Cord Injury In Rats Research Articles

Amantadine prevented hypersensitivity and decreased oxidative stress by NMDA receptor antagonism after spinal cord injury in rats.

Neuropathic pain (NP) after spinal cord injury (SCI) is a disabling condition, without an effective treatment. Hyperexcitability of N-methyl-D-aspartate (NMDA) receptors and oxidative stress have been reported to be associated with pain development. Amantadine, an NMDA receptor antagonist, has been proposed as a potential therapy for NP. However, its use has not been tested for NP after SCI. To produce SCI, 120 female Wistar rats were used, a contusion injury to the T10 and T12 thoracic vertebrae was performed from heights of 6.25mm and 12.5mm. Nociceptive behaviour, was evaluated with the use of von Frey filaments for 31days. The final products of lipid peroxidation (LP) and concentration of reduced glutathione (GSH) in the injured tissue were quantified by fluorescence spectrophotometry. The antinociceptive effect of the acute (15days after the injury) and chronic (once daily for three days immediately after the injury) with amantadine (6.25-50mg/Kg. I.p.) was determined. Finally, the LP and GSH were quantified in the injured tissue. Acute treatment with amantadine reduced nociceptive behaviour. Concomitantly, LP was decreased by Amantadine treatment while GSH increased in the injured tissue. Similar effects were observed with chronic treatment with amantadine. Data from this study suggested that the antinociceptive effects of amantadine treatment are modulated through oxidative stress and excitotoxicity reduction associated with N-methyl-D-aspartate receptors activation. This study suggests that acute treatment with amantadine decreases hypersensitivity threshold and frequency of hypersensitivity response in a dose-dependent manner, in rats with SCI, by decreasing oxidative stress. Since amantadine is an easily accessible drug and has fewer adverse effects than current treatments for hypersensitivity threshold and frequency of hypersensitivity response, amantadine could represent a safe and effective therapy for the treatment of neuropathic pain. However, further research is required to provide evidence of the effectiveness and feasibility.

Tetrahydropalmatine reduces cell death and improves functional recovery after traumatic spinal cord injury in ratsTetrahydropalmatine reduces cell death and improves functional recovery after traumatic spinal cord injury in rats

Purpose: To investigate the effectiveness of tetrahydropalmatine (THP) in the treatment of spinal cord injury (SCI) in rats.
 Methods: Adult Sprague Dawley rats were divided into 3 groups: normal control group, SCI group, and SCI group treated with THP (100 mg kg-1). The effect of THP on spinal cord water content, levels of inflammatory mediators, oxidative stress and apoptosis were determined. Locomotor activity in rats was measured using Basso, Beattie and Bresnahan (BBB) scores. Various oxidative stress markers as well as cytokine levels (NF-ĸB, IL-6, IL-1β and TNF-α were determined. Apoptotic index was measured using TUNEL assay.
 Results: After 72 h of treatment with THP, BBB scores in SCI group of rats significantly increased from 4.19 ± 0.41 to 8.89 ± 0.47 (p < 0.05). Tunel assay revealed a higher apoptotic index (42.50 ± 3.19) in the tissues of SCI rats than in SCI rats treated with THP (31.48 ± 1.19, p < 0.01). Expressions of inflammatory cytokines were significantly upregulated in SCI rats. However, THP administration resulted in significant downregulation of the expressions (p < 0.01).
 Conclusion: These results indicate that THP attenuates traumatic SCI in rats via modulation of the levels of anti-inflammatory mediators. Thus, THP has a promising potential for the management of SCI.

