Spinal cord injury: time to move?

Mechanism of Neuroprotection Against Experimental Spinal Cord Injury by Riluzole or Methylprednisolone

Any spinal cord injury carries the potential for persistent disability affecting motor, sensory and autonomic functions. To prevent this outcome, it is highly desirable to block a chain of deleterious reactions developing in the spinal areas immediately around the primary lesion. Thus, early timing of pharmacological neuroprotection should be one major strategy whose impact may be first studied with preclinical models. Using a simple in vitro model of the rat spinal cord it is possible to mimic pathological processes like excitotoxicity that damages neurons because of excessive glutamate receptor activation due to injury, or hypoxic/dysmetabolic insult that preferentially affects glia following vascular dysfunction. While ongoing research is exploring the various components of pathways leading to cell death, current treatment principally relies on the off-label use of riluzole (RLZ) or methylprednisolone sodium succinate (MPSS). The mechanism of action of these drugs is diverse as RLZ targets mainly neurons and MPSS targets glia. Even when applied after a transient excitotoxic stimulus, RLZ can provide effective prevention of secondary excitotoxic damage to premotoneurons, although not to motoneurons that remain very vulnerable. This observation indicates persistent inability to express locomotor activity despite pharmacological treatment conferring some histological protection. MPSS can protect glia from dysmetabolic insult, yet it remains poorly effective to prevent neuronal death. In summary, it appears that these pharmacological agents can produce delayed protection for certain cell types only, and that their combined administration does not provide additional benefit. The search should continue for better, mechanism-based neuroprotective agents.

Treatment with albumin-hydroxyoleic acid complex restores sensorimotor function in rats with spinal cord injury: Efficacy and gene expression regulation

Sensorimotor dysfunction following incomplete spinal cord injury (SCI) is often characterized by paralysis, spasticity and pain. Previously, we showed that intrathecal (i.t.) administration of the albumin-oleic acid (A-OA) complex in rats with SCI produced partial improvement of these symptoms and that oral 2-hydroxyoleic acid (HOA, a non-hydrolyzable OA analogue), was efficacious in the modulation and treatment of nociception and pain-related anxiety, respectively. Here we observed that intrathecal treatment with the complex albumin-HOA (A-HOA) every 3 days following T9 spinal contusion injury improved locomotor function assessed with the Rotarod and inhibited TA noxious reflex activity in Wistar rats. To investigate the mechanism of action of A-HOA, microarray analysis was carried out in the spinal cord lesion area. Representative genes involved in pain and neuroregeneration were selected to validate the changes observed in the microarray analysis by quantitative real-time RT-PCR. Comparison of the expression between healthy rats, SCI rats, and SCI treated with A-HOA rats revealed relevant changes in the expression of genes associated with neuronal morphogenesis and growth, neuronal survival, pain and inflammation. Thus, treatment with A-HOA not only induced a significant overexpression of growth and differentiation factor 10 (GDF10), tenascin C (TNC), aspirin (ASPN) and sushi-repeat-containing X-linked 2 (SRPX2), but also a significant reduction in the expression of prostaglandin E synthase (PTGES) and phospholipases A1 and A2 (PLA1/2). Currently, SCI has very important unmet clinical needs. A-HOA downregulated genes involved with inflammation and upregulated genes involved in neuronal growth, and may serve to promote recovery of function after experimental SCI.

The p53 Pathway Controls SOX2-Mediated Reprogramming in the Adult Mouse Spinal Cord

Although the adult mammalian spinal cord lacks intrinsic neurogenic capacity, glial cells can be reprogrammed in vivo to generate neurons after spinal cord injury (SCI). How this reprogramming process is molecularly regulated, however, is not clear. Through a series of in vivo screens, we show here that the p53-dependent pathway constitutes a critical checkpoint for SOX2-mediated reprogramming of resident glial cells in the adult mouse spinal cord. While it has no effect on the reprogramming efficiency, the p53 pathway promotes cell-cycle exit of SOX2-induced adult neuroblasts (iANBs). As such, silencing of either p53 or p21 markedly boosts the overall production of iANBs. A neurotrophic milieu supported by BDNF and NOG can robustly enhance maturation of these iANBs into diverse but predominantly glutamatergic neurons. Together, these findings have uncovered critical molecular and cellular checkpoints that may be manipulated to boost neuron regeneration after SCI.

Arterial Blood Supply to the Spinal Cord in Animal Models of Spinal Cord Injury. A Review

Animal models are used to examine the results of experimental spinal cord injury. Alterations in spinal cord blood supply caused by complex spinal cord injuries contribute significantly to the diversity and severity of the spinal cord damage, particularly ischemic changes. However, the literature has not completely clarified our knowledge of anatomy of the complex three-dimensional arterial system of the spinal cord in experimental animals, which can impede the translation of experimental results to human clinical applications. As the literary sources dealing with the spinal cord arterial blood supply in experimental animals are limited and scattered, the authors performed a review of the anatomy of the arterial blood supply to the spinal cord in several experimental animals, including pigs, dogs, cats, rabbits, guinea pigs, rats, and mice and created a coherent format discussing the interspecies differences. This provides researchers with a valuable tool for the selection of the most suitable animal model for their experiments in the study of spinal cord ischemia and provides clinicians with a basis for the appropriate translation of research work to their clinical applications. Anat Rec, 300:2091-2106, 2017. © 2017 Wiley Periodicals, Inc.

Pericytes Make Spinal Cord Breathless after Injury

Traumatic spinal cord injury is a devastating condition that leads to significant neurological deficits and reduced quality of life. Therapeutic interventions after spinal cord lesions are designed to address multiple aspects of the secondary damage. However, the lack of detailed knowledge about the cellular and molecular changes that occur after spinal cord injury restricts the design of effective treatments. Li and colleagues using a rat model of spinal cord injury and in vivo microscopy reveal that pericytes play a key role in the regulation of capillary tone and blood flow in the spinal cord below the site of the lesion. Strikingly, inhibition of specific proteins expressed by pericytes after spinal cord injury diminished hypoxia and improved motor function and locomotion of the injured rats. This work highlights a novel central cellular population that might be pharmacologically targeted in patients with spinal cord trauma. The emerging knowledge from this research may provide new approaches for the treatment of spinal cord injury.

Ibuprofen-loaded fibrous patches-taming inhibition at the spinal cord injury site

It is now widely accepted that a therapeutic strategy for spinal cord injury (SCI) demands a multi-target approach. Here we propose the use of an easily implantable bilayer polymeric patch based on poly(trimethylene carbonate-co-ε-caprolactone) (P(TMC-CL)) that combines physical guidance cues provided by electrospun aligned fibres and the delivery of ibuprofen, as a mean to reduce the inhibitory environment at the lesion site by taming RhoA activation. Bilayer patches comprised a solvent cast film onto which electrospun aligned fibres have been deposited. Both layers were loaded with ibuprofen. In vitro release (37°C, in phosphate buffered saline) of the drug from the loaded scaffolds under sink condition was found to occur in the first 24 h. The released ibuprofen was shown to retain its bioactivity, as indicated by the reduction of RhoA activation when the neuronal-like cell line ND7/23 was challenged with lysophosphatidic acid. Ibuprofen-loaded P(TMC-CL) bilayer scaffolds were successfully implanted in vivo in a dorsal hemisection rat SCI model mediating the reduction of RhoA activation after 5 days of implantation in comparison to plain P(TMC-CL) scaffolds. Immunohistochemical analysis of the tissue shows βIII tubulin positive cells close to the ibuprofen-loaded patches further supporting the use of this strategy in the context of regeneration after a lesion in the spinal cord.

