Transcription profiling of moderately injuried mouse spinal cord at different time points after the injury to characterize the temporal changes in gene expression that underlie the secondary injury responses.
ABSTRACT: Traumatic spinal cord injury (SCI) initiates a complex series of pathophysiological secondary responses that lead to tissue loss and functional deficits.This study represents a comprehensive database of temporal changes in gene expression that underlie the secondary injury response that occurs in a well-defined mouse model of contusion injury. Experiment Overall Design: Global changes in gene expression that contribute to secondary injury in a C57BL6 mouse model of contusion injury were evaluated using Affymetrix Mouse Genome 430 2.0 arrays.Mice were subjected to a moderate injury at the T8 spinal segment under isoflurane anesthesia.Sections of cord (0.4 cm in length) were analyzed from the site of impact and from the immediately adjacent rostral and caudal regions at 0.5, 4, 24, 72 h and 7 and 28 days after injury (n=3/per group), sham-injury (n=2 per group), or from naive mice (n=2). Four mice were pooled for each individual n, for a total of 12 mice for each injury time point.
Project description:Identification of temporal variations in miRNA expression after spinal cord injury caused by thoracic (T8) moderate (200 Kdynes) contusion. Expression changes were analyzed 1, 3 and 7 days after injury and compared to expression of control (untreated) and sham (laminectony but no contusion) individuals. Included groups: control (untreated), 1 day after lesion, 3 days after lesion, 7 days after lesion, 1 days after SHAM cirugy, 3 days after SHAM cirugy, and 7 days after SHAM cirugy. Each of these 7 groups included 5 biological replicates.
Project description:Identification of temporal variations in miRNA expression after spinal cord injury caused by thoracic (T8) moderate (200 Kdynes) contusion. Expression changes were analyzed 1, 3 and 7 days after injury and compared to expression of control (untreated) and sham (laminectony but no contusion) individuals. Overall design: Included groups: control (untreated), 1 day after lesion, 3 days after lesion, 7 days after lesion, 1 days after SHAM cirugy, 3 days after SHAM cirugy, and 7 days after SHAM cirugy. Each of these 7 groups included 5 biological replicates.
Project description:Secretory leukocyte protease inhibitor is a serine protease inhibitor produced by various cell types, including neutrophils and activated macrophages, and has anti-inflammatory properties. It has been shown to promote wound healing in the skin and other non-neural tissues, however, its role in central nervous system injury was not known. We now report a beneficial role for secretory leukocyte protease inhibitor after spinal cord injury. After spinal cord contusion injury in mice, secretory leukocyte protease inhibitor is expressed primarily by astrocytes and neutrophils but not macrophages. We show, using transgenic mice over-expressing secretory leukocyte protease inhibitor, that this molecule has an early protective effect after spinal cord contusion injury. Furthermore, wild-type mice treated for the first week after spinal cord contusion injury with recombinant secretory leukocyte protease inhibitor exhibit sustained improvement in locomotor control and reduced secondary tissue damage. Recombinant secretory leukocyte protease inhibitor injected intraperitoneally localizes to the nucleus of circulating leukocytes, is detected in the injured spinal cord, reduces activation of nuclear factor-kappaB and expression of tumour necrosis factor-alpha. Administration of recombinant secretory leukocyte protease inhibitor might therefore be useful for the treatment of acute spinal cord injury.
Project description:Expansion of the secondary injury following primary spinal cord injury is a major pathological event that increases destruction in the spinal cord, so measures to reduce secondary injury are needed. Our previous study demonstrated that, at the front of the expanding secondary injury in the spinal cord, there is an ischemic area in which many neurons can still be rescued. Therefore, enhancement of blood circulation in the cord may be helpful, and indeed, we found that a traditional Chinese medicine, shu-xue-tong, efficiently reduces the secondary injury. The aim of the present study was to investigate the effect of reducing fibrinogen with Batroxobin, a drug widely used clinically for ischemia, in rats with spinal cord contusion. We found that both 2 and 4 Batroxobin units (BU)/kg efficiently decreased the plasma fibrinogen, and 2 BU/kg significantly increased spinal blood flow, enhanced neuronal survival, mitigated astrocyte and microglia activation, and improved locomotor recovery. However, 4 BU/kg had no effect on the secondary spinal cord injury. These data suggest that Batroxobin has multiple beneficial effects on spinal cord injury, indicating a potential clinical application.
Project description:Tau protein, a microtubule-associated protein, has a high specific expression in neurons and axons. Because traumatic spinal cord injury mainly affects neurons and axons, we speculated that tau protein may be a promising biomarker to reflect the degree of spinal cord injury and prognosis of motor function. In this study, 160 female Sprague-Dawley rats were randomly divided into a sham group, and mild, moderate, and severe spinal cord injury groups. A laminectomy was performed at the T8 level to expose the spinal cord in all groups. A contusion lesion was made with the NYU-MASCIS impactor by dropping a 10 g rod from heights of 12.5 mm (mild), 25 mm (moderate) and 50 mm (severe) upon the exposed dorsal surface of the spinal cord. Tau protein levels were measured in serum and cerebrospinal fluid samples at 1, 6, 12, 24 hours, 3, 7, 14 and 28 days after operation. Locomotor function of all rats was assessed using the Basso, Beattie and Bresnahan locomotor rating scale. Tau protein concentration in the three spinal cord injury groups (both in serum and cerebrospinal fluid) rapidly increased and peaked at 12 hours after spinal cord injury. Statistically significant positive linear correlations were found between tau protein level and spinal cord injury severity in the three spinal cord injury groups, and between the tau protein level and Basso, Beattie, and Bresnahan locomotor rating scale scores. The tau protein level at 12 hours in the three spinal cord injury groups was negatively correlated with Basso, Beattie, and Bresnahan locomotor rating scale scores at 28 days (serum: r = -0.94; cerebrospinal fluid: r = -0.95). Our data suggest that tau protein levels in serum and cerebrospinal fluid might be a promising biomarker for predicting the severity and functional outcome of traumatic spinal cord injury.
