Recovery Of Motor Function In Rats Research Articles

Screening strategy identified idebenone loaded ROS-responsive nano-polyphenolic vesicle for spinal cord injury therapy

Spinal cord injury (SCI) is a severe central nerve diseases which lacks effective of treatment. Oxidative stress is a major pathological factor for SCI. It may induce mitochondrial damage, which further lead to ferroptosis and apoptosis in neural cells during SCI. Thus, targeting oxidative stress may be the key strategy for SCI treatment. In this study, we carried out screening experiment in the natural product library against oxidative stress in neural cells. It was identified that idebenone (IDE) may potently suppress oxidative stress induced cell death in neural cells. Furthermore, we successfully developed a multifunctional nanovesicles, which we named IDE@PPNs, by encapsulating IDE within proanthocyanidin polyphenol nanovesicles (PPNs). IDE@PPNs exhibited lysosomal escape capability and mitochondrial ROS responsiveness; meanwhile, they may suppress ferroptosis and apoptosis in neural cells. In vivo study demonstrated that IDE@PPNs may promote motor function recovery in rats and suppress ferroptosis and apoptosis in neurons. It may also show high biocompatibility in in vivo study. In summary, we fabricated a novel natural product loaded ROS responsive nanovesicles, IDE@PPNs may have the great potential for SCI therapy.

Rehabilitation training enhanced the therapeutic effect of calycosin on neurological function recovery of rats following spinal cord injury

BackgroundCalycosin (CA), a flavonoids component, has demonstrated potential neuroprotection effects by inhibiting oxidative stress in spinal cord injury (SCI) models. This study aims to investigate the impact of combined rehabilitation training (RT) and calycosin therapy on neurological function following SCI, primarily by assessing changes in motor function recovery, neuronal survival, neuronal oxidative stress levels, and neural proliferation, in order to provide novel insights for the treatment of SCI. Materials and MethodsThe SCI model was constructed by compressing the spinal cord using vascular clamps. Calycosin was injected intraperitoneally into the SCI model rats, and a group of 5 rats underwent RT. The motor function of rats after SCI was evaluated using the Basso Beattle Bresnaha (BBB) score and the inclined plate test. Histopathological changes were evaluated by NeuN immunohistochemistry, HE and Nissl staining. Apoptosis was detected by TUNEL staining. The antioxidant effect of combined treatment was assessed by measuring changes in oxidative stress markers after SCI. Western blot analysis was conducted to examine changes in Hsp90-Akt/ASK1-p38 pathway-related proteins. Finally, cell proliferation was detected by BrdU and Ki67 assays. ResultsRT significantly improved the BBB score and angle of incline promoted by calycosin, resulting in enhanced motor function recovery in rats with SCI. Combining rehabilitation training with calycosin has a positive effect on morphological recovery. Similarly, combined RT enhanced the Nissl and NeuN staining signals of spinal cord neurons increased by calycosin, thereby increasing the number of neurons. TUNEL staining results indicated that calycosin treatment reduced the apoptosis signal in SCI, and the addition of RT further reduced the apoptosis. Moreover, RT combined with calycosin reduced oxidative stress by increasing SOD and GSH levels, while decreasing MDA, NO, ROS, and LDH expressions compared to the calycosin alone. RT slightly enhanced the effect of calycosin in activating Hsp90 and Akt and inhibiting the activation of ASK1 and p38, leading to enhanced inhibition of oxidative stress by calycosin. Additionally, the proliferation indexes (Ki67 and BrdU) assays showed that calycosin treatment alone increased both, whereas the combination treatment further promoted cell proliferation. ConclusionOur research findings demonstrate that rehabilitation training enhances the ability of calycosin to reduce oxidative stress, resulting in a decrease in neuronal apoptosis and an increase in proliferation, ultimately promoting neuronal survival.

Mechanism of Valeriana Jatamansi Jones for the treatment of spinal cord injury based on network pharmacology and molecular docking.

