Spinal Cord Contusion Research Articles

An Injectable Ros-Responsive Hydrogel Containing Cycloastragenol Promotes Functional Recovery in Spinal Cord Contusion Rats by Repairing the Blood-Spinal Cord Barrier

An Injectable Ros-Responsive Hydrogel Containing Cycloastragenol Promotes Functional Recovery in Spinal Cord Contusion Rats by Repairing the Blood-Spinal Cord Barrier

Histomorphometric study of the soleus muscle under conditions of modeling of spinal cord contusion injury: experimental morphological study

Objective. To conduct a morphometric analysis of the soleus muscle of rats after moderate spinal cord contusion injury.Material and Methods. Experiments were performed on female Wistar rats aged 8–12 months, weighing 270–320 g. Animals of the experimental group (n = 25) underwent laminectomy at the T9 level under general anesthesia and modeling of spinal contusion injury of moderate severity. Intact rats constituted the control group (n = 10). Euthanasia was performed on the 5th, 15th, 30th, 60th, 90th, and 180th days of the experiment. Paraffin sections were stained with hematoxylin-eosin and Masson, the diameters of muscle fibers were determined by computer morphometry, and histograms of their distribution were obtained.Results. In the soleus muscle, the signs of reversible reparative processes prevailed in response to neurotrophic damage. It was evidenced by a local increase in the diversity of myocyte diameters and the loss of polygonality of their profiles, focal destruction of muscle fibers, activation of the connective tissue component, disorganization of some intramuscular nerve conductors, and vascular fibrosis of perimysium. Nevertheless, the histostructure of an intact muscle prevailed in the course of the experiment, which was confirmed by the data of morphometric analysis. All histograms of the distribution of the muscle fiber diameters are unimodal with a mode in the range of 30–41 μm. On the 180th day, the maximum myocyte diameters in the histogram of the left limb muscle belonged to the range of 21–30 μm, which was typical for histograms in the intact group.Conclusion. The nature of the plastic reorganization of the soleus muscle when neurotrophic control is impaired indicates compensatory regeneration of muscle tissue by the type of restitution, which opens up the possibility of predicting the rehabilitation period. It is advisable to take this into account when developing medical and social programs and therapeutic measures, where the most important role is played by superficial neuromuscular and functional electrical stimulation.

Critical role of mitochondrial aldehyde dehydrogenase 2 in acrolein sequestering in rat spinal cord injury.

Lipid peroxidation-derived aldehydes, such as acrolein, the most reactive aldehyde, have emerged as key culprits in sustaining post-spinal cord injury (SCI) secondary pathologies leading to functional loss. Strong evidence suggests that mitochondrial aldehyde dehydrogenase-2 (ALDH2), a key oxidoreductase and powerful endogenous anti-aldehyde machinery, is likely important for protecting neurons from aldehydes-mediated degeneration. Using a rat model of spinal cord contusion injury and recently discovered ALDH2 activator (Alda-1), we planned to validate the aldehyde-clearing and neuroprotective role of ALDH2. Over an acute 2 day period post injury, we found that ALDH2 expression was significantly lowered post-SCI, but not so in rats given Alda-1. This lower enzymatic expression may be linked to heightened acrolein-ALDH2 adduction, which was revealed in co-immunoprecipitation experiments. We have also found that administration of Alda-1 to SCI rats significantly lowered acrolein in the spinal cord, and reduced cyst pathology. In addition, Alda-1 treatment also resulted in significant improvement of motor function and attenuated post-SCI mechanical hypersensitivity up to 28 days post-SCI. Finally, ALDH2 was found to play a critical role in in vitro protection of PC12 cells from acrolein exposure. It is expected that the outcome of this study will broaden and enhance anti-aldehyde strategies in combating post-SCI neurodegeneration and potentially bring treatment to millions of SCI victims. All animal work was approved by Purdue Animal Care and Use Committee (approval No. 1111000095) on January 1, 2021.

Limited changes in locomotor recovery and unaffected white matter sparing after spinal cord contusion at different times of day.

