Spinal Cord Compression Injury Research Articles

Different Time-Frequency Distribution Patterns of Somatosensory Evoked Potentials in Dual- and Single-Level Spinal Cord Compression.

Among patients with cervical myelopathy, the most common level of stenosis at spinal cord of all ages was reported to be between cervical levels C5-6. Previous studies found that time-frequency components (TFCs) of somatosensory evoked potentials (SEPs) possess location information of spinal cord injury (SCI) in single-level deficits in the spinal cord. However, the clinical reality is that there are multiple compressions at multiple spinal cord segments. This study proposed a new algorithm to differentiate distribution patterns of SEP TFCs between the dual-level compression and the corresponding single-level compression, which is potential in providing precise diagnosis of cervical myelopathy. In the present animal study, a group of rats with dual-level compressive (C5+6) injury to cervical spinal cord was investigated. SEPs were collected at 2 weeks after surgery, while SEP TFCs were calculated. The SEP TFCs under dual-level compression were compared to an existent dataset with one sham control group and three single level compression groups at C4, C5, C6. Behavioral evaluation showed very similar scale of injury severity between individual rats, while histology evaluation confirmed the precise location of injury. According to time-frequency distribution patterns, it showed that the middle-energy components of dual-level showed similar patterns as that of each single-level group. In addition, the low-energy components of the dual-level C5+6 group had the highest correlation with C5 (R = 0.3423, p < 0.01) and C6 (R = 0.4000, p < 0.01) groups, but much lower with C4 group (R = 0.1071, p = 0.012). These results indicated that SEP TFCs components possess information regarding the location of neurological lesion after spinal cord compression. It preliminarily demonstrated that SEP TFCs are likely a useful measure to provide location information of neurological lesions after compression SCI.

Spinal Cord Injury in the Mouse Using the Infinite Horizon Spinal Cord Impactor.

Death of central nervous system neurons is a critical feature of spinal cord injury (SCI). The Infinite Horizon spinal cord impactor can be used to create both contusion and compression SCI, with a high degree of reproducibility. The device can also be positioned at different locations along the spinal cord to evaluate how the location of injury may alter neuronal death and functional recovery. A mouse with a successful SCI can experience a period of loss of bladder function, weight loss, and paralysis of the hind limbs, with more severe injuries resulting in further deficits. This chapter describes the surgical protocol along with pre- and postoperative care, as well as mitigation strategies for any setbacks that might occur.

Rehabilitative training improves skilled forelimb motor function after cervical unilateral contusion spinal cord injury in rats

Animal models of cervical spinal cord injury (SCI) have frequently utilized partial transection injuries to evaluate plasticity promoting treatments such as rehabilitation training of skilled reaching and grasping tasks. Though highly useful for studying the effects of cutting specific spinal tracts that are important for skilled forelimb motor function, cervical partial-transection SCI-models underappreciate the extensive spread of most human SCIs, thus offering poor predictability for the clinical setting. Conversely, moderate cervical contusion SCI models targeting the spinal tracts important for skilled reaching and grasping can better replicate the increased size of most human SCIs and are often considered more clinically relevant. However, it is unknown whether animals with moderate cervical contusion SCIs that damage key spinal motor tracts can train in skilled reaching and grasping tasks. In this study, we quantify the impact of injury size and distribution on recovery in a skilled motor task called the single pellet reaching, grasping and retrieval (SPRGR) task in rats with cervical unilateral contusion injuries (UCs), and compare to rats with a partial transection SCIs (i.e., dorsolateral quadrant transection; DLQ). We found that UCs damage key tracts important for performing skilled motor tasks, similar to DLQs, but UCs also produce more extensive grey matter damage and more ventral white matter damage than DLQs. We also compared forelimb functionality at 1, 3, and 5 weeks of rehabilitative motor training between trained and untrained rats and found a more severe drop in SPRGR performance than in DLQ SCIs. Nevertheless, despite more severe injuries and initially low SPRGR performance, rehabilitative training for contusion animals resulted in significant improvements in SPRGR performance and proportionally more recovery than DLQ rats. Our findings show that rehabilitative motor training can facilitate considerable amounts of motor recovery despite extensive spinal cord damage, especially grey matter damage, thus supporting the use of contusion or compression SCI models and showing that ventral grey and white matter damage are not necessarily detrimental to recovery after training.

