Query: crush spinal cord injury

title: Low level laser facilitates alternatively activated macrophage/microglia polarization and promotes functional recovery after crush spinal cord injury in rats
abstract: Macrophages and resident microglia play an import role in the secondary neuroinflammation response following spinal cord injury. Reprogramming of macrophage/microglia polarization is an import strategy for spinal cord injury restoration. Low level laser therapy (LLLT) is a noninvasive treatment that has been widely used in neurotrauma and neurodegenerative diseases. However, the influence of low level laser on polarization of macrophage/microglia following spinal cord injury remains unknown. The present study applied low level laser therapy on a crush spinal cord injury rat model. Using immunofluorescence, flow cytometry, RT qPCR, and western blot assays, we found that low level laser therapy altered the polarization state to a M2 tendency. A greater number of neurons survived in the pare injury site, which was accompanied by higher BBB scores in the LLLT group. Furthermore, low level laser therapy elevated expression of interleukin 4 (IL 4) and interleukin 13 (IL 13) Results from this study show that low level laser therapy has the potential for reducing inflammation, regulating macrophage/microglia polarization, and promoting neuronal survival. These beneficial effects demonstrate that low level laser therapy may be an effective candidate for clinical treatment of spinal cord injury.

title: A mouse model of complete crush transection spinal cord injury made by two operations.
abstract: More and more studies have focused on the treatment of spinal cord injury (SCI) by tissue engineering, but there is still no ideal animal model that can genuinely and objectively simulate the real pathological process in clinical practice. Also, given the increasing availability and use of genetically modified animals in basic science research, it has become essential to develop clinically related models for SCI for use in mice.  Forty eight C57BL/6 mice were divided into three groups (injured/sham/uninjured) We determined the scar range made by the first crush injury by specimen observation, hematoxylin and eosin (HE) staining, and immunofluorescence staining. Transection to completely remove a 2 mm spinal cord segment centered on the lesion core was completed 6 weeks after the first injury in injured groups, whereas the sham group only underwent re exposure of the spinal cord without transection injury. The characteristics of this SCI model were fully ascertained by specimen observation, HE staining, immunofluorescence staining, and quantitative real time polymerase chain reaction (qRT PCR) Results No mice died after the first injury. Histopathological findings suggested a scar range of 2 mm. After the second operation, 2 mice of the injured group and 1 mouse of the sham group died. The Basso Mouse Scale (BMS) score and motor evoked potential (MEP) results showed that the neurological function of mice did not recover. Immunostaining showed that there were no neurons or neurofilament residues in the lesion core 4 weeks after the second injury. Astrocytes encapsulated immune cells to form dense glial scars. Most immune cells were confined to the core of the lesion and formed fibrous scars with the fibroblasts. At the same time, there was considerable angiogenesis in the lesion core and around the injury. The results of qRT PCR showed that Ptprc was highly expressed in the lesion core, while Gfap, nestin, Cnp, and Sv2b were highly expressed in the adjacent region. This suggests that the lesion core is a highly inflammatory zone, but there may be spontaneous neurogenesis adjacent to the lesion core.  The mouse crash complete transection SCI model made by the two operations has good simulation, high feasibility, and high reproducibility; it will be a useful tool for pre clinical testing of SCI treatment.

title: Effects of melatonin on severe crush spinal cord injury induced reactive astrocyte and scar formation
abstract: The present work aimed at analyzing the effects of melatonin on scar formation after spinal cord injury (SCI) Upregulation of reactive astrocyte under SCI pathological conditions has been presented in several studies. It has been proved that the crucial factor in triggering this upregulation is proinflammatory cytokines. Moreover, scar formation is an important barrier to axonal regeneration through the lesion area. Melatonin plays an important role in reducing inflammation, but its effects on scar formation in the injured spinal cord remain unknown. Hence, we used the model of severe crush injury in mice to investigate the effects of melatonin on scar formation. Mice were randomly separated into four groups; SCI, SCI+Melatonin 1 (single dose) SCI+Melatonin 14 (14 daily doses) and control. Melatonin was administered by intraperitoneal injection (10 mg/kg) after injury. Immunohistochemical analysis, Western blot, and behavioral evaluation were used to explore the effects of melatonin after SCI for 14 days. The melatonin treated mice presented higher expression of neuronal markers (P 0.001) Remarkably, the inflammatory response appeared to be greatly reduced in the SCI+Melatonin 14 group (P 0.001) which also displayed less scar formation (P 0.05) These findings suggest that melatonin inhibits scar formation by acting on inflammatory cytokines after SCI. Overall, our results suggest that melatonin is a promising treatment strategy after SCI that deserves further investigation.