Transplantation of tauroursodeoxycholic acid–inducing M2‐phenotype macrophages promotes an anti‐neuroinflammatory effect and functional recovery after spinal cord injury in rats

ObjectivesIn this study, we study the transplantation of tauroursodeoxycholic acid (TUDCA)‐induced M2‐phenotype (M2) macrophages and their ability to promote anti‐neuroinflammatory effects and functional recovery in a spinal cord injury (SCI) model.MethodsTo this end, compared to the granulocyte‐macrophage colony‐stimulating factor (GM‐CSF), we evaluated whether TUDCA effectively differentiates bone marrow–derived macrophages (BMDMs) into M2 macrophages.ResultsThe M2 expression markers in the TUDCA‐treated BMDM group were increased more than those in the GM‐CSF‐treated BMDM group. After the SCI and transplantation steps, pro‐inflammatory cytokine levels and the mitogen‐activated protein kinase (MAPK) pathway were significantly decreased in the TUDCA‐induced M2 group more than they were in the GM‐CSF‐induced M1 group and in the TUDCA group. Moreover, the TUDCA‐induced M2 group showed significantly enhanced tissue volumes and improved motor functions compared to the GM‐CSF‐induced M1 group and the TUDCA group. In addition, biotinylated dextran amine (BDA)–labelled corticospinal tract (CST) axons and neuronal nuclei marker (NeuN) levels were increased in the TUDCA‐induced M2 group more than those in the GM‐CSF‐induced M1 group and the TUDCA group.ConclusionsThis study demonstrates that the transplantation of TUDCA‐induced M2 macrophages promotes an anti‐neuroinflammatory effect and motor function recovery in SCI. Therefore, we suggest that the transplantation of TUDCA‐induced M2 macrophages represents a possible alternative cell therapy for SCI.

Acute intrathecal BDNF enhances functional recovery after cervical spinal cord injury in rats.

Unilateral C2 hemisection (C2SH) disrupts descending inspiratory-related drive to phrenic motor neurons and thus, silences rhythmic diaphragm muscle (DIAm) activity. There is gradual recovery of rhythmic DIAm EMG activity over time post-C2SH, consistent with neuroplasticity, which is enhanced by chronic (2 wk) intrathecal BDNF treatment. In the present study, we hypothesized that acute (30 min) intrathecal BDNF treatment also enhances recovery of DIAm EMG activity after C2SH. Rats were implanted with bilateral DIAm EMG electrodes to verify the absence of ipsilateral eupneic DIAm EMG activity at the time of C2SH and at 3 days post-C2SH. In those animals displaying no recovery of DIAm EMG activity after 28 days (n = 7), BDNF was administered intrathecally (450 mcg) at C4. DIAm EMG activity was measured continuously both before and for 30 min after BDNF treatment, during eupnea, hypoxia-hypercapnia, and spontaneous sighs. Acute BDNF treatment restored eupneic DIAm EMG activity in all treated animals to an amplitude that was 78% ± 9% of pre-C2SH root mean square (RMS) (P < 0.001). In addition, acute BDNF treatment increased DIAm RMS EMG amplitude during hypoxia-hypercapnia (P = 0.023) but had no effect on RMS EMG amplitude during sighs. These results support an acute modulatory role of BDNF signaling on excitatory synaptic transmission at phrenic motor neurons after cervical spinal cord injury.NEW & NOTEWORTHY Brain-derived neurotrophic factor (BDNF) plays an important role in promoting neuroplasticity following unilateral C2 spinal hemisection (C2SH). BDNF was administered intrathecally in rats displaying lack of ipsilateral inspiratory-related diaphragm (DIAm) EMG activity after C2SH. Acute BDNF treatment (30 min) restored eupneic DIAm EMG activity in all treated animals to 78% ± 9% of pre-C2SH level. In addition, acute BDNF treatment increased DIAm EMG amplitude during hypoxia-hypercapnia but had no effect on EMG amplitude during sighs.

