Application of dexamethasone in the treatment of acute spinal cord injury

Immune response following traumatic spinal cord injury: Pathophysiology and therapies

Traumatic spinal cord injury (SCI) is a devastating condition that is often associated with significant loss of function and/or permanent disability. The pathophysiology of SCI is complex and occurs in two phases. First, the mechanical damage from the trauma causes immediate acute cell dysfunction and cell death. Then, secondary mechanisms of injury further propagate the cell dysfunction and cell death over the course of days, weeks, or even months. Among the secondary injury mechanisms, inflammation has been shown to be a key determinant of the secondary injury severity and significantly worsens cell death and functional outcomes. Thus, in addition to surgical management of SCI, selectively targeting the immune response following SCI could substantially decrease the progression of secondary injury and improve patient outcomes. In order to develop such therapies, a detailed molecular understanding of the timing of the immune response following SCI is necessary. Recently, several studies have mapped the cytokine/chemokine and cell proliferation patterns following SCI. In this review, we examine the immune response underlying the pathophysiology of SCI and assess both current and future therapies including pharmaceutical therapies, stem cell therapy, and the exciting potential of extracellular vesicle therapy.

Phenotypes of Motor Deficit and Pain after Experimental Spinal Cord Injury

Motor disability is a common outcome of spinal cord injury (SCI). The recovery of motor function after injury depends on the severity of neurotrauma; motor deficit can be reversible, at least partially, due to the innate tissue capability to recover, which, however, deteriorates with age. Pain is often a comorbidity of injury, although its prediction remains poor. It is largely unknown whether pain can attend motor dysfunction. Here, we implemented SCI for modelling severe and moderate neurotrauma and monitored SCI rats for up to 5 months post-injury to determine the profiles of both motor deficit and nociceptive sensitivity. Our data showed that motor dysfunction remained persistent after a moderate SCI in older animals (5-month-old); however, there were two populations among young SCI rats (1 month-old) whose motor deficit either declined or exacerbated even more over 4–5 weeks after identical injury. All young SCI rats displayed changed nociceptive sensitivity in thermal and mechanical modalities. The regression analysis of the changes revealed a population trend with respect to hyper- or hyposensitivity/motor deficit. Together, our data describe the phenotypes of motor deficit and pain, the two severe complications of neurotrauma. Our findings also suggest the predictability of motor dysfunction and pain syndromes following SCI that can be a hallmark for long-term rehabilitation and recovery after injury.

The Aging Population Faces Increased Risk for Musculoskeletal Pathologies: The Problematic Atlas-Axis Instability

Spinal cord injury (SCI), particularly of the traumatic variety, is a relatively common condition that disproportionately affects the elderly. Cases of SCI with nontraumatic etiologies in the geriatric population have increased over the last 20 years, however. Pannus formation, resulting from chronic inflammation of the spine, is one such etiology that may progress to SCI and potentially result in rapid neurological degeneration. Here we describe a case of an elderly woman who presented with a sudden onset of quadriplegia without a history of trauma. Radiography revealed upper cervical instability and fracture due to the presence of a large erosive pannus formation. Unfortunately, in the context of severe SCI, the reversibility of neurological decline is not always guaranteed. Additionally, surgical intervention is not always appropriate, especially among the elderly population, where medical management and end-of-life care are more often delivered.

On the therapeutic targets and pharmacological treatments for pain relief following spinal cord injury: A mechanistic review