Effect of electroacupuncture combined with Schwann cell transplantation on remyelination of axons and neuregulin1 expression in rats with compressed spinal injury

To explore the effect of electroacupuncture (EA) combined with Schwann cell (SC) transplantation (SCT) on remyelination of axons and neuregulin (Nrg1) in rats with compressed spinal cord injury(CSCI),so as to explore the mechanism of EA and SCT underlying improvement of CSCI. SD female rats were randomly divided into normal, mo-del, EA, SCT, and EA+ SCT groups (n=40 per group). A self-developed model of spinal compressed injury was adopted in this study. Rats of the model group were administrated laminectomy without treatment. Rats in the EA group were administrated EA stimulation at "Dazhui"(GV14), "Mingmen"(GV7), bilateral "Zusanli" (ST36) and "Taixi" (KI3) on the second day post-surgery for 10 min. Rats in the SC group were administrated SCT at 1 week post-surgery, and in the EA+SC group were given EA stimulation combined with SCT. The injured spinal cord tissue was obtained 0, 2, 4 and 8 weeks after compressed spinal injury. The functional recovery was assessed by Basso-Beattie-Bresnahan (BBB) score. The survivals and migration of SC after transplantation, myelination were observed by immunofluorescence. The ultrastructure of myelin in injured site was observed by transmission electron microscope，and the expression levels of glial fibrillary acidic protein (GFAP), protein zero(P0), and Nrg1 and Nrg1-ntf (cleavage protein of Nrg1) proteins of the spinal cord were detected by Western blot. Compared with the normal group, BBB scores in the model group was significantly decreased（P<0.05）,nervous fibers were demyelinated, numbers of normal and newborn myelination were decreased(P<0.05)，expression of P0 was significantly increased (P<0.05)，expression of GFAP was significantly increased(P<0.05)，and the expression levels of Nrg1 and Nrg1-ntf proteins were decreased(P<0.05). In comparison with the model group, the BBB scores in the EA, SCT and EA+SCT groups were significantly increased（P<0.05,P<0.01）, demyelination was improved, numbers of normal and newborn myelinations were increased(P<0.05,P<0.01)，expressions of P0 were significantly increased (P<0.05,P<0.01)，expressions of GFAP were significantly decreased(P<0.05)，and the expression levels of Nrg1 and Nrg1-ntf proteins were increased (P<0.05, P<0.01).The differences were most significant in the EA+SCT group among the three groups. EA can improve the locomotor function in CSCI rats, which may be rela-ted to its functions in promoting the survival and migration of transplanted SC and remyelination, and increasing the expressions of Nrg1 and its cleavage protein after SC transplantation.

Bazedoxifene, a Selective Estrogen Receptor Modulator, Promotes Functional Recovery in a Spinal Cord Injury Rat Model.

In research on various central nervous system injuries, bazedoxifene acetate (BZA) has shown two main effects: neuroprotection by suppressing the inflammatory response and remyelination by enhancing oligodendrocyte precursor cell differentiation and oligodendrocyte proliferation. We examined the effects of BZA in a rat spinal cord injury (SCI) model. Anti-inflammatory and anti-apoptotic effects were investigated in RAW 264.7 cells, and blood-spinal cord barrier (BSCB) permeability and angiogenesis were evaluated in a human brain endothelial cell line (hCMEC/D3). In vivo experiments were carried out on female Sprague Dawley rats subjected to moderate static compression SCI. The rats were intraperitoneally injected with either vehicle or BZA (1mg/kg pre-SCI and 3 mg/kg for 7 days post-SCI) daily. BZA decreased the lipopolysaccharide-induced production of proinflammatory cytokines and nitric oxide in RAW 264.7 cells and preserved BSCB disruption in hCMEC/D3 cells. In the rats, BZA reduced caspase-3 activity at 1 day post-injury (dpi) and suppressed phosphorylation of MAPK (p38 and ERK) at dpi 2, hence reducing the expression of IL-6, a proinflammatory cytokine. BZA also led to remyelination at dpi 20. BZA contributed to improvements in locomotor recovery after compressive SCI. This evidence suggests that BZA may have therapeutic potential to promote neuroprotection, remyelination, and functional outcomes following SCI.