Spinal cord injury (SCI) is characterized by high rates of disability and death. Valeriana jatamansi Jones (VJJ), a Chinese herbal medicine, has been identified to improve motor function recovery in rats with SCI. The study aimed to analyze the potential molecular mechanisms of action of VJJ in the treatment of SCI. The main ingredients of VJJ were obtained from the literature and the SwissADME platform was used to screen the active ingredients. The Swiss TargetPrediction platform was used to predict the targets of VJJ, and the targets of SCI were obtained from the GeneCards and OMIM databases. The intersecting genes were considered potential targets of VJJ in SCI. The protein-protein interaction network was constructed using the STRING database and the hub genes of VJJ for SCI treatment were screened according to their degree values. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes enrichment analyses were performed using the Metascape database. Cytoscape software was used to construct the "herb-ingredient-target-pathway" network. Preliminary validation was performed using molecular docking via Auto Dock Vina software. A total of 56 active ingredients of VJJ, mainly iridoids, were identified. There were 1493 GO items (P < .01) and 173 signaling pathways (P < .01) obtained from GO and Kyoto Encyclopedia of Genes and Genomes enrichment, including the phosphoinositide-3-kinase (PI3K)-protein kinase B (Akt) signaling pathway, hypoxia-inducible factor 1 signaling pathway, and tumor necrosis factor signaling pathway. Molecular docking revealed that 12 hub genes enriched in the PI3K/Akt signaling pathway had a high binding affinity for the active ingredient of VJJ. VJJ may exert its therapeutic effects on SCI through the iridoid fraction, acting on signal transducer and activator of transcription 3, CASP3, AKT1, tumor necrosis factor, mammalian target of rapamycin, interleukin 6, and other hub genes, which may be related to the PI3K/Akt signaling pathway.

Coordination function index: A novel indicator for assessing hindlimb locomotor recovery in spinal cord injury rats based on catwalk gait parameters

In preclinical studies of spinal cord injury (SCI), behavioral assessments are crucial for evaluating treatment effectiveness. Commonly used methods include Basso, Beattie, Bresnahan (BBB) score and the Louisville swim scale (LSS), relying on subjective observations. The CatWalk automated gait analysis system is also widely used in SCI studies, providing extensive gait parameters from footprints. However, these parameters are often used independently or combined simply without utilizing the vast amount of data provided by CatWalk. Therefore, it is necessary to develop a novel approach encompassing multiple CatWalk parameters for a comprehensive and objective assessment of locomotor function. In this work, we screened 208 CatWalk XT gait parameters and identified 38 suitable for assessing hindlimb motor function recovery in a rat thoracic contusion SCI model. Exploratory factor analysis was used to reveal structural relationships among these parameters. Weighted scores for Coordination effectively differentiated hindlimb motor function levels, termed as the Coordinated Function Index (CFI). CFI showed high reliability, exhibiting high correlations with BBB scores, LSS, and T2WI lesion area. Finally, we simplified CFI based on factor loadings and correlation analysis, obtaining a streamlined version with reliable assessment efficacy. In conclusion, we developed a systematic assessment indicator utilizing multiple CatWalk parameters to objectively evaluate hindlimb motor function recovery in rats after thoracic contusion SCI.

IKVAV peptide-containing hydrogel decreases fibrous scar after spinal cord injury by inhibiting fibroblast migration and activation

Fibrous scar is one of the major factors that hinder functional recovery in patients with spinal cord injury (SCI). Studies have shown that the laminin α1 peptide chain ile-les-val-ala-Val (IKVAV) promoted axonal growth and motor function recovery in rats after SCI. However, whether IKVAV could ameliorate SCI via reducing the formation of fibrous scar was not clear. A SCI model was constructed by transecting the rat spinal cord with a scalpel and implanting poly (N-propan-2-ylprop-2-enamide) (PNIPAM)-b-poly (AC-PEG-COOH) (PNPP) or PNIPAM-b-poly (AC-PEG-IKVAV) (PNPP-IKVAV) hydrogel. 14 days later hematoxylin-eosin staining and immunohistochemical staining were used to assess the effect of PNPP-IKVAV on scar formation. The effect of PNPP-IKVAV on endoplasmic reticulum (ER) stress was investigated by immunohistochemical staining. NIH-3T3 cells were used for in vitro scratching experiments and a transforming growth factor 1 (TGF-β1) activation model was constructed to assess the role of PNPP-IKVAV. In this study, PNPP-IKVAV inhibited fibroblast migration and suppressed TGF-β1 activation and ER stress (ERS) to reduce the extracellular matrix secretion by fibroblasts.