Spinal cord injury (SCI) is globally considered as one of the most debilitating disorders, which interferes with daily activities and life of the affected patients. Despite many developments in related recognizing and treating procedures, post-SCI neuropathic pain (NP) is still a clinical challenge for clinicians with no distinct treatments. Accordingly, a comprehensive search was conducted in PubMed, Medline, Scopus, Web of Science, and national database (SID and Irandoc). The relevant articles regarding signaling pathways, therapeutic targets and pharmacotherapy of post-SCI pain were also reviewed. Data were collected with no time limitation until November 2020. The present study provides the findings on molecular mechanisms and therapeutic targets, as well as developing the critical signaling pathways to introduce novel neuroprotective treatments of post-SCI pain. From the pathophysiological mechanistic point of view, post-SCI inflammation activates the innate immune system, in which the immune cells elicit secondary injuries. So, targeting the critical signaling pathways for pain management in the SCI population has significant importance in providing new treatments. Indeed, several receptors, ion channels, excitatory neurotransmitters, enzymes, and key signaling pathways could be used as therapeutic targets, with a pivotal role of n-methyl-D-aspartate, gamma-aminobutyric acid, and inflammatory mediators. The current review focuses on conventional therapies, as well as crucial signaling pathways and promising therapeutic targets for post-SCI pain to provide new insights into the clinical treatment of post-SCI pain. The need to develop innovative delivery systems to treat SCI is also considered.

Recent Findings on the Effects of Pharmacological Agents on the Nerve Regeneration after Peripheral Nerve Injury

Peripheral nerve injuries (PNIs) are accompanied with neuropathic pain and functional disability. Despite improvements in surgical repair techniques in recent years, the functional recovery is yet unsatisfied. Indeed a successful nerve repair depends not only on the surgical strategy but also on the cellular and molecular mechanisms involved in traumatic nerve injury. In contrast to all strategies suggested for nerve repair, pharmacotherapy is a cheap, accessible and non-invasive treatment that can be used immediately after nerve injury. This study aimed to review the effects of some pharmacological agents on the nerve regeneration after traumatic PNI evaluated by functional, histological and electrophysiological assessments. In addition, some cellular and molecular mechanisms responsible for their therapeutic actions, restricted to neural tissue, are suggested. These findings can not only help to find better strategies for peripheral nerve repair, but also to identify the neuropathic effects of various medications and their mechanisms of action.

The safety and efficacy of steroid treatment for acute spinal cord injury: A Systematic Review and meta-analysis

Introduction

The role for steroids in acute spinal cord injury (ASCI) remains unclear; while some studies have demonstrated the risks of steroids outweigh the benefits,a meta-analyses conducted on heterogeneous patient populations have shown significant motor improvement at short-term but not at long-term follow-up. Given the heterogeneity of the patient population in previous meta-analyses and the publication of a recent trial not included in these meta-analyses, we sought to re-assess and update the safety and short-term and long-term efficacy of steroid treatment following ASCI in a more homogeneous patient population.

Materials and methods

A literature search was conducted on PubMed, EMBASE and Cochrane Library through June 2019 for studies evaluating the utility of steroids within the first 8 h following ASCI. Neurological and safety outcomes were extracted for patients treated and not treated with steroids. Pooled effect estimates were calculated using the random-effects model.

Results

Twelve studies, including five randomized controlled trials (RCTs) and seven observational studies (OBSs), were meta-analyzed. Overall, methylprednisolone was not associated with significant short-term or long-term improvements in motor or neurological scores based on RCTs or OBSs. An increased risk of hyperglycemia was shown in both RCTs (RR: 13.7; 95% CI: 1.93, 97.4; 1 study) and OBSs (RR: 2.9; 95% CI: 1.55, 5.41; 1 study). Risk for pneumonia was increased with steroids; while this increase was not statistically significant in the RCTs (pooled RR: 1.16; 95% C.I: 0.59, 2.29; 3 studies), it reached statistical significance in the OBSs (pooled RR: 2.00; 95% C.I: 1.32, 3.02; 6 studies). There was no statistically significant increased risk of gastrointestinal bleeding, decubitus ulcers, surgical site infections, sepsis, atelectasis, venous thromboembolism, urinary tract infections, or mortality among steroid-treated ASCI patients compared to untreated controls in either RCTs or OBSs.

