Motor Neurons In Anterior Horn Research Articles

Evaluating the clinical efficacy of a long-read sequencing-based approach for carrier screening of spinal muscular atrophy

Spinal muscular atrophy (SMA) is the second most common fatal genetic disease in infancy. It is caused by deletion or intragenic pathogenic variants of the causative gene SMN1, which degenerates anterior horn motor neurons and leads to progressive myasthenia and muscle atrophy. Early treatment improves motor function and prognosis in patients with SMA, but drugs are expensive and do not cure the disease. Therefore, carrier screening seems to be the most effective way to prevent SMA birth defects. In this study, we genetically analyzed 1400 samples using multiplex ligation-dependent probe amplification (MLPA) and quantitative polymerase chain reaction (qPCR), and compared the consistency of the results. We randomly selected 44 samples with consistent MLPA and qPCR results for comprehensive SMA analysis (CASMA) using a long-read sequencing (LRS)-based approach. CASMA results showed 100% consistency, visually and intuitively explained the inconsistency between exons 7 and 8 copy numbers detected by MLPA in 13 samples. A total of 16 samples showed inconsistent MLPA and qPCR results for SMN1 exon 7. CASMA was performed on all samples and the results were consistent with those of resampling for MLPA and qPCR detection. CASMA also detected an additional intragenic variant c.-39A>G in a sample with two copies of SMN1 (RT02). Finally, we detected 23 SMA carriers, with an estimated carrier rate of 1/61 in this cohort. In addition, CASMA identified the “2 + 0” carrier status of SMN1 and SMN2 in a family by analyzing the genotypes of only three samples (parents and one sibling). CASMA has great advantages over MLPA and qPCR assays, and could become a powerful technical support for large-scale screening of SMA.

Linarin inhibits microglia activation-mediated neuroinflammation and neuronal apoptosis in mouse spinal cord injury by inhibiting the TLR4/NF-κB pathway

To investigate the mechanism underlying the neuroprotective effect of linarin (LIN) against microglia activation-mediated inflammation and neuronal apoptosis following spinal cord injury (SCI). Fifty C57BL/6J mice (8- 10 weeks old) were randomized to receive sham operation, SCI and linarin treatment at 12.5, 25, and 50 mg/kg following SCI (n=10). Locomotor function recovery of the SCI mice was assessed using the Basso Mouse Scale, inclined plane test, and footprint analysis, and spinal cord tissue damage and myelination were evaluated using HE and LFB staining. Nissl staining, immunofluorescence assay and Western blotting were used to observe surviving anterior horn motor neurons in injured spinal cord tissue. In cultured BV2 cells, the effects of linarin against lipopolysaccharide (LPS)‑induced microglia activation, inflammatory factor release and signaling pathway changes were assessed with immunofluorescence staining, Western blotting, RT-qPCR, and ELISA. In a BV2 and HT22 cell co-culture system, Western blotting was performed to examine the effect of linarin against HT22 cell apoptosis mediated by LPS-induced microglia activation. Linarin treatment significantly improved locomotor function (P < 0.05), reduced spinal cord damage area, increased spinal cord myelination, and increased the number of motor neurons in the anterior horn of the SCI mice (P < 0.05). In both SCI mice and cultured BV2 cells, linarin effectively inhibited glial cell activation and suppressed the release of iNOS, COX-2, TNF-α, IL-6, and IL-1β, resulting also in reduced neuronal apoptosis in SCI mice (P < 0.05). Western blotting suggested that linarin-induced microglial activation inhibition was mediated by inhibition of the TLR4/NF- κB signaling pathway. In the cell co-culture experiments, linarin treatment significantly decreased inflammation-mediated apoptosis of HT22 cells (P < 0.05). The neuroprotective effect of linarin is medicated by inhibition of microglia activation via suppressing the TLR4/NF‑κB signaling pathway, which mitigates neural inflammation and reduce neuronal apoptosis to enhance motor function of the SCI mice.