Selection of modeling methods for acute compressive spinal cord injury: a network Meta-analysis

Selection of modeling methods for acute compressive spinal cord injury: a network Meta-analysis

Pentadecapeptide BPC 157 and the central nervous system.

We reviewed the pleiotropic beneficial effects of the stable gastric pentadecapeptide BPC 157, three very recent demonstrations that may be essential in the gut-brain and brain-gut axis operation, and therapy application in the central nervous system disorders, in particular. Firstly, given in the reperfusion, BPC 157 counteracted bilateral clamping of the common carotid arteries-induced stroke, sustained brain neuronal damages were resolved in rats as well as disturbed memory, locomotion, and coordination. This therapy effect supports particular gene expression in hippocampal tissues that appeared in BPC 157-treated rats. Secondly, there are L-NG-nitro arginine methyl ester (L-NAME)- and haloperidol-induced catalepsy as well as the rat acute and chronic models of ‘positive-like’ schizophrenia symptoms, that BPC 157 counteracted, and resolved the complex relationship of the nitric oxide-system with amphetamine and apomorphine (dopamine agents application), MK-801 (non-competitive antagonist of the N-methyl-D-aspartate receptor) and chronic methamphetamine administration (to induce sensitivity). Thirdly, after rat spinal cord compression, there were advanced healing and functional recovery (counteracted tail paralysis). Likewise, in BPC 157 therapy, there is specific support for each of these topics: counteracted encephalopathies; alleviated vascular occlusion disturbances (stroke); counteracted dopamine disturbances (dopamine receptors blockade, receptors super sensitivity development, or receptor activation, over-release, nigrostriatal damage, vesicles depletion), and nitric oxide-system disturbances (“L-NAME non-responsive, L-arginine responsive,” and “L-NAME responsive, L-arginine responsive”) (schizophrenia therapy); inflammation reduction, nerve recovery in addition to alleviated hemostasis and vessels function after compression (spinal cord injury therapy). Thus, these disturbances may be all resolved within the same agent’s beneficial activity, i.e., the stable gastric pentadecapeptide BPC 157.

Intrathecal Administration of Melatonin Ameliorates the Neuroinflammation- Mediated Sensory and Motor Dysfunction in A Rat Model of Compression Spinal Cord Injury.

Spinal cord injury (SCI), often characterized by sensory-motor dysfunction, is a major debilitating disorder of the central nervous system. As no useful treatment for post- SCI complications has been approved thus far, finding novel treatments is of great importance. Considering the promising effects of melatonin (MEL) against destructive mechanisms in other models of brain damage, in the current study, we evaluated its ameliorative effects on sensory- motor outcomes, inflammatory mediators, histological changes and other post-SCI complications. Rats in SCI and MEL groups underwent laminectomy followed by a severe compression injury by an aneurysm clip. Then, intrathecal treatment with vehicle (5% dimethyl sulfoxide) or MEL was carried out post-injury. Acetone drop, von Frey, inclined plane, and BBB tests as well as weight changes and auricle temperature, were used to evaluate the neuropathic pain, motor function, and other post-SCI complications. The effects of MEL on the activity of MMP-2 and MMP-9 were assessed using the gelatin zymography method every week till day 28 post-SCI. Histopathological assessments were performed on days 14, 21, and 28. MEL treatment resulted in decreased motor dysfunction, mechanical and cold allodynia, auricle temperature, and also ameliorated weight loss. Moreover, MEL suppressed MMP-9 activity while increasing that of MMP-2 post-SCI, indicating its anti-neuroinflammatory effects. Also, MEL significantly preserved white matter myelinated areas and the number of sensory neurons post-SCI. The results suggest MEL as a promising candidate for medical therapies with advantageous effects on improving functional recovery through suppressing inflammatory mediators, and attenuating spinal tissue damages.