The circadian gene expression rhythmicity drives diurnal oscillations of physiological processes that may determine the injury response. While outcomes of various acute injuries are affected by the time of day at which the original insult occurred, such influences on recovery after spinal cord injury (SCI) are unknown. We report that mice receiving moderate, T9 contusive SCI at ZT0 (zeitgeber time 0, time of lights on) and ZT12 (time of lights off) showed similar hindlimb function recovery in the Basso mouse scale (BMS) over a 6 week post-injury period. In an independent study, no significant differences in BMS were observed after SCI at ZT18 vs. ZT6. However, the ladder walking test revealed modestly improved performance for ZT18 vs. ZT6 mice at week 6 after injury. Consistent with those minor effects on functional recovery, terminal histological analysis revealed no significant differences in white matter sparing at the injury epicenter. Likewise, blood-spinal cord barrier disruption and neuroinflammation appeared similar when analyzed at 1 week post injury at ZT6 or ZT18. Therefore, locomotor recovery after thoracic contusive SCI is not substantively modulated by the time of day at which the neurotrauma occurred.

Selective Myostatin Inhibition Spares Sublesional Muscle Mass and Myopenia-Related Dysfunction after Severe Spinal Cord Contusion in Mice.

Clinically relevant myopenia accompanies spinal cord injury (SCI), and compromises function, metabolism, body composition, and health. Myostatin, a transforming growth factor (TGF)β family member, is a key negative regulator of skeletal muscle mass. We investigated inhibition of myostatin signaling using systemic delivery of a highly selective monoclonal antibody - muSRK-015P (40 mg/kg) - that blocks release of active growth factor from the latent form of myostatin. Adult female mice (C57BL/6) were subjected to a severe SCI (65 kdyn) at T9 and were then immediately and 1 week later administered test articles: muSRK-015P (40 mg/kg) or control (vehicle or IgG). A sham control group (laminectomy only) was included. At euthanasia, (2 weeks post-SCI) muSRK-015P preserved whole body lean mass and sublesional gastrocnemius and soleus mass. muSRK-015P-treated mice with SCI also had significantly attenuated myofiber atrophy, lipid infiltration, and loss of slow-oxidative phenotype in soleus muscle. These outcomes were accompanied by significantly improved sublesional motor function and muscle force production at 1 and 2 weeks post-SCI. At 2 weeks post-SCI, lean mass was significantly decreased in SCI-IgG mice, but was not different in SCI-muSRK-015P mice than in sham controls. Total energy expenditure (kCal/day) at 2 weeks post-SCI was lower in SCI-immunoglobulin (Ig)G mice, but not different in SCI-muSRK-015P mice than in sham controls. We conclude that in a randomized, blinded, and controlled study in mice, myostatin inhibition using muSRK-015P had broad effects on physical, metabolic, and functional outcomes when compared with IgG control treated SCI animals. These findings may identify a useful, targeted therapeutic strategy for treating post-SCI myopenia and related sequelae in humans.

Inhibition of TGF-β Signaling Attenuates Disuse-induced Trabecular Bone Loss After Spinal Cord Injury in Male Mice.

Bone loss is one of the most common complications of immobilization after spinal cord injury (SCI). Whether transforming growth factor (TGF)-β signaling plays a role in SCI-induced disuse bone loss has not been determined. Thus, 16-week-old male mice underwent sham or spinal cord contusion injury to cause complete hindlimb paralysis. Five days later, 10 mg/kg/day control (IgG) or anti-TGF-β1,2,3 neutralizing antibody (1D11) was administered twice weekly for 4 weeks. Femurs were examined by micro-computed tomography (micro-CT) scanning and histology. Bone marrow (BM) supernatants were analyzed by enzyme-linked immunosorbent assay for levels of procollagen type 1 intact N-terminal propeptide (P1NP), tartrate-resistant acid phosphatase (TRAcP-5b), receptor activator of nuclear factor-kappa B ligand (RANKL), osteoprotegerin (OPG), and prostaglandin E2 (PGE2). Distal femoral micro-CT analysis showed that SCI-1D11 mice had significantly (P < .05) attenuated loss of trabecular fractional bone volume (123% SCI-1D11 vs 69% SCI-IgG), thickness (98% vs 81%), and connectivity (112% vs 69%) and improved the structure model index (2.1 vs 2.7). Histomorphometry analysis revealed that osteoclast numbers were lower in the SCI-IgG mice than in sham-IgG control. Biochemically, SCI-IgG mice had higher levels of P1NP and PGE2 but similar TRAcP-5b and RANKL/OPG ratio to the sham-IgG group. The SCI-1D11 group exhibited higher levels of P1NP but similar TRAcP-5b, RANKL/OPG ratio, and PGE2 to the sham-1D11 group. Furthermore, 1D11 treatment prevented SCI-induced hyperphosphorylation of tau protein in osteocytes, an event that destabilizes the cytoskeleton. Together, inhibition of TGF-β signaling after SCI protects trabecular bone integrity, likely by balancing bone remodeling, inhibiting PGE2 elevation, and preserving the osteocyte cytoskeleton.