Regeneration of synapses in the olfactory pathway of locusts after antennal deafferentation

The olfactory pathway of the locust is capable of fast and precise regeneration on an anatomical level. Following deafferentation of the antenna either of young adult locusts, or of fifth instar nymphs, severed olfactory receptor neurons (ORNs) reinnervate the antennal lobe (AL) and arborize in AL microglomeruli. In the present study we tested whether these regenerated fibers establish functional synapses again. Intracellular recordings from AL projection neurons revealed that the first few odor stimulus evoked postsynaptic responses from regenerated ORNs from day 4-7 post crush on. On average, synaptic connections of regenerated afferents appeared faster in younger locusts operated as fifth instar nymphs than in adults. The proportions of response categories (excitatory vs. inhibitory) changed during regeneration, but were back to normal within 21 days. Odor-evoked oscillating extracellular local field potentials (LFP) were recorded in the mushroom body. These responses, absent after antennal nerve crush, reappeared, in a few animals as soon as 4 days post crush. Odor-induced oscillation patterns were restored within 7 days post crush. Both intra- and extracellular recordings indicate the capability of the locust olfactory system to re-establish synaptic contacts in the antennal lobe after antennal nerve lesion.

Weight Bearing Over-ground Stepping in an Exoskeleton with Non-invasive Spinal Cord Neuromodulation after Motor Complete Paraplegia

We asked whether coordinated voluntary movement of the lower limbs could be regained in an individual having been completely paralyzed (>4 year) and completely absent of vision (>15 year) using two novel strategies-transcutaneous electrical spinal cord stimulation at selected sites over the spine as well as pharmacological neuromodulation by buspirone. We also asked whether these neuromodulatory strategies could facilitate stepping assisted by an exoskeleton (EKSO, EKSO Bionics, CA) that is designed so that the subject can voluntarily complement the work being performed by the exoskeleton. We found that spinal cord stimulation and drug enhanced the level of effort that the subject could generate while stepping in the exoskeleton. In addition, stimulation improved the coordination patterns of the lower limb muscles resulting in a more continuous, smooth stepping motion in the exoskeleton along with changes in autonomic functions including cardiovascular and thermoregulation. Based on these data from this case study it appears that there is considerable potential for positive synergistic effects after complete paralysis by combining the over-ground step training in an exoskeleton, combined with transcutaneous electrical spinal cord stimulation either without or with pharmacological modulation.

HSYA alleviates secondary neuronal death through attenuating oxidative stress, inflammatory response, and neural apoptosis in SD rat spinal cord compression injury

Background

Hydroxysafflor yellow A (HSYA) is a major active component of yellow pigment extracted from safflowers; this compound possesses potent neuroprotective effects both in vitro and in vivo. However, underlying mechanism of HSYA is not fully elucidated. The present study investigated the protective effects of HSYA in rat spinal cord compression injury model and related mechanisms involved.

Methods

Sprague–Dawley rats were divided as Sham, Control, and HSYA groups (n = 30 per group). Spinal cord injury (SCI) model was induced by application of vascular clips (force of 50 g, 1 min) to the dura at T9–T10 level of vertebra. Injured animals were administered with either HSYA (8 mg/kg at 1 and 6 h after injury, then 14 mg/kg, for a total of 7 days at 24-h time intervals) or equal volume of saline by intraperitoneal injection.

Results

From this experiment, we discovered that SCI in rats resulted in severe trauma, which is characterized by tissue damage, lipid peroxidation, neutrophil infiltration, inflammation mediator release, and neuronal apoptosis. However, HSYA treatment significantly reduced the following: (1) degree of tissue injury (histological score) and edema; (2) neutrophil infiltration (myeloperoxidase activity); (3) oxidative stress (superoxide dismutase, malondialdehyde, and nitric oxide); (4) pro-inflammatory cytokine expression (tumor necrosis factor-α, interleukin-6, inducible nitric oxide synthase, cyclooxygenase-2); (5) nuclear factor-κB activation; (6) apoptosis (terminal deoxynucleotidyl transferase dUTP nick end labeling staining and cysteine-aspartic protease-3 activity). Moreover, in a separate set of experiments, we clearly demonstrated that HSYA treatment significantly ameliorated recovery of limb function (as evaluated by Basso, Beattie, and Bresnahan behavioral recovery scores).

Conclusions

Treatment with HSYA restrains development of oxidative stress, inflammation response, and apoptotic events associated with SCI of rats, demonstrating that HSYA is a potential neuroprotectant for human SCI therapy.

The regulatory effect of electro-acupuncture on the expression of NMDA receptors in a SCI rat model

BACKGROUND

In early spinal cord injury (SCI), glutamate receptors, including N-methyl-d-aspartate (NMDA) receptors (NMDARs), are over-stimulated by excessively released glutamate. The enhanced activity of NMDARs may cause cell death by overloading calcium (Ca²⁺) into cells based on their high permeability to Ca²⁺. Studies in SCI animals have shown that treatment with electro-acupuncture (EA) is able to reduce cell death and to improve functional recovery. One possible mechanism of this neuroprotective effect is that EA has regulatory effect on NMDARs.

AIMS

To test whether EA could protect the spinal cord after SCI by decreasing the expression levels of NR1 and NR2A.

MAIN METHODS

We conducted EA treatment on a rat SCI model produced with a New York University (NYU) Impactor and measured hindlimb locomotor function by Basso, Beattie and Bresnahan Locomotor Rating Scale (BBB Scale). The expression of NR1 and NR2, the subunits of NMDARs, in the injured spinal cord was measured by Immunofluorescence stainings, western blot and real-time quantitative PCR (RT-qPCR).

KEY FINDING

Our results showed that two days after the SCI the expression of NR1 and NR2 were dramatically enhanced at both protein and mNRA levels, which were significantly reduced by EA treatment at two specific acupoints, Dazhui (DU14) and Mingmen (DU4).

SIGNIFICANCE

EA is a potential therapeutic method for treating early SCI in human.

Spatiotemporal correlation of spinal network dynamics underlying spasms in chronic spinalized mice

Spasms after spinal cord injury (SCI) are debilitating involuntary muscle contractions that have been associated with increased motor neuron excitability and decreased inhibition. However, whether spasms involve activation of premotor spinal excitatory neuronal circuits is unknown. Here we use mouse genetics, electrophysiology, imaging and optogenetics to directly target major classes of spinal interneurons as well as motor neurons during spasms in a mouse model of chronic SCI. We find that assemblies of excitatory spinal interneurons are recruited by sensory input into functional circuits to generate persistent neural activity, which interacts with both the graded expression of plateau potentials in motor neurons to generate spasms, and inhibitory interneurons to curtail them. Our study reveals hitherto unrecognized neuronal mechanisms for the generation of persistent neural activity under pathophysiological conditions, opening up new targets for treatment of muscle spasms after SCI.