WITHDRAWN: The mechanism of AMPA receptor subunit GluR1 in electroacupuncture treatment of acute spinal cord injury in rats

Glutamate excitotoxicity plays a role in spinal cord injury (SCI). This study aimed to explore whether electroacupuncture (EA) improved the functional recovery of spinal cord anterior horn neurons of rats with acute SCI by regulating the GluR1 AMPA subunit in the SCI area. Eighty Sprague-Dawley rats were randomly divided into 5 groups: sham operation, model, AMPA antagonist (DNQX), EA and DNQX+EA group (n=16/group). The models were obtained by using the modified Allen's impact method. DNQX was given by intrathecal injection 0.5 h after modeling. EA was performed at the "Dazhui" and "Mingmen" acupoints for 30 min at 0.5, 12, and 24 h. The BBB scores were evaluated before modeling and at 6, 24, and 48 h after modeling. Histopathological changes were evaluated. GluR1 expression was evaluated through immunofluorescence and western blot. Compared to the sham group, the BBB scores at 6, 24, and 48 h in the model group were all lower. The BBB scores and histopathological changes in the EA, DNQX and DNQX+EA group were between that of the sham and model group. GluR1 expression in the model group was higher than the sham group. Compared with the model group, the expression of GluR1 protein in the EA, DNQX, and DNQX+EA group was decreased, but similar among the three treatment groups, supporting the histopathological observations. In conclusion, these findings indicated that EA treatment might inhibit GluR1 expression, thus contributing to prevention of secondary nerve injury after primary acute SCI.

The CatWalk XT® Gait Analysis Is Closely Correlated with Tissue Damage after Cervical Spinal Cord Injury in Rats

Objective and consistent assessment of locomotion recovery remains challenging in rodent spinal cord injury (SCI). We, therefore, studied the validity and relevance of the CatWalk XT® gait analysis as a tool for assessing functional outcome in a clinically relevant cervical SCI model in rats. In total, 20 Wistar rats were randomly assigned to either a C6 clip compression/contusion SCI or a sham laminectomy. Locomotion recovery was assessed weekly using the CatWalk XT® gait analysis and the BBB open field score. Six weeks after SCI, the percentage of preserved spinal cord tissue was measured by glial fibrillary acidic protein (GFAP) immunohistochemistry (IHC) staining. Statistical analyses were performed to assess the correlation of the BBB and the percentage of preserved tissue with 30 different CatWalk XT® parameters. SCI caused a bilateral and significant functional impairment in all studied CatWalk XT® parameters. Similar to the BBB, a significant spontaneous recovery could be observed in most of the CatWalk XT® parameters in the following weeks. Correlation between the hindlimb CatWalk XT® parameters and the BBB was good (53% of r values &gt; 0.6) while the correlation between the forelimb and the hindlimb CatWalk XT® parameters and the percentage of preserved tissue was even stronger (83% of r values &gt; 0.6). The CatWalk XT® gait analysis is closely correlated with tissue damage after cervical contusion/compression SCI and can be used as an objective and consistent tool for assessing locomotion recovery.

Synergistic neuroprotective effects of hyperbaric oxygen and methylprednisolone following contusive spinal cord injury in rat

Objective Recent studies revealed the neuroprotective effects of hyperbaric oxygen (HBO) on spinal cord injury (SCI). Meanwhile, the use of methylprednisolone (MP) is one of the current protocols with limited effects in SCI patients. Accordingly, the aim of the present study was to investigate the effect of combined HBO and MP treatment on SCI. Design The present study was conducted on five groups of rats each as follows: Sham group (underwent laminectomy alone at T9 level vertebra); SCI group (underwent moderate contusive SCI); MP group (underwent SCI and received MP); HBO group (underwent SCI and received HBO); HBO + MP group (underwent SCI and simultaneously received MP and HBO). Blood serum and Spinal cord tissue samples were taken 48 h after SCI for analysis of serum ferric reducing antioxidant power (FRAP) and tissue malodialdehyde (MDA) levels as well as immunohistochemistry of caspase-3 and tumor necrosis factor-alpha (TNF-α). Neurological function was evaluated by the Basso–Beattie–Bresnehan (BBB) locomotion scores until the end of experiments. Additionally, histopathology was assessed at the end of the study. Setting Mazandaran University of Medical Sciences, Sari, Iran. Results Combination therapy with HBO and MP in the HBO + MP group significantly decreased MDA as well as increased FRAP levels compared to other treatment groups. Meanwhile, attenuated TNF-α and Caspase-3 expression could be significantly detected in the HBO + MP group. At the end of treatment, the neurological outcome was significantly improved and the extent of injured spinal tissue was also significantly reduced in the HBO + MP compared to other treatment groups. Conclusion The results suggest that combined therapy with MP and HBO has synergistic effects on SCI treatment.