Conclusions

Methylprednisolone therapy within the first 8 h following ASCI failed to show a statistically significant short-term or long-term improvement in patients' overall motor or neurological scores compared to controls who were not administered steroids. For the same comparison, there was an increased risk of pneumonia and hyperglycemia compared to controls. Routine use of methylprednisone following ASCI should be carefully considered in the context of these results.

Enhanced Neural Regeneration with a Concomitant Treatment of Framework Nucleic Acid and Stem Cells in Spinal Cord Injury

Spinal cord injury (SCI), began with a primary injury including contusion and compression, is a common disease caused by various pathogenesis. Characterized disruption of axons and irreversible loss of neurons in SCI, and further damage in spinal cord tissue caused by following secondary injuries, such as the formation of glial scar and inflammation, makes it even harder to recover for affected patients. Tetrahedral framework nucleic acid (tFNA), which possesses the capability of promoting neuroprotection and neuroregeneration in vitro, might alleviate the injuries, and facilitate the neural tissue regeneration in experimental animal models of SCI. Here, we developed a concomitant treatment of tFNA and neural stem cells (NSCs) for the synergistic therapy in treating the injury of the spinal cord. We first observed that tFNA could promote cell proliferation of NSCs then verified that the concomitant treatment of tFNA and NSCs showed the neuroprotective actions by increasing the survival of transplanted NSCs. Furthermore, the recovery of motor function and the tissue regeneration in the lesion site of the spinal cord achieved the best performance in the SCI rats treated with the combination of tFNA and NSCs than others, and the formation of glial scar was the least. Our findings provide novel evidence of a promising strategy for synergistic treatment of SCI in the future.

Effective improvement of the neuroprotective activity after spinal cord injury by synergistic effect of glucocorticoid with biodegradable amphipathic nanomicelles

Dexamethasone acetate (DA) produces neuroprotective effects by inhibiting lipid peroxidation and inflammation by reducing cytokine release and expression. However, its clinical application is limited by its hydrophobicity, low biocompatibility and numerous side effects when using large dosage. Therefore, improving DA's water solubility, biocompatibility and reducing its side effects are important goals that will improve its clinical utility. The objective of this study is to use a biodegradable polymer as the delivery vehicle for DA to achieve the synergism between inhibiting lipid peroxidation and inflammation effects of the hydrophobic-loaded drugs and the amphipathic delivery vehicle. We successfully prepared DA-loaded polymeric micelles (DA/MPEG-PCL micelles) with monodispersed and approximately 25 nm in diameter, and released DA over an extended period in vitro. Additionally, in the hemisection spinal cord injury (SCI) model, DA micelles were more effective in promoting hindlimb functional recover, reducing glial scar and cyst formation in injured site, decreasing neuron lose and promoting axon regeneration. Therefore, our data suggest that DA/MPEG-PCL micelles have the potential to be applied clinically in SCI therapy.

Spinal Cord Stroke Presenting With Acute Monoplegia in a 17-Year-Old Tennis Player

BACKGROUND

Acute monoplegia is a rare presentation for spinal cord stroke, which usually presents with paraplegia or paraparesis.

PATIENT DESCRIPTION

We describe an athletic girl who presented after a week of heavy athletic activity complaining of back and left leg pain, followed by flaccid left leg paralysis.

RESULTS

The prothrombotic evaluation was unremarkable. Cerebrospinal fluid studies demonstrated elevated myelin basic protein but no oligoclonal bands. Magnetic resonance imaging revealed a lesion in the anterior cord from T9 to T11 with T2 hyperintensity, contrast enhancement, and diffusion restriction, suggesting infarction. There was a herniated disc at T10-T11 contacting the spinal cord and Schmorl's nodes at T11 and T12. Magnetic resonance angiography of the spinal cord was limited by movement artifact.

CONCLUSIONS

The combination of our patient's clinical presentation, imaging studies, and laboratory evaluation suggests that our patient had a spinal cord infarct. A fibrocartilaginous embolism was the likely mechanism of infarct due to the presence of Schmorl's nodes and disc herniation on imaging. In addition to spinal cord stroke, other possible mechanisms leading to presentation with monoplegia, such as transverse myelitis, neuromyelitis optica, and multiple sclerosis, are discussed.