DOI:http://dx.doi.org/10.7554/eLife.23011.001

Patients with Chronic Spinal Cord Injury Exhibit Reduced Autonomic Modulation during an Emotion Recognition Task

Spinal cord injury (SCI) is a devastating event for individuals, who frequently develop motor and sensory impairment as well as autonomic dysfunction. Previous studies reported that autonomic activity plays a major role in social cognition and that difficulties in the ability to interpret social information are commonly observed in a variety of mental disorders, which in turn correlate with a poor autonomic nervous system (ANS) regulation. It is well established that subjects with SCI have an alteration in ANS regulation mechanisms. We hypothesized that subjects diagnosed with SCI, who are experiencing a period of adaptation and socio-labor insertion suffer alterations in an emotion recognition task, a component of social cognition, which correlate with poor ANS regulation. We evaluated ANS function by measuring the heart rate variability (HRV) in 18 healthy subjects and 10 subjects with SCI. A 5-min baseline HRV was compared to a task period while performing The reading the mind in the eyes test (RMET). We found that while both groups have similar general performance in the test, healthy subjects responded with greater certainty during the RMET. This level of certainty during the RMET was positively correlated with baseline HRV measures in this group. Also, the group of healthy subjects exhibited higher HRV at baseline than participants with SCI. Finally, the changes in HRV between baseline and task condition were significantly higher in healthy individuals than in SCI participants. Our results show that patients with SCI have low levels of autonomic regulation mechanisms which may promote social cognition problems during their reinsertion to daily life.

Regeneration of axotomized olfactory neurons in young and adult locusts quantified by fasciclin I immunofluorescence

The olfactory pathway of the locust Locusta migratoria is characterized by a multiglomerular innervation of the antennal lobe (AL) by olfactory receptor neurons (ORNs). After crushing the antenna and thereby severing ORN axons, changes in the AL were monitored. First, volume changes were measured at different times post-crush with scanning laser optical tomography in 5th instar nymphs. AL volume decreased significantly to a minimum volume at 4 days post-crush, followed by an increase. Second, anterograde labeling was used to visualize details in the AL and antennal nerve (AN) during de- and regeneration. Within 24 h post-crush (hpc) the ORN fragments distal to the lesion degenerated. After 48 hpc, regenerating fibers grew through the crush site. In the AL, labeled ORN projections disappeared completely and reappeared after a few days. A weak topographic match between ORN origin on the antenna and the position of innervated glomeruli that was present in untreated controls did not reappear after regeneration. Third, the cell surface marker fasciclin I that is expressed in ORNs was used for quantifying purposes. Immunofluorescence was measured in the AL during de- and regeneration in adults and 5th instar nymphs: after a rapid but transient, decrease, it reappeared. Both processes happen faster in 5th instar nymphs than in adults.

Experimental Research on Differentiation-Inducing Growth of Nerve Lateral Bud by HUC-MSCs Chitosan Composite Conduit

This study is intended to explore the role of human umbilical-cord-derived mesenchymal stem cells (HUC-MSCs) in nerve end-to-side anastomosis, as well as in the induction and promotion of growth of nerve lateral bud. The chitosan nerve conduit was prepared based on the biological characteristics of chitosan, and the nerve conduit was filled with HUC-MSCs, and was used to bridge the nerve end-to-side anastomotic stoma. The experimental animals were randomly assigned into three groups (10 in each group), and the nerve end-to-side anastomosis was conducted: (1) group A (control group): traditional tibial nerve-common peroneal nerve end-to-side anastomosis; (2) group B (experimental group 1): tibial nerve-common peroneal nerve end-to-side anastomotic stoma bridged with chitosan nerve conduit; (3) group C (experimental group 2): tibial nerve-common peroneal nerve end-to-side anastomotic stoma bridged by chitosan nerve conduit filled with HUC-MSCs. General morphological observation, nerve electrophysiology, and anti-S-100 immunohistochemistry were performed. All experimental animals survived, and no infections were found at operative incisions. The nerve continuity was in good condition through visual observation when sampling, which is mild adhesion to the surrounding tissue and easy to be separated. 12 W HUC-MSCs chitosan composite nerve conduits were degraded completely after operation. Electrophysiological test showed that the nerve conduction velocity (NCV) in group C was significantly higher than that in group A or group B (p < 0.01). There were no significant differences between NCVs of group A and group B. Toluidine blue staining and transmission electron microscope showed that the number of the medullated fibers and the myelin sheath thickness in group C were larger than those in group A or B. There were no significant differences between the numbers of the medullated fibers and between the myelin sheath thicknesses of groups A and B. By means of anti-S-100 immunohistochemistry, the arrangement of a large number of brown-red proliferating schwann cells around the regenerated nerve fibers in group C could be found, while fewer and sparse brown-red matters and very poor growth of schwann cells could be observed in groups A and B. Slightly more favorable situation could be observed in group B compared with group A. HUC-MSCs play obviously an important role in promoting nerve regeneration during the nerve end-to-side anastomosis, which induces the growth of axis bud, accelerates the growth velocity of regenerated fiber, and promotes the growth and maturity of schwann cells.

Anatomical mechanism of spontaneous recovery in regions caudal to thoracic spinal cord injury lesions in rats

Background

The nerve fibre circuits around a lesion play a major role in the spontaneous recovery process after spinal cord hemisection in rats. The aim of the present study was to answer the following question: in the re-control process, do all spinal cord nerves below the lesion site participate, or do the spinal cord nerves of only one vertebral segment have a role in repair?

Methods

First we made a T7 spinal cord hemisection in 50 rats. Eight weeks later, they were divided into three groups based on distinct second operations at T7: ipsilateral hemisection operation, contralateral hemisection, or transection. We then tested recovery of hindlimbs for another eight weeks. The first step was to confirm the lesion had role or not in the spontaneous recovery process. Secondly, we performed T7 spinal cord hemisections in 125 rats. Eight weeks later, we performed a second single hemisection on the ipsilateral side at T8–T12 and then tested hindlimb recovery for another six weeks.

Results

In the first part, the Basso, Beattie, Bresnahan (BBB) scores and the electrophysiology tests of both hindlimbs weren’t significantly different after the second hemisection of the ipsilateral side. In the second part, the closer the second hemisection was to T12, the more substantial the resulting impairment in BBB score tests and prolonged latency periods.

Conclusions

The nerve regeneration from the lesion area after hemisection has no effect on spontaneous recovery of the spinal cord. Repair is carried out by all vertebrae caudal and ipsilateral to the lesion, with T12 being most important.

Effect of hierarchically aligned fibrin hydrogel in regeneration of spinal cord injury demonstrated by tractography: A pilot study

Some studies have reported that scaffold or cell-based transplantation may improve functional recovery following SCI, but no imaging information regarding regeneration has been provided to date. This study used tractography to show the regenerating process induced by a new biomaterial-aligned fibrin hydrogel (AFG). A total of eight canines subjected to SCI procedures were assigned to the control or the AFG group. AFG was implanted into the SCI lesion immediately after injury in 5 canines. A follow-up was performed at 12 weeks to evaluate the therapeutic effect including the hindlimb functional recovery, anisotropy and continuity of fibers on tractography. Using tractography, we found new fibers running across the SCI in three canines of the AFG group. Further histological examination confirmed limited glial scarring and regenerated nerve fibers in the lesions. Moreover, Repeated Measures Analysis revealed a significantly different change in fractional anisotropy (FA) between the two groups during the follow-up interval. An increase in FA during the post injury time interval was detected in the AFG group, indicating a beneficial effect of AFG in the rehabilitation of injured axons. Using tractography, AFG was suggested to be helpful in the restoration of fibers in SCI lesions, thus leading to promoted functional recovery.