Morphometric analysis of spinal motor neuron degeneration in sporadic amyotrophic lateral sclerosis

ObjectivesThis study aimed to clarify the relationship between 43-kDa TAR DNA-binding protein (TDP-43) pathology and spinal cord anterior horn motor neuron (AHMN) atrophy in sporadic amyotrophic lateral sclerosis (SALS). MethodsEight patients with SALS and 12 controls were included in this study. Formalin-fixed specimens of lumbar spinal cord samples were paraffin-embedded and sectioned at the level of the fourth lumbar spinal cord with a 4 μm thickness. Using a microscope, the long diameters of the neurons with nucleoli were measured in spinal AHMNs stained with an anti-SMI-32 antibody. AHMNs were divided into medial and lateral nuclei for statistical analysis. We also used previously reported data to measure the long diameter of AHMNs with initial TDP-43 pathology, in which TDP-43 was present both in the nucleus and cytoplasm. ResultsThe long diameter of the lumbar spinal AHMNs in patients with SALS was smaller in the medial nucleus (42.54 ± 9.33 μm, n = 24) and the lateral nucleus (49.41 ± 13.86 μm, n = 129) than in controls (medial nucleus: 55.84 ± 13.49 μm, n = 85, p < 0.001; lateral nucleus: 62.39 ± 13.29 μm, n = 756, p < 0.001, Mann–Whitney U test). All 21 motor neurons with initial TDP-43 pathology were in the lateral nucleus, and their long diameter (67.60 ± 18.3 μm, p = 0.352) was not significantly different from that of controls. ConclusionMotor neuron atrophy in SALS does not occur during the initial stages of TDP-43 pathology, and TDP-43 pathology is already advanced in the atrophied motor neurons.

Histopathological Changes in The Spinal Cord Tissue of Rats Administered an Experimental Mussel Diet

Aim: Regional eating habits show that it causes neurodegenerative problems due to heavy metals that can accumulate in consumed foods and affect tissues such as the nervous system. Since crustaceans such as mussels feed by filtering the water, they are exposed to toxic plankton and various chemicals, especially heavy metals. Due to the limitations of experimental studies on this subject, the effects of mussel consumption on the spinal cord were investigated. Methods: In this study, histopathological changes in the spinal cord tissue of rats fed with shellfish collected from the Dardanelles were determined. The subjects were divided into two groups, and the first group was fed standard rat food for 4 weeks, and the second group was fed a mussel diet. At the end of the study, spinal cord tissue samples taken from rats were subjected to routine histopathological procedures and evaluated under a light microscope. Results: In the experimental group, a decrease in the number of neurons in the medulla spinalis and an increase in the number of astrocytes were noted. TUNEL staining showed that apoptosis occurred intensively in glial cells, but did not occur in anterior and posterior horn motor neurons. Conclusion: The findings showed that long-term mussel consumption can cause axonal damage in motor and sensory neurons and degeneration in glial cells. For this reason, it is important for health that marine diets in coastal areas are made with healthy and hygienic products.

Magnetic Stimulation of Gigantocellular Reticular Nucleus with Iron Oxide Nanoparticles Combined Treadmill Training Enhanced Locomotor Recovery by Reorganizing Cortico-Reticulo-Spinal Circuit.

Gigantocellular reticular nucleus (GRNs) executes a vital role in locomotor recovery after spinal cord injury. However, due to its unique anatomical location deep within the brainstem, intervening in GRNs for spinal cord injury research is challenging. To address this problem, this study adopted an extracorporeal magnetic stimulation system to observe the effects of selective magnetic stimulation of GRNs with iron oxide nanoparticles combined treadmill training on locomotor recovery after spinal cord injury, and explored the possible mechanisms. Superparamagnetic iron oxide (SPIO) nanoparticles were stereotactically injected into bilateral GRNs of mice with moderate T10 spinal cord contusion. Eight-week selective magnetic stimulation produced by extracorporeal magnetic stimulation system (MSS) combined with treadmill training was adopted for the animals from one week after surgery. Locomotor function of mice was evaluated by the Basso Mouse Scale, Grid-walking test and Treadscan analysis. Brain MRI, anterograde virus tracer and immunofluorescence staining were applied to observe the tissue compatibility of SPIO in GRNs, trace GRNs' projections and evaluate neurotransmitters' expression in spinal cord respectively. Motor-evoked potentials and H reflex were collected for assessing the integrity of cortical spinal tract and the excitation of motor neurons in anterior horn. (1) SPIO persisted in GRNs for a minimum of 24 weeks without inducing apoptosis of GRN cells, and degraded slowly over time. (2) MSS-enabled treadmill training dramatically improved locomotor performances of injured mice, and promoted cortico-reticulo-spinal circuit reorganization. (3) MSS-enabled treadmill training took superimposed roles through both activating GRNs to drive more projections of GRNs across lesion site and rebalancing neurotransmitters' expression in anterior horn of lumbar spinal cord. These results indicate that selective MSS intervention of GRNs potentially serves as an innovative strategy to promote more spared fibers of GRNs across lesion site and rebalance neurotransmitters' expression after spinal cord injury, paving the way for the structural remodeling of neural systems collaborating with exercise training, thus ultimately contributing to the reconstruction of cortico-reticulo-spinal circuit.