Neuroprotective Effect of Ginsenoside Rd in Spinal Cord Injury Rats

In this study, the neuroprotective effects of ginsenoside Rd (GS Rd) were evaluated in a rat model of spinal cord injury (SCI). Rats in SCI groups received a T8 laminectomy and a spinal contusion injury. GS Rd 12.5, 25 and 50 mg/kg were administered intraperitoneally 1 hr before the surgery and once daily for 14 days. Dexamethasone 1 mg/kg was administered as a positive control. Locomotor function was evaluated using the BBB score system. H&E staining and Nissl staining were performed to observe the histological changes in the spinal cord. The levels of MDA and GSH and the activity of SOD were assessed to reflect the oxidative stress state. The production of TNF-α, IL-1β and IL-1 was assessed using ELISA kits to examine the inflammatory responses in the spinal cord. TUNEL staining was used to detect the cell apoptosis in the spinal cord. Western blot analysis was used to examine the expression of apoptosis-associated proteins and MAPK proteins. The results demonstrated that GS Rd 25 and 50 mg/kg significantly improved the locomotor function of rats after SCI, reduced tissue injury and increased neuron survival in the spinal cord. Mechanically, GS Rd decreased MDA level, increased GSH level and SOD activity, reduced the production of pro-inflammatory cytokines and prevented cell apoptosis. The effects were equivalent to those of dexamethasone. In addition, GS Rd effectively inhibited the activation of MAPK signalling pathway induced by SCI, which might be involved in the protective effects of GS Rd against SCI. In conclusion, GS Rd attenuates SCI-induced secondary injury through reversing the redox-state imbalance, inhibiting the inflammatory response and apoptosis in the spinal cord tissue.

Methylprednisolone for the Treatment of Patients with Acute Spinal Cord Injuries: A Propensity Score-Matched Cohort Study from a Canadian Multi-Center Spinal Cord Injury Registry

In prior analyses of the effectiveness of methylprednisolone for the treatment of patients with acute traumatic spinal cord injuries (TSCIs), the prognostic importance of patients' neurological levels of injury and their baseline severity of impairment has not been considered. Our objective was to determine whether methylprednisolone improved motor recovery among participants in the Rick Hansen Spinal Cord Injury Registry (RHSCIR). We identified RHSCIR participants who received methylprednisolone according to the Second National Spinal Cord Injury Study (NASCIS-II) protocol and used propensity score matching to account for age, sex, time of neurological exam, varying neurological level of injury, and baseline severity of neurological impairment. We compared changes in total, upper extremity, and lower extremity motor scores using the Wilcoxon signed-rank test and performed sensitivity analyses using negative binomial regression. Forty-six patients received methylprednisolone and 1555 received no steroid treatment. There were no significant differences between matched participants for each of total (13.7 vs. 14.1, respectively; p=0.43), upper extremity (7.3 vs. 6.4; p=0.38), and lower extremity (6.5 vs. 7.7; p=0.40) motor recovery. This result was confirmed using a multivariate model and, as predicted, only cervical (C1-T1) rather than thoracolumbar (T2-L3) injury levels (p<0.01) and reduced baseline injury severity (American Spinal Injury Association [ASIA] Impairment Scale grades; p<0.01) were associated with greater motor score recovery. There was no in-hospital mortality in either group; however, the NASCIS-II methylprednisolone group had a significantly higher rate of total complications (61% vs. 36%; p=0.02) NASCIS-II methylprednisolone did not improve motor score recovery in RHSCIR patients with acute TSCIs in either the cervical or thoracic spine when the influence of anatomical level and severity of injury were included in the analysis. There was a significantly higher rate of total complications in the NASCIS-II methylprednisolone group. These findings support guideline recommendations against routine administration of methylprednisolone in acute TSCI.