Evaluation of the effect of pitavastatin on motor deficit and functional recovery in sciatic nerve injury: A CatWalk study.

This study aims to investigate the electrophysiological, scintigraphic, and histopathological effects of pitavastatin and its impact on functional status in rats with sciatic nerve injury. A total of 30 Wistar albino rats were divided into three equal groups including 10 rats in each group: sham group (no injury), control group (nerve injury induced), and pitavastatin group (nerve injury induced and 2 mg/kg of pitavastatin administered orally once a day for 21 days). Before and at the end of intervention, quantitative gait analysis with the CatWalk system and sciatic nerve conduction studies were performed. After the intervention, the gastrocnemius muscle was scintigraphically evaluated, and the sciatic nerve was histopathologically examined. There was no significant difference in the sciatic nerve conduction before the intervention and Day 21 among the groups (p>0.05). According to the quantitative gait analysis, there were significant differences in the control group in terms of the individual, static, dynamic, and coordination parameters (p<0.05). The histopathological examination revealed a significant difference in the total myelinated axon count and mean axon diameter among the groups (p<0.001). Pitavastatin is effective in nerve regeneration and motor function recovery in rats with sciatic nerve injury.

Comparative efficacy of five most common traditional Chinese medicine monomers for promoting recovery of motor function in rats with blunt spinal cord injury: a network meta-analysis.

This research employed a network meta-analysis (NMA) to examine the effectiveness of five traditional Chinese medicine (TCM) monomers for promoting motor function recovery in rats with blunt spinal cord injury (SCI). Wangfang, China National Knowledge Infrastructure, Web of Science, Embase, Chinese Scientific Journal Database, PubMed, and the Chinese Biomedical Literature Databases were searched for retrieving relevant articles published from their inception to December 2022. Two reviewers performed screening of search results, data extraction, and literature quality assessment independently. For this meta-analysis, 59 publications were included. Based on the recovery of motor function at weeks 1, 2, 3, and 4 in NMA, almost all TCM groups had significantly increased positive effects than the negative control animals. In terms of cumulative probability, the tanshinone IIA (TIIA) group ranked first in restoring motor function in the first week after blunt SCI, and the resveratrol (RSV) group ranked first during the last 3 weeks. The NMA revealed that TCM monomers could effectively restore motor function in the rat model of blunt SCI. In rats with blunt SCI, TIIA may be the most effective TCM monomer during the first week, whereas RSV may be the most effective TCM monomer during the last 3 weeks in promoting motor function recovery. For better evidence reliability in preclinical investigations and safer extrapolation of those findings into clinical settings, further research standardizing the implementation and reporting of animal experiments is required. https://inplasy.com/, identifier INPLASY202310070.

Tail nerve electrical stimulation promoted the efficiency of transplanted spinal cord-like tissue as a neuronal relay to repair the motor function of rats with transected spinal cord injury

Following transected spinal cord injury (SCI), there is a critical need to restore nerve conduction at the injury site and activate the silent neural circuits caudal to the injury to promote the recovery of voluntary movement. In this study, we generated a rat model of SCI, constructed neural stem cell (NSC)-derived spinal cord-like tissue (SCLT), and evaluated its ability to replace injured spinal cord and repair nerve conduction in the spinal cord as a neuronal relay. The lumbosacral spinal cord was further activated with tail nerve electrical stimulation (TNES) as a synergistic electrical stimulation to better receive the neural information transmitted by the SCLT. Next, we investigated the neuromodulatory mechanism underlying the action of TNES and its synergism with SCLT in SCI repair. TNES promoted the regeneration and remyelination of axons and increased the proportion of glutamatergic neurons in SCLT to transmit brain-derived neural information more efficiently to the caudal spinal cord. TNES also increased the innervation of motor neurons to hindlimb muscle and improved the microenvironment of muscle tissue, resulting in effective prevention of hindlimb muscle atrophy and enhanced muscle mitochondrial energy metabolism. Tracing of the neural circuits of the sciatic nerve and tail nerve identified the mechanisms responsible for the synergistic effects of SCLT transplantation and TNES in activating central pattern generator (CPG) neural circuits and promoting voluntary motor function recovery in rats. The combination of SCLT and TNES is expected to provide a new breakthrough for patients with SCI to restore voluntary movement and control their muscles.