Oscillating field stimulation promotes axon regeneration and locomotor recovery after spinal cord injury.

Oscillating field stimulation (OFS) is a potential method for treating spinal cord injury. Although it has been used in spinal cord injury (SCI) therapy in basic and clinical studies, its underlying mechanism and the correlation between its duration and nerve injury repair remain poorly understood. In this study, we established rat models of spinal cord contusion at T10 and then administered 12 weeks of OFS. The results revealed that effectively promotes the recovery of motor function required continuous OFS for more than 6 weeks. The underlying mechanism may be related to the effects of OFS on promoting axon regeneration, inhibiting astrocyte proliferation, and improving the linear arrangement of astrocytes. This study was approved by the Animal Experiments and Experimental Animal Welfare Committee of Capital Medical University (supplemental approval No. AEEI-2021-204) on July 26, 2021.

Deletion or Inhibition of Astrocytic Transglutaminase 2 Promotes Functional Recovery after Spinal Cord Injury.

Following CNS injury, astrocytes become “reactive” and exhibit pro-regenerative or harmful properties. However, the molecular mechanisms that cause astrocytes to adopt either phenotype are not well understood. Transglutaminase 2 (TG2) plays a key role in regulating the response of astrocytes to insults. Here, we used mice in which TG2 was specifically deleted in astrocytes (Gfap-Cre+/− TG2fl/fl, referred to here as TG2-A-cKO) in a spinal cord contusion injury (SCI) model. Deletion of TG2 from astrocytes resulted in a significant improvement in motor function following SCI. GFAP and NG2 immunoreactivity, as well as number of SOX9 positive cells, were significantly reduced in TG2-A-cKO mice. RNA-seq analysis of spinal cords from TG2-A-cKO and control mice 3 days post-injury identified thirty-seven differentially expressed genes, all of which were increased in TG2-A-cKO mice. Pathway analysis revealed a prevalence for fatty acid metabolism, lipid storage and energy pathways, which play essential roles in neuron–astrocyte metabolic coupling. Excitingly, treatment of wild type mice with the selective TG2 inhibitor VA4 significantly improved functional recovery after SCI, similar to what was observed using the genetic model. These findings indicate the use of TG2 inhibitors as a novel strategy for the treatment of SCI and other CNS injuries.

E3 ubiquitin ligase Triad1 promotes neuronal apoptosis by regulating the p53-caspase3 pathway after spinal cord injury

Purpose Spinal cord injury entails a high risk of major disability, but there is still no effective treatment for this condition. This study aims to explore the neuronal apoptosis after spinal cord injury, which is a key component of secondary injury processes, and plays a critical role in the development of neurological dysfunction. Materials and Methods We studied the expression of the E3 ubiquitin ligase Triad1 and its interaction with p53 in the spinal cord after a spinal cord contusion injury in rats. We explored the regulation function of Triad1 to the neuronal apoptosis through p53-caspase3 pathway in primary neurons. Results Triad1 was markedly up-regulated in the grey matter one day after injury, and the distribution and time point of Triad1 expression correlated with the presence of apoptotic neurons. Co-immunoprecipitation experiments further demonstrated that Triad1 interacted with p53 after spinal cord injury. Specific siRNA and overexpression plasmids for Triad1 were transfected into primary neurons, and the expression of both p53 and caspase3 was altered following the change of Triad1. Conclusions These findings indicate that Triad1 is involved in regulating the pathological process of neuronal apoptosis mediated by p53-caspase3 pathway after spinal cord injury.