Effect of Schwann cell transplantation combined with electroacupuncture on axonal regeneration and remyelination in rats with spinal cord injury.

Axonal impairment and demyelination after compressed spinal cord injury lead to serious neurological dysfunction. Increasing studies have suggested that Schwann cells (SCs) transplantation is a reliable, effective, and promising method for treating spinal cord injury. However, single SCs transplantation is insufficient to promote the full recovery of neurological function. Additional approaches are required to support SCs transplantation as a treatment for spinal cord injury. In the study, we investigated whether the combination of electroacupuncture (EA) and SCs transplantation was a reliable intervention for spinal cord injury. We found that rats in the combination group had significantly higher functional locomotor scores than those received single treatment. By immunostaining, we found EA can not only improve survival and proliferation of transplanted SCs but also inhibit SC apoptosis and block the formation of an astrocytic scar. Additionally, EA promoted regenerated axons extending "bullet-shaped" growth cones into the lesion. Remarkably, EA can modify astrogliosis to promote axonal regeneration following SCs transplantation through inducing extension of astrocytic processes in the SCs graft interface. More importantly, the combination of SCs engraftment and EA can enhance corticospinal-tract axonal regeneration and remyelination after spinal cord injury through up-regulating neuregulin 1 type III in SCs and its downstream signaling mediators. Thus, it is concluded that SCs effectively promote axonal recovery after spinal cord injury when combined with EA stimulation. The experimental results have reinforced the theoretical basis of EA for its clinical efficacy in patients with spinal cord injury and merited further investigation for potential clinical application.

Efficacy of dental pulp-derived stem cells conditioned medium loaded in collagen hydrogel in spinal cord injury in rats: Stereological evidence

Spinal cord injury (SCI) causes histological alterations which in turn affects functional activity. Studies have demonstrated that dental pulp-derived stem cells conditioned medium has beneficial effects on the nervous system. Besides, collagen hydrogel acts as a drug releasing system in SCI investigations.This research aimed to evaluate effects of dental pulp-derived stem cells conditioned medium loaded in collagen hydrogel in SCI.After culturing of Stem cells from human exfoliated deciduous teeth (SHEDs), SHED-conditioned medium (SHED-CM) was harvested and concentrated. Collagen hydrogel containing SHED-CM was prepared. The rats were divided into five groups receiving laminectomy, compressive SCI with or without intraspinal injection of biomaterials (SHED-CM and collagen hydrogel with or without SHED-CM). After 6 weeks, histological parameters were estimated using stereological methods.The total volume of preserved white matter and gray matter (p < 0.05) as well as the total number of neurons and oligodendrocytes in the rats received SHED-CM loaded in collagen hydrogel were significantly higher, and also lesion volume and lesion length were significantly lower (p < 0.05) compared to those of the other injured groups.In conclusion, intraspinal administration of SHED-CM loaded in collagen hydrogel leads to neuroprotection, proposing a cell-free therapeutic approach in SCI.