title: Effects of melatonin on myelin associated inhibitors after severe crush spinal cord injury in a mouse model

title: Toll like receptor 4 (TLR4) influences the glial reaction in the spinal cord and the neural response to injury following peripheral nerve crush
abstract: After peripheral axotomy, there is a selective retraction of synaptic terminals in contact with injured motoneurons. This process, which actively involves glial cells, is influenced by the expression of immune related molecules. Since toll like receptors (TLRs) are upregulated by astrocytes and microglia following lesions, they might be involved in synaptic plasticity processes. Therefore, we administered lipopolysaccharide (LPS) to enhance TLR4 expression in mice and studied retrograde changes in the spinal cord ventral horn following sciatic nerve crush. To this end, adult C57BL/6 J male mice were subjected to unilateral sciatic nerve crush at the mid thigh level and, after a survival time of seven and forty days (acute and chronic phases, respectively) the spinal cords were paraformaldehyde fixed and dissected out for immunolabeling for synaptophysin, glial fibrillary acidic protein (GFAP) and ionized calcium binding adapter molecule 1 (Iba1) The results show that TLR4 upregulation leads to synaptophysin downregulation close to spinal motoneuron cell bodies, indicating increased synaptic elimination. LPS exposure also further increases astrogliosis and microglial reactions in the both ventral and dorsal horns, especially ipsilateral to nerve axotomy, compared to those in untreated mice. Notably, LPS administration to TLR4 mice produces results similar to those observed in untreated wild type counterparts, reinforcing the role of this receptor in the glial response to injury. Therefore, our results suggest that the overexpression of the TLR4 receptor results in augmented astrogliosis/microglial reactions and the excessive loss of synapses postinjury, which may, in turn, affect the motoneuronal regenerative response and functionality. Additionally, treatment with LPS increases the expression of b2 microglobulin, a subcomponent of MHC I. Importantly, the absence of TLR4 results in imbalanced axonal regeneration, inducing subsequent improvements and setbacks. In conclusion, our results show the involvement of TLR4 in the process of synaptic remodeling, indicating a new target for future research aimed at developing therapies for CNS and SNP repair.

title: A graded forceps crush spinal cord injury model in mice.
abstract: Given the rising availability and use of genetically modified animals in basic science research, it has become increasingly important to develop clinically relevant models for spinal cord injury (SCI) for use in mice. We developed a graded forceps crush model of SCI in mice that uses three different forceps with spacers of 0.25, 0.4, and 0.55 mm, to produce severe, moderate, and mild injuries, respectively. Briefly, each mouse was subjected to laminectomy of T5 T7, 15 second spinal cord crush using one of those forceps, behavioral assessments, and post mortem neuroanatomical analyses. There were significant differences among the three injury severity groups on behavioral measures (Basso Mouse Score, footprint, and ladder analyses) demonstrating an increase in neurological deficits for groups with greater injury severity. Quantitative analysis of the lesion demonstrated that as injury severity increased, lesion size and GFAP negative area increased, and spared tissue, spinal cord cross sectional area, spared grey matter and spared white matter decreased. These measures strongly correlated with the behavioral outcomes. Similar to other studies of SCI in mice, we report a dense laminin and fibronectin positive extracellular matrix in the lesion sites of injured mice, but unlike those previous studies, we also report the presence of numerous p75 positive Schwann cells in and around the lesion epicenter. These results provide evidence that the graded forceps crush model is an attractive alternative for the study of SCI and related therapeutic interventions. Because of its demonstrated consistency, ease of use, low cost, and clinical relevance, this graded forceps crush is an attractive alternative to the other mouse models of SCI currently available.

title: Local Serpin Treatment via Chitosan Collagen Hydrogel after Spinal Cord Injury Reduces Tissue Damage and Improves Neurologic Function
abstract: Spinal cord injury (SCI) results in massive secondary damage characterized by a prolonged inflammation with phagocytic macrophage invasion and tissue destruction. In prior work, sustained subdural infusion of anti inflammatory compounds reduced neurological deficits and reduced pro inflammatory cell invasion at the site of injury leading to improved outcomes. We hypothesized that implantation of a hydrogel loaded with an immune modulating biologic drug, Serp 1, for sustained delivery after crush induced SCI would have an effective anti inflammatory and neuroprotective effect. Rats with dorsal column SCI crush injury, implanted with physical chitosan collagen hydrogels (CCH) had severe granulomatous infiltration at the site of the dorsal column injury, which accumulated excess edema at 28 days post surgery. More pronounced neuroprotective changes were observed with high dose (100 ug/50 uL) Serp 1 CCH implanted rats, but not with low dose (10 ug/50 uL) Serp 1 CCH. Rats treated with Serp 1 CCH implants also had improved motor function up to 20 days with recovery of neurological deficits attributed to inhibition of inflammation associated tissue damage. In contrast, prolonged low dose Serp 1 infusion with chitosan did not improve recovery. Intralesional implantation of hydrogel for sustained delivery of the Serp 1 immune modulating biologic offers a neuroprotective treatment of acute SCI.