Thymus persicus (Ronniger ex Rech. f.) Jalas alleviates nociceptive and neuropathic pain behavior in mice: Multiple mechanisms of action

Ethnopharmacological relevanceThymus persicus (Roniger ex Reach F.) is an Iranian endemic medicinal plant of which essential oil and various products have numerous food and pharmaceutical applications (headache and fever treatments). ObjectiveThis modern research included Swiss mice to investigate the anti-nociceptive and anti-neuropathic effects of Thymus persicus aerial parts essential oil (TPEO). Materials and methodsTo determine TPEO's anti-nociceptive function in the formalin-induced paw licking (FML), researchers looked at the L-arginine/NO/cGMP/KATP channel signaling pathway as well as multiple receptors as with serotonin, morphine, dopamine, and peroxisome proliferator-activated receptors. The CVC or cervical spinal cord contusion exemplar has also been used to induce neuropathic pain. ResultsTPEO (50, 100, and 150 mg/kg) relative to control mice in the phase-II of FML provided strong antinociception (p < 0.05, p < 0.01, p < 0.001, respectively). Furthermore, methylene blue, glibenclamide, Nω-nitro-L-arginine methyl ester, naloxonazine, nor-binaltorphimine, prazosin, yohimbine, and ondansetron pre-treating restored the TPEO anti-nociceptive activity in the FML (phase-II) exemplar (p < 0.05). In phase-II of the FML exemplar, carvacrol (one of the active components of TPEO) also greatly reduced pain (p < 0.001). Likewise, in CVC mice, TPEO altered mechanical allodynia and hyperalgesia. ConclusionIt was attained magnificently that TPEO could exerts antinociceptive effects through the involvement of L-arginine/NO/cGMP/KATP signaling pathway, adrenergic, opioid, and serotonin receptors. Moreover, it is demonstrate that anti-neuropathic activity of TPEO may be mediated by inflammatory function.

A2B5-positive oligodendrocyte precursor cell transplantation improves neurological deficits in rats following spinal cord contusion associated with changes in expression of factors involved in the Notch signaling pathway

BackgroundOligodendrocyte precursor cells (OPCs) are myelinated glial cells of the central nervous system (CNS), able to regenerate oligodendrocytes and myelin. This study aimed to elucidate the effect of A2B5-positive (A2B5+) OPC transplantation in rats with spinal cord contusion (SCC) and to investigate changes in expression of various factors involved in the Notch signaling pathway after OPC transplantation. MethodsOPCs were obtained from induced pluripotent stem cells (iPSCs) originating from mouse embryo fibroblasts (MEFs). After identification of iPSCs and iPSC-derived OPCs, A2B5+ OPCs were transplanted into the injured site of rats with SCC one week after SCC insult. Behavioral tests evaluated motor and sensory function 7 days after OPC transplantation. Real-time quantitative polymerase chain reaction (RT-qPCR) determined the expression of various cytokines related to the Notch signaling pathway after OPC transplantation. ResultsIPSC-derived OPCs were successfully generated from MEFs, as indicated by positive immunostaining of A2B5, PDGFα and NG2. Further differentiation of OPCs was identified by immunostaining of Olig2, Sox10, Nkx2.2, O4, MBP and GFAP. Importantly, myelin formation was significantly enhanced in the SCC+ OPC group and SCI-induced motor and sensory dysfunction was largely alleviated by A2B5+ OPC transplantation. Expression of factors involved in the Notch signaling pathway (Notch-1, Numb, SHARP1 and NEDD4) was significantly increased after OPC transplantation. ConclusionsA2B5+ OPC transplantation attenuates motor and sensory dysfunction in SCC rats by promoting myelin formation, which may be associated with change in expression of factors involved in the Notch signaling pathway.