Minocycline targets multiple secondary injury mechanisms in traumatic spinal cord injury

Minocycline hydrochloride (MH), a semi-synthetic tetracycline derivative, is a clinically available antibiotic and anti-inflammatory drug that also exhibits potent neuroprotective activities. It has been shown to target multiple secondary injury mechanisms in spinal cord injury, via its anti-inflammatory, anti-oxidant, and anti-apoptotic properties. The secondary injury mechanisms that MH can potentially target include inflammation, free radicals and oxidative stress, glutamate excitotoxicity, calcium influx, mitochondrial dysfunction, ischemia, hemorrhage, and edema. This review discusses the potential mechanisms of the multifaceted actions of MH. Its anti-inflammatory and neuroprotective effects are partially achieved through conserved mechanisms such as modulation of p38 mitogen-activated protein kinase (MAPK) and phosphoinositide 3-kinase (PI3K)/Akt signaling pathways as well as inhibition of matrix metalloproteinases (MMPs). Additionally, MH can directly inhibit calcium influx through the N-methyl-D-aspartate (NMDA) receptors, mitochondrial calcium uptake, poly(ADP-ribose) polymerase-1 (PARP-1) enzymatic activity, and iron toxicity. It can also directly scavenge free radicals. Because it can target many secondary injury mechanisms, MH treatment holds great promise for reducing tissue damage and promoting functional recovery following spinal cord injury.

The protective effect of curcumin in Olfactory Ensheathing Cells exposed to hypoxia

Curcumin, a phytochemical component derived from the rhizomes of Curcuma longa, has shown a great variety of pharmacological activities, such as anti-inflammatory, anti-tumor, anti-depression and anti-oxidant activity. Therefore, in the last years it has been used as a therapeutic agent since it confers protection in different neurodegenerative diseases, cerebral ischemia and excitotoxicity. Olfactory Ensheathing Cells (OECs) are glial cells of the olfactory system. They are able to secrete several neurotrophic growth factors, promote axonal growth and support the remyelination of damaged axons. OEC transplantation has emerged as a possible experimental therapy to induce repair of spinal cord injury, even if the functional recovery is still limited. Since hypoxia is a secondary effect in spinal cord injury, this in vitro study investigates the protective effect of curcumin in OECs exposed to hypoxia. Primary OECs were obtained from neonatal rat olfactory bulbs and placed both in normal and hypoxic conditions. Furthermore, some cells were grown with basic Fibroblast Growth Factor (bFGF) and/or curcumin at different concentration and times. The results obtained through immunocytochemical procedures and MTT test show that curcumin stimulates cell viability in OECs grown in normal and hypoxic conditions. Furthermore, the synergistic effect of curcumin and bFGF is the most effective exerting protection on OECs. Since spinal cord injury is often accompanied by secondary insults, such as ischemia or hypoxia, our results suggest that curcumin in combination with bFGF might be considered a possible approach for restoration in injuries.

Spinal Plasticity and Behavior: BDNF-Induced Neuromodulation in Uninjured and Injured Spinal Cord

Brain-derived neurotrophic factor (BDNF) is a member of the neurotrophic factor family of signaling molecules. Since its discovery over three decades ago, BDNF has been identified as an important regulator of neuronal development, synaptic transmission, and cellular and synaptic plasticity and has been shown to function in the formation and maintenance of certain forms of memory. Neural plasticity that underlies learning and memory in the hippocampus shares distinct characteristics with spinal cord nociceptive plasticity. Research examining the role BDNF plays in spinal nociception and pain overwhelmingly suggests that BDNF promotes pronociceptive effects. BDNF induces synaptic facilitation and engages central sensitization-like mechanisms. Also, peripheral injury-induced neuropathic pain is often accompanied with increased spinal expression of BDNF. Research has extended to examine how spinal cord injury (SCI) influences BDNF plasticity and the effects BDNF has on sensory and motor functions after SCI. Functional recovery and adaptive plasticity after SCI are typically associated with upregulation of BDNF. Although neuropathic pain is a common consequence of SCI, the relation between BDNF and pain after SCI remains elusive. This article reviews recent literature and discusses the diverse actions of BDNF. We also highlight similarities and differences in BDNF-induced nociceptive plasticity in naïve and SCI conditions.

Neuroprotective effect of propofol against excitotoxic injury to locomotor networks of the rat spinal cord in vitro

Although neuroprotection to contain the initial damage of spinal cord injury (SCI) is difficult, multicentre studies show that early neurosurgery under general anaesthesia confers positive benefits. An interesting hypothesis is that the general anaesthetic itself might largely contribute to neuroprotection, although in vivo clinical settings hamper studying this possibility directly. To further test neuroprotective effects of a widely used general anaesthetic, we studied if propofol could change the outcome of a rat isolated spinal cord SCI model involving excitotoxicity evoked by 1 h application of kainate with delayed consequences on neurons and locomotor network activity. Propofol (5 μm; 4-8 h) enhanced responses to GABA and depressed those to NMDA together with decrease in polysynaptic reflexes that partly recovered after 1 day washout. Fictive locomotion induced by dorsal root stimuli or NMDA and serotonin was weaker the day after propofol application. Kainate elicited a significant loss of spinal neurons, especially motoneurons, whose number was halved. When propofol was applied for 4-8 h after kainate washout, strong neuroprotection was observed in all spinal areas, including attenuation of motoneuron loss. Although propofol had minimal impact on recovery of electrophysiological characteristics 24 h later, it did not further depress network activity. A significant improvement in disinhibited burst periodicity suggested potential to ameliorate neuronal excitability in analogy to histological data. Functional recovery of locomotor networks perhaps required longer time due to the combined action of excitotoxicity and anaesthetic depression at 24 h. These results suggest propofol could confer good neuroprotection to spinal circuits during experimental SCI.

Impact of neural cell adhesion molecule deletion on regeneration after mouse spinal cord injury

The neural cell adhesion molecule (NCAM) plays important functional roles in development of the nervous system. We investigated the influence of a constitutive ablation of NCAM on the outcome of spinal cord injury. Transgenic mice lacking NCAM (NCAM-/-) were subjected to severe compression injury of the lower thoracic spinal cord using wild-type (NCAM+/+) littermates as controls. According to the single-frame motion analysis, the NCAM-/- mice showed reduced locomotor recovery in comparison to control mice at 3 and 6 weeks after injury, indicating an overall positive impact of NCAM on recovery after injury. Also the Basso Mouse Scale score was lower in NCAM-/- mice at 3 weeks after injury, whereas at 6 weeks after injury the difference between genotypes was not statistically significant. Worse locomotor function was associated with decreased monoaminergic and cholinergic innervation of the spinal cord caudal to the injury site and decreased axonal regrowth/sprouting at the site of injury. Astrocytic scar formation at the injury site, as assessed by immunohistology for glial fibrillary acidic protein at and around the lesion site was increased in NCAM-/- compared with NCAM+/+ mice. Migration of cultured monolayer astrocytes from NCAM-/- mice was reduced as assayed by scratch wounding. Numbers of Iba-1 immunopositive microglia were not different between genotypes. We conclude that constitutive NCAM deletion in young adult mice reduces recovery after spinal cord injury, validating the hypothesized beneficial role of this molecule in recovery after injury.