Cilostazol protects against degenerative cervical myelopathy injury and cell pyroptosis via TXNIP-NLRP3 pathway

Degenerative cervical myelopathy (DCM) is one of the most common and serious neurological diseases. Cilostazol has protective effects of anterior horn motor neurons and prevented the cell apoptosis. However, there was no literatures of Cilostazol on DCM. In this study, we established the DCM rat model to detect the effects of Cilostazol. Meanwhile, the neurobehavioral assessments, histopathology changes, inflammatory cytokines, Thioredoxin-interacting protein (TXNIP), NOD‑like receptor pyrin domain containing 3 (NLRP3) and pro-caspase-1 expressions were detected by Basso, Beattie, and Bresnahan score assessment, Hematoxylin and Eosin Staining, Enzyme-linked immunosorbent assay, immunofluorescence and Western blotting, respectively. After treated with Cilostazol, the Basso, Beattie, and Bresnahan (BBB) score, inclined plane test and forelimb grip strength in DCM rats were significantly increased meanwhile the histopathology injury and inflammatory cytokines were decreased. Additionally, TXNIP, NLRP3 and pro-caspase-1 expressions levels were decreased in Cilostazol treated DCM rats. Interestingly, the using of siTXNIP significantly changed inflammatory cytokines, TXNIP, NLRP3 and pro-caspase-1 expressions, however there was no significance between siTXNIP and Cilostazol + siTXNIP group. These observations showed that Cilostazol rescues DCM injury and ameliorates neuronal destruction mediated by TXNIP/NLRP3/caspase-1 and pro-inflammatory cytokines. As a result of our study, these findings provide further evidence that Cilostazol may represent promising therapeutic candidates for DCM.

Cerebrolysin recovers diaphragmatic function and reduces injury-associated astrogliosis following a cervical spinal cord hemi-section injury in rats

BackgroundSpinal cord injury (SCI) is widely considered the most disastrous medical condition. With no available treatment to date, SCI continues to cause disabilities to the patients and affect their own and their caregivers' quality of life. Cerebrolysin (CBL) is a neuropeptide preparation derived from purified brain proteins with suggested neuroprotective and neurotrophic properties. CBL showed earlier the ability to target multiple pathways that helped in the improvement of the recovery following different groups of neurological diseases and injuries, including ischemic stroke, traumatic brain injuries, and even neurodegenerative diseases. In the current study, the neuroprotective effect of CBL following a SCI is called into question using a rat model of spinal cord cervical hemi-section validated earlier by our lab and others. Using 32 rats divided into four groups randomly, CBL treatment was implemented for either 7 or 21 days duration, following the cervical spinal cord hemi-section.ResultsFollowing the CBL treatment, rats with cervical cord hemi-section showed functional improvement of diaphragmatic muscle as recorded by electromyography (EMG). In addition, the histopathological assessment of the spinal cord showed improved neuronal viability and reduced astrogliosis at the site of the injury compared to the non-treated group. 21-day treatment showed significant improvement when compared to the shorter 7-day regimen.ConclusionOur data suggest that CBL is capable of protecting and regenerating anterior horn motor neurons with functional recovery of diaphragmatic muscle functions in rats, suggesting the potential use of CBL for future regenerative and neuroprotective therapy following SCI.

Re-evaluation of the symptoms of Hirayama disease through anatomical perspective.