Extracellular vesicles derived from CD73 modified human umbilical cord mesenchymal stem cells\xa0ameliorate inflammation after spinal cord injury

BackgroundSpinal cord injury (SCI) is an inflammatory condition, and excessive adenosine triphosphate (ATP) is released into the extracellular space, which can be catabolized into adenosine by CD73. Extracellular vesicles have been designed as nano drug carriers in many diseases. However, their impacts on delivery of CD73 after SCI are not yet known. We aimed to construct CD73 modified extracellular vesicles and explore the anti-inflammatory effects after SCI.MethodsCD73 engineered extracellular vesicles (CD73+ hucMSC-EVs) were firstly established, which were derived from human umbilical cord mesenchymal stem cells (hucMSCs) transduced by lentiviral vectors to upregulate the expression of CD73. Effects of CD73+ hucMSC-EVs on hydrolyzing ATP into adenosine were detected. The polarization of M2/M1 was verified by immunofluorescence. Furthermore, A2aR and A2bR inhibitors and A2bR knockdown cells were used to investigate the activated adenosine receptor. Biomarkers of microglia and levels of cAMP/PKA were also detected. Repetitively in vivo study, morphology staining, flow cytometry, cytokine analysis, and ELISA assay, were also applied for verifications.ResultsCD73+ hucMSC-EVs reduced concentration of ATP and promoted the level of adenosine. In vitro experiments, CD73+ hucMSC-EVs increased macrophages/microglia M2:M1 polarization, activated adenosine 2b receptor (A2bR), and then promoted cAMP/PKA signaling pathway. In mice using model of thoracic spinal cord contusion injury, CD73+ hucMSC-EVs improved the functional recovery after SCI through decreasing the content of ATP in cerebrospinal fluid and improving the polarization from M1 to M2 phenotype. Thus, the cascaded pro-inflammatory cytokines were downregulated, such as TNF-α, IL-1β, and IL-6, while the anti-inflammatory cytokines were upregulated, such as IL-10 and IL-4.ConclusionsCD73+ hucMSC-EVs ameliorated inflammation after spinal cord injury by reducing extracellular ATP, promoting A2bR/cAMP/PKA pathway and M2/M1 polarization. CD73+ hucMSC-EVs might be promising nano drugs for clinical application in SCI therapy.Graphical

Role of the Polyol Pathway in Locomotor Recovery and Wallerian Degeneration after Spinal Cord Contusion Injury.

Spinal cord contusion injury leads to Wallerian degeneration of axonal tracts, resulting in irreversible paralysis. Contusion injury causes perfusion loss by thrombosis and vasospasm, resulting in spinal cord ischemia. In several tissues, including heart and brain, ischemia activates polyol pathway enzymes—aldose reductase (AR) and sorbitol dehydrogenase (SDH)—that convert glucose to sorbitol and fructose in reactions, causing oxidative stress and tissue loss. We sought to determine whether activation of this pathway, which has been termed glucotoxicity, contributes to tissue loss after spinal cord contusion injury. We tested individual treatments with AR inhibitors (sorbinil or ARI-809), SDH inhibitor (CP-470711), superoxide dismutase mimetic (tempol), or combined sorbinil and tempol. Each treatment significantly increased locomotor recovery and reduced loss of spinal cord tissue in a standard model of spinal cord contusion in rats. Tissue levels of sorbitol and axonal AR (AKR1B10) expression were increased after contusion injury, consistent with activation of the polyol pathway. Sorbinil treatment inhibited the above changes and also decreased axonal swelling and loss, characteristic of Wallerian degeneration. Treatment with tempol induced recovery of locomotor function that was similar in magnitude, but non-additive to sorbinil, suggesting a shared mechanism of action by reactive oxygen species (ROS). Exogenous induction of hyperglycemia further increased injury-induced axonal swelling, consistent with glucotoxicity. Unexpectedly, contusion increased spinal cord levels of glucose, the primary polyol pathway substrate. These results support roles for spinal glucose elevation and tissue glucotoxicity by the polyol pathway after spinal cord contusion injury that results in ROS-mediated axonal degeneration.

Clinical and Radiological Differences in Patients Following Traumatic SCI at Different Ages.