Proteomic Analysis of the Spatio-temporal Based Molecular Kinetics of Acute Spinal Cord Injury Identifies a Time- and Segment-specific Window for Effective Tissue Repair

Spinal cord injury (SCI) represents a major debilitating health issue with a direct socioeconomic burden on the public and private sectors worldwide. Although several studies have been conducted to identify the molecular progression of injury sequel due from the lesion site, still the exact underlying mechanisms and pathways of injury development have not been fully elucidated. In this work, based on OMICs, 3D matrix-assisted laser desorption ionization (MALDI) imaging, cytokines arrays, confocal imaging we established for the first time that molecular and cellular processes occurring after SCI are altered between the lesion proximity, i.e. rostral and caudal segments nearby the lesion (R1-C1) whereas segments distant from R1-C1, i.e. R2-C2 and R3-C3 levels coexpressed factors implicated in neurogenesis. Delay in T regulators recruitment between R1 and C1 favor discrepancies between the two segments. This is also reinforced by presence of neurites outgrowth inhibitors in C1, absent in R1. Moreover, the presence of immunoglobulins (IgGs) in neurons at the lesion site at 3 days, validated by mass spectrometry, may present additional factor that contributes to limited regeneration. Treatment in vivo with anti-CD20 one hour after SCI did not improve locomotor function and decrease IgG expression. These results open the door of a novel view of the SCI treatment by considering the C1 as the therapeutic target.

Propitious Therapeutic Modulators to Prevent Blood-Spinal Cord Barrier Disruption in Spinal Cord Injury

The blood-spinal cord barrier (BSCB) is a specialized protective barrier that regulates the movement of molecules between blood vessels and the spinal cord parenchyma. Analogous to the blood-brain barrier (BBB), the BSCB plays a crucial role in maintaining the homeostasis and internal environmental stability of the central nervous system (CNS). After spinal cord injury (SCI), BSCB disruption leads to inflammatory cell invasion such as neutrophils and macrophages, contributing to permanent neurological disability. In this review, we focus on the major proteins mediating the BSCB disruption or BSCB repair after SCI. This review is composed of three parts. Section 1. SCI and the BSCB of the review describes critical events involved in the pathophysiology of SCI and their correlation with BSCB integrity/disruption. Section 2. Major proteins involved in BSCB disruption in SCI focuses on the actions of matrix metalloproteinases (MMPs), tumor necrosis factor alpha (TNF-α), heme oxygenase-1 (HO-1), angiopoietins (Angs), bradykinin, nitric oxide (NO), and endothelins (ETs) in BSCB disruption and repair. Section 3. Therapeutic approaches discusses the major therapeutic compounds utilized to date for the prevention of BSCB disruption in animal model of SCI through modulation of several proteins.

Delayed application of the anesthetic propofol contrasts the neurotoxic effects of kainate on rat organotypic spinal slice cultures

Excitotoxicity due to hyperactivation of glutamate receptors is thought to underlie acute spinal injury with subsequent strong deficit in spinal network function. Devising an efficacious protocol of neuroprotection to arrest excitotoxicity might, therefore, spare a substantial number of neurons and allow later recovery. In vitro preparations of the spinal cord enable detailed measurement of spinal damage evoked by the potent glutamate analogue kainate. Any clinically-relevant neuroprotective treatment should start after the initial lesion and spare networks for at least 24h when cell damage plateaus. Using this strategy, we have observed that the gas anesthetic methoxyflurane provided strong, delayed neuroprotection. It is unclear if this beneficial effect was due to the mechanism of action by methoxyflurane, or it was the consequence of anesthetic depression. To test this hypothesis, we investigated the effect by propofol (commonly injected i.v. for general anesthesia) after kainate excitotoxicity induced on organotypic spinal slices. At 5μM concentration, propofol significantly attenuated cell death, including neuronal losses and, especially, damage to the highly vulnerable motoneurons. The action by propofol was fully prevented when co-applied with the GABAA antagonist bicuculline, indicating that neuroprotection required intact GABAA receptor function. Although bicuculline per se was not neurotoxic, it largely enhanced the lesional effects of kainate, suggesting that GABAA receptor activity could limit excitotoxicity. Our data might offer an explanation for the beneficial clinical outcome of neurosurgery performed as soon as possible after spinal lesion: we posit that general anesthesia contributes to this outcome, regardless of the type of anesthetic used.

Lentiviral-Mediated Netrin-1 Overexpression Improves Motor and Sensory Functions in SCT Rats Associated with SYP and GAP-43 Expressions

Spinal cord injury (SCI), as a major cause of disability, usually causes serious loss of motor and sensory functions. As a bifunctional axonal guidance cue, netrin-1 can attract axons via the deleted in colorectal cancer (DCC) receptors and repelling others via Unc5 receptors, but its exact role in the recovery of motor and sensory function has not well been studied, and the mechanisms remains elusive. The aim of this experiment is to determine whether lentiviral (LV)-mediated overexpression of netrin-1 or RNA interference (RNAi) can regulate the functional recovery in rats subjected to spinal cord transection (SCT). Firstly, two lentiviral vectors including Lv-exNtn-1 (netrin-1 open reading frame (ORF)) and Lv-shNtn-1 (netrin-1 sh) were constructed and injected into spinal cords rostral and caudal to the transected lesion site. Overexpressing netrin-1 enhanced significantly locomotor function, and reduced thermal and mechanical stimuli in vivo, compared with the control, while silencing netrin-1 did not significantly change the situation. Western blot and immunostaining analysis confirmed that netrin-1 ORF treatment not only effectively increased the expression level of netrin-1, also up-regulated the level of synaptophysin (SYP) in spinal cord rostral to the lesion, but also enhanced growth-associated protein-43 (GAP-43) expression in spinal cord caudal to the lesion site. Comparatively, knockdown of netrin-1 did not give rise to positive findings in our experimental condition. These findings therefore pointed that Lv-mediated netrin-1 overexpression could promote motor and sensory functional recoveries following SCT, and the underlying mechanisms were associated with SYP and GAP-43 expressions. The present study therefore provided a novel strategy for the treatment of SCI and explained the possible mechanisms for the functional improvement.

Germline ablation of dermatan-4O-sulfotransferase1 reduces regeneration after mouse spinal cord injury

Chondroitin/dermatan sulfate proteoglycans (CSPGs/DSPGs) are major components of the extracellular matrix. Their expression is generally upregulated after injuries to the adult mammalian central nervous system, which is known for its low ability to restore function after injury. Several studies support the view that CSPGs inhibit regeneration after injury, whereas the functions of DSPGs in injury paradigms are less certain. To characterize the functions of DSPGs in the presence of CSPGs, we studied young adult dermatan-4O-sulfotransferase1-deficient (Chst14(-/-)) mice, which express chondroitin sulfates (CSs), but not dermatan sulfates (DSs), to characterize the functional outcome after severe compression injury of the spinal cord. In comparison to their wild-type (Chst14(+/+)) littermates, regeneration was reduced in Chst14(-/-) mice. No differences between genotypes were seen in the size of spinal cords, numbers of microglia and astrocytes neither in intact nor injured spinal cords after injury. Monoaminergic innervation and re-innervation of the spinal cord caudal to the lesion site as well as expression levels of glial fibrillary acidic protein (GFAP) and myelin basic protein (MBP) were similar in both genotypes, independent of whether they were injured and examined 6weeks after injury or not injured. These results suggest that, in contrast to CSPGs, DSPGs, being the products of Chst14 enzymatic activity, promote regeneration after injury of the adult mouse central nervous system.