Chemical priming for spinal cord injury: a review of the literature part II-potential therapeutics

INTRODUCTION

Spinal cord injury is a complex cascade of reactions secondary to the initial mechanical trauma that puts into action the innate properties of the injured cells, the circulatory, inflammatory, and chemical status around them, into a non-permissive and destructive environment for neuronal function and regeneration. Priming means putting a cell, in a state of "arousal" towards better function. Priming can be mechanical as trauma is known to enhance activity in cells.

MATERIALS AND METHODS

A comprehensive review of the literature was performed to better understand the possible chemical primers used for spinal cord injuries.

CONCLUSIONS

Taken together, many studies have shown various promising results using the substances outlined herein for treating SCI.

Chemical priming for spinal cord injury: a review of the literature. Part I-factors involved

INTRODUCTION

There are significant differences between the propensity of neural regeneration between the central and peripheral nervous systems.

MATERIALS AND METHODS

Following a review of the literature, we describe the role of growth factors, guiding factors, and neurite outgrowth inhibitors in the physiology and development of the nervous system as well as the pathophysiology of the spinal cord. We also detail their therapeutic role as well as those of other chemical substances that have recently been found to modify regrowth following cord injury.

CONCLUSIONS

Multiple factors appear to have promising futures for the possibility of improving spinal cord injury following injury.

Pregabalin as a neuroprotector after spinal cord injury in rats

The over-expression of excitotoxic neurotransmitter, such as glutamate, is an important mechanism of secondary injury after spinal cord injury. The authors examined the neuroprotective effect of pregabalin (GP) which is known as to reduce glutamate secretion, in a rat model of spinal cord injury. Thirty-two male Sprague-Dawley rats were randomly allocated to four groups; the control group (contusion injury only), the methylprednisolone treated group, the minocycline treated group and the GP treated group. Spinal cord injury was produced by contusion using the New York University impactor (25 g-cm, at the 9th-10th thoracic). Functional evaluations were done using the inclined plane test and a motor rating scale. Anti-apoptotic and anti-inflammatory effects were evaluated by in situ nick-end labeling staining technique (TUNEL) and immunofluorescence staining of cord tissues obtained at 7 days post-injury. Pregabalin treated animals showed significantly better functional recovery, and anti-apoptotic and anti-inflammatory effects. Mean numbers of TUNEL positive cells in the respective groups were 63.5 +/- 7.4, 53.6 +/- 4.0, 44.2 +/- 3.9 and 36.5 +/- 3.6. Double staining (TUNEL and anti-CC1) for oligodendrocyte apoptosis, was used to calculate oligodendrocyte apoptotic indexes (AI), using the following formula AI = (No. of doubly stained cells/No. of anti-CC1 positive cells) x 100. Mean group AIs were 88.6, 46.7, 82.1 and 70.3%, respectively. Mean numbers of activated microglia (anti-OX-42 positive cells) in high power fields were 29.8 +/- 3.9, 22.7 +/- 4.1, 21.0 +/- 3.9 and 17.8 +/- 4.3, respectively. This experiment demonstrates that GP can act as a neuroprotector after SCI in rats, and its anti-apoptotic and anti-inflammatory effects are related to its neuroprotective effect. Further studies are needed to unveil the specific mechanism involved at the receptor level.

Effects of MPSS and a potent iNOS inhibitor on traumatic spinal cord injury

ONO-1714, a selective inhibitor of inducible nitric oxide synthetase (iNOS) attenuated the increase of apoptosis and improved the functional outcome of urinary bladder after traumatic spinal cord injury. These findings suggest that iNOS plays a role in the process of SCI. Early treatment with 30 mg/kg methylprednisolone sodium succinate (MPSS) could also inhibit the expression of iNOS gene, apoptosis and the loss of urinary bladder function. We confirmed that early MPSS treatment may prevent injury associated with apoptosis and urinary bladder disability by reducing iNOS mRNA. However, delayed single MPSS treatment 8 h after spinal cord injury was not effective. Early repeated MPSS treatment might allow greater recovery from acute spinal cord injury.