Traumatic spinal cord injury (SCI) is a lesion that can affect several spinal structures, including the vertebrae, spinal cord, ligaments, and other adjacent parts of the spine. Traumatic spinal cord injury (SCI) can cause functional changes in patients of different ages. The study aims to determine whether there are social, clinical, and radiological differences between young, middle-aged, and elderly adults with SCI caused by a ground-level fall. This retrospective study analyzed the records of patients with a clinical diagnosis of SCI. It enrolled patients with traumatic spinal cord injury after a ground-level fall divided as follows: young aged adults 18-35 years of age (G1); middle-aged adults aged 36-60 years (G2); and elderly adults aged over 60 years (G3). Their clinical, social, and radiological variables were analyzed. It is observed that low schooling level, being widowed, and being a homemaker were more frequently encountered among elderly adults, whereas being single was more common in middle-aged adults. The morphologic diagnosis of compression fracture and the associated injury of facial trauma occurred more frequently in elderly adults, with an increasing tendency with age. Conservative therapeutic management was most commonly encountered in elderly adults, compared to surgery from a posterior approach in middle-aged adults. Listhesis was better identified in middle-aged adults by computed tomography (CT). Spinal cord contusion and injury to the C1 vertebra were demonstrated in young adults by magnetic resonance imaging (MRI). 1. Elderly adults with low education level, widowed, and homemakers were more susceptible to SCI caused by a fall. 2. Single marital status was more frequently noted in young adults. 3. The most frequent clinical aspects were the morphological aspect of compression fracture and fa-cial trauma as an associated injury in elderly adults, with the occurrence of facial trauma increasing with age. 4. Conservative therapeutic management was more common in elderly adults than surgery from a po-sterior approach in middle-aged adults. 5. Re-garding the radiological aspects of CT, listhesis was better identified in middle-aged adults. Spi-nal cord contusions and C1 vertebra lesions were better identified in young adults by MRI.

A Perennial Threat: A Case Series of Tree-Related Neurotrauma.

BackgroundDespite their devastating nature, injuries due to tree-related- traumas are sparsely reported in the literature. Over the last several years, the incidence of tree-related traumatic injuries presenting to our level one trauma center, in Westchester, New York, has been concerning. The present study was undertaken to evaluate the clinical presentation, injury pattern, and outcomes of tree-related neurotrauma at our institution. In addition, we describe the injury pattern and medical management of several relevant cases of tree-related neurotrauma.MethodsWe conducted a retrospective analysis of tree-related neurotrauma over a five-year period from January of 2014 to March of 2019 at Westchester Medical Center (WMC) and Maria Fareri Children’s Hospital, a level one trauma center. Patients presenting with neurotrauma that necessitated neurosurgical care were eligible for inclusion in this case series. Tree-related injury was defined as any trauma that was sustained as a direct result of collision with a tree.ResultsWe identified 21 patients who sustained tree-related trauma. The cohort age ranged from 15 to 68 (mean=38 years). Injuries included seven skull fractures, four cases of subdural hematoma (SDH), six cases of intracranial hemorrhagic contusion, 14 spinal fractures, three cases of epidural hematoma (EDH), one case of spinal cord contusion, three vascular injuries, one case of dural laceration, and one case of pneumocephalus, with several patients suffering multiple injuries. Of the 21 patients, seven were female, and 12 were injured when their motor vehicle struck a tree. All but four patients were taken to the operating room for neurosurgical treatment, and nine of 21 patients were taken emergently to the operating room upon arrival.ConclusionThe potential for serious head injuries with long-term neurologic sequelae exists with tree-related trauma. Clinicians should be advised of the challenging management of injuries secondary to tree-related trauma, and a greater emphasis should be placed on raising awareness of these accidental, but devastating injuries. Finally, a great majority of these injuries can be prevented or reduced in severity through helmet use and by adhering to safety guidelines.

Swim test for joint angles dispersion analysis during hind limb motor function assessment in SCI models

In the most of functional studies, various stress tests are used to assess functional improvement following spinal cord injury in animal models. However, available methods of motor function evaluation are not always accurate and unbiased. The main objective of the study was to create a new method of motor activity assessment in minor animal models of spinal cord injury. This method should provide an objective and accurate evaluation of limb motor function in models having severe neurological disorders following contusion spinal cord injury. The swimming test was used as the key behavioral test. To assess the motor function of swimming animals’ hind limbs, we measured angles of hind limbs movements adjusted to the motion direction axis. Then we calculated individual angles dispersion for each joint and limb using the parameters of angles sample dispersion and amplitude-depending dispersion. The current study included two groups of Sprague-Dawley rats: control group and a group of animals having moderate thoracic spinal cord contusion injury. Control animals demonstrated stable dispersion indicators for 6 weeks of follow-up. In the experimental group, a tendency to the improvement of motor function in hind limbs between 1 and 3 weeks was revealed followed by stabilization and preservation of both indicators between 3 and 6 weeks. Provided method based on the measurement of joint angles adjusted to the movement direction axis followed by calculation of indicators of variance of a random variable and amplitude-depending variance can be an effective and objective alternative for motor function evaluation.

