A novel vertebral stabilization method for producing contusive spinal cord injury

Clinically-relevant animal cervical spinal cord injury (SCI) models are essential for developing and testing potential therapies; however, producing reliable cervical SCI is difficult due to lack of satisfactory methods of vertebral stabilization. The conventional method to stabilize the spine is to suspend the rostral and caudal cervical spine via clamps attached to cervical spinous processes.  However, this method of stabilization fails to prevent tissue yielding during the contusion as the cervical spinal processes are too short to be effectively secured by the clamps (Figure 1).  Here we introduce a new method to completely stabilize the cervical vertebra at the same level of the impact injury.  This method effectively minimizes movement of the spinal column at the site of impact, which greatly improves the production of consistent SCIs.  We provide visual description of the equipment (Figure 2-4), methods, and a step-by-step protocol for the stabilization of the cervical 5 vertebra (C5) of adult rats, to perform laminectomy (Figure 5) and produce a contusive SCI thereafter.  Although we only demonstrate a cervical hemi-contusion using the NYU/MASCIS impactor device, this vertebral stabilization technique can be applied to other regions of the spinal cord, or be adapted to other SCI devices.  Improving spinal cord exposure and fixation through vertebral stabilization may be valuable for producing consistent and reliable injuries to the spinal cord.  This vertebral stabilization method can also be used for stereotactic injections of cells and tracers, and for imaging using two-photon microscopy in various neurobiological studies.

Association of dietary intake of folate, vitamin B6 and B12 and MTHFR genotype with breast cancer risk

AIM

We aimed to investigate the associations of dietary intake of folate, vitamin B6 and B12 and MTHFR genotype with breast cancer in a Chinese population.

METHODS

A matched case-control study was conducted, and 435 patients with newly diagnosed and histologically confirmed breast cancer and 435 controls were collected. The folate intake, vitamin B6 and vitamin B12 were calculated, and MTHFR C665T, C677T and A1298C were analyzed by PCR-RFLP.

RESULTS

We found vitamin B12 was likely to reduce the risk of breast cancer, and MTHFR 665TT was associated with increased risk of breast cancer. Folate intake, vitamin B12 intake and variants of MTHFR C677T and MTHFR A1298C demonstrated no association with risk of breast cancer. However, we found patients with low intake of vitamin B6 and MTHFR 665TT genotype had a higher risk of breast cancer (OR=1.87, 95% CI=1.29-2.77), the association being less pronounced among subjects with a moderate intake of vitamin B6 and MTHFR 665TT genotype (OR=1.58, 95% CI=1.03-2.49, P=0.03).

CONCLUSION

Our study indicated that the MTHFR C665T polymorphism and vitamin B6 are associated with risk of breast cancer, which indicated roles for nutrients in developing breast cancer.

Assessment of white matter loss using bond-selective photoacoustic imaging in a rat model of contusive spinal cord injury

White matter (WM) loss is a critical event after spinal cord injury (SCI). Conventionally, such loss has been measured with histological and histochemical approaches, although the procedures are complex and may cause artifact. Recently, coherent Raman microscopy has been proven to be an emerging technology to study de- and remyelination of the injured spinal cord; however, limited penetration depth and small imaging field prevent it from comprehensive assessments of large areas of damaged tissues. Here, we report the use of bond-selective photoacoustic (PA) imaging with 1730-nm excitation, where the first overtone vibration of CH2 bond is located, to assess WM loss after a contusive SCI in adult rats. By employing the first overtone vibration of CH2 bond as the contrast, the mapping of the WM in an intact spinal cord was achieved in a label-free three-dimensional manner, and the physiological change of the spinal cord before and after injury was observed. Moreover, the recovery of the spinal cord from contusive injury with the treatment of a neuroprotective nanomedicine ferulic-acid-conjugated glycol chitosan (FA-GC) was also observed. Our study suggests that bond-selective PA imaging is a valuable tool to assess the progression of WM pathology after SCI as well as neuroprotective therapeutics in a label-free manner.