Correlation of Nogo A release with glia scar formation in spinal cord injury

Several axonal growth inhibitors have already been identified following spinal cord injury, the most known being myelin-derived proteins, such as Nogo-A. The present study aimed to correlate the formation of glial scar with the beginning of growth inhibitor, Nogo-A, release in rats previously submitted to compressive spinal cord injury. For this, 12 male and female Wistar rats (250 ± 50g) were divided into 3 groups of 4 animals each, according to the animals' euthanasia time after spinal cord injury (G3 - three days; G5 - five days; G7 - seven days). Spinal cord injuries were induced by means of dorsal laminectomy of the T10 vertebra and epidural compression. Histopathological evaluation and immunoreactivity of the Nogo-A axonal growth inhibitor were performed. It was observed that there was the release of the axonal inhibitor Nogo-A after 24h after the occurrence of spinal cord injury, and that the glial scar must be maintained, in this time interval, in order to guarantee the rebalancing of the post-trauma environment. Thus, it is suggested that the glial scar should be maintained in the acute phase of the lesion, guaranteeing its numerous benefits for the rebalancing of the post-injured environment and, after 24 hours, when the release of the studied axonal growth inhibitor begins, it should be removed.

Honokiol exerts protective effects on neural myelin sheaths after compressed spinal cord injury by inhibiting oligodendrocyte apoptosis through regulation of ER-mitochondrial interactions

Objective To investigate the effect of honokiol on demyelination after compressed spinal cord injury (CSCI) and it's possible mechanism. Design Animal experiment study. Setting Institute of Neuroscience of Chongqing Medical University. Interventions Total of 69 Sprague–Dawley (SD) rats were randomly divided into 3 groups: sham group (n=15), honokiol group (n=27) and vehicle group (n=27). After established CSCI model by a custom-made compressor successfully, the rats of sham group were subjected to the limited laminectomy without compression; the rats of honokiol group were subjected to CSCI surgery and intraperitoneal injection of 20 mg/kg honokiol; the rats of vehicle group were subjected to CSCI surgery and intraperitoneal injection of an equivalent volume of saline. Outcome measures: The locomotor function of each group was assessed using the Basso, Beattie and Bresnahan (BBB) rating scale. The pathological changes of myelinated nerve fibers of spinal cord in 3 groups were detected by osmic acid staining and transmission electron microcopy (TME). Immunofluorescence and Western blot were used to research the experessions of active caspase-3, caspase-12, cytochrome C and myelin basic protein (MBP) respectively. Results In the vehicle group, the rats became paralyzed and spastic after injury, and the myelin sheath became swollen and broken down along with decreased number of myelinated nerve fibers. Western blot analysis manifested that active caspase-3, caspase-12 and cytochrome C began to increase 1 d after injury while the expression of MBP decreased gradually. After intervened with honokiol for 6 days, compared with the vehicle group, the locomotor function and the pathomorphological changes of myelin sheath of the CSCD rats were improved with obviously decreased expression of active caspase-3, caspase-12 and cytochrome C. Conclusions Honokiol may improve locomotor function and protect neural myelin sheat from demyelination via prevention oligodendrocytes (OLs) apoptosis through mediate endoplasmic reticulum (ER)-mitochondria pathway after CSCI.

MiR-219 overexpressing oligodendrocyte progenitor cells for treating compression spinal cord injury.

Oligodendrocyte progenitor cells (OPCs) transplantation has been considered a promising treatment for spinal cord injury, according to previous studies. Recent research shed light on the importance of microRNA 219 (miR-219) in oligodendrocyte development, so here miR-219-overexpressing OPCs (miR-219 OPCs) were transplanted in animal models of spinal cord injury to evaluate the impact of miR-219 on oligodendrocyte differentiation and functional recovery in vivo. Our findings demonstrate that transplanted cells were distributed in the tissue sections and contributed to reducing the size of cavity in the injury site. Interestingly, miR-219 promoted OPC differentiation into mature oligodendrocyte expressing MBP in vivo whereas in absence of miR-219, less number of cells differentiated into mature oligodendrocytes. An eight week evaluation using the Basso Beattie Bresnahan (BBB) locomotor test confirmed improvement in functional recovery of hind limbs. Overall, this study demonstrated that miR-219 promoted differentiation and maturation of OPCs after transplantation and can be used in cell therapy of spinal cord injury.