Mesenchymal stem cells in the treatment of spinal cord injury: Mechanisms, current advances and future challenges.

Spinal cord injury (SCI) has considerable impact on patient physical, mental, and financial health. Secondary SCI is associated with inflammation, vascular destruction, and subsequent permanent damage to the nervous system. Mesenchymal stem cells (MSCs) have anti-inflammatory properties, promoting vascular regeneration and the release neuro-nutrients, and are a promising strategy for the treatment of SCI. Preclinical studies have shown that MSCs promote sensory and motor function recovery in rats. In clinical trials, MSCs have been reported to improve the American Spinal Injury Association (ASIA) sensory and motor scores. However, the effectiveness of MSCs in treating patients with SCI remains controversial. MSCs promote tumorigenesis and ensuring the survival of MSCs in the hostile environment of SCI is challenging. In this article we examine the evidence on the pathophysiological changes occurring after SCI. We then review the underlying mechanisms of MSCs in the treatment of SCI and summarize the potential application of MSCs in clinical practice. Finally, we highlight the challenges surrounding the use of MSCs in the treatment of SCI and discuss future applications.

Effects of Early Weight-Bearing Treadmill Training Combined with Pre-Emptive Analgesia on Femoral Fracture Recovery.

The effect of pre-emptive analgesia plus early weight-bearing treadmill training (EWBTT) on healing and motor function recovery of femoral shaft fracture is not clear. A total of 60 SD male rats were randomly allocated into 4 groups: group A (pre-emptive analgesia with EWBTT), group B (pre-emptive analgesia with delayed weight-bearing treadmill training, DWBTT), group C (pre-emptive analgesia with no weight-bearing), and group D (EWBTT with no pre-emptive analgesia). All rats were molded by internal fixation with Kirschner wire after right femoral shaft fracture. In groups A, B, and C, tramadol was intramuscularly injected 15 minutes before surgery. EWBTT was performed at day 1 postoperatively in groups A and D, and DWBTT was performed at day 14 postoperatively in group B. Oblique plate test was accomplished to assess hindlimb motor function recovery of rats in each group. Status of fracture healing was assessed through digital radiography (DR). Hematoxylin-eosin (HE) staining and immunohistochemistry of bone morphogenetic protein-2 (MBP-2) and vascular endothelial growth factor (VEGF) in callus were performed to explore fracture healing. The expression of BMP-2 and VEGF protein in quadriceps femoris muscle was detected by Western blot technique and mRNA expression of BMP-2 and VEGF in callus ascertained via reverse transcription-polymerase chain reaction (RT-PCR) technique. For oblique plate test, rats in group A outperformed those in groups B and C at all time points after operation. DR image revealed that large numbers of callus growth, blurred fracture line, and obvious continuous callus passing through the fracture line can be found in group A at day 28 postoperatively, which is the best healing status among all groups. HE staining of callus confirmed the optimal effect of healing for rats in group A. VEGF and BMP-2 expression by immunohistochemistry showed a significantly higher positive score for callus in group A while those in group C being the lowest at all time points postoperatively. Significantly higher expression level of VEGF and BMP-2 protein was detected in quadriceps femoris muscle from group A, which exceeded those in all other groups at all time points. RT-PCR testing proved the highest expression of BMP-2 and VEGF mRNA in callus of rats from group A, significantly higher than those of other groups. Both pre-emptive analgesia and EWBTT can effectively invoke the expression of VEGF and BMP-2 and promote recovery of hindlimb locomotor function in rats with femoral fracture, and the combination of them leads to more superior results.

Adipose-derived mesenchymal stem cell exosomes ameliorate spinal cord injury in rats by activating the Nrf2/HO-1 pathway and regulating microglial polarization.