Biphasic bisperoxovanadium administration and Schwann cell transplantation for repair after cervical contusive spinal cord injury

Schwann cells (SCs) hold promise for spinal cord injury (SCI) repair; however, there are limitations for its use as a lone treatment. We showed that acute inhibition of the phosphatase and tensin homolog deleted on chromosome ten (PTEN) by bisperoxovanadium (bpV) was neuroprotective and enhanced function following cervical hemicontusion SCI. We hypothesized that combining acute bpV therapy and delayed SC engraftment would further improve neuroprotection and recovery after cervical SCI. Adult female Sprague-Dawley (SD) rats were randomly sorted into 5 groups: sham, vehicle, bpV, SC transplantation, and bpV+SC transplantation. SCs were isolated from adult green fluorescent protein (GFP)-expressing SD rats (GFP-SCs). 200 μg/kg bpV(pic) was administered intraperitoneally (IP) twice daily for 7 days post-SCI in bpV-treated groups. GFP-SCs (1×10(6) in 5 μl medium) were transplanted into the lesion epicenter at the 8th day post-SCI. Forelimb function was tested for 10 weeks and histology was assessed. bpV alone significantly reduced lesion (by 40%, p<0.05) and cavitation (by 65%, p<0.05) and improved functional recovery (p<0.05) compared to injury alone. The combination promoted similar neuroprotection (p<0.01 vs. injury); however, GFP-SCs alone did not. Both SC-transplanted groups exhibited remarkable long-term SC survival, SMI-31(+) axon ingrowth and RECA-1(+) vasculature presence in the SC graft; however, bpV+SCs promoted an 89% greater axon-to-lesion ratio than SCs only. We concluded that bpV likely contributed largely to the neuroprotective and functional benefits while SCs facilitated considerable host-tissue interaction and modification. The combination of the two shows promise as an attractive strategy to enhance recovery after SCI.

Sweetest Protein -Thaumatin

Thaumatin, commercially available under the trade name Talin, is known as a sweetest compound (100,000 times sweeter than sucrose on molar basis) which can be used not only as a sweetener but also as a flavor enhancer. This sweetener is a protein found in plant Thaumatococcus daniellii. Biotechnology has also seen as alternative method of production of thaumatin. The plant source of this protein is limited and very expensive. Although the sweetener is the sweetest one, its application is not so common because of its liquorice taste and delayed sweetness. This article reviews brie y on the property, production, application and safety aspects of Thaumatin which is known as a sweetest compound till date. DOI: http://dx.doi.org/10.3126/jfstn.v7i0.11210 J. Food Sci. Technol. Nepal, Vol. 7 (112-118), 2012  

Schwann cell transplantation and descending propriospinal regeneration after spinal cord injury

After spinal cord injury (SCI), poor ability of damaged axons of the central nervous system (CNS) to regenerate causes very limited functional recovery. Schwann cells (SCs) have been widely explored as promising donors for transplantation to promote axonal regeneration in the CNS including the spinal cord. Compared with other CNS axonal pathways, injured propriospinal tracts display the strongest regenerative response to SC transplantation. Even without providing additional neurotrophic factors, propriospinal axons can grow into the SC environment which is rarely seen in supraspinal tracts. Propriospinal tract has been found to respond to several important neurotrophic factors secreted by SCs. Therefore, the SC is considered to be one of the most promising candidates for cell-based therapies for SCI. Since many reviews have already appeared on topics of SC transplantation in SCI repair, this review will focus particularly on the rationale of SC transplantation in mediating descending propriospinal axonal regeneration as well as optimizing such regeneration by using different combinatorial strategies. This article is part of a Special Issue entitled SI: Spinal cord injury.