Tissue expression of 165-aa vascular permeability factor after spinal cord injury is not influenced by dexamethasone administration in rats

Using immunohistochemistry, RT-PCR, and Western Blot techniques, we studied the tissue expression of the 165-aa Vascular permeability factor (VPF) after spinal cord injury (SCI) in adult Wistar rats. The results were compared according to that the animals received or non-dexamethasone, at the dose of 1mg/kg and day after trauma. Furthermore, the different functional recovery between treated and non-treated animals was recorded. Although the administration of dexamethasone showed a beneficial effect on the functional recovery of the animals, the tissue expression of VPF after SCI is not influenced by dexamethasone administration. Therefore, the neuroprotective effect of the dexamethasone after experimental SCI is not mediated through an interference on the biological effects of the 165-aa vascular permeability factor.

High-dose methylprednisolone for acute closed spinal cord injury--only a treatment option

BACKGROUND

A systematic review of the evidence pertaining to methylprednisolone infusion following acute spinal cord injury was conducted in order to address the persistent confusion about the utility of this treatment.

METHODS

A committee of neurosurgical and orthopedic spine specialists, emergency physicians and physiatrists engaged in active clinical practice conducted an electronic database search for articles about acute spinal cord injuries and steroids, from January 1, 1966 to April 2001, that was supplemented by a manual search of reference lists, requests for unpublished additional information, translations of foreign language references and study protocols from the author of a Cochrane systematic review and Pharmacia Inc. The evidence was graded and recommendations were developed by consensus.

RESULTS

One hundred and fifty-seven citations that specifically addressed spinal cord injuries and methylprednisolone were retrieved and 64 reviewed. Recommendations were based on one Cochrane systematic review, six Level I clinical studies and seven Level II clinical studies that addressed changes in neurological function and complications following methylprednisolone therapy.

CONCLUSIONS

There is insufficient evidence to support the use of high-dose methylprednisolone within eight hours following an acute closed spinal cord injury as a treatment standard or as a guideline for treatment. Methylprednisolone, prescribed as a bolus intravenous infusion of 30 mg per kilogram of body weight over fifteen minutes within eight hours of closed spinal cord injury, followed 45 minutes later by an infusion of 5.4 mg per kilogram of body weight per hour for 23 hours, is only a treatment option for which there is weak clinical evidence (Level I- to II-1). There is insufficient evidence to support extending methylprednisolone infusion beyond 23 hours if chosen as a treatment option.

Effects of dexamethasone on apoptosis-related cell death after spinal cord injury

OBJECT

The purpose of this study was to analyze the expression of F7-26 (Apostain) in injured spinal cord tissue, and the modifying effects of dexamethasone administration.

METHODS

A total of 56 adult female Wistar rats were subjected to traumatic spinal cord injury (SCI) to induce complete paraplegia. These rats were divided into two groups according to whether they received dexamethasone (doses of 1 mg/kg daily) post-SCI. Injured spinal cord tissue was studied by means of conventional histological techniques, and Apostain expression was determined by immunohistochemical analysis at 1, 4, 8, 24, and 72 hours, and at 1 and 2 weeks after SCI in all the animals. Apostain-positive cells, mainly neurons and glial cells, were detected 1 hour after injury, peaking at 8 hours, after which the number decreased. One week after injury, apoptosis was limited to a few glial cells, mainly oligodendrocytes, and 2 weeks after injury there was no evidence of Apostain-positive cells. In the group of paraplegic rats receiving post-SCI intraperitoneal dexamethasone, there was a significant decrease in the number of Apostain-positive cells.

CONCLUSIONS

Analysis of the results indicated that apoptosis plays a role in the early period after SCI and that administration of dexamethasone decreases apoptosis-related cell death in the injured spinal cord tissue.