As of now, there are no satisfactory treatments for spinal cord injury (SCI), so new therapeutic approaches are necessary to be explored. Adipose-derived mesenchymal stem cell exosomes (ADMSC-Exo), delightfully, show remarkable therapeutic effects. Therefore, we try to investigate the effects and mechanisms of ADMSC-Exo on SCI, as well as to provide novel approaches for the treatment of SCI. Adipose-derived mesenchymal stem cells (ADMSC) were isolated from rats and then exosomes (Exo) were extracted from the cells. The extracted Exo were identified by flow cytometry, transmission electron microscopy and nanoparticle tracking analysis (NTA). Then, the SCI rat model was established by the spinal cord impactor and injected with 200 µl PBS or Exo into their tail veins at 30 min, 24 h, and 48 h after surgery. The rats in the Control group and Exo group only exposed the spine. Motor function recovery was assessed on days 0, 7, 14, 21, and 28; histopathological changes and apoptosis levels in spinal cord tissues were observed by HE staining and TUNEL staining; the levels of inflammatory cytokines TNF-a, IL-6, and MCP-1 in spinal cord tissues were measured by ELISA; the expression levels of iNOS, IL-12, Arg1, and Mrc1 in spinal cord tissues were detected by qRT-PCR; and Nrf2, HO-1, and NQO1 protein expression in spinal cord tissues were detected by Western blot. ADMSC-Exo were successfully isolated and identified. ADMSC-Exo significantly relieved SCI and promoted motor function recovery in SCI rats. Moreover, ADMSC-Exo inhibited the expression of both inflammatory factors in the spinal cord tissues and M1 microglia, promoted the expression of M2 microglia, and activated the Nrf2/HO-1 pathway. Altogether, ADMSC-Exo can not only ameliorate SCI, but also promote the motor function recovery of rats. And the mechanism of ADMSC-Exo improving SCI may be achieved by activating Nrf2/HO-1 pathway and microglial polarization.

Photobiomodulation provides neuroprotection through regulating mitochondrial fission imbalance in the subacute phase of spinal cord injury.

Increasing evidence indicates that mitochondrial fission imbalance plays an important role in delayed neuronal cell death. Our previous study found that photobiomodulation improved the motor function of rats with spinal cord injury. However, the precise mechanism remains unclear. To investigate the effect of photobiomodulation on mitochondrial fission imbalance after spinal cord injury, in this study, we treated rat models of spinal cord injury with 60-minute photobiomodulation (810 nm, 150 mW) every day for 14 consecutive days. Transmission electron microscopy results confirmed the swollen and fragmented alterations of mitochondrial morphology in neurons in acute (1 day) and subacute (7 and 14 days) phases. Photobiomodulation alleviated mitochondrial fission imbalance in spinal cord tissue in the subacute phase, reduced neuronal cell death, and improved rat posterior limb motor function in a time-dependent manner. These findings suggest that photobiomodulation targets neuronal mitochondria, alleviates mitochondrial fission imbalance-induced neuronal apoptosis, and thereby promotes the motor function recovery of rats with spinal cord injury.

Serum response factor promotes axon regeneration following spinal cord transection injury.

Studies have shown that serum response factor is beneficial for axonal regeneration of peripheral nerves. However, its role after central nervous system injury remains unclear. In this study, we established a rat model of T9-T10 spinal cord transection injury. We found that the expression of serum response factor in injured spinal cord gray matter neurons gradually increased with time, reached its peak on the 7th day, and then gradually decreased. To investigate the role of serum response factor, we used lentivirus vectors to overexpress and silence serum response factor in spinal cord tissue. We found that overexpression of serum response factor promoted motor function recovery in rats with spinal cord injury. Qualitative observation of biotinylated dextran amine anterograde tracing showed that overexpression of serum response factor increased nerve fibers in the injured spinal cord. Additionally, transmission electron microscopy showed that axon and myelin sheath morphology was restored. Silencing serum response factor had the opposite effects of overexpression. These findings suggest that serum response factor plays a role in the recovery of motor function after spinal cord injury. The underlying mechanism may be related to the regulation of axonal regeneration.

Astragaloside IV ameliorates spinal cord injury through controlling ferroptosis in H2O2-damaged PC12 cells in vitro.