The Anti-Inflammatory Compound Curcumin Enhances Locomotor and Sensory Recovery after Spinal Cord Injury in Rats by Immunomodulation

Well known for its anti-oxidative and anti-inflammation properties, curcumin is a polyphenol found in the rhizome of Curcuma longa. In this study, we evaluated the effects of curcumin on behavioral recovery, glial scar formation, tissue preservation, axonal sprouting, and inflammation after spinal cord injury (SCI) in male Wistar rats. The rats were randomized into two groups following a balloon compression injury at the level of T9–T10 of the spinal cord, namely vehicle- or curcumin-treated. Curcumin was applied locally on the surface of the injured spinal cord immediately following injury and then given intraperitoneally daily; the control rats were treated with vehicle in the same manner. Curcumin treatment improved behavioral recovery within the first week following SCI as evidenced by improved Basso, Beattie, and Bresnahan (BBB) test and plantar scores, representing locomotor and sensory performance, respectively. Furthermore, curcumin treatment decreased glial scar formation by decreasing the levels of MIP1α, IL-2, and RANTES production and by decreasing NF-κB activity. These results, therefore, demonstrate that curcumin has a profound anti-inflammatory therapeutic potential in the treatment of spinal cord injury, especially when given immediately after the injury.

Bridging the lesion-engineering a permissive substrate for nerve regeneration

Biomaterial-based strategies to restore connectivity after lesion at the spinal cord are focused on bridging the lesion and providing an favourable substrate and a path for axonal re-growth. Following spinal cord injury (SCI) a hostile environment for neuronal cell growth is established by the activation of multiple inhibitory mechanisms that hamper regeneration to occur. Implantable scaffolds can provide mechanical support and physical guidance for axon re-growth and, at the same time, contribute to alleviate the hostile environment by the in situ delivery of therapeutic molecules and/or relevant cells. Basic research on SCI has been contributing with the description of inhibitory mechanisms for regeneration as well as identifying drugs/molecules that can target inhibition. This knowledge is the background for the development of combined strategies with biomaterials. Additionally, scaffold design is significantly evolving. From the early simple hollow conduits, scaffolds with complex architectures that can modulate cell fate are currently being tested. A number of promising pre-clinical studies combining scaffolds, cells, drugs and/or nucleic acids are reported in the open literature. Overall, it is considered that to address the multi-factorial inhibitory environment of a SCI, a multifaceted therapeutic approach is imperative. The progress in the identification of molecules that target inhibition after SCI and its combination with scaffolds and/or cells are described and discussed in this review.

Interleukin-33 treatment reduces secondary injury and improves functional recovery after contusion spinal cord injury

Interleukin-33 (IL-33) is a member of the interleukin-1 cytokine family and highly expressed in the naïve mouse brain and spinal cord. Despite the fact that IL-33 is known to be inducible by various inflammatory stimuli, its cellular localization in the central nervous system and role in pathological conditions is controversial. Administration of recombinant IL-33 has been shown to attenuate experimental autoimmune encephalomyelitis progression in one study, yet contradictory reports also exist. Here we investigated for the first time the pattern of IL-33 expression in the contused mouse spinal cord and demonstrated that after spinal cord injury (SCI) IL-33 was up-regulated and exhibited a nuclear localization predominantly in astrocytes. Importantly, we found that treatment with recombinant IL-33 alleviated secondary damage by significantly decreasing tissue loss, demyelination and astrogliosis in the contused mouse spinal cord, resulting in dramatically improved functional recovery. We identified both central and peripheral mechanisms of IL-33 action. In spinal cord, IL-33 treatment reduced the expression of pro-inflammatory tumor necrosis factor-alpha and promoted the activation of anti-inflammatory arginase-1 positive M2 microglia/macrophages, which chronically persisted in the injured spinal cord for up to at least 42 days after the treatment. In addition, IL-33 treatment showed a tendency towards reduced T-cell infiltration into the spinal cord. In the periphery, IL-33 treatment induced a shift towards the Th2 type cytokine profile and reduced the percentage and absolute number of cytotoxic, tumor necrosis factor-alpha expressing CD4+ cells in the spleen. Additionally, IL-33 treatment increased expression of T-regulatory cell marker FoxP3 and reduced expression of M1 marker iNOS in the spleen. Taken together, these results provide the first evidence that IL-33 administration is beneficial after CNS trauma. Treatment with IL33 may offer a novel therapeutic strategy for patients with acute contusion SCI.

A microfluidic neuronal platform for neuron axotomy and controlled regenerative studies

We have presented here a simple microfluidic approach to model mechanical and synchronized axotomy of a large number of axons to study axonal regeneration, and to facilitate rapid screening and discovery of novel pharmaceutical compounds.

Function of microglia and macrophages in secondary damage after spinal cord injury

Spinal cord injury (SCI) is a devastating type of neurological trauma with limited therapeutic opportunities. The pathophysiology of SCI involves primary and secondary mechanisms of injury. Among all the secondary injury mechanisms, the inflammatory response is the major contributor and results in expansion of the lesion and further loss of neurologic function. Meanwhile, the inflammation directly and indirectly dominates the outcomes of SCI, including not only pain and motor dysfunction, but also preventingneuronal regeneration. Microglia and macrophages play very important roles in secondary injury. Microglia reside in spinal parenchyma and survey the microenvironment through the signals of injury or infection. Macrophages are derived from monocytes recruited to injured sites from the peripheral circulation. Activated resident microglia and monocyte-derived macrophages induce and magnify immune and inflammatory responses not only by means of their secretory moleculesand phagocytosis, but also through their influence on astrocytes, oligodendrocytes and demyelination. In this review, we focus on the roles of microglia and macrophages in secondary injury and how they contribute to the sequelae of SCI.

Survival of neural stem cell grafts in the lesioned spinal cord is enhanced by a combination of treadmill locomotor training via insulin-like growth factor-1 signaling

Combining cell transplantation with activity-based rehabilitation is a promising therapeutic approach for spinal cord repair. The present study was designed to investigate potential interactions between the transplantation (TP) of neural stem cells (NSCs) obtained at embryonic day 14 and treadmill training (TMT) in promoting locomotor recovery and structural repair in rat contusive injury model. Combination of TMT with NSC TP at 1 week after injury synergistically improved locomotor function. We report here that combining TMT increased the survival of grafted NSCs by >3-fold and >5-fold at 3 and 9 weeks after injury, respectively. The number of surviving NSCs was significantly correlated with the extent of locomotor recovery. NSCs grafted into the injured spinal cord were under cellular stresses induced by reactive nitrogen or oxygen species, which were markedly attenuated by TMT. TMT increased the concentration of insulin-like growth factor-1 (IGF-1) in the CSF. Intrathecal infusion of neutralizing IGF-1 antibodies, but not antibodies against either BDNF or Neurotrophin-3 (NT-3), abolished the enhanced survival of NSC grafts by TMT. The combination of TP and TMT also resulted in tissue sparing, increased myelination, and restoration of serotonergic fiber innervation to the lumbar spinal cord to a larger extent than that induced by either TP or TMT alone. Therefore, we have discovered unanticipated beneficial effects of TMT in modulating the survival of grafted NSCs via IGF-1. Our study identifies a novel neurobiological basis for complementing NSC-based spinal cord repair with activity-based neurorehabilitative approaches.