The thrombin receptor links brain derived neurotrophic factor to neuron cholesterol production, resiliency and repair after spinal cord injury

Despite concerted efforts to identify CNS regeneration strategies, an incomplete understanding of how the needed molecular machinery is regulated limits progress. Here we use models of lateral compression and FEJOTA clip contusion-compression spinal cord injury (SCI) to identify the thrombin receptor (Protease Activated Receptor 1 (PAR1)) as an integral facet of this machine with roles in regulating neurite growth through a growth factor- and cholesterol-dependent mechanism. Functional recovery and signs of neural repair, including expression of cholesterol biosynthesis machinery and markers of axonal and synaptic integrity, were all increased after SCI in PAR1 knockout female mice, while PTEN was decreased. Notably, PAR1 differentially regulated HMGCS1, a gene encoding a rate-limiting enzyme in cholesterol production, across the neuronal and astroglial compartments of the intact versus injured spinal cord. Pharmacologic inhibition of cortical neuron PAR1 using vorapaxar in vitro also decreased PTEN and promoted neurite outgrowth in a cholesterol dependent manner, including that driven by suboptimal brain derived neurotrophic factor (BDNF). Pharmacologic inhibition of PAR1 also augmented BDNF-driven HMGCS1 and cholesterol production by murine cortical neurons and by human SH-SY5Y and iPSC-derived neurons. The link between PAR1, cholesterol and BDNF was further highlighted by demonstrating that the deleterious effects of PAR1 over-activation are overcome by supplementing cultures with BDNF, cholesterol or by blocking an inhibitor of adenylate cyclase, Gαi. These findings document PAR1-linked neurotrophic coupling mechanisms that regulate neuronal cholesterol metabolism as an important component of the machinery regulating CNS repair and point to new strategies to enhance neural resiliency after injury.

Role of MK2 signaling pathway mediating microglia/macrophages polarization in chronic compression injury of cervical spinal cord.

The role of inflammatory factors in the chronic compression injury of cervical spinal cord has drawn more attenion recently, however, the mechanism of which is still unclear. In this study, microglia/ macrophages polarization in the inflammatory responses to the injury and its regulation by MK2 signaling pathway have been investigated. twy/twy mice at the age of 6-24 weeks were used in the animal model for the chronic compression of cervical spinal cord. ICR (Institute of Cancer Research) mice were used as the control group. MK2 inhibitor (PF-3644022, 30 mg/kg) was administrated intragastrically to twy/twy mice from weeks 20 to 24. The compression of cervical spinal cord was identified by CT/MRI. The cervical spinal cord between C2 and C3 of vertebral segments were investigated by Western blot and Real-time PCR. The animal behaviors were evaluated by BMS score. Western blot and Real-time PCR showed that the expressions of iNOS and Arg-1 in the compressed spinal cord of twy/twy mice were significantly higher than those of the control group. After treatment with PF-3644022, the expression of Arg1 was increased while that of iNOS decreased. Realtime PCR revealed the increased expressions of inflammation related factors (such as IL-1β, NF-κB, TNF-α, MK2) and pro-apoptotic gene (Bax) except the decreased expression of anti-apoptotic gene (Bcl-2). Nevertheless, such increases were vanished after treatment of PF-3644022 except an increased expression of Bcl-2. The BMS score showed a reduced motor function of the twy/twy mice. The motor function was enhanced again with the treatment of PF-3644022. Microglia/macrophages polarization may be involved in the inflammatory response to the chronic compression of cervical spinal cord. It can be regulated by the MK2 signaling pathway. Therefore, it is possible to relieve the chronic compression of cervical spinal cord by regulating microglia/macrophages polarization through MK2 signaling pathway.

Pathophysiological Changes and the Role of Notch-1 Activation After Decompression in a Compressive Spinal Cord Injury Rat Model.