Identification of four genes and biological characteristics associated with acute spinal cord injury in rats integrated bioinformatics analysis.

Spinal cord injury (SCI) is a serious condition that can cause physical disability and sensory dysfunction. Cytokines play an extremely important role in the acute phase of SCI. Clarifying the cytokine expression profile is of great importance. Cytokine array analysis was used to explore the changes in 67 different proteins at 0 hours, 2 hours, 1 day, 3 days, and 7 days after acute SCI in rats. The differentially expressed cytokines in the various periods were analyzed and compared. The biological processes related to the differentially expressed proteins were examined using Gene Ontology (GO) analysis. Immediately after SCI (0 hours), only ciliary neurotrophic factor (CNTF) was slightly up-regulated, while 23 other proteins were down-regulated. At 2 hours after SCI, there were 3 upregulated and 21 downregulated proteins. At 1 day after SCI, there were 5 upregulated and 6 downregulated proteins. At 3 days after SCI, there were 6 upregulated and 4 downregulated proteins. At 7 days after SCI, there were 4 upregulated and 9 downregulated proteins. Erythropoietin (EPO) and Fms related tyrosine kinase 3 ligand (Flt-3L) were downregulated at all time points. CD48 was decreased at 2 hours to 7 days after SCI. Monocyte chemotactic protein-1 (MCP-1) was the only protein that was upregulated at 2 hours to 7 days. The GO and pathway analyses revealed that the cytokine-related pathways, cell death, and proliferation might play a key role during secondary SCI. This study identified 3 downregulated proteins during SCI, that being EPO, Flt-3L, and CD48. MCP-1 was the only upregulated protein, and its expression was upregulated till day 7 following SCI. These 4 identified genes may be potential therapeutic targets for the treatment of SCI.

EphB2 knockdown decreases the formation of astroglial-fibrotic scars to promote nerve regeneration after spinal cord injury in rats.

AimsAt the beginning of spinal cord injury (SCI), the expression of EphB2 on fibroblasts and ephrin‐B2 on astrocytes increased simultaneously and their binding triggers the formation of astroglial‐fibrotic scars, which represent a barrier to axonal regeneration. In the present study, we sought to suppress scar formation and to promote recovery from SCI by targeting EphB2 in vivo.MethodsThe female rats SCI models were used in vivo experiments by subsequently injecting with EphB2 shRNA lentiviruses. The effect on EphB2 knockdown was evaluated at 14 days after injury. The repair outcomes were evaluated at 3 months by electrophysiological and morphological assessments to regenerated nerve tissue. The EphB2 expression and TGF‐β1 secretion were detected in vitro using a lipopolysaccharides (LPS)‐induced astrocyte injury model.ResultsRNAi decreased the expression of EphB2 after SCI, which effectively inhibited fibroblasts and astrocytes from aggregating at 14 days. The expression of EphB2 in activated astrocytes, in addition to fibroblasts, was significantly increased after SCI in vivo, in line with upregulated expression of EphB2 and increased secretion of TGF‐β1 in astrocyte culture treated with LPS. Compared to the scramble control, RNAi targeting with EphB2 could promote more nerve regeneration and better myelination.ConclusionsEphB2 knockdown may effectively inhibit the formation of astroglial‐fibrotic scars at the beginning of SCI. It is beneficial to eliminate the barrier of nerve regeneration.