Hirayama disease is a rare disease of the anterior horn motor neuron caused by compression of the cervical spinal cord when the neck is flexed. Cervical myelopathy may accompany the disease. It is characterized by symmetrical or asymmetrical muscle weakness and atrophy of muscles innervated by lower cervical and upper thoracic motor neurons. We recorded two male cases of Hirayama disease between the ages of 15 and 21 based on magnetic resonance imaging (MRI) features obtained from the cervical neutral state and from the flexion position which appeared in the right upper extremity. Loss of strength and atrophy in the right upper extremities was existent in clinical findings of these patients. When MRI was taken in the flexion position, there were dilated veins as hypointense signal void on T2 weighted series in posterior epidural area. The contrast enhancement was seen on these veins. It was observed that the posterior dura was displaced anteriorly and the anterior subarachnoid space was narrow. In cases which show clinical findings such as atrophy and loss of strength, having normal MRI results obtained in the neutral position makes it difficult to diagnose Hirayama Disease. In case of a suspicion of Hirayama disease the diagnosis can be made more easily by MRI taken in the flexion position. These case reports aim to bring Hirayama disease to mind and optimize the management of affected individuals.

Inhibition by rno-circRNA-013017 of the apoptosis of motor neurons in anterior horn and descending axonal degeneration in rats after traumatic spinal cord injury.

Spinal cord injury (SCI) often causes continuous neurological damage to clinical patients. Circular RNAs (circRNAs) are related to a lot of diseases, including SCI. We previously found five candidate circRNAs which were likely to regulate the secondary pathophysiological changes in rat model after traumatic SCI. In this study, we first selected and overexpressed target circRNA in rats. We then explored its functional roles using various functional assays in a rat model after SCI. We found that rno-circRNA-013017-the selected target circRNA-reduced neuron apoptosis, preserved the survival and activity of motor neurons, and regulated apoptosis-related proteins at 3 days post-SCI using western blot, immunofluorescence and polymerase chain reaction. Additionally, we found that rno-circRNA-013017 inhibited descending axonal degeneration and preserved motor neurons and descending axons at 6 weeks post-SCI using immunofluorescence, biotin dextran amine diffusion tensor imaging. Finally, the overexpression of rno-circRNA-013017 promoted the locomotor function of rats after SCI using open-field test and gait analysis. Focusing on the functions of rno-circRNA-013017, this study provides new options for future studies exploring therapeutic targets and molecular mechanisms for SCI.

Effects of targeted muscle reinnervation on spinal cord motor neurons in rats following tibial nerve transection.

Targeted muscle reinnervation (TMR) is a surgical procedure used to transfer residual peripheral nerves from amputated limbs to targeted muscles, which allows the target muscles to become sources of motor control information for function reconstruction. However, the effect of TMR on injured motor neurons is still unclear. In this study, we aimed to explore the effect of hind limb TMR surgery on injured motor neurons in the spinal cord of rats after tibial nerve transection. We found that the reduction in hind limb motor function and atrophy in mice caused by tibial nerve transection improved after TMR. TMR enhanced nerve regeneration by increasing the number of axons and myelin sheath thickness in the tibial nerve, increasing the number of anterior horn motor neurons, and increasing the number of choline acetyltransferase-positive cells and immunofluorescence intensity of synaptophysin in rat spinal cord. Our findings suggest that TMR may enable the reconnection of residual nerve fibers to target muscles, thus restoring hind limb motor function on the injured side.

L4-to-L4 nerve root transfer for hindlimb hemiplegia after hypertensive intracerebral hemorrhage.

There is no effective treatment for hemiplegia after hypertensive intracerebral hemorrhage. Considering that the branches of L4 nerve roots in the lumbar plexus root control the movement of the lower extremity anterior and posterior muscles, we investigated a potential method of nerve repair using the L4 nerve roots. Rat models of hindlimb hemiplegia after a hypertensive intracerebral hemorrhage were established by injecting autogenous blood into the posterior limb of internal capsule. The L4 nerve root on the healthy side of model rats was transferred and then anastomosed with the L4 nerve root on the affected side to drive the extensor and flexor muscles of the hindlimbs. We investigated whether this method can restore the flexible movement of the hindlimbs of paralyzed rats after hypertensive intracerebral hemorrhage. In a beam-walking test and ladder rung walking task, model rats exhibited an initial high number of slips, but improved in accuracy on the paretic side over time. At 17 weeks after surgery, rats gained approximately 58.2% accuracy from baseline performance and performed ankle motions on the paretic side. At 9 weeks after surgery, a retrograde tracing test showed a large number of fluoro-gold-labeled motoneurons in the left anterior horn of the spinal cord that supports the L4-to-L4 nerve roots. In addition, histological and ultramicrostructural findings showed axon regeneration of motoneurons in the anterior horn of the spinal cord. Electromyography and paw print analysis showed that denervated hindlimb muscles regained reliable innervation and walking coordination improved. These findings suggest that the L4-to-L4 nerve root transfer method for the treatment of hindlimb hemiplegia after hypertensive intracerebral hemorrhage can improve the locomotion of hindlimb major joints, particularly of the distal ankle. Findings from study support that the L4-to-L4 nerve root transfer method can effectively repair the hindlimb hemiplegia after hypertensive intracerebral hemorrhage. All animal experiments were approved by the Animal Ethics Committee of the First Affiliated Hospital of Nanjing Medical University (No. IACUC-1906009) in June 2019.