Intrathecal injection of a therapeutic gene-containing polyplex to treat spinal cord injury

Spinal cord injury (SCI) is a serious clinical problem that suddenly deprives patients of neurologic function and drastically diminishes their quality of life. Gene introduction has the potential to be effective for various pathological states of SCI because various proteins can be produced just by modifying nucleic acid sequences. In addition, the sustainable protein expression allows to maintain its concentration at an effective level at the target site in the spinal cord. Here we propose an approach using a polyplex system composed of plasmid DNA (pDNA) and a cationic polymer, poly{N'-[N-(2-aminoethyl)-2-aminoethyl]aspartamide} [PAsp(DET)], that has high capacity to promote endosome escape and the long-term safety by self-catalytically degrading within a few days. We applied brain-derived neurotrophic factor (BDNF)-expressing pDNA for SCI treatment by intrathecal injection of PAsp(DET)/pDNA polyplex. A single administration of polyplex for experimental SCI provided sufficient therapeutic effects including prevention of neural cell death and enhancement of motor function recovery. This lasted for a few weeks after SCI, demonstrating the capability of this system to express BDNF in a safe and responsible manner for treatment of various pathological states in SCI.

Neural stem cell-conditioned medium protects neurons and promotes propriospinal neurons relay neural circuit reconnection after spinal cord injury

Human fetal neural stem cells (hNSCs) are used to treat a variety of neurological disorders involving spinal cord injury (SCI). Although their mechanism of action has been attributed to cell substitution, we examined the possibility that NSCs may have neuroprotective activities. The present article studied the action of hNSCs on protecting neurons and promoting corticospinal tract (CST) axon regeneration after SCI. hNSCs were isolated from the cortical tissue of spontaneously aborted human fetuses. The cells were removed from the NSC culture medium to acquire NSCM, thus excluding the effect of cell substitution. Continuous administration of the NSCM after the SCI resulted in extensive growth of the CST in the cervical region and more than tripled the formation of synaptic contacts between CST collaterals and propriospinal interneurons that project from the cervical level of the spinal cord to the lumbar level. NSCM reduced the number of caspase 3-positive apoptotic profiles at 7 days and protected against loss of the neurons 6 weeks after injury. NSCM promoted locomotor recovery with a five-point improvement on the BBB scale in adult rats. Thus, hNSCs help to set up a contour neural circuit via secretory factors, which may be the mechanism for their action in SCI rats. This manuscript is published as part of the International Association of Neurorestoratology (IANR) special issue of Cell Transplantation.

Spinal cord contusion

Spinal cord injury is a major cause of disability with devastating neurological outcomes and limited therapeutic opportunities, even though there are thousands of publications on spinal cord injury annually. There are two major types of spinal cord injury, transaction of the spinal cord and spinal cord contusion. Both can theoretically be treated, but there is no well documented treatment in human being. As for spinal cord contusion, we have developed an operation with fabulous result.

Peripheral noxious stimulation reduces withdrawal threshold to mechanical stimuli after spinal cord injury: role of tumor necrosis factor alpha and apoptosis

We previously showed that peripheral noxious input after spinal cord injury (SCI) inhibits beneficial spinal plasticity and impairs recovery of locomotor and bladder functions. These observations suggest that noxious input may similarly affect the development and maintenance of chronic neuropathic pain, an important consequence of SCI. In adult rats with a moderate contusion SCI, we investigated the effect of noxious tail stimulation, administered 1 day after SCI on mechanical withdrawal responses to von Frey stimuli from 1 to 28 days after treatment. In addition, because the proinflammatory cytokine tumor necrosis factor alpha (TNFα) is implicated in numerous injury-induced processes including pain hypersensitivity, we assessed the temporal and spatial expression of TNFα, TNF receptors, and several downstream signaling targets after stimulation. Our results showed that unlike sham surgery or SCI only, nociceptive stimulation after SCI induced mechanical sensitivity by 24h. These behavioral changes were accompanied by increased expression of TNFα. Cellular assessments of downstream targets of TNFα revealed that nociceptive stimulation increased the expression of caspase 8 and the active subunit (12 kDa) of caspase 3, indicative of active apoptosis at a time point consistent with the onset of mechanical allodynia. In addition, immunohistochemical analysis revealed distinct morphological signs of apoptosis in neurons and microglia at 24h after stimulation. Interestingly, expression of the inflammatory mediator NFκB was unaltered by nociceptive stimulation. These results suggest that noxious input caudal to the level of SCI can increase the onset and expression of behavioral responses indicative of pain, potentially involving TNFα signaling.

Glucocorticoid-induced leucine zipper (GILZ) controls inflammation and tissue damage after spinal cord injury

AIMS

Spinal cord injury (SCI) occurs following damage to the spinal column. Following trauma, tissue damage is further exacerbated by a secondary damage due to a SCI-activated inflammatory process. Control of leukocytes activity is essential to therapeutic inhibition of the spinal cord damage to ameliorate the patient's conditions. The mechanisms that regulate neuroinflammation following SCI, including T-cell infiltration, have not been completely clarified. Glucocorticoids (GC) are antiinflammatory drugs widely used in therapy, including treatment of SCI. GC efficacy may be linked to many molecular mechanisms that are involved in regulation of leukocytes migration, activation, and differentiation. We have previously shown that the antiinflammatory activity of GC is in part mediated by glucocorticoid-induced leucine zipper (GILZ). Here, we investigated the role of GILZ in inflammation and spinal cord tissue damage following a spinal trauma.

METHODS

We address the role of GILZ in SCI-induced inflammation and tissue damage using a model of SCI in gilz knockout (gilz KO) and wild-type (WT) mice.

RESULTS

We found that GILZ deficiency is associated with a strong reduction of SCI-induced inflammation and a significantly reduced lesion area following SCI.

CONCLUSION

These results demonstrate that GILZ is involved in induction of neuroinflammation and functional outcomes of spinal cord trauma.

Viability of olfactory ensheathing cells after hypoxia and serum deprivation: Implication for therapeutic transplantation

Olfactory ensheathing cells (OECs) represent glial cells supporting neuronal turnover in the olfactory system. In vitro, OECs promote axonal growth as a source of neurotrophic growth factors; in vivo, they produce myelin, promoting remyelination of damaged axons. Consequently, OEC transplantation appears to be a promising treatment for spinal cord injury, although the functional recovery is limited. This might be ascribed to the microenvironment at the lesion site, lacking growth factors (GFs), nutrients, and oxygen. To mimic this condition, we used an in vitro approach by growing primary neonatal mouse OECs under hypoxic conditions and/or serum deprivation. In addition, we compared OECs survival/proliferation with that of primary cultures of Schwann cells (SCs) and astrocytes under the same experimental conditions. Cultures were analyzed by immunocytochemistry, and cell viability was evaluated by MTT assay. Different GFs, such as NGF, bFGF, and GDNF, and their combination were used to rescue cells from serum and/or oxygen deprivation. We show that the cell types were differently sensitive to the tested stress conditions and that OECs were the most sensitive among them. Moreover, OEC viability was rescued by bFGF under serum-deprived or hypoxic condition but not under conditions of drastic serum deprivation and hypoxia. bFGF was effective also for the other cell types, whereas the effect of the other GFs was negligible. This model suggests that administration of bFGF might be considered useful to sustain cell survival/proliferation after transplantation of OECs either alone or in combination with other glial cell types.

