. RNA-seq analysis revealed that Gel-P@Z accelerated healing via upregulation of the TGF-β signaling pathway, driving fibroblast-to-myofibroblast transition and promoting tissue fibrosis. This work not only proposes a novel strategy for antibacterial polymer delivery but also offers a promising solution for the management of infected wounds.

Objective:To review recent research progress in the use of auxiliary components of nerve conduits for the treatment of peripheral nerve injuries. Methods:An extensive review of recent domestic and international literature was conducted to evaluate the role of auxiliary components in nerve conduits for peripheral nerve repair, with a focus on their effects and underlying mechanisms. Results:By incorporating auxiliary components such as bioactive molecules, therapeutic cells, and their derivatives, nerve conduits can create a more biomimetic regenerative microenvironment. This is achieved by providing neurotrophic support, modulating the immune microenvironment, improving blood and oxygen supply, and offering directional guidance for nerve regeneration. Consequently, the nerve conduit is transformed from a simple physical scaffold into an active, bio-functional repair system, which enhances the effectiveness for PNI. Conclusion:While nerve conduits augmented with auxiliary components demonstrate improved effectiveness, further advancements are required in drug delivery systems and the integration of cellular components. Moreover, most current studies are based on animal or in vitro experiments. Randomized controlled clinical trials are necessary to validate their clinical effectiveness.

Plant-derived extracellular vesicles (P-EVs) possess remarkable therapeutic potential, yet the regenerative capabilities of sea buckthorn-derived extracellular vesicles (SAEVs) remain underexplored. This study aims to elucidate the osteogenic and bone-healing properties of SAEVs. SAEVs were isolated from sea buckthorn juice via differential centrifugation and characterized using electron microscopy and dynamic light scattering. Bone marrow mesenchymal stromal cells (BMSCs) were treated with SAEVs, and cellular uptake was evaluated through fluorescence microscopy and flow cytometry. In vivo, DiD-labeled SAEVs were orally administered to mice to determine biodistribution using IVIS imaging. A murine femoral defect model was employed to assess the bone regenerative efficacy of SAEVs delivered with or without GelMA hydrogels, analyzed by micro-CT and histological staining. Small RNA sequencing identified SAEV-derived miRNAs, and luciferase reporter assays validated the miRNA-mediated regulation of osteogenic genes. SAEVs efficiently internalized into BMSCs via macropinocytosis, promoting the expression of key osteogenic markers such as Runx2 and osteocalcin. In vivo, SAEV-GelMA hydrogels significantly accelerated bone regeneration in a femoral defect model without inducing adverse hematological effects, affirming the safety of SAEV administration. Mechanistic investigations revealed an enrichment of miRNAs, particularly aau-miR168, which modulates osteogenesis through the aau-miR168/LBH/RUNX2 signaling cascade. This study highlights SAEVs as a transformative and biocompatible therapeutic strategy for fracture healing and osteoporosis management, offering a novel avenue for regenerative medicine.

Partial reprogramming (pulsed expression of reprogramming transcription factors) ameliorates multiple tissue functions in aged mice; however, its impact on peripheral nerve regeneration remains largely unexplored. In this study, the temporal dynamics of Schwann cells following sciatic nerve injury in young and aged rats are systematically examined using single-cell transcriptomics to identify a Runx2+ cell population highly enriched with stress granules as transitional homeostatic cells during Schwann cell differentiation. It is found that pathological accumulation of this cluster during axonal regeneration constitutes a critical contributing factor to impaired neural repair in aging. Intriguingly, partial reprogramming enhances axonal regeneration and attenuates senescence-associated phenotypes and functional deficits in aged Schwann cells, demonstrating that partial reprogramming promotes peripheral nerve regeneration through Schwann cell rejuvenation. Mechanistically, aged Schwann cells exhibit a stress granule homeostatic imbalance, characterized by compromised formation and impaired degradation, which is effectively reset by partial reprogramming. Importantly, this homeostatic resetting ameliorated the pathological aggregation of Runx2+ Schwann cells during nerve repair in aged rats. The findings reveal that dysregulated stress granule homeostasis drives the pathological accumulation of Runx2+ Schwann cells, representing a key mechanism underlying age-related axonal regeneration deficits in peripheral nerve repair. This study establishes that partial reprogramming can restore this critical cellular homeostasis and enhance peripheral nerve regeneration during aging.