The role of steroids in acute spinal cord injury: an evidence-based analysis

STUDY DESIGN

Literature review.

OBJECTIVES

The purpose of this article is to review the available literature and formulate evidence-based recommendations for the use of methylprednisone in the setting of acute spinal cord injury (SCI).

SUMMARY OF BACKGROUND DATA

Since the early 1990s, methylprednisolone has become widely prescribed for the treatment of acute SCI. Arguably, it has become a standard of care.

METHODS

Through an electronic database search strategy and by cross-reference with published literature, appropriate clinical studies were identified. They were reviewed in chronologic order with respect to study design, outcome measures, results, and conclusions.

RESULTS

Nine studies were identified that attempted to evaluate the role of steroids in nonpenetrating (blunt) spinal cord injury. Five of these were Class I clinical trials, and four were Class II studies. All of the studies failed to demonstrate improvement because of steroid administration in any of the a priori hypotheses testing. Although post hoc analyses were interesting, they failed to demonstrate consistent significant treatment effects.

CONCLUSIONS

From an evidence-based approach, methylprednisolone cannot be recommended for routine use in acute nonpenetrating SCI. Prolonged administration of high-dose steroids (48 hours) may be harmful to the patient. Until more evidence is forthcoming, methylprednisolone should be considered to have investigational (unproven) status only.

Dexamethasone reduces the expression of p75 neurotrophin receptor and apoptosis in contused spinal cord

Apoptosis is an important cause of secondary cell death in spinal cord injury (SCI). SCI induces the expression of the low affinity neurotrophin receptor p75 (p75NTR), that in the absence of the high affinity component, TrkA, can promote cell death by apoptosis. We therefore hypothesized that a reduction of p75NTR expression in SCI may increase tissue sparing and therefore improve recovery of function. As a tool to test our hypothesis we used the synthetic glucocorticoid dexamethasone (DEX) to down-regulate p75NTR expression. A standardized thoracic spinal cord contusion injury was produced in female rats. Laminectomized and SCI rats received various doses of DEX immediately after injury and the treatment was continued daily for 7 days. DEX, given at high doses (20 mg/kg, s.c.) but not at low doses (1 or 8 mg/kg) prevented the increase in p75NTR mRNA and protein in SCI rats, without affecting the expression of TrkA. High doses of DEX also reduced cellular apoptosis both in white and gray matters. This effect correlated with the ability of DEX to accelerate behavioral recovery of function measured by a combined behavioral score. These data suggest that reduction of p75NTR in SCI may be a therapeutic strategy to limit cell and tissue damage and therefore to improve recovery of function in SCI patients.

Prolonged corticosterone treatment of adult rats inhibits the proliferation of oligodendrocyte progenitors present throughout white and gray matter regions of the brain

It is well established that glucocorticoids inhibit the proliferation of progenitor cells that occurs in the hippocampal dentate gyrus of adult mammals. Active cell proliferation also occurs in the subventricular zone (SVZ) of the lateral ventricle and, to a lesser extent, throughout white and gray matter regions of the adult brain. The aim of the present study was to determine whether extrahippocampal cell proliferation is also affected by glucocorticoids. The cell proliferation marker bromodeoxyuridine (BrdU) was administered to control rats, to adrenalectomized rats, and to rats treated with a daily injection of corticosterone (10 mg/kg) for a period of 15 days. In control and adrenalectomized rats, high to low numerical densities of BrdU-labeled nuclei were detected within the different forebrain regions examined. In rats treated with corticosterone, a dramatic decrease of cell proliferation was detected in the dentate gyrus, but also throughout all white and gray matter regions examined, except for the SVZ of the lateral ventricle. Double-labeling experiments indicated that throughout the different white and gray forebrain regions examined, except for the SVZ, BrdU-labeled nuclei were essentially associated with cells immunostained for the marker of oligodendrocyte progenitors NG2. These data indicate that glucocorticoids inhibit the proliferation of oligodendrocyte precursors located throughout the white and gray matter regions of the adult rat brain. Since the proliferation of oligodendrocyte precursors plays a major role in the processes of remyelination, these data raise the question of possible detrimental effects of therapeutic treatments of CNS trauma based on the administration of glucocorticoids.