Spinal cord injury (SCI) is associated with significant paralysis and high fatality. Recent research has revealed that ferroptosis participates in the pathogenesis of SCI. Astragaloside IV (AS-IV), the main active ingredient of the plant Astragalus membranaceus, has been reported to promote motor function recovery in rats with SCI. This study explored the effects of AS-IV in H2O2-treated PC12 pheochromocytoma cells. The optimal concentration and duration of AS-IV treatment in PC12 cells was assessed using the cell counting kit 8 (CCK-8) assay. Subsequently, the SCI cell model was established in PC12 cells using H2O2. The effects of AS-IV, FIN56, and transcription factor EB (TFEB) small interfering (si)RNA on cell viability and apoptosis in the SCI model were determined using the CCK-8 assay and flow cytometry, respectively. Caspase‑3 and lactate dehydrogenase (LDH) levels were measured by colorimetric assay and enzyme-linked immunosorbent assay (ELISA), respectively. Cellular reactive oxygen species (ROS) were detected by flow cytometry combined with dichloro-dihydro-fluorescein diacetate (DCFH-DA) assay. The cellular ultrastructure was analyzed by transmission electron microscopy (TEM). The ferroptosis pathway-related proteins were confirmed using Western blot analysis. TFEB expression was confirmed by Western blot and immunofluorescence. The optimal concentration and duration of AS-IV treatment in PC12 cells was determined to be 1.0 µM and 48 h, respectively. AS-IV markedly accelerated proliferation, suppressed apoptosis, and reduced ROS and LDH accumulation. Furthermore, AS-IV enhanced TFEB expression in H2O2-damaged PC12 cells. The effects of AS-IV on SCI were inhibited by si-TFEB, and this inhibition was further reinforced by the addition of FIN56. The results of this investigation using the SCI cell model suggested that AS-IV alleviated SCI by promoting TFEB expression and subsequently mediating ferroptosis. This may represent a potential clinical treatment for SCI.

Intermittent hypoxia promotes the recovery of motor function in rats with cerebral ischemia by regulating mitochondrial function.

Hypoxia preconditioning is neuroprotective, but the therapeutic effects of intermittent hypoxia were not fully considered. The present study investigated the neuroprotective effect and mechanism of intermittent hypoxia on motor function after cerebral ischemia and explored alternative clinical treatment options. In total, 36 8-week-old male Sprague-Dawley rats were subjected to 60 min of transient middle cerebral artery occlusion (tMCAO) and then randomly divided into a sham-operated group (SHAM), tMCAO-sedentary group (SED), and tMCAO-intermittent hypoxia group (IH). The intervention was performed 1 week after tMCAO and lasted 4 weeks. Rats in the IH group were placed in an animal hypoxic chamber (altitude 5000 m and oxygen concentration of 13%) for 4 h/day and 7 days/week, and rats in the SED group were placed in a normoxic environment for 4 weeks. Body weights, neurological deficit scores, cerebral infarction volume ratios, gait analyses, mitochondrial structure, adenosine triphosphate (ATP) content and AMO-activated protein kinase (AMPK), peroxisome proliferator-activated receptor γ co-activator-1α (PGC-1α), and silencing regulatory protein 3 (Sirt3) expression in the peri-ischemic region brain tissues were detected during the intervention. Compared with the SED group, the body weight of the IH group gradually recovered, and the neurological deficit scores were significantly reduced (P < 0.05). The gait analysis results showed that the pressure of the affected paw and the maximum content area, swing speed, stride length, and other parameters were significantly restored (P < 0.05). The cerebral infarction volume ratio was significantly reduced (P < 0.01). Mitochondrial morphological structure damage in the peri-ischemic region brain tissues recovered, the number was significantly increased (P < 0.05), and the expression of AMPK, PGC-1α, and Sirt3 proteins (P < 0.05), and ATP content were significantly increased (P < 0.05). Intermittent hypoxia may activate the AMPK-PGC-1α-Sirt3 signaling pathway, promote mitochondrial biogenesis, repair mitochondrial ultrastructural damage, and improve mitochondrial function to reduce brain damage and promote motor function recovery in rats with cerebral ischemia.