After peripheral nerve injury, decreased nerve growth factor (NGF) levels and interrupted bioelectrical signal transmission are key factors leading to delayed nerve regeneration. However, the nerve conduits currently applied in clinical practice fail to simultaneously achieve sustained nutritional support and electrical activity maintenance for the injured microenvironment, limiting their repair effects. Herein, a dual-functional-layer nerve conduit loaded with NGF and exhibiting a high piezoelectric response was fabricated using electrospinning technology. The inner layer was composed of heparin-functionalized chitosan nanofibers loaded with NGF (CPHN), whereas the outer layer was formed from polyvinylidene fluoride (PVDF) nanofibers incorporated with ZnO nanoparticles (PZ). The results showed that the heparin-functionalized chitosan nanofibers significantly enhanced the loading density and stability of NGF. Additionally, PZ nanofibers with 1 wt

Diabetic wound healing, characterized by persistent inflammation, impaired angiogenesis, and dysfunctional cellular responses, remains a major clinical challenge due to its complex pathophysiology. This challenge is most evident in diabetic foot ulcers (DFUs), which carry high risks of infection, recurrence, and amputation, contributing substantially to patient morbidity, mortality, and healthcare costs. Despite multidisciplinary care, debridement, and advanced dressings, healing outcomes are often suboptimal, highlighting an urgent need for deeper pathophysiological insights and more effective therapeutic strategies. This review synthesizes current understanding of DFU pathogenesis, emphasizing how sustained metabolic dysfunction disrupts fibroblast and immune cell function, thereby perpetuating chronic wounds. We also critically examine commonly used animal models and their limitations in replicating the complexity of human DFUs and discuss emerging therapeutic approaches with translational promise. Advancing our understanding of these mechanisms and validating innovative interventions may ultimately reduce DFU-related amputations and mortality, improve healing outcomes, and enhance patient quality of life. This review aims to catalyze future research and therapeutic innovation in diabetic wound care.

Macrophages play a critical role in the repair process following spinal cord injury (SCI), yet the complex mechanisms underlying their functionality remain poorly understood. Using single-cell RNA sequencing, we identified distinct macrophage subpopulations post-SCI, with lipid-laden macrophages, or foam cells, representing the terminal differentiation stage and persisting throughout the chronic phase. Our findings reveal that foam cells display increased expression of C1q, a complement component, which thereby activates microglial phagocytosis of synapses adjacent to the lesion site. This process results in synaptic loss, impairing motor function recovery in SCI mice. Through high-content screening, we identified bazedoxifene as a potential therapeutic candidate that significantly attenuates lipid droplet accumulation within foam cells. This reduction in lipid load diminishes C1q expression by foam cells, thereby mitigating synaptic pathology and promoting synaptic preservation near the injury site. Our findings establish a novel connection between lipid metabolism and C1q-dependent synaptic damage, providing new insights into the mechanisms by which macrophages hinder functional recovery after SCI. Single-cell sequencing uncovers foamy macrophages that fuel C1q-mediated synapse loss after spinal cord injury; bazedoxifene curbs their lipid load, preserving synapses and improving motor recovery.

Background: Inhibiting ROS overproduction is considered a very effective strategy for the treatment of peripheral nerve injuries, and Se has a remarkable antioxidant effect; however, since the difference between the effective concentration of Se and the toxic dose is not large, we synthesized a nanomaterial that can release Se slowly so that it can be used more effectively. Methods: Se@SiO2 2 NPs were synthesized using a mixture of Cu 2-x Se nanocrystals, and the mechanism of action of Se@SiO2 2 NPs was initially explored by performing sequencing, immunofluorescence staining and Western blotting of cellular experiments. The mechanism of action of Se@SiO2 2 NPs was further determined by performing behavioral assays after animal experiments and by sampling the material for histological staining, immunofluorescence staining, and ELISA. The effects, mechanisms and biocompatibility of Se@SiO2 2 NPs for peripheral nerve regeneration were determined. Results: Porous Se@SiO2 2 was successfully synthesized, had good particle properties, and could release Se slowly. CCK-8 experiments revealed that the optimal experimental doses were 100 mu M H2O2 2 O 2 and 200 mu g/mL Se@SiO2, 2 , and RNA-seq revealed that porous Se@SiO2 2 was associated with cell proliferation, apoptosis, and the PI3K/AKT pathway. WB showed that porous Se@SiO2 2 could increase the expression of cell proliferation antigens (PCNA and S100) and antiapoptotic proteins (Bcl-2), decrease the expression of proapoptotic proteins (Bax), and increase the expression of antioxidative stress proteins (Nrf2, HO-1, and SOD2). EdU cell proliferation and ROS fluorescence assays showed that porous Se@SiO2 promoted cell proliferation and reduced ROS levels. The therapeutic effect of LY294002 (a PI3K/AKT pathway inhibitor) was decreased significantly and its effect was lost when it was added simultaneously with porous Se@SiO2. 2 . Animal experiments revealed that the regenerated nerve fiber density, myelin thickness, axon area, gastrocnemius muscle wet-to-weight ratio, myofiber area, sciatic nerve function index (SFI), CMAP, apoptotic cell ratio, and levels of antioxidative stress proteins and anti-inflammatory factors were increased following the administration of porous Se@SiO2. 2 . The levels of oxidative stress proteins and anti-inflammatory factors were significantly greater in the Se@SiO2 2 group than in the PNI group, and the effect of LY294002 was decreased significantly and was lost when it was added simultaneously with porous Se@SiO2. 2 . Conclusion: Se@SiO2 2 NPs are promising, economical and effective Se-releasing nanomaterials that can effectively reduce ROS production, inhibit apoptosis and promote cell proliferation after nerve injury via the PI3K/AKT pathway, ultimately accelerating nerve regeneration. These findings could be used to design new, promising drugs for the treatment of peripheral nerve injury.