Somatosensory spinal cord evoked potentials in the evaluation of the effect of dexamethasone in experimental spinal cord injury

We studied the effects of high-dose dexamethasone on amplitude and latency values of spinal cord evoked potentials. Thirty-three rabbits were divided into three equal groups. The first group served as the control group, the others received high-dose (2.5 mg/kg) dexamenthasone, the second group 1 hour prior to and the third group immediately after the induction of a spinal cord trauma in segment T12. The spinal cord evoked potentials were recorded epidurally from T12 segment 5 min before and 5, 30, 60, 90, 120 and 150 min after trauma. Pretreatment with dexamethasone (group II) prevented the latency delay, and later treatment with dexemethasone (group III) prevented the latency delay partially. Our results suggest that when dexamethasone is given prophylactically it prevents latency alteration, while treatment with dexamethasone after lesioning prevents latency alteration partially. From our results we conclude that pretreatment with dexamethasone may involve different mechanisms than were activated in the posttreatment group.

Consequences of high-dose steroid therapy for acute spinal cord injury

OBJECTIVE

High-dose Solu-Medrol (Upjohn, Kalamazoo, Mich) therapy has become standard care in the management of acute spinal cord injury (ASCI). This study attempts to define the adverse effects that Solu-Medrol therapy has on these patients.

DESIGN

Retrospective review with historical control.

MATERIALS AND METHODS

From May 1990 to April 1994, all patients with ASCI admitted within 8 hours of injury received high-dose Solu-Medrol per the National Acute Spinal Injury Study (NASCIS-2) protocol. Their demographic and outcome parameters were compared with those of a group admitted from March 1986 to December 1993 with an associated ASCI who received no steroid therapy.

MEASUREMENTS AND MAIN RESULTS

Steroid therapy was associated with a 2.6-fold increase in the incidence of pneumonia and an increase in ventilated and intensive care days. However, it was associated with a decrease in duration of rehabilitation and had no significant impact on other outcome parameters, including mortality.

CONCLUSIONS

Although the NASCIS-2 protocol may promote early infectious complications, it has no adverse impact on long-term outcome in patients with ASCIs.

Methylprednisolone inhibits early inflammatory processes but not ischemic cell death after experimental spinal cord lesion in the rat

Experimental studies and clinical observations show that spinal cord lesions are greatly enlarged by a process called secondary cell death. A detailed understanding of the molecular and cellular processes underlying these events is still lacking. In clinical studies using methylprednisolone in spinal cord injured patients a mega-dose of methylprednisolone applied during the first few hours after injury was found to improve the neurological outcome. In the present study the possible neuroprotective mechanism of methylprednisolone was assessed by histologically studying its effect on the extent of secondary cell death and on early inflammatory reactions following partial transection of the spinal cord in the rat. Our results show that a single high dose of 30 or 60 mg/kg methylprednisolone affects neither the time course nor the extent of secondary cell death. In contrast, methylprednisolone markedly suppressed the invasion of the injured spinal cord tissue by polymorphonuclear granulocytes and macrophages. The role of these inflammatory cells in traumatic CNS lesions is very unclear at present. It is possible that they lead to further damage of the injured spinal cord tissue and that the beneficial effect of methylprednisolone is at least partially due to its anti-inflammatory effect, thereby inhibiting bystander damage of invading inflammatory cells.

Medical and surgical emergencies of the nervous system of horses: diagnosis, treatment, and sequelae

Trauma to the nervous system in horses may involve the brain, brainstem, spinal cord, or peripheral nerves. Trauma may occur to any part of the nervous system with or without a fracture.