PLGA-PEG-PLGA hydrogel with NEP1-40 promotes the functional recovery of brachial plexus root avulsion in adult rats.

Adult brachial plexus root avulsion can cause serious damage to nerve tissue and impair axonal regeneration, making the recovery of nerve function difficult. Nogo-A extracellular peptide residues 1-40 (NEP1-40) promote axonal regeneration by inhibiting the Nogo-66 receptor (NgR1), and poly (D, L-lactide-co-glycolide)-poly (ethylene glycol)-poly (D, L-lactide-co-glycolide) (PLGA-PEG-PLGA) hydrogel can be used to fill in tissue defects and concurrently function to sustain the release of NEP1-40. In this study, we established an adult rat model of brachial plexus nerve root avulsion injury and conducted nerve root replantation. PLGA-PEG-PLGA hydrogel combined with NEP1-40 was used to promote nerve regeneration and functional recovery in this rat model. Our results demonstrated that functional recovery was enhanced, and the survival rate of spinal anterior horn motoneurons was higher in rats that received a combination of PLGA-PEG-PLGA hydrogel and NEP1-40 than in those receiving other treatments. The combined therapy also significantly increased the number of fluorescent retrogradely labeled neurons, muscle fiber diameter, and motor endplate area of the biceps brachii. In conclusion, this study demonstrates that the effects of PLGA-PEG-PLGA hydrogel combined with NEP1-40 are superior to those of other therapies used to treat brachial plexus nerve root avulsion injury. Therefore, future studies should investigate the potential of PLGA-PEG-PLGA hydrogel as a primary treatment for brachial plexus root avulsion.

#16: Enterovirus D68 Visualized in the Anterior Horn of the Spinal Cord of a Pediatric Patient with Flaccid Paralysis

Abstract Background Acute flaccid myelitis (AFM) is a polio-like paralyzing illness of children. AFM incidence is increasing during every other year outbreaks that occur in the United States simultaneously with outbreaks of enterovirus D68 (EV-D68) infection. Demonstrating that EV-D68 directly causes AFM has been challenging due to rare detection of the virus in the cerebrospinal fluid (CSF) of patients despite frequent detection at nonsterile sites. Murine studies have shown that EV-D68 can infect spinal cord anterior horn motor neurons and cause paralysis, similar to poliovirus. However, a key outstanding question is whether EV-D68 causes AFM in humans by direct viral pathogenesis or by indirect host immunopathogenesis. Methods We investigated the pathogenesis of AFM using tissues from a previously reported case of a 5-year-old boy who presented in fall 2008 with four days of progressive limb and voice weakness followed by incontinence, apnea, and death. He had a CSF pleocytosis of 2094/µL with EV-D68 identified in the CSF by sequencing of the VP1 gene. We designed probes for in situ hybridization (ISH) based on this sequence to stain formalin fixed paraffin embedded tissues from his autopsy. For immunohistochemistry (IHC) we used both commercial polyclonal anti-EV-D68 antibodies and our own human monoclonal antibodies that stain virus infected cells in vitro. Immunophenotyping was done by IHC. To analyze gene transcription in the inflammatory transcriptome of these infected areas of spinal cord we used the GeoMx platform from Nanostring. Results We identified EV-D68 in the anterior horn of the patient’s spinal cord, corresponding to the location of motor neuron cell bodies. This area was highly inflamed, with an infiltrate of CD8 T cells and many macrophages. Viral RNA (see figure) and viral protein was visualized in motor neurons but not supporting cells using ISH and IHC, respectively. Viral RNA but not viral protein was detected rarely in the lungs in macrophages, which had extensive inflammatory infiltrate. The infiltrate was predominantly composed of macrophages with a CD8 T cell component as well. The transcriptome of cells in the inflamed tissue was enriched for genes involved in antigen presentation on MHC. Conclusions Deaths in AFM patients are rare and often distant from initial presentation, but this patient died four days after onset of weakness, allowing us to directly demonstrate that EV-D68 can infect the human spinal cord. Motor neurons but not neural support cells are directly infected by EV-D68 with a corresponding infiltrate of macrophages and CD8 T cells. Antigen presentation processes are upregulated in inflamed tissues. Therefore, both direct viral pathology and immune factors likely contribute to AFM disease in EV-D68 infection.