Objective:Surgical intervention and fixation is the recognized measurement to treat pubic symphysis diastasis caused by high-energy trauma. The purpose of this retrospective study was to assess the clinical application of modified pedicle screw-rod fixation (modified PSRF) and open reduction plate fixation (ORPF) for treating pubic symphysis diastasis. Methods:The data of this retrospective analysis were collected from 32 patients with pubic symphysis diastasis managed with modified PSRF or ORPF from January 2012 to December 2017, with or without posterior fixation. Indicators of clinical assessments including operating time, intraoperative blood loss, relevant surgical complications as well as follow-up were recorded. Majeed scores were performed for functional evaluation, as well as Matta criteria were applied to evaluate the quality of reduction. Results:The average time from injury to operation was 2.9 days in modified PSRF group and 3.2 days in ORPF group. Significant differences regarding average operation time (41.8 min versus 64.3 min) and average intraoperative blood loss (46.6 ml versus 304.6 ml) were presented between modified PSRF groups and ORPF group. Neither Majeed scores nor Matta evaluation showed a significant difference between two groups. In ORPF group, the incision infection occurred in one patient and two patients developed loosening of screws. In modified PSRF group, loosening of screws was found in one patient during the operative procedure and one patient experienced femoral nerve palsy. Irritation to the lateral femoral cutaneous nerve (LFCN) was detected in two patients in modified PSRF group. Conclusions:Satisfactory clinical outcomes were provided with applications of both fixation methods for treating pubic symphysis diastasis. Modified PSRF, as a minimal invasive technique, could serve as an effective and reasonable option for treating pubic symphysis diastasis.Level of evidence: III: retrospective cohort study.Trial registration: researchregistry3906.