Neuroprotective effect and mechanism study of forsythin on acute spinal cord injury in rats

Neuroprotective effect and mechanism study of forsythin on acute spinal cord injury in rats

Severe Spinal Cord Injury in Rats Induces Chronic Changes in the Spinal Cord and Cerebral Cortex Metabolism, Adjusted by Thiamine That Improves Locomotor Performance.

Our study aims at developing knowledge-based strategies minimizing chronic changes in the brain after severe spinal cord injury (SCI). The SCI-induced long-term metabolic alterations and their reactivity to treatments shortly after the injury are characterized in rats. Eight weeks after severe SCI, significant mitochondrial lesions outside the injured area are demonstrated in the spinal cord and cerebral cortex. Among the six tested enzymes essential for the TCA cycle and amino acid metabolism, mitochondrial 2-oxoglutarate dehydrogenase complex (OGDHC) is the most affected one. SCI downregulates this complex by 90% in the spinal cord and 30% in the cerebral cortex. This is associated with the tissue-specific changes in other enzymes of the OGDHC network. Single administrations of a pro-activator (thiamine, or vitamin B1, 1.2 mmol/kg) or a synthetic pro-inhibitor (triethyl glutaryl phosphonate, TEGP, 0.02 mmol/kg) of OGDHC within 15–20 h after SCI are tested as protective strategies. The biochemical and physiological assessments 8 weeks after SCI reveal that thiamine, but not TEGP, alleviates the SCI-induced perturbations in the rat brain metabolism, accompanied by the decreased expression of (acetyl)p53, increased expression of sirtuin 5 and an 18% improvement in the locomotor recovery. Treatment of the non-operated rats with the OGDHC pro-inhibitor TEGP increases the p53 acetylation in the brain, approaching the brain metabolic profiles to those after SCI. Our data testify to an important contribution of the OGDHC regulation to the chronic consequences of SCI and their control by p53 and sirtuin 5.

NIX Mediates Mitophagy in Spinal Cord Injury in Rats by Interacting with LC3.

Excessive mitophagy plays a role in neuronal death in spinal cord injury (SCI), its molecular regulation remains largely unknown. The present study aims to determine the role of NIX, a member of a unique subfamily of death-inducing mitochondrial proteins, in the regulation of mitophagy in SCI. Here we show that NIX is highly upregulated in SCI and hypoxia, and localized to mitochondria. The mitochondria-bound NIX interacts with autophagosome-localized LC3 (Microtubule-associated protein 1 light chain 3) to form a mitochondria-NIX-LC3-autophagosome complex, resulting in excessive mitophagy in SCI. Downregulation of NIX by RNA interference restores the function of mitochondria in spinal cord neurons under hypoxia. Importantly, inhibition of NIX improves recovery of locomotor function in rats after SCI. The present study demonstrates that NIX interacts with LC3 to activate excessive mitophagy in SCI. Inhibition of NIX is therefore likely a neuroprotective strategy.

Early escitalopram administration as a preemptive treatment strategy against spasticity after contusive spinal cord injury in rats

In the majority of spinal cord injury (SCI) patients, spasticity develops in the subacute phase and chronically persists with muscle hypertonia. Among various pathological conditions underlying spasticity, upregulated expression of 5-HT receptors (5-HTR) on the spinal motor neurons due to 5-HT denervation is considered one of crucial factors for hyperexcitability of the spinal circuit. As a 5-HT signal modulator, selective serotonin re-uptake inhibitors (SSRIs) are ordinarily prescribed for diseases associated with 5-HT in the CNS, and are known for their ability to increase 5-HT levels as well as to desensitize 5-HTR. Here, we hypothesized that early SSRI administration as a preemptive treatment strategy would effectively prevent the onset of spasticity. We used a rat model of contusive SCI and administered escitalopram during the first 4 weeks after injury, which is the period required for spasticity development in rodent models. We performed a swimming test to quantify spastic behaviors and conducted the Hoffman reflex test as well as histological analyses for 5-HT2AR and KCC2 expressions. Four weeks of escitalopram administration suppressed spastic behaviors during the swimming test and reduced the population of spasticity-strong rats. Moreover, the treatment resulted in decreased immunoreactivity of 5-HT2AR in the spinal motor neurons. Result of the H-reflex test and membrane expression of KCC2 were not significantly altered. In summary, early escitalopram administration could prevent the onset of spastic behaviors via regulation of 5-HT system after SCI, but could not modulate exaggerated spinal reflex. Our results suggest a novel application of SSRIs for preventative treatment of spasticity.