DMH1 increases glucose metabolism through activating Akt in L6 rat skeletal muscle cells

DMH1(4-[6-(4-Isopropoxyphenyl)pyrazolo [1,5-a]pyrimidin-3-yl] quinoline) is a compound C analogue with the structural modifications at the 3- and 6-positions in pyrazolo[1,5-a]pyrimidine backbone. Compound C was reported to inhibit both AMPK and Akt. Our preliminary work found that DMH1 activated Akt. Since Akt was involved in glucose metabolism, we aimed to identify the effects of DMH1 on glucose metabolism in L6 rat muscle cells and the potential mechanism. Results showed that DMH1 increased lactic acid release and glucose consumption in L6 rat muscle cells in a dose-dependent manner. DMH1 activated Akt in L6 cells. Akt inhibitor inhibited DMH1-induced Akt activation and DMH1-induced increases of glucose uptake and consumption. DMH1 had no cytotoxicity in L6 cells, but inhibited mitochondrial function and reduced ATP production. DMH1 showed no effect on AMPK, but in the presence of Akt inhibitor, DMH1 significantly activated AMPK. Compound C inhibited DMH1-induced Akt activation in L6 cells. Compound C inhibited DMH1-induced increase of glucose uptake, consumption and lactic acid release in L6 cells. DMH1 inhibited PP2A activity, and PP2A activator forskolin reversed DMH1-induced Akt activation. We concluded that DMH1 increased glucose metabolism through activating Akt and DMH1 activated Akt through inhibiting PP2A activity in L6 rat muscle cells. In view of the analogue structure of DMH1 and compound C and the contrasting effects of DMH1 and compound C on Akt, the present study provides a novel leading chemical structure targeting Akt with potential use for regulating glucose metabolism.

Association of xeroderma pigmentosum complementation group G Asp1104His polymorphism with breast cancer risk: A cumulative meta-analysis

The xeroderma pigmentosum complementation group G (XPG) gene plays an important role in the DNA nucleotide excision repair (NER) pathway. Several studies have investigated the association between the XPG Asp1104His polymorphism and breast cancer; however, the results have been inconsistent. Therefore, we conducted a meta-analysis of 8 published articles (10 case-control studies) including a total of 5,235 patients with breast cancer and 5,685 healthy controls. The results demonstrated that the XPG Asp1104His polymorphism was not associated with breast cancer in the overall population [His vs. Asp, odds ratio (OR)=1.00, 95% confidence interval (CI): 0.91-1.08; His/His vs. Asp/Asp, OR=0.96, 95% CI: 0.83-1.11; Asp/His vs. Asp/Asp, OR=1.02, 95% CI: 0.94-1.11; His/His+Asp/His vs. Asp/Asp, OR=1.03, 95% CI: 0.92-1.15; and His/His vs. Asp/Asp+Asp/His, OR=0.93, 95% CI: 0.81-1.06]. In the subgroup analysis by ethnicity, no significant association was observed in European subjects. In conclusion, this meta-analysis suggested that the XPG Asp1104His polymorphism is not associated with breast cancer risk.

Minimum information about a spinal cord injury experiment: a proposed reporting standard for spinal cord injury experiments

The lack of reproducibility in many areas of experimental science has a number of causes, including a lack of transparency and precision in the description of experimental approaches. This has far-reaching consequences, including wasted resources and slowing of progress. Additionally, the large number of laboratories around the world publishing articles on a given topic make it difficult, if not impossible, for individual researchers to read all of the relevant literature. Consequently, centralized databases are needed to facilitate the generation of new hypotheses for testing. One strategy to improve transparency in experimental description, and to allow the development of frameworks for computer-readable knowledge repositories, is the adoption of uniform reporting standards, such as common data elements (data elements used in multiple clinical studies) and minimum information standards. This article describes a minimum information standard for spinal cord injury (SCI) experiments, its major elements, and the approaches used to develop it. Transparent reporting standards for experiments using animal models of human SCI aim to reduce inherent bias and increase experimental value.