Omega-conotoxin MVIIC attenuates neuronal apoptosis in vitro and improves significant recovery after spinal cord injury in vivo in rats

Excessive accumulation of intracellular calcium is the most critical step after spinal cord injury (SCI). Reducing the calcium influx should result in a better recovery from SCI. Calcium channel blockers have been shown a great potential in reducing brain and spinal cord injury. In this study, we first tested the neuroprotective effect of MVIIC on slices of spinal cord subjected to ischemia evaluating cell death and caspase-3 activation. Thereafter, we evaluated the efficacy of MVIIC in ameliorating damage following SCI in rats, for the first time in vivo. The spinal cord slices subjected a pretreatment with MVIIC showed a cell protection with a reduction of dead cells in 24.34% and of caspase-3-specific protease activation. In the in vivo experiment, Wistar rats were subjected to extradural compression of the spinal cord at the T12 vertebral level using a weigh of 70 g/cm, following intralesional treatment with either placebo or MVIIC in different doses (15, 30 and 60 pmol) five minutes after injury. Behavioral testing of hindlimb function was done using the Basso Beattie Bresnahan locomotor rating scale, and revealed significant recovery with 15 pmol (G15) compared to other trauma groups. Also, histological bladder structural revealed significant outcome in G15, with no morphological alterations, and anti-NeuN and TUNEL staining showed that G15 provided neuron preservation and indicated that this group had fewer neuron cell death, similar to sham. These results showed the neuroprotective effects of MVIIC in in vitro and in vivo model of SCI with neuronal integrity, bladder and behavioral improvements.

Systemic effects induced by intralesional injection of ω-conotoxin MVIIC after spinal cord injury in rats

Background

Calcium channel blockers such as conotoxins have shown a great potential to reduce brain and spinal cord injury. MVIIC neuroprotective effects analyzed in in vitro models of brain and spinal cord ischemia suggest a potential role of this toxin in preventing injury after spinal cord trauma. However, previous clinical studies with MVIIC demonstrated that clinical side effects might limit the usefulness of this drug and there is no research on its systemic effects. Therefore, the present study aimed to investigate the potential toxic effects of MVIIC on organs and to evaluate clinical and blood profiles of rats submitted to spinal cord injury and treated with this marine toxin. Rats were treated with placebo or MVIIC (at doses of 15, 30, 60 or 120 pmol) intralesionally following spinal cord injury. Seven days after the toxin administration, kidney, brain, lung, heart, liver, adrenal, muscles, pancreas, spleen, stomach, and intestine were histopathologically investigated. In addition, blood samples collected from the rats were tested for any hematologic or biochemical changes.

Results

The clinical, hematologic and biochemical evaluation revealed no significant abnormalities in all groups, even in high doses. There was no significant alteration in organs, except for degenerative changes in kidneys at a dose of 120 pmol.

Conclusions

These findings suggest that MVIIC at 15, 30 and 60 pmol are safe for intralesional administration after spinal cord injury and could be further investigated in relation to its neuroprotective effects. However, 120 pmol doses of MVIIC may provoke adverse effects on kidney tissue.

Combinatorial treatment of acute spinal cord injury with ghrelin, ibuprofen, C16, and ketogenic diet does not result in improved histologic or functional outcome

Because of the complex, multifaceted nature of spinal cord injury (SCI), it is widely believed that a combination of approaches will be superior to individual treatments. Therefore, we employed a rat model of cervical SCI to evaluate the combination of four noninvasive treatments that individually have been reported to be effective for acute SCI during clinically relevant therapeutic time windows. These treatments included ghrelin, ibuprofen, C16, and ketogenic diet (KD). These were selected not only because of their previously reported efficacy in SCI models but also for their potentially different mechanisms of action. The administration of ghrelin, ibuprofen, C16, and KD several hours to days postinjury was based on previous observations by others that each treatment had profound effects on the pathophysiology and functional outcome following SCI. Here we showed that, with the exception of a modest improvement in performance on the Montoya staircase test at 8-10 weeks postinjury, the combinatorial treatment with ghrelin, ibuprofen, C16, and KD did not result in any significant improvements in the rearing test, grooming test, or horizontal ladder. Histologic analysis of the spinal cords did not reveal any significant differences in tissue sparing between treatment and control groups. Although single approaches of ghrelin, ibuprofen, C16, and KD have been reported to be beneficial after SCI, our results show that the combination of the four interventions did not confer significant functional or histological improvements in a cervical model of SCI. Possible interactions among the treatments may have negated their beneficial effects, emphasizing the challenges that have to be addressed when considering combinatorial drug therapies for SCI.

Inosine enhances axon sprouting and motor recovery after spinal cord injury

Although corticospinal tract axons cannot regenerate long distances after spinal cord injury, they are able to sprout collateral branches rostral to an injury site that can help form compensatory circuits in cases of incomplete lesions. We show here that inosine enhances the formation of compensatory circuits after a dorsal hemisection of the thoracic spinal cord in mature rats and improves coordinated limb use. Inosine is a naturally occurring metabolite of adenosine that crosses the cell membrane and, in neurons, activates Mst3b, a protein kinase that is part of a signal transduction pathway that regulates axon outgrowth. Compared to saline-treated controls, rats with dorsal hemisections that were treated with inosine showed three times as many synaptic contacts between corticospinal tract collaterals and long propriospinal interneurons that project from the cervical cord to the lumbar level. Inosine-treated rats also showed stronger serotonergic reinnervation of the lumbar cord than saline-treated controls, and performed well above controls in both open-field testing and a horizontal ladder rung-walking test. Inosine was equally effective whether delivered intracranially or intravenously, and has been shown to be safe for other indications in humans. Thus, inosine might be a useful therapeutic for improving outcome after spinal cord injury.

Treino locomotor com suporte parcial de peso corporal na reabilitação da lesão medular: revisão da literatura

INTRODUÇÃO: O treino locomotor com suporte de peso corporal (TLSP) é utilizado há aproximadamente 20 anos no campo da reabilitação em pacientes que sofrem de patologias neurológicas. O TLSP favorece melhoras osteomusculares, cardiovasculares e psicológicas, pois desenvolve ao máximo o potencial residual do organismo, proporcionando a reintegração na convivência familiar, profissional e social. OBJETIVO: Identificar as principais modalidades de TLSP e seus parâmetros de avaliação com a finalidade de contribuir com o estabelecimento de evidências confiáveis para as práticas reabilitativas de pessoas com lesão medular. MATERIAIS E MÉTODOS: Foram analisados artigos originais, publicados entre 2000 e 2011, que envolvessem treino de marcha após a lesão medular, com ou sem suporte parcial de peso corporal, e tecnologias na assistência do treino, como biofeedback e estimulação elétrica funcional, entre outras. RESULTADOS: A maioria dos participantes dos estudos era do sexo masculino; os níveis de lesão variavam de C3 a L3; ASIA teve pontuações de A a D; os tempos de lesão variaram entre 0,3 meses a 33 anos. Também se verificou que não há consenso em relação ao protocolo de TLSP. CONCLUSÃO: O treino locomotor com suporte de peso corporal mostra-se viável na reabilitação de pacientes que sofrem de uma patologia neurológica como a lesão medular. Independentemente do protocolo de treino utilizado, os benefícios referentes ao aumento da força muscular, manutenção ou aumento da densidade óssea, diminuição da frequência cardíaca e aumento do condicionamento físico estão presentes