Additive Effects of Environmental Enrichment and Ketamine on Neuropathic Pain Relief by Reducing Glutamatergic Activation in Spinal Cord Injury in Rats.

Spinal cord injury (SCI) impairs mobility and often results in complications like intractable neuropathic pain. A multi-approach management of this chronic pain condition has been encouraged, but little has been explored of the field. Here, we focus on the effect and underlying mechanism of environmental enrichment (EE), which promotes voluntary social and physical activities, combined with a clinical analgesic, ketamine, on SCI-induced neuropathic pain as well as motor dysfunction. We performed T13 spinal hemisection in rats, which induced unilateral motor impairment and neuropathic pain-like behaviors in the hindlimb. Treatment regimen started a week after SCI, which consists of ketamine administration (30 mg kg–1 day–1; intramuscular) for 10 days, or EE housing for 20 days, or their combination. Paw withdrawal response to mechanical and thermal stimuli, motor function, burrowing behaviors, and body weight was monitored. Spinal segments at T13 lesion and L4–L6 were collected for histopathological and protein analyses. The joint treatment of EE and ketamine provided greater relief of pain-like behaviors and locomotor recovery than did either paradigm alone. These improvements were associated with reduced cavitation area, astrogliosis, and perilesional phosphorylation of glutamate N-methyl-D-aspartate receptor (NMDAR). Concurrently, lumbar spinal analysis of NMDAR-linked excitatory markers in hypersensitization showed reduced activation of NMDAR, mitogen-activated protein kinase (MAPK) family, nuclear factor (NF)-κB, interleukin (IL)-1β signaling, and restored excitatory amino acid transporter 2 level. Our data support a better therapeutic efficacy of the combination, EE, and ketamine, in the attenuation of neuropathic pain and motor recovery by reducing spinal glutamatergic activation, signifying a potential multifaceted neurorehabilitation strategy to improve SCI patient outcome.

Design and development of 1,3,5-triazine derivatives as protective agent against spinal cord injury in rat via inhibition of NF-ĸB

Spinal cord injury (SCI) is a chronic disease causing motor and sensory loss in the affected individuals. The SCI has a huge impact on the lives of patients that makes them susceptible to life-long disability. However, the current clinical modalities are ineffective to cope the aftermath of SCI. Thus, in the present study, we aimed to develop a series of 1,3,5-triazine derivatives as a protective agent against SCI. The molecules were developed by facile synthetic route and obtained in excellent yield. The compounds were tested for their efficacy to inhibit the transcription of NF-κB in RAW 264.7 cells, where they displayed mild to potent activity. Compound 8a was identified as most potent NF-κB inhibitor among the tested analogues. The effect of compound 8a was further scrutinized against the SCI injury in rats induced by contusion injury. It has been found that compound 8a improves motor function of rats together with reduction in inflammation and edema in spinal cord of rats. It also showed to inhibit oxidative stress and inflammation in the SCI rats. In a western blot analysis, after SCI induction, compound 8a inhibited NF-κB and its upstream regulator TLR4 in a dose-dependent manner. Collectively, our study provides a novel class of agent that provide protective action against SCI.

Dapsone Prevents Allodynia and Hyperalgesia and Decreased Oxidative Stress After Spinal Cord Injury in Rats.