Increasing toll-like receptor 2 on astrocytes induced by Schwann cell-derived exosomes promotes recovery by inhibiting CSPGs deposition after spinal cord injury

BackgroundTraumatic spinal cord injury (SCI) is a severely disabling disease that leads to loss of sensation, motor, and autonomic function. As exosomes have great potential in diagnosis, prognosis, and treatment of SCI because of their ability to easily cross the blood–brain barrier, the function of Schwann cell-derived exosomes (SCDEs) is still largely unknown.MethodsA T10 spinal cord contusion was established in adult female mice. SCDEs were injected into the tail veins of mice three times a week for 4 weeks after the induction of SCI, and the control group was injected with PBS. High-resolution transmission electron microscope and western blot were used to characterize the SCDEs. Toll-like receptor 2 (TLR2) expression on astrocytes, chondroitin sulfate proteoglycans (CSPGs) deposition and neurological function recovery were measured in the spinal cord tissues of each group by immunofluorescence staining of TLR2, GFAP, CS56, 5-HT, and β-III-tublin, respectively. TLR2f/f mice were crossed to the GFAP-Cre strain to generate astrocyte specific TLR2 knockout mice (TLR2−/−). Finally, western blot analysis was used to determine the expression of signaling proteins and IKKβ inhibitor SC-514 was used to validate the involved signaling pathway.ResultsHere, we found that TLR2 increased significantly on astrocytes post-SCI. SCDEs treatment can promote functional recovery and induce the expression of TLR2 on astrocytes accompanied with decreased CSPGs deposition. The specific knockout of TLR2 on astrocytes abolished the decreasing CSPGs deposition and neurological functional recovery post-SCI. In addition, the signaling pathway of NF-κB/PI3K involved in the TLR2 activation was validated by western blot. Furthermore, IKKβ inhibitor SC-514 was also used to validate this signaling pathway.ConclusionThus, our results uncovered that SCDEs can promote functional recovery of mice post-SCI by decreasing the CSPGs deposition via increasing the TLR2 expression on astrocytes through NF-κB/PI3K signaling pathway.

Disrupting RhoA activity by blocking Arhgef3 expression mitigates microglia-induced neuroinflammation post spinal cord contusion

Excess inflammatory microglia activation deteriorates the pathological degree of spinal cord injury (SCI). We here employed microglia samples in vitro and murine model in vivo to trace the role of inhibition of Arhgef3 in inflammatory response post SCI. From the specimen analysis of lipopolysaccharide (LPS)-induced inflammatory microglia, we found that Arhgef3 expression was positively relative to microglia activation. In vitro, LPS caused the microglia inflammatory activation and induced upregulation of the Arhgef3 expression. Interestingly, presence of Arhgef3 could activate RhoA through promoting Rho GTPases, but silencing of Arhgef3 decreased RhoA activation and inhibited the microglia inflammation. Moreover, disruption of Arhgef3 inhibited the GTP-RhoA, resulted in a suppression of proinflammatory cytokines, and alleviated the LPS-elicited inflammatory genes expression. Moreover, artificially decreasing Arhgef3 expression remarkedly reduced ROS generation after LPS treatment. In vivo of a mouse mechanical contusion-induced SCI model, inhibition of Arhgef3 reduced the ratio of GTP-RhoA/Total-RhoA, and prevented SCI via mitigating the microglial inflammatory phenotype and decreased secondary neurological injury. Besides, inhibition of Arhgef3 prevented alleviated the degree of demyelination but did not affect neuronal regeneration. Meaningfully, absence of Arhgef3 improved mouse locomotor recovery post SCI. Taken together, Arhgef3 involves the microglial activation and inflammatory response following neural injury, and targeted disrupting of which may indicate a promising therapeutic direction in preventing SCI.