Surgical decompression is the primary treatment for cervical spondylotic myelopathy (CSM) patients with compressive spinal cord injury (CSCI). However, the prognosis of patients with CSCI varies, and the pathophysiological changes following decompression remain poor. This study aimed to investigate the pathophysiological changes and the role of Notch-1 activation after decompression in a rat CSCI model. Surgical decompression was conducted at 1 week post-injury (wpi). DAPT was intraperitoneally injected to down-regulate Notch-1 expression. Basso, Beattie, and Bresnahan scores and an inclined plane test were used to evaluate the motor function recovery. Hematoxylin and eosin staining was performed to assess pathophysiological changes, while hypoxia-inducible factor 1 alpha, vascular endothelial growth factor (VEGF), von Willebrand factor (vWF), matrix metalloproteinase (MMP)-9, MMP-2, Notch-1, and Hes-1 expression in the spinal cord were examined by immunohistochemical analysis or quantitative PCR. The results show that early decompression can partially promote motor function recovery. Improvements in structural and cellular damage and hypoxic levels were also observed in the decompressed spinal cord. Moreover, decompression resulted in increased VEGF and vWF expression, but decreased MMP-9 and MMP-2 expression at 3 wpi. Expression levels of Notch-1 and its downstream gene Hes-1 were increased after decompression, and the inhibition of Notch-1 significantly reduced the decompression-induced motor function recovery. This exploratory study revealed preliminary pathophysiological changes in the compressed and decompressed rat spinal cord. Furthermore, we confirmed that early surgical decompression partially promotes motor function recovery may via activation of the Notch-1 signaling pathway after CSCI. These results could provide new insights for the development of drug therapy to enhance recovery following surgery.

Motor, sensitive, and vegetative recovery in rats with compressive spinal-cord injury after combined treatment with erythropoietin and whole-body vibration.

Physical therapy with whole body vibration (WBV) following compressive spinal cord injury (SCI) in rats restores density of perisomatic synapses, improves body weight support and leads to a better bladder function. The purpose of the study was to determine whether the combined treatment with WBV plus erythropoietin (EPO) would further improve motor, sensory and vegetative functions after SCI in rats. Severe compressive SCI at low thoracic level was followed by a single i.p. injection of 2,5μg (250 IU) human recombinant EPO. Physical therapy with WBV started on 14th day after injury and continued over a 12-week post injury period. Locomotor recovery, sensitivity tests and urinary bladder scores were analysed at 1, 3, 6, 9, and 12 weeks after SCI. The closing morphological measurements included lesion volume and numbers of axons in the preserved perilesional neural tissue bridges (PNTB). Assessment of motor performance sensitivity and bladder function revealed no significant effects of EPO when compared to the control treatments. EPO treatment neither reduced the lesion volume, nor increased the number of axons in PNTB. The combination of WBV + EPO exerts no positive effects on hind limbs motor performance and bladder function after compressive SCI in rats.

Knockdown of miR-130a-3p alleviates spinal cord injury induced neuropathic pain by activating IGF-1/IGF-1R pathway

BackgroundRecent studies have elucidated the instrumental role of microRNAs (miRNAs) in neuropathic pain (NP) progression. As one member of miRNAs, miR-130a-3p has been proved as a mediator in inflammation and neuronal maturation. The present study attempted to elucidate what effect miR-130a-3p exerts on NP. Materials and methodsThe miR-130a-3p expression in the spinal cord tissues of rat with spinal cord compression injury (SCI) and LPS-induced BV2 microglia was determined with RT-PCR, which was further applied to analyze the clinical relevance between miR-130a-3p and neuropathic pain. Besides, the expression of IGF-1, IL-1β, IL-6, and TNF-α in the spinal cord tissues of rats was measured using RT-PCR and ELISA after intrathecal injection of miR-130a-3p inhibitors and tail vein injection of IGF-1 low-expression lentivirus (Lv-shIGF-1). Further, neuronal apoptosis (labeled by Caspase3) and microglial activation (labeled by Iba1) were examined by immunohistochemistry (IHC), and the levels of IGF-1, IGF-1R, NF-κB were determined by western blot. Additionally, bioinformatic was employed to analyze the potential target genes of miR-130a-3p. Furthermore, the dual luciferase activity assay and RNA immunoprecipitation assay were conducted to further substantiate whether miR-130a-3p targets IGF-1. ResultsIn comparison with the sham group, the miR-130a-3p expression was remarkably up-regulated in the spinal cord lesions of SCI rats. The ELISA results showed that inhibiting the miR-130a-3p significantly reduced NP symptoms of SCI rats, mitigated neuronal apoptosis, microglial activation, repressed NF-κB phosphorylation and the IL-1β, IL-6 and TNF-α expressions in SCI rats. Contrarily, downregulation of miR-130a-3p increased IGF-1 and IGF-1R expression. What's more, we observed the same effects in BV2 microglia. In addition, the bioinformatics analysis showed that miR-130-3p targeted at the 3′-untranslated region of IGF-1 and inhibiting its expression. However, abolishing IGF-1 not only promoted the inflammatory responses in the SCI lesions, but also aggravated NP of SCI rats, while those effects were attenuated by the downregulation of miR-130a-3p. ConclusionThe inhibition of miR-130a-3p expression up-regulates the IGF-1/IGF-1R signaling pathway, thus reducing neuropathic pain caused by spinal cord injury.