Prospective longitudinal experimental study. We evaluate the effect of dapsone on tactile allodynia and mechanical hyperalgesia and to determine its anti-oxidant effect in a spinal cord injury (SC) model in rats. Neuropathic pain (NP) as result of traumatic spinal cord injury is a deleterious medical condition with temporal or permanent time-course. Painful stimuli trigger a cascade of events that activate the N-methyl-D-aspartate (NMDA) receptor, inducing an increase in oxidative stress. Since there is no effective treatment for this condition, dapsone (4,4'diaminodiphenylsulfone) is proposed as potential treatment for NP. Its anti-oxidant, neuroprotective, and anti-inflammatory properties have been documented, however, there is no evidence regarding its use for treatment of NP induced by SCI. In this study, we evaluated the anti-allodynic and anti-hyperalgesic effect of dapsone as preventive or acute treatment after NP was already established. Furthermore, participation of oxidative stress was evaluated by measuring lipid peroxidation (LP) and glutathione concentration (GSH) in rats with SCI. Acute treatment with dapsone (3.1-25 mg/kg, i.p.) decreased nociceptive behaviors in a dose-dependent manner, decreased LP, and increased GSH in the injured tissue 15 days after the injury was produced. On the other hand, preventive treatment (3 h post-injury, once daily for 3 days) with dapsone (3.1-25 mg/kg, i.p.) yielded similar results. The findings suggest that the anti-nociceptive effect of dapsone is regulated through the decrease of oxidative stress and the excitotoxicity is associated with the activation of NMDA receptors.Level of Evidence: N/A.

Enoxaparin promotes functional recovery after spinal cord injury by antagonizing PTPRσ

The receptor-type protein tyrosine phosphatase sigma (PTPRσ) regulates axonal regeneration/sprouting as a molecular switch in response to glycan ligands. Cell surface heparan sulfate oligomerizes PTPRσ and inactivates its enzymatic activity, which in turn promotes axonal growth. In contrast, matrix-associated chondroitin sulfate monomerizes PTPRσ and activates it. This leads to dephosphorylation of its specific substrates, such as cortactin, resulting in a failure of axonal regeneration after injury. However, this molecular switch model has never been challenged in a clinical situation. In this study, we demonstrated that enoxaparin, a globally approved anticoagulant consisting of heparin oligosaccharides with an average molecular weight of 45 kDa, induced clustering and inactivated PTPRσ in vitro. Enoxaparin induced PTPRσ clustering, and counteracted PTPRσ-mediated dephosphorylation of cortactin, which was shown to be important for inhibition of axonal regeneration. Systemic administration of enoxaparin promoted anatomical recovery after both optic nerve and spinal cord injuries in rats at clinically tolerated doses. Moreover, enoxaparin promoted recovery of motor function without obvious hemorrhage. Collectively, our data provide a new strategy for the treatment of traumatic axonal injury.

AAV2-mediated and hypoxia response element-directed expression of bFGF in neural stem cells showed therapeutic effects on spinal cord injury in rats

Neural stem cell (NSCs) transplantation has been one of the hot topics in the repair of spinal cord injury (SCI). Fibroblast growth factor (FGF) is considered a promising nerve injury therapy after SCI. However, owing to a hostile hypoxia condition in SCI, there remains a challenging issue in implementing these tactics to repair SCI. In this report, we used adeno-associated virus 2 (AAV2), a prototype AAV used in clinical trials for human neuron disorders, basic FGF (bFGF) gene under the regulation of hypoxia response element (HRE) was constructed and transduced into NSCs to yield AAV2-5HRE-bFGF-NSCs. Our results showed that its treatment yielded temporally increased expression of bFGF in SCI, and improved scores of functional recovery after SCI compared to vehicle control (AAV2-5HRE-NSCs) based on the analyses of the inclined plane test, Basso–Beattie–Bresnahan (BBB) scale and footprint analysis. Mechanistic studies showed that AAV2-5HRE-bFGF-NSCs treatment increased the expression of neuron-specific neuronal nuclei protein (NeuN), neuromodulin GAP43, and neurofilament protein NF200 while decreased the expression of glial fibrillary acidic protein (GFAP) as compared to the control group. Further, the expressions of autophagy-associated proteins LC3-II and Beclin 1 were decreased, whereas the expression of P62 protein was increased in AAV2-5HRE-bFGF-NSCs treatment group. Taken together, our data indicate that AAV2-5HRE-bFGF-NSCs treatment improved the recovery of SCI rats, which is accompanied by evidence of nerve regeneration, and inhibition of SCI-induced glial scar formation and cell autophagy. Thus, this study represents a step forward towards the potential use of AAV2-5HRE-bFGF-NSCs for future clinical trials of SCI repair.