Effect of Valproic Acid on NLR Family Pyrin Domain Containing 1/3 (NLRP1/3) Inflammasome in Rats with Acute Spinal Cord Injury

Our study assesses valproic acid’s effect on NLRP1/3 inflammasome in rats with acute spinal cord injury (SCI). SD rats were clamped by aneurysm clips to establish SCI model followed by analysis of functional recovery by BBB score, degree of inflammatory infiltration, by H&amp;E staining, NLRP1/NLRP3 and P2X7 level by western blot, IL-1β and IL-18 level by ELISA, blood spinal cord barrier by EVANS blue method. After SCI, the lower limb motor function of rats decreased and recovered after valproic acid treatment (P &lt; 0.05). Inflammatory cell infiltration of SCI group increased and decreased after treatment. After SCI, NLRP1/3 level increased and P2X7 protein level elevated which were reversed after valproic acid treatment (P &lt; 0.05). In rats with SCI, IL-1β level in spinal cord was higher than sham operation and lower after treatment (P &lt; 0.05) without difference of IL-18 between injury group and treatment group (P &gt; 0.05). In addition, fluorescence was higher in injury group than sham operation group and lower in valproic acid injection group than injury group. In conclusion, Valproic acid can promote motor function recovery in rats after SCI and inhibit inflammasome 1 and 3 expression, thereby inhibiting the maturation and release of IL-1β, and reducing P2X7 level after SCI.

Metformin Protects against Spinal Cord Injury and Cell Pyroptosis via AMPK/NLRP3 Inflammasome Pathway.

Spinal cord injury (SCI) is an extreme neurological impairment with few effective drug treatments. Pyroptosis is a recently found and proven type of programmed cell death that is characterized by a reliance on inflammatory caspases and the release of a large number of proinflammatory chemicals. Pyroptosis differs from other cell death mechanisms such as apoptosis and necrosis in terms of morphological traits, incidence, and regulatory mechanism. Pyroptosis is widely involved in the occurrence and development of SCI. In-depth research on pyroptosis will help researchers better understand its involvement in the onset, progression, and prognosis of SCI, as well as provide new therapeutic prevention and treatment options. Herein, we investigated the role of AMPK-mediated activation of the NLRP3 inflammasome in the neuroprotection of MET-regulated pyroptosis. We found that MET treatment reduced NLRP3 inflammasome activation by activating phosphorylated AMPK and reduced proinflammatory cytokine (IL-1β, IL-6, and TNF-α) release. At the same time, MET improved motor function recovery in rats after SCI by reducing motor neuron loss in the anterior horn of the spinal cord. Taken together, our study confirmed that MET inhibits neuronal pyroptosis after SCI via the AMPK/NLRP3 signaling pathway, which is mostly dependent on the AMPK pathway increase, hence decreasing NLRP3 inflammasome activation.

Repair of Spinal Cord Injury by Inhibition of PLK4 Expression Through Local Delivery of siRNA-Loaded Nanoparticles

Polo-like kinase 4 (PLK4) is one of the key regulators of centrosomal replication. However, its role and mechanism in spinal cord injury (SCI) are still unclear. The SCI model on rats was constructed and the expression and localization of PLK4 in the spinal cord are analyzed with Western blot and immunofluorescence, respectively. Then the specific siRNAs were encapsulated in nanoparticles for the inhibition of PLK4 expression. Afterward, the role of PLK4 on astrocytes was investigated by knocking down its expression in the primary astrocytes. Moreover, siRNA-loaded nanoparticles were injected into the injured spinal cord of rats, and the motor function recovery of rats after SCI was assessed using the Basso, Beattie, and Bresnahan (BBB) locomotor scale method. Notably, the siRNA-loaded nanoparticles effectively transfect primary astrocytes and significantly inhibit PLK4 expression, together with the expression of PCNA with significance. After treatment, restoration of the motor function following SCI was significantly improved in the PLK4 knockdown group compared with the control group. Therefore, we speculate that inhibition of Plk4 may inhibit the proliferation of astrocytes and decrease the inflammatory response mediated by astrocytes, so as to promote the functional recovery of SCI. In conclusion, inhibition of PLK4 expression via siRNA-loaded nanoparticles may be a potential treatment for SCI.