Local delivery of RhoA siRNA by PgP nanocarrier reduces inflammatory response and improves neuronal cell survival in a rat TBI model

Traumatic brain injury (TBI) is a leading cause of death and disability with complex pathophysiology including prolonged neuroinflammation, apoptosis, and glial scar formation. The upregulation of RhoA is a key factor in the pathological development of secondary injury following TBI. Previously, we developed a novel cationic, amphiphilic copolymer, poly (lactide-co-glycolide)-graft-polyethylenimine (PgP), as a nanocarrier for delivery of therapeutic nucleic acids. In a rat compression spinal cord injury model, delivery of siRNA targeting RhoA (siRhoA) by PgP resulted in RhoA knockdown; reduced astrogliosis and inflammation; and promoted axonal regeneration/sparing. Here, we evaluated the effect of RhoA knockdown by PgP/siRhoA nanoplexes in a rat controlled cortical impact TBI model. A single intraparenchymal injection of PgP/siRhoA nanoplexes significantly reduced RhoA expression, lesion volume, neuroinflammation, and apoptosis, and increased neuronal survival in the ipsilateral cortex. These results suggest that PgP/siRhoA nanoplexes can efficiently knockdown RhoA expression in the injured brain and reduce secondary injury.

Intensive Locomotor Training Provides Sustained Alleviation of Chronic Spinal Cord Injury-Associated Neuropathic Pain: A Two-Year Pre-Clinical Study.

Neuropathic pain often accompanies the functional deficits associated with spinal cord injury (SCI) and further reduces a patient's quality of life. Clinical and pre-clinical research is beginning to highlight the beneficial role that rehabilitative therapies such as locomotor training can have not only on functional recovery but also on chronic pain management. Our group has previously developed an intensive locomotor training (ILT) treadmill protocol on rats that reduced SCI neuropathic pain symptoms for at least 3 months. We have extended these findings in the current study to evaluate the ability of regular ILT regimen over a 2 year period post-SCI to maintain neuropathic pain reduction. To assess this, the rat clip compression SCI model (T7/8) was used and treadmill training was initiated starting 4 weeks after SCI and continuing through the duration of the study. Results showed continued suppression of SCI neuropathic pain responses (reduced mechanical, heat, and cold hypersensitivity throughout the entire time course of the study). In contrast, non-exercised rats showed consistent and sustained neuropathic pain responses during this period. In addition, prolonged survival and improved locomotor outcomes were observed in rats undergoing ILT as the study longevity progressed. Potential contributory mechanisms underlying beneficial effects of ILT include reduced inflammation and restoration of anti-nociceptive inhibitory processes as indicated by neurochemical assays in spinal tissue of remaining rats at 2 years post-SCI. The benefits of chronic ILT suggest that long-term physical exercise therapy can produce powerful and prolonged management of neuropathic pain, partly through sustained reduction of spinal pathological processes.