Isolation and characterization of a novel hydrocarbon-degrading bacterium Achromobacter sp. HZ01 from the crude oil-contaminated seawater at the Daya Bay, southern China

Microorganisms play an important role in the biodegradation of petroleum contaminants, which have attracted great concern due to their persistent toxicity and difficult biodegradation. In this paper, a novel hydrocarbon-degrading bacterium HZ01 was isolated from the crude oil-contaminated seawater at the Daya Bay, South China Sea, and identified as Achromobacter sp. Under the conditions of pH 7.0, NaCl 3% (w/v), temperature 28 °C and rotary speed 150 rpm, its degradability of the total n-alkanes reached up to 96.6% after 10 days of incubation for the evaporated diesel oil. Furthermore, Achromobacter sp. HZ01 could effectively utilize polycyclic aromatic hydrocarbons (PAHs) as its sole carbon source, and could remove anthracene, phenanthrene and pyrence about 29.8%, 50.6% and 38.4% respectively after 30 days of incubation. Therefore, Achromobacter sp. HZ01 may employed as an excellent degrader to develop one cost-effective and eco-friendly method for the bioremediation of marine environments polluted by crude oil.

A semicircular controlled cortical impact produces long-term motor and cognitive dysfunction that correlates well with damage to both the sensorimotor cortex and hippocampus

Animal models of traumatic brain injury (TBI) are essential for testing novel hypotheses and therapeutic interventions. Unfortunately, due to the broad heterogeneity of TBI in humans, no single model has been able to reproduce the entire spectrum of these injuries. The controlled cortical impact (CCI) model is one of the most commonly used models of contusion TBI. However, behavioral evaluations have revealed transient impairment in motor function after CCI in rats and mice. Here we report a new semicircular CCI (S-CCI) model by increasing the impact tip area to cover both the motor cortex and hippocampal regions in adult mice. Mice were subjected to S-CCI or CCI using an electromagnetic impactor (Impactor One, MyNeuroLab; semicircular tip: 3mm radius; CCI tip diameter: 3mm). We showed that S-CCI, at two injury severities, significantly decreased the neuroscore and produced deficits in performance on a rotarod device for the entire duration of the study. In contrast, the CCI induced motor deficits only at early stages after the injury, suggesting that the S-CCI model produces long-lasting motor deficits. Morris water maze test showed that both CCI and S-CCI produced persisting memory deficits. Furthermore, adhesive removal test showed significant somatosensory and motor deficits only in the S-CCI groups. Histological analysis showed a large extent of cortical contusion lesions, including both the sensory and motor cortex, and hippocampal damage in the S-CCI. These findings collectively suggest that the current model may offer sensitive, reliable, and clinically relevant outcomes for assessments of therapeutic strategies for TBI.

Long-term survival, axonal growth-promotion, and myelination of Schwann cells grafted into contused spinal cord in adult rats

Schwann cells (SCs) have been considered to be one of the most promising cell types for transplantation to treat spinal cord injury (SCI) due to their unique growth-promoting properties. Despite the extensive use as donor cells for transplantation in SCI models, the fate of SCs is controversial due in part to the lack of a reliable marker for tracing the grafted SCs. To precisely assess the fate and temporal profile of transplanted SCs, we isolated purified SCs from sciatic nerves of adult transgenic rats overexpressing GFP (SCs-GFP). SCs-GFP were directly injected into the epicenter of a moderate contusive SCI at the mid-thoracic level at 1week post-injury. The number of SCs-GFP or SCs-GFP labeled with Bromodeoxyuridine (BrdU) was quantified at 5min, 1day, and 1, 2, 4, 12 and 24weeks after cell injection. Basso, Beattie, and Bresnahan (BBB) locomotor rating scale, footfall error, thermal withdrawal latency, and footprint analysis were performed before and after the SCs-GFP transplantation. After transplantation, SCs-GFP quickly filled the lesion cavity. A remarkable survival of grafted SCs-GFP up to 24weeks post-grafting was observed with clearly identified SC individuals. SCs-GFP proliferated after injection, peaked at 2weeks (26% of total SCs-GFP), decreased thereafter, and ceased at 12weeks post-grafting. Although grafted SCs-GFP were mainly confined within the border of surrounding host tissue, they migrated along the central canal for up to 5.0mm at 4weeks post-grafting. Within the lesion site, grafted SCs-GFP myelinated regenerated axons and expressed protein zero (P0) and myelin basic protein (MBP). Within the SCs-GFP grafts, new blood vessels were formed. Except for a significant decrease of angle of rotation in the footprint analysis, we did not observe significant behavioral improvements in BBB locomotor rating scale, thermal withdrawal latency, or footfall errors, compared to the control animals that received no SCs-GFP. We conclude that SCs-GFP can survive remarkably well, proliferate, migrate along the central canal, and myelinate regenerated axons when being grafted into a clinically-relevant contusive SCI in adult rats. Combinatorial strategies, however, are essential to achieve a more meaningful functional regeneration of which SCs may play a significant role.