1408. Enterovirus D68 RNA Visualized in the Anterior Horn of the Spinal Cord of a Pediatric Patient with Flaccid Paralysis

BackgroundAcute flaccid myelitis (AFM) is a polio-like paralyzing illness of children. AFM incidence is increasing during every other year outbreaks that occur in the United States simultaneously with outbreaks of enterovirus D68 (EV-D68) infection. Demonstrating that EV-D68 directly causes AFM has been challenging due to rare detection of the virus in the cerebrospinal fluid (CSF) of patients despite frequent detection at nonsterile sites. Murine studies have shown that EV-D68 can infect spinal cord anterior horn motor neurons and cause paralysis, similar to poliovirus. However, a key outstanding question is whether EV-D68 causes AFM in humans by direct viral pathogenesis or by indirect host immunopathogenesis.MethodsWe investigated the pathogenesis of AFM using tissues from a previously reported case of a 5-year-old boy who presented in fall 2008 with four days of progressive limb and voice weakness followed by incontinence, apnea, and death. He had a CSF pleocytosis of 2094/µL with EV-D68 identified in the CSF by sequencing of the VP1 gene. We designed probes for in situ hybridization (ISH) based on this sequence to stain formalin fixed paraffin embedded tissues from his autopsy. For immunohistochemistry (IHC) we used both commercial polyclonal anti-EV-D68 antibodies and our own human monoclonal antibodies that stain virus infected cells in vitro. Immunophenotyping was done by IHC.ResultsWith ISH we identified EV-D68 RNA in the anterior horn of the patient’s spinal cord, corresponding to the location of motor neuron cell bodies. This area was highly inflamed, with an infiltrate of lymphocytes and macrophages. Viral RNA was in low abundance, and we could not detect viral surface proteins by IHC. Neither RNA nor viral antigen was detected in the lungs, which had extensive inflammatory infiltrate.ConclusionDeaths in AFM patients are rare and often distant from initial presentation, but this patient died four days after onset of weakness, allowing us to directly demonstrate that EV-D68 can infect the human spinal cord. Low abundance of virus suggests the virus either reached the spinal cord prior to weakness onset or was cleared rapidly by the immune response. Therefore, both direct viral pathology and immune factors likely contribute to AFM disease in EV-D68 infection.Disclosures James E. Crowe, Jr, MD, IDBiologics (Board Member, Consultant, Grant/Research Support)Vanderbilt University (Other Financial or Material Support, Inventor on patent related to this abstract)

Wnt-3a improves functional recovery through autophagy activation via inhibiting the mTOR signaling pathway after spinal cord injury

Little is known about the effect of wnt-3a on motor nerve function and its specific molecular mechanisms after spinal cord injury (SCI). This study demonstrates that the downregulated expression levels of caspases-3, caspases-9 and chondroitin sulfate proteoglycan (CSPG) proteins and number of proportion of transferase UTP nick end labeling (TUNEL)-positive neurons by wnt-3a treatment. Then, Nissl and hematoxylin-eosin (HE) staining showed that wnt-3a significantly reduced the loss of spinal anterior horn motor neurons and promoted repair of injured spinal cord tissues after SCI. The above factors constructed a favorable microenvironment for the recovery of motor nerve function after SCI. To elucidate the molecular mechanism of neuroprotection of wnt-3a on SCI, the study showed that the expression levels of Beclin-1 and light chain (LC)3-II/I in spinal cord neurons were significantly improved by wnt-3a after SCI in vitro and vivo experiments, while the effect of wnt-3a was inhibited after mechanistic target of rapamycin (mTOR) signaling pathway being activated by MHY-1485. Besides, the level of p70S6K phosphorylation was inhibited by wnt-3a treatment, on the contrary, the level of p70S6K protein was elevated by wnt-3a, indicating that wnt-3a significantly activated neuronal autophagy by inhibiting mTOR signaling pathway after SCI. To further verify the correlation between neuroprotection of wnt-3a and autophagy, we found that after the rats and spinal cord neurons were combined treatment with wnt-3a and MHY-1485, the neuroprotection of wnt-3a on SCI was significantly inhibited. This study is the first to report that wnt-3a improves functional recovery through autophagy activation via inhibiting the mTOR signaling pathway after SCI.