Effects of combination treatment with transcranial magnetic stimulation and bone marrow mesenchymal stem cell transplantation or Raf inhibition on spinal cord injury in rats.

Spinal cord injury (SCI) remains a global challenge due to limited treatment strategies. Transcranial magnetic stimulation (TMS), bone marrow mesenchymal stem cell (BMSC) transplantation and downregulation of Raf/MEK/ERK signaling effectively improve SCI. The combination of BMSCs and TMS displays synergistic effects on vascular dementia. However, whether TMS displays a synergistic effect when combined with BMSC transplantation or Raf inhibitor (RafI) therapy for the treatment of SCI is not completely understood. The present study aimed to compare the therapeutic effect of monotherapy and combination therapy on SCI. In the present study, 8-week-old female Sprague Dawley rats were used to establish a model of SCI using the weight-drop method followed by treatment with monotherapy (TMS, BMSCs or RafI) or combination therapy (TMS+BMSCs or TMS+RafI). The effect of monotherapy and combination therapy on locomotor function, pathological alterations, neuronal apoptosis and expression of axonal regeneration-associated factors and Raf/MEK/ERK signaling-associated proteins in the spinal cord was analyzed by Basso, Beattie and Bresnahan (BBB) scoring, hematoxylin and eosin staining, TUNEL-neuronal nuclei (NeuN) staining and immunofluorescence or western blotting, respectively. The results demonstrated that compared with untreated SCI model rats, monotherapy significantly enhanced locomotor functional recovery, as evidenced by higher BBB scores, and slightly alleviated histopathological lesions of the spinal cord in SCI model rats. Furthermore, monotherapy markedly suppressed neuronal apoptosis and promoted axonal regeneration, as well as inhibiting astroglial activation in SCI model rats. The aforementioned results were demonstrated by significantly decreased numbers of apoptotic neurons, markedly decreased expression levels of glial fibrillary acidic protein (GFAP), significantly increased numbers of NeuN+ cells, markedly increased expression levels of growth-associated protein 43 (GAP-43) and significantly upregulated nerve growth factor (NGF) and brain derived neurotrophic factor (BDNF) expression levels in monotherapy groups (excluding the RafI monotherapy group) compared with untreated SCI model rats. In addition, monotherapy markedly suppressed activation of the Raf/MEK/ERK signaling pathway, as evidenced by significantly reduced p-Raf/Raf, p-MEK/MEK and p-ERK/ERK protein expression levels in monotherapy groups (excluding the BMSC monotherapy group) compared with untreated SCI model rats. Notably, combination therapy further alleviated SCI-induced spinal cord lesions and neuronal apoptosis, increased GAP-43, NGF and BDNF expression levels, downregulated GFAP expression levels and inhibited activation of the Raf/MEK/ERK signaling pathway in SCI model rats compared with the corresponding monotherapy groups. Therefore, it was hypothesized that compared with monotherapy, combination therapy displayed an improved therapeutic effect on SCI by further suppressing Raf/MEK/ERK signaling. The results of the present study provided an important basis for the clinical application of combination therapy.

WITHDRAWN: Role of microRNA-19b-3p on osteoporosis after experimental spinal cord injury in rats

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