Cytosolic phospholipase A2 protein as a novel therapeutic target for spinal cord injury

Objective

The objective of this study was to investigate whether cytosolic phospholipase A₂ (cPLA₂), an important isoform of PLA₂ that mediates the release of arachidonic acid, plays a role in the pathogenesis of spinal cord injury (SCI).

Methods

A combination of molecular, histological, immunohistochemical, and behavioral assessments were used to test whether blocking cPLA₂ activation pharmacologically or genetically reduced cell death, protected spinal cord tissue, and improved behavioral recovery after a contusive SCI performed at the 10th thoracic level in adult mice.

Results

SCI significantly increased cPLA₂ expression and activation. Activated cPLA₂ was localized mainly in neurons and oligodendrocytes. Notably, the SCI-induced cPLA₂ activation was mediated by the extracellular signal-regulated kinase signaling pathway. In vitro, activation of cPLA₂ by ceramide-1-phosphate or A23187 induced spinal neuronal death, which was substantially reversed by arachidonyl trifluoromethyl ketone, a cPLA₂ inhibitor. Remarkably, blocking cPLA₂ pharmacologically at 30 minutes postinjury or genetically deleting cPLA₂ in mice ameliorated motor deficits, and reduced cell loss and tissue damage after SCI.

Interpretation

cPLA₂ may play a key role in the pathogenesis of SCI, at least in the C57BL/6 mouse, and as such could be an attractive therapeutic target for ameliorating secondary tissue damage and promoting recovery of function after SCI.

Relationship between genetic polymorphisms in the DRD5 gene and paranoid schizophrenia in northern Han Chinese

Dopamine (DA) has been implicated in the pathophysiol-ogy of several psychiatric disorders, including schizophrenia. Thus, genes related to the dopaminergic (DAergic) system are good candidate genes for schizophrenia. One of receptors of the DA receptor system is dopa-mine receptor 5 (DRD5). Single nucleotide polymorphisms (SNPs) in the regulatory regions of DRD5 gene may affect gene expression, influence biosynthesis of DA and underlie various neuropsychiatric disorders re-lated to DA dysfunction. The present study explored the association of SNPs within the DRD5 gene with paranoid schizophrenia in Han Chinese. A total of 176 patients with schizophrenia and 206 healthy controls were genotyped for four DRD5 SNPs (rs77434921, rs2076907, rs6283, and rs1800762). Significant group differences were observed in the allele and genotype frequencies of rs77434921 and rs1800762 and in the frequen-cies of GC haplotypes corresponding to rs77434921-rs1800762. Our find-ings suggest that common genetic variations of DRD5 are likely to con-tribute to genetic susceptibility to paranoid schizophrenia in Han Chinese. Further studies in larger samples are needed to replicate this association.

TPH2 gene polymorphisms in the regulatory region are associated with paranoid schizophrenia in Northern Han Chinese

In the last years, serotonin (5-HT) has been related with the pathophysiology of several psychiatric disorders, including schizophrenia. Thus, genes related to the serotonergic (5-HTergic) system are good candidate genes for schizophrenia. The rate-limiting enzyme of 5-HT synthesis is tryptophan hydroxylase 2 (TPH2). Single nucleotide polymorphisms (SNPs) in the regulatory regions of TPH2 gene may affect gene expression and biosynthesis of 5-HT triggering to various neuropsychiatric disorders related to 5-HT dysfunction. The present study explored the association of SNPs within the TPH2 gene with paranoid schizophrenia in Han Chinese. A total of 164 patients with schizophrenia and 244 healthy controls were genotyped for six TPH2 SNPs (rs4570625, rs11178997, rs11178998, rs41317118, rs17110747, and rs41317114). Significant group differences were observed in the allele and genotype frequencies of rs4570625 and in the frequencies of GTA and TTA haplotypes corresponding to rs4570625-rs11178997-rs11178998. Our findings suggest that common genetic variations of TPH2 are likely to contribute to genetic susceptibility to paranoid schizophrenia in Han Chinese. Further studies in larger samples are needed to replicate this association.