Operative Treatment of Severe Cervical Spine Injuries Sustained in Youth Sports: Experience from a Pediatric Level 1 Trauma Center over a 16-Year Period

Background:Sports-related cervical spine injuries (CSI) are devastating traumas with the potential for permanent disability. There is a paucity of literature on operative CSI sustained in youth athletes.Hypothesis/Purpose:The aims of this study aims were to review injury characteristics, surgical treatment, and outcomes of severe pediatric CSI encountered in youth sports.Methods:We reviewed children less than 18 years old with operative sports-related CSI at a pediatric Level 1 pediatric trauma center between 2004−2019. All cases underwent modern cervical spine instrumentation and fusion. SCI were stratified according to the American Spinal Injury Association Impairment Scale (ASIA). Clinical, radiographic, and surgical characteristics were compared between groups of patients with and without spinal cord injury (SCI).Results:Three thousand two hundred and thirty-one children (mean, 11.3y±4.6y) were evaluated for CSI at our institution during the 16-year period. The majority of traumas resulted from sports/recreational activities and were seen in 1365 cases (42.3%). Of these, 171/1365 patients (12.5%) were admitted and 29/1365 patients (2.1%) required surgical intervention (mean age, 14.5y±2.88y; range, 6.4y–17.8y). Sports included: eight football (28%), seven wrestling (24%), five gymnastics (17%), four diving (14%), two trampoline (7%), one hockey (3%), one snowboarding (3%), and one biking injury (3%). Mechanisms were 19 hyperflexion (65%), eight axial loading (28%), and two hyperextension injuries (7%). The majority of operative CSI were fractures (79%) and/or subaxial defects (72%). Seven patients (30%) sustained SCI and three patients (10%) spinal cord contusion or myelomalacia without neurologic deficits. The risk of SCI increased with age (15.8y vs. 14.4y; p=0.03) and axial loading mechanism (71% vs. 14%; p=0.003).Postoperatively, two SCI patients (29%) improved 1 ASIA Grade and one (14%) improved 2 ASIA Grades. Increased complications developed in SCI than patients without SCI (mean, 2.0 vs 0.1 complications; p=0.02). Clinical and radiographic fusion occurred in 24/26 patients (92%) with adequate follow-up (median, 32 months). Ten patients returned to their previous activity and nine to sports with a lower level of activity.Conclusion:The overall incidence of sports-related operative CSI is low. Age- and gender discrepancies exist, with male adolescent athletes most commonly requiring surgery. Hyperflexion injuries had a good prognosis; however, older males with axial loading CSI sustained in contact sports were at greatest risk of SCI, complications, and permanent disability.Figure 1.1:Etiology of all cervical spine injuries between 2004-2019

Therapeutic Effect of BDNF-Overexpressing Human Neural Stem Cells (F3.BDNF) in a Contusion Model of Spinal Cord Injury in Rats.

The most common type of spinal cord injury is the contusion of the spinal cord, which causes progressive secondary tissue degeneration. In this study, we applied genetically modified human neural stem cells overexpressing BDNF (brain-derived neurotrophic factor) (F3.BDNF) to determine whether they can promote functional recovery in the spinal cord injury (SCI) model in rats. We transplanted F3.BDNF cells via intrathecal catheter delivery after a contusion of the thoracic spinal cord and found that they were migrated toward the injured spinal cord area by MR imaging. Transplanted F3.BDNF cells expressed neural lineage markers, such as NeuN, MBP, and GFAP and were functionally connected to the host neurons. The F3.BDNF-transplanted rats exhibited significantly improved locomotor functions compared with the sham group. This functional recovery was accompanied by an increased volume of spared myelination and decreased area of cystic cavity in the F3.BDNF group. We also observed that the F3.BDNF-transplanted rats showed reduced numbers of Iba1- and iNOS-positive inflammatory cells as well as GFAP-positive astrocytes. These results strongly suggest the transplantation of F3.BDNF cells can modulate inflammatory cells and glia activation and also improve the hyperalgesia following SCI.