Neuropathologic description of CHCHD10 mutated amyotrophic lateral sclerosis.

ObjectiveTo present the postmortem neuropathologic report of a patient with a CHCHD10 mutation exhibiting an amyotrophic lateral sclerosis (ALS) clinical phenotype.MethodsA 54-year-old man without significant medical history or family history presented with arm weakness, slowly progressed over 19 years to meet the El Escorial criteria for clinically probable ALS with bulbar and respiratory involvement, and was found to have a CHCHD10 p.R15L mutation. Postmortem neuropathologic examination took place including immunohistochemical staining with CHCHD10, and double immunofluorescence combining CHCHD10 with TDP43 and neurofilament was performed and the results were compared with normal controls and sporadic ALS cases.ResultsPostmortem examination of the CHCHD10 mutation carrier showed severe loss of hypoglossal and anterior horn motor neurons, mild corticospinal tract degeneration, and a relative lack of TDP43 immunopathology. CHCHD10 immunohistochemistry for the 3 controls and the 5 sporadic ALS cases showed strong neuronal cytoplasmic and axonal labeling, with the CHCHD10 mutation carrier also having numerous CHCHD10 aggregates within their anterior horns. These aggregates may be related to the CHCHD10 aggregates recently described to cause mitochondrial degeneration and disease in a tissue-selective toxic gain-of-function fashion in a CHCHD10 knock-in mouse model. The CHCHD10 aggregates did not colocalize with TDP43 and were predominantly extracellular on double immunofluorescence labeling with neurofilament.ConclusionsThe neuropathology of CHCHD10 mutated ALS includes predominantly lower motor neuron degeneration, absent TDP43 immunopathology, and aggregates of predominantly extracellular CHCHD10, which do not contain TDP43.

Localised delivery of quercetin by thermo-sensitive PLGA-PEG-PLGA hydrogels for the treatment of brachial plexus avulsion

Accumulating evidence indicates that oxidative stress and inflammation are implicated in brachial plexus avulsion (BPA). Quercetin has anti-inflammatory, anti-oxidant, anti-apoptotic, and neuroprotective properties. This study investigated the therapeutic efficacy of a temperature-sensitive poly(D,L-lactide-co-glycolide)-poly(ethylene-glycol)-poly(D,L-lactide-co-glycolide) (PLGA-PEG-PLGA) hydrogel sustained-release system of quercetin in BPA. In situ injections of the hydrogel loaded with different concentrations of quercetin were conducted in a rat model of BPA. Significantly reduced reactive oxygen species and interleukin-6 levels in the injured spinal cord 24 h post-surgery, increased number of anterior horn motor and functional neurons in the spinal cord 6 weeks post-surgery, thickened biceps muscle fibres and enlarged endplate area with clear structure, reduced demyelinated peripheral nerves, and significantly increased Terzis grooming test scores were found in the groups with 50 or 100 mg/mL quercetin-loaded hydrogels compared with the control and blank hydrogel groups. In conclusion, the temperature-sensitive quercetin loaded PLGA-PEG-PLGA hydrogel sustained-release system can alleviate oxidative damage and inflammation in the spinal cord, increase neuron survival rate, and promote nerve regeneration and motor function recovery in rats with early BPA. The findings suggest that this drug-loaded hydrogel has potential applications in the clinical treatment of BPA.

Peripheral axotomy-induced changes of motor function and histological structure of spinal anterior horn.

The aim of this study was to evaluate changes of both peripheral motor function and histology of spinal anterior horn in adult rats after unilateral sciatectomy. Ten adult healthy rats served as control group, while in the ten rat experimental group the right sciatic nerve was severed. We followed-up nerve motor function using a sciatic function index and electromyography activity of the gastrocnemious muscle. The rats of the experimental group presented the expected gross locomotor deficit and leg muscle atrophy. At 12 weeks post sciatectomy, L4 and L5 spinal cord segments were removed from the twenty rats and were analysed by istological stereological methods. In the axotomized animals volume of the anterior horn and its content of motor neurons decreased, while the content of astrocytes increased (p < 0.05). Thus, in adult rats, beside the obvious peripheral nerve disfuction, the sciatic nerve axotomy have severe consequences on the soma of the injured motor neurons in the spinal anterior horn. All these quantitative analyses may be usefull to quantify changes occurring in adult animals after axotomy and eventual management to modify the final outcomes in peripheral nerve disorders.