PTEN inhibitor bisperoxovanadium protects oligodendrocytes and myelin and prevents neuronal atrophy in adult rats following cervical hemicontusive spinal cord injury

Cervical spinal cord injury (SCI) damages axons and motor neurons responsible for ipsilateral forelimb function and causes demyelination and oligodendrocyte death. Inhibition of the phosphatase and tensin homologue, PTEN, promotes neural cell survival, neuroprotection and regeneration in vivo and in vitro. PTEN inhibition can also promote oligodendrocyte-mediated myelination of axons in vitro likely through Akt activation. We recently demonstrated that acute treatment with phosphatase PTEN inhibitor, bisperoxovanadium (bpV)-pic reduced tissue damage, neuron death, and promoted functional recovery after cervical hemi-contusion SCI. Evidence suggests bpV can promote myelin stability; however, bpV effects on myelination and oligodendrocytes in contusive SCI models are unclear. We hypothesized that bpV could increase myelin around the injury site through sparing or remyelination, and that bpV treatment may promote increased numbers of oligodendrocytes. Using histological and immunofluorescence labeling, we found that bpV treatment promoted significant spared white matter (30%; p<0.01) and relative Luxol Fast Blue (LFB)(+) myelin area rostral (Veh: 0.56 ± 0.01 vs. bpV: 0.64 ± 0.02; p<0.05) and at the epicenter (Veh: 0.42 ± 0.03 vs. bpV: 0.54 ± 0.03; p<0.05). VLF oligodendrocytes were also significantly greater with bpV therapy (109 ± 5.3 vs. Veh: 77 ± 2.7 mm(-2); p<0.01). In addition, bpV increased mean motor neuron soma area versus vehicle-treatment (1.0 ± 0.02 vs. Veh: 0.77 ± 0.02) relative to Sham neuron size. This study provides key insight into additional cell and tissue effects that could contribute to bpV-mediated functional recovery observed after contusive cervical SCI.

Traumatic brain injury using mouse models

The use of mouse models in traumatic brain injury (TBI) has several advantages compared to other animal models including low cost of breeding, easy maintenance, and innovative technology to create genetically modified strains. Studies using knockout and transgenic mice demonstrating functional gain or loss of molecules provide insight into basic mechanisms of TBI. Mouse models provide powerful tools to screen for putative therapeutic targets in TBI. This article reviews currently available mouse models that replicate several clinical features of TBI such as closed head injuries (CHI), penetrating head injuries, and a combination of both. CHI may be caused by direct trauma creating cerebral concussion or contusion. Sudden acceleration-deceleration injuries of the head without direct trauma may also cause intracranial injury by the transmission of shock waves to the brain. Recapitulation of temporary cavities that are induced by high-velocity penetrating objects in the mouse brain are difficult to produce, but slow brain penetration injuries in mice are reviewed. Synergistic damaging effects on the brain following systemic complications are also described. Advantages and disadvantages of CHI mouse models induced by weight drop, fluid percussion, and controlled cortical impact injuries are compared. Differences in the anatomy, biomechanics, and behavioral evaluations between mice and humans are discussed. Although the use of mouse models for TBI research is promising, further development of these techniques is warranted.