title: Comparative gene expression profiling between optic nerve and spinal cord injury in Xenopus laevis reveals a core set of genes inherent in successful regeneration of vertebrate central nervous system axons
abstract: The South African claw toed frog, Xenopus laevis, is uniquely suited for studying differences between regenerative and non regenerative responses to CNS injury within the same organism, because some CNS neurons (e.g. retinal ganglion cells after optic nerve crush (ONC) regenerate axons throughout life, whereas others (e.g. hindbrain neurons after spinal cord injury (SCI) lose this capacity as tadpoles metamorphose into frogs. Tissues from these CNS regions (frog ONC eye, tadpole SCI hindbrain, frog SCI hindbrain) were used in a three way RNA seq study of axotomized CNS axons to identify potential core gene expression programs for successful CNS axon regeneration. Despite tissue specific changes in expression dominating the injury responses of each tissue, injury induced changes in gene expression were nonetheless shared between the two axon regenerative CNS regions that were not shared with the non regenerative region. These included similar temporal patterns of gene expression and over 300 injury responsive genes. Many of these genes and their associated cellular functions had previously been associated with injury responses of multiple tissues, both neural and non neural, from different species, thereby demonstrating deep phylogenetically conserved commonalities between successful CNS axon regeneration and tissue regeneration in general. Further analyses implicated the KEGG adipocytokine signaling pathway, which links leptin with metabolic and gene regulatory pathways, and a novel gene regulatory network with genes regulating chromatin accessibility at its core, as important hubs in the larger network of injury response genes involved in successful CNS axon regeneration. This study identifies deep, phylogenetically conserved commonalities between CNS axon regeneration and other examples of successful tissue regeneration and provides new targets for studying the molecular underpinnings of successful CNS axon regeneration, as well as a guide for distinguishing pro regenerative injury induced changes in gene expression from detrimental ones in mammals.

title: An injectable recombinant human milk fat globule epidermal growth factor 8 loaded copolymer system for spinal cord injury by reducing inflammation through NF kB pathway and neuronal cell death.
abstract: Spinal cord injury (SCI) is a common disease and a major cause of paralysis, carrying much burden around the world. Despite the progress made with growth factors therapy, the response rate of acute SCI treatment still remains unsatisfactory, due largely to complex and severe inflammatory reactions. Herein, we prepare a MFG E8 loaded copolymer system based anti inflammation therapy for SCI treatment. It is shown that the MFG E8 loaded copolymer system can decrease pro inflammatory cytokine expression and neuron death. In a rat model of crush caused SCI, the copolymer system shows significant therapeutic efficacy by ameliorating inflammation, decreasing fibrotic scar, promoting myelin regeneration and suppressing overall SCI severity.

title: G Protein Gated Inwardly Rectifying Potassium Channel Subunit 3 is Upregulated in Rat DRGs and Spinal Cord After Peripheral Nerve Injury
abstract: G protein gated inwardly rectifying potassium (GIRK) channels are involved in the regulation of neuronal excitability. Four GIRK subunits (GIRK1 4) are expressed in rat dorsal root ganglia (DRGs) Recently, we have characterized the expression of GIRK1 and 2, and both are downregulated in rat DRGs and spinal cord after a complete sciatic nerve transection (axotomy) Here, we aimed to study the neurochemical characteristics of GIRK3, and its regulation in rat DRGs and spinal cord induced by nerve injury.  A sciatic nerve axotomy was performed to study the influences of injury on GIRK3 expression in DRGs and spinal cord. A dorsal root rhizotomy and a sciatic nerve crush were employed to study the axonal transport of GIRK3 protein, respectively. Immunohistochemistry analysis was employed for investigating the neurochemical characteristics of GIRK3.  In control DRGs, ~18% of neuron profiles (NPs) were GIRK3 positive and ~41% ~48% and ~45% of GIRK3+ NPs were CGRP+ IB4+ and NF200+ respectively. GIRK3 like immunoreactivity was observed in glabrous skin of hind paws and axons originating from DRG neurons. Fourteen days after axotomy, more than one third of DRG NPs were GIRK3+ and among these ~51% and ~56% coexpressed galanin and neuropeptide Y, respectively. In control animals, a small group of interneurons found in the dorsal horn was GIRK3+ In addition, GIRK3+ processes could be observed in superficial laminae of spinal dorsal horn. After nerve injury, the intensity of GIRK3 like immunoreactivity in the superficial layers was increased. Evidence based on rhizotomy and sciatic nerve crush indicated both anterograde and retrograde transport of GIRK3.  Our study demonstrates that GIRK3 is expressed in sensory neurons and spinal cord. GIRK3 has both anterograde and retrograde axonal transport. GIRK3 expression can be regulated by peripheral nerve injury.