Objective:To investigate the feasibility of selenium-methylselenocysteine (SMC) to promote peripheral nerve regeneration and its mechanism of action.Methods:Rat Schwann cells RSC96 cells were randomly divided into 5 groups, which were group A (without any treatment, control group), group B (adding 100 μmol/L H 2O 2), group C (adding 100 μmol/L H 2O 2+100 μmol/L SMC), group D (adding 100 μmol/L H 2O 2+200 μmol/L SMC), group E (adding 100 μmol/L H 2O 2+400 μmol/L SMC); the effect of SMC on cell proliferation was detected by MTT method, and the level of oxidative stress was detected by immunofluorescence for free radicals [reactive oxygen species (ROS)] after determining the appropriate dose group. Thirty-six 4-week-old male Sprague Dawley rats were randomly divided into 3 groups, namely, the sham operation group (Sham group), the sciatic nerve injury group (PNI group), and the SMC treatment group (SMC group), with 12 rats in each group; the rats in the PNI group were fed with food and water normally after modelling operation, and the rats in the SMC group were added 0.75 mg/kg SMC to the drinking water every day. At 4 weeks after operation, the sciatic nerves of rats in each group were sampled for neuroelectrophysiological detection of highest potential of compound muscle action potential (CMAP). The levels of inflammatory factors [interleukin 17 (IL-17), IL-6, IL-10 and oxidative stress factors catalase (CAT), superoxide dismutase (SOD), and malondialdehyde (MDA)] were detected by ELISA assay. The luxol fast blue (LFB) staining was used to observe the myelin density, fluorescence intensity of glial fibrillary acidic protein (GFAP) and myelin basic protein (MBP) was observed by immunofluorescence staining, and myelin morphology was observed by transmission electron microscopy with measurement of axon diameter. Western blot was used to detect the protein expressions of p38 mitogen-activated protein kinases (p38MAPK), phosphorylated p38MAPK (p-p38MAPK), heme oxygenase 1 (HO-1), and nuclear factor erythroid 2-related factor 2 (Nrf2).Results:MTT assay showed that the addition of SMC significantly promoted the proliferation of RSC96 cells, and the low concentration could achieve an effective effect, so the treatment method of group C was selected for the subsequent experiments; ROS immunofluorescence test showed that group B showed a significant increase in the intensity of ROS fluorescence compared with that of group A, and group C showed a significant decrease in the intensity of ROS fluorescence compared with that of group B ( P<0.05). Neuroelectrophysiological tests showed that the highest potential of CMAP in SMC group was significantly higher than that in PNI and Sham groups ( P<0.05). ELISA assay showed that the levels of IL-6, IL-17, and MDA in PNI group were significantly higher than those in Sham group, and the levels of IL-10, SOD, and CAT were significantly lower; the levels of IL-6, IL-17, and MDA in SMC group were significantly lower than those in PNI group, and the levels of IL-10, SOD, and CAT were significantly higher ( P<0.05). LFB staining and transmission electron microscopy showed that the myelin density and the diameter of axons in the SMC group were significantly higher than those of the PNI group and the Sham group ( P<0.05). Immunofluorescence staining showed that the fluorescence intensity of GFAP and MBP in the SMC group were significantly stronger than those in the PNI group and Sham group ( P<0.05). Western blot showed that the relative expressions of Nrf2 and HO-1 proteins in the SMC group were significantly higher than those in the PNI group and Sham group, and the ratio of p-p38MAPK/p38MAPK proteins was significantly higher in the PNI group than that in the SMC group and Sham group ( P<0.05).Conclusion:SMC may inhibit oxidative stress and inflammation after nerve injury by up-regulating the Nrf2/HO-1 pathway, and then inhibit the phosphorylation of p38MAPK pathway to promote the proliferation of Schwann cells, which ultimately promotes the formation of myelin sheaths and accelerates the regeneration of peripheral nerves.

Background:Inhibiting ROS overproduction is considered a very effective strategy for the treatment of peripheral nerve injuries, and Se has a remarkable antioxidant effect; however, since the difference between the effective concentration of Se and the toxic dose is not large, we synthesized a nanomaterial that can release Se slowly so that it can be used more effectively. Methods:Se@SiO2 NPs were synthesized using a mixture of Cu2-x Se nanocrystals, and the mechanism of action of Se@SiO2 NPs was initially explored by performing sequencing, immunofluorescence staining and Western blotting of cellular experiments. The mechanism of action of Se@SiO2 NPs was further determined by performing behavioral assays after animal experiments and by sampling the material for histological staining, immunofluorescence staining, and ELISA. The effects, mechanisms and biocompatibility of Se@SiO2 NPs for peripheral nerve regeneration were determined. Results:Porous Se@SiO2 was successfully synthesized, had good particle properties, and could release Se slowly. CCK-8 experiments revealed that the optimal experimental doses were 100 μM H2O2 and 200 μg/mL Se@SiO2, and RNA-seq revealed that porous Se@SiO2 was associated with cell proliferation, apoptosis, and the PI3K/AKT pathway. WB showed that porous Se@SiO2 could increase the expression of cell proliferation antigens (PCNA and S100) and antiapoptotic proteins (Bcl-2), decrease the expression of proapoptotic proteins (Bax), and increase the expression of antioxidative stress proteins (Nrf2, HO-1, and SOD2). EdU cell proliferation and ROS fluorescence assays showed that porous Se@SiO2 promoted cell proliferation and reduced ROS levels. The therapeutic effect of LY294002 (a PI3K/AKT pathway inhibitor) was decreased significantly and its effect was lost when it was added simultaneously with porous Se@SiO2. Animal experiments revealed that the regenerated nerve fiber density, myelin thickness, axon area, gastrocnemius muscle wet-to-weight ratio, myofiber area, sciatic nerve function index (SFI), CMAP, apoptotic cell ratio, and levels of antioxidative stress proteins and anti-inflammatory factors were increased following the administration of porous Se@SiO2. The levels of oxidative stress proteins and anti-inflammatory factors were significantly greater in the Se@SiO2 group than in the PNI group, and the effect of LY294002 was decreased significantly and was lost when it was added simultaneously with porous Se@SiO2. Conclusion:Se@SiO2 NPs are promising, economical and effective Se-releasing nanomaterials that can effectively reduce ROS production, inhibit apoptosis and promote cell proliferation after nerve injury via the PI3K/AKT pathway, ultimately accelerating nerve regeneration. These findings could be used to design new, promising drugs for the treatment of peripheral nerve injury.