Artemisinin Facilitates Motor Function Recovery by Enhancing Motoneuronal Survival and Axonal Remyelination in Rats Following Brachial Plexus Root Avulsion.

Artemisinin (ART), a well-known antimalarial medicine originally isolated from the plant Artemisia annua, exerts neuroprotective effects in the nervous system owing to an antioxidant effect. Here, we determined whether ART is capable of inhibiting the oxidative stress to enhance motoneuronal (MN) survival to promote motor function recovery of rats following brachial plexus root avulsion (BPRA) with reimplantation surgery. Rats following BPRA and reimplantation were subcutaneously injected with 500 μL of PBS or 16 mg/mL ART once daily for 7 days after surgery. Terzis grooming test (TGT), histochemical staining, real-time polymerase chain reaction, and Western blot were conducted to determine the recovery of motor function of the upper limb, the survival rate of MNs, the oxidative stress levels in the ventral horn of the spinal cord, the morphology of abnormal musculocutaneous nerve fibers, the remyelination of axons in musculocutaneous nerves, and the degree of bicep atrophy. ART significantly increased TGT score, improved the survival of MNs, inhibited the oxidative stress, ameliorated the abnormal morphology of fibers in the musculocutaneous nerve, promoted the remyelination of axons, and alleviated muscle atrophy. Take together, ART can improve the survival of MNs and axonal remyelination to promote the motor function recovery via inhibiting oxidative stress, suggesting that ART may represent a new approach to the therapy of spinal root avulsion.

Bone marrow mesenchymal stem cells promote remyelination in spinal cord by driving oligodendrocyte progenitor cell differentiation via TNF\u03b1/RelB-Hes1 pathway: a rat model study of 2,5-hexanedione-induced neurotoxicity

BackgroundN-hexane, with its metabolite 2,5-hexanedine (HD), is an industrial hazardous material. Chronic hexane exposure causes segmental demyelination in the peripheral nerves, and high-dose intoxication may also affect central nervous system. Demyelinating conditions are difficult to treat and stem cell therapy using bone marrow mesenchymal stem cells (BMSCs) is a promising novel strategy. Our previous study found that BMSCs promoted motor function recovery in rats modeling hexane neurotoxicity. This work aimed to explore the underlying mechanisms and focused on the changes in spinal cord.MethodsSprague Dawley rats were intoxicated with HD (400 mg/kg/day, i.p, for 5 weeks). A bolus of BMSCs (5 × 107 cells/kg) was injected via tail vein. Demyelination and remyelination of the spinal cord before and after BMSC treatment were examined microscopically. Cultured oligodendrocyte progenitor cells (OPCs) were incubated with HD ± BMSC-derived conditional medium (BMSC-CM). OPC differentiation was studied by immunostaining and morphometric analysis. The expressional changes of Hes1, a transcription factor negatively regulating OPC-differentiation, were studied. The upstream Notch1 and TNFα/RelB pathways were studied, and some key signaling molecules were measured. The correlation between neurotrophin NGF and TNFα was also investigated. Statistical significance was evaluated using one-way ANOVA and performed using SPSS 13.0.Results The demyelinating damage by HD and remyelination by BMSCs were evidenced by electron microscopy, LFB staining and NG2/MBP immunohistochemistry. In vitro cultured OPCs showed more differentiation after incubation with BMSC-CM. Hes1 expression was found to be significantly increased by HD and decreased by BMSC or BMSC-CM. The change of Hes1 was found, however, independent of Notch1 activation, but dependent on TNFα/RelB signaling. HD was found to increase TNFα, RelB and Hes1 expression, and BMSCs were found to have the opposite effect. Addition of recombinant TNFα to OPCs or RelB overexpression similarly caused upregulation of Hes1 expression. The secretion of NGF by BMSC and activation of NGF receptor was found important for suppression of TNFα production in OPCs.Conclusions Our findings demonstrated that BMSCs promote remyelination in the spinal cord of HD-exposed rats via TNFα/RelB-Hes1 pathway, providing novel insights for evaluating and further exploring the therapeutical effect of BMSCs on demyelinating neurodegenerative disease.