Project description:Traumatic spinal cord injury has dramatic consequences and a huge social impact. We propose a new mouse model of spinal trauma that induces a complete paralysis of hindlimbs, still observable 30 days after injury. The contusion, performed without laminectomy and deriving from the pressure exerted directly on the bone, mimics more closely many features of spinal injury in humans. Spinal cord was injured at thoracic level 10 (T10) in adult anesthetized female CD1 mice, mounted on stereotaxic apparatus and connected to a precision impactor device. Following severe injury, we evaluated motor and sensory functions, and histological/morphological features of spinal tissue at different time points. Moreover, we studied the effects of early and subchronic administration of Docosahexaenoic acid, investigating functional responses, structural changes proximal and distal to the lesion in primary and secondary injury phases, proteome modulation in injured spinal cord. Docosahexaenoic acid was able i) to restore behavioural responses and ii) to induce pro-regenerative effects and neuroprotective action against demyelination, apoptosis and neuroinflammation. Considering the urgent health challenge represented by spinal injury, this new and reliable mouse model together with the positive effects of docosahexaenoic acid provide important translational implications for promising therapeutic approaches for spinal cord injuries.
Project description:Spinal cord injury (SCI) is a debilitating condition that can cause impaired motor function or full paralysis. In the days to weeks following the initial mechanical injury to the spinal cord, inflammation and apoptosis can cause additional damage to the injured tissues. This secondary injury impairs recovery. Brain-derived neurotrophic factor is a secreted protein that has been shown to improve a variety of neurological conditions, including SCI, by promoting neuron survival and synaptic plasticity. This study treated a mouse model of contusion SCI using a single dose of brain-derived neurotrophic factor (BDNF) mRNA nanomicelles prepared with polyethylene glycol polyamino acid block copolymer directly injected into the injured tissue. BDNF levels in the injured spinal cord tissue were approximately doubled by mRNA treatment. Motor function was monitored using the Basso Mouse Scale and Noldus CatWalk Automated Gait Analysis System for 6 weeks post-injury. BDNF-treated mice showed improved motor function recovery, demonstrating the feasibility of mRNA delivery to treat SCI.
Project description:We profiled spinal cord tissue at the site of a moderate contusion injury at the level of the thoracic spinal cord We examined several timepoints following injury, including sham and days 1,3 and 7 following injury and compared differential expression of genes within a genotype and across genotypes (trkB.T1KO/trkB.T1WT) at each timepoint. Tissue was profiled at baseline (sham) condition and then 1, 3 and 7 days after thoracic moderate contusion injury
Project description:Secondary manifestations of spinal cord injury beyond motor and sensory dysfunction can negatively affect a person's quality of life. Spinal cord injury is associated with an increased incidence of depression and anxiety; however, the mechanisms of this relationship are currently not well understood. Human and animal studies suggest that changes in the composition of the intestinal microbiota (dysbiosis) are associated with mood disorders. The objective of the current study is to establish a model of anxiety following a cervical contusion spinal cord injury in rats and to determine whether the microbiota play a role in the observed behavioural changes. We found that spinal cord injury caused dysbiosis and increased symptoms of anxiety-like behaviour. Treatment with a fecal transplant prevented both spinal cord injury-induced dysbiosis as well as the development of anxiety-like behaviour. These results indicate that an incomplete unilateral cervical spinal cord injury can cause affective disorders and intestinal dysbiosis, and that both can be prevented by treatment with fecal transplant therapy.
Project description:Spinal cord injury is characterized by initial neural tissue disruption that triggers secondary damage and extensive non-resolving inflammation, which aggravates loss of function and hinders recovery. The early onset of inflammation following traumatic spinal cord injury underscores the importance of acute intervention after the initial trauma. Injections of mesenchymal stromal cells (MSCs) can reduce inflammation following spinal cord injury. We asked if extracellular vesicles (EVs) can substitute the anti-inflammatory and anti-scarring activities of their parental MSCs in a rat model of contusion spinal cord injury. We report that MSC-EVs were as potent as the parental intact cells in reducing the level of neuroinflammation for up to 2 weeks post-injury. Acute application of EVs after spinal cord injury was shown to robustly decrease the expression of pro-inflammatory cytokines in the spinal cord parenchyma in the very early phase of secondary damage. Moreover, the anti-scarring impact of MSC-EVs was even more efficient than the parental cells. We therefore conclude that anti-inflammatory and anti-scarring activities of MSC application can be mediated by their secreted EVs. In light of their substantial safety and druggability advantages, EVs may have a high potential in early therapeutic treatment following traumatic spinal cord injury.