Surgical decompression in acute spinal cord injury: A review of clinical evidence, animal model studies, and potential future directions of investigation

The goal for treatment in acute spinal cord injury (SCI) is to reduce the extent of secondary damage and facilitate neurologic regeneration and functional recovery. Although multiple studies have investigated potential new therapies for the treatment of acute SCI, outcomes and management protocols aimed at ameliorating neurologic injury in patients remain ineffective. More recent clinical and basic science research have shown surgical interventions to be a potentially valuable modality for treatment; however, the role and timing of surgical decompression, in addition to the optimal surgical intervention, remain one of the most controversial topics pertaining to surgical treatment of acute SCI. As an increasing number of potential treatment modalities emerge, animal models are pivotal for investigating its clinical application and translation into human trials. This review critically appraises the available literature for both clinical and basic science studies to highlight the extent of investigation that has occurred, specific therapies considered, and potential areas for future research.

Characterizing phospholipase A2-induced spinal cord injury-a comparison with contusive spinal cord injury in adult rats

To assess whether phospholipase A2 (PLA2) plays a role in the pathogenesis of spinal cord injury (SCI), we compared lesions either induced by PLA2 alone or by a contusive SCI. At 24-h post-injury, both methods induced a focal hemorrhagic pathology. The PLA2 injury was mainly confined within the ventrolateral white matter, whereas the contusion injury widely affected both the gray and white matter. A prominent difference between the two models was that PLA2 induced a massive demyelination with axons remaining in the lesion area, whereas the contusion injury induced axonal damage and myelin breakdown. At 4 weeks, no cavitation was found within the PLA2 lesion, and numerous axons were myelinated by host-migrated Schwann cells. Among them, 45% of animals had early transcranial magnetic motor-evoked potential (tcMMEP) responses. In contrast, the contusive SCI induced a typical centralized cavity with reactive astrocytes forming a glial border. Only 15% of rats had early tcMMEP responses after the contusion. BBB scores were similarly reduced in both models. Our study indicates that PLA2 may play a unique role in mediating secondary SCI likely by targeting glial cells, particularly those of oligodendrocytes. This lesion model could also be used for studying demyelination and remyelination in the injured spinal cord associated with PLA2-mediated secondary SCI.

Cotransplantation of Glial Restricted Precursor Cells and Schwann Cells Promotes Functional Recovery after Spinal Cord Injury

Oligodendrocyte (OL) replacement can be a promising strategy for spinal cord injury (SCI) repair. However, the poor posttransplantation survival and inhibitory properties to axonal regeneration are two major challenges that limit their use as donor cells for repair of CNS injuries. Therefore, strategies aimed at enhancing the survival of grafted oligodendrocytes as well as reducing their inhibitory properties, such as the use of more permissive oligodendrocyte progenitor cells (OPCs), also called glial restricted precursor cells (GRPs), should be highly prioritized. Schwann cell (SC) transplantation is a promising translational strategy to promote axonal regeneration after CNS injuries, partly due to their expression and secretion of multiple growth-promoting factors. Whether grafted SCs have any effect on the biological properties of grafted GRPs remains unclear. Here we report that either SCs or SC-conditioned medium (SCM) promoted the survival, proliferation, and migration of GRPs in vitro. When GRPs and SCs were cografted into the normal or injured spinal cord, robust survival, proliferation, and migration of grafted GRPs were observed. Importantly, grafted GRPs differentiated into mature oligodendrocytes and formed new myelin on axons caudal to the injury. Finally, cografts of GRPs and SCs promoted recovery of function following SCI. We conclude that cotransplantation of GRPs and SCs, the only two kinds of myelin-forming cells in the nervous system, act complementarily and synergistically to promote greater anatomical and functional recovery after SCI than when either cell type is used alone.

Nanomedicine for treating spinal cord injury

Spinal cord injury results in significant mortality and morbidity, lifestyle changes, and difficult rehabilitation. Treatment of spinal cord injury is challenging because the spinal cord is both complex to treat acutely and difficult to regenerate. Nanomaterials can be used to provide effective treatments; their unique properties can facilitate drug delivery to the injury site, enact as neuroprotective agents, or provide platforms to stimulate regrowth of damaged tissues. We review recent uses of nanomaterials including nanowires, micelles, nanoparticles, liposomes, and carbon-based nanomaterials for neuroprotection in the acute phase. We also review the design and neural regenerative application of electrospun scaffolds, conduits, and self-assembling peptide scaffolds.