Reinnervation of spinal cord anterior horn cells after median nerve repair using transposition with other nerves.

Our previous studies have confirmed that during nerve transposition repair to injured peripheral nerves, the regenerated nerve fibers of motor neurons in the anterior horn of the spinal cord can effectively repair distal nerve and target muscle tissue and restore muscle motor function. To observe the effect of nerve regeneration and motor function recovery after several types of nerve transposition for median nerve defect (2 mm), 30 Sprague-Dawley rats were randomly divided into sham operation group, epineurial neurorrhaphy group, musculocutaneous nerve transposition group, medial pectoral nerve transposition group, and radial nerve muscular branch transposition group. Three months after nerve repair, the wrist flexion test was used to evaluate the recovery of wrist flexion after regeneration of median nerve in the affected limbs of rats. The number of myelinated nerve fibers, the thickness of myelin sheath, the diameter of axons and the cross-sectional area of axons in the proximal and distal segments of the repaired nerves were measured by osmic acid staining. The ratio of newly produced distal myelinated nerve fibers to the number of proximal myelinated nerve fibers was calculated. Wet weights of the flexor digitorum superficialis muscles were measured. Muscle fiber morphology was detected using hematoxylin-eosin staining. The cross-sectional area of muscle fibers was calculated to assess the recovery of muscles. Results showed that wrist flexion function was restored, and the nerve grew into the distal effector in all three nerve transposition groups and the epineurial neurorrhaphy group. There were differences in the number of myelinated nerve fibers in each group. The magnification of proximal to distal nerves was 1.80, 3.00, 2.50, and 3.12 in epineurial neurorrhaphy group, musculocutaneous nerve transposition group, medial pectoral nerve transposition group, and radial nerve muscular branch transposition group, respectively. Nevertheless, axon diameters of new nerve fibers, cross-sectional areas of axons, thicknesses of myelin sheath, wet weights of flexor digitorum superficialis muscle and cross-sectional areas of muscle fibers of all three groups of donor nerves from different anterior horn motor neurons after nerve transposition were similar to those in the epineurial neurorrhaphy group. Our findings indicate that donor nerve translocation from different anterior horn motor neurons can effectively repair the target organs innervated by the median nerve. The corresponding spinal anterior horn motor neurons obtain functional reinnervation and achieve some degree of motor function in the affected limbs.

Qian-Zheng-San promotes regeneration after sciatic nerve crush injury in rats

Qian-Zheng-San, a traditional Chinese prescription consisting of Typhonii Rhizoma, Bombyx Batryticatus, Scorpio, has been found to play an active therapeutic role in central nervous system diseases. However, it is unclear whether Qian-Zheng-San has therapeutic value for peripheral nerve injury. Therefore, we used Sprague-Dawley rats to investigate this. A sciatic nerve crush injury model was induced by clamping the right sciatic nerve. Subsequently, rats in the treatment group were administered 2 mL Qian-Zheng-San (1.75 g/mL) daily as systemic therapy for 1, 2, 4, or 8 weeks. Rats in the control group were not administered Qian-Zheng-San. Rats in sham group did not undergo surgery and systemic therapy. Footprint analysis was used to assess nerve motor function. Electrophysiological experiments were used to detect nerve conduction function. Immunofluorescence staining was used to assess axon counts and morphological analysis. Immunohistochemical staining was used to observe myelin regeneration of the sciatic nerve and the number of motoneurons in the anterior horn of the spinal cord. At 2 and 4 weeks postoperatively, the sciatic nerve function index, nerve conduction velocity, the number of distant regenerated axons and the axon diameter of the sciatic nerve increased in the Qian-Zheng-San treatment group compared with the control group. At 2 weeks postoperatively, nerve fiber diameter, myelin thickness, and the number of motor neurons in the lumbar spinal cord anterior horn increased in the Qian-Zheng-San treatment group compared with the control group. These results indicate that Qian-Zheng-San has a positive effect on peripheral nerve regeneration.