Recovery Of Motor Function In Rats Research Articles

Repair of Spinal Cord Injury by Inhibition of PLK4 Expression Through Local Delivery of siRNA-Loaded Nanoparticles

Polo-like kinase 4 (PLK4) is one of the key regulators of centrosomal replication. However, its role and mechanism in spinal cord injury (SCI) are still unclear. The SCI model on rats was constructed and the expression and localization of PLK4 in the spinal cord are analyzed with Western blot and immunofluorescence, respectively. Then the specific siRNAs were encapsulated in nanoparticles for the inhibition of PLK4 expression. Afterward, the role of PLK4 on astrocytes was investigated by knocking down its expression in the primary astrocytes. Moreover, siRNA-loaded nanoparticles were injected into the injured spinal cord of rats, and the motor function recovery of rats after SCI was assessed using the Basso, Beattie, and Bresnahan (BBB) locomotor scale method. Notably, the siRNA-loaded nanoparticles effectively transfect primary astrocytes and significantly inhibit PLK4 expression, together with the expression of PCNA with significance. After treatment, restoration of the motor function following SCI was significantly improved in the PLK4 knockdown group compared with the control group. Therefore, we speculate that inhibition of Plk4 may inhibit the proliferation of astrocytes and decrease the inflammatory response mediated by astrocytes, so as to promote the functional recovery of SCI. In conclusion, inhibition of PLK4 expression via siRNA-loaded nanoparticles may be a potential treatment for SCI.

Artemisinin Facilitates Motor Function Recovery by Enhancing Motoneuronal Survival and Axonal Remyelination in Rats Following Brachial Plexus Root Avulsion.

Artemisinin (ART), a well-known antimalarial medicine originally isolated from the plant Artemisia annua, exerts neuroprotective effects in the nervous system owing to an antioxidant effect. Here, we determined whether ART is capable of inhibiting the oxidative stress to enhance motoneuronal (MN) survival to promote motor function recovery of rats following brachial plexus root avulsion (BPRA) with reimplantation surgery. Rats following BPRA and reimplantation were subcutaneously injected with 500 μL of PBS or 16 mg/mL ART once daily for 7 days after surgery. Terzis grooming test (TGT), histochemical staining, real-time polymerase chain reaction, and Western blot were conducted to determine the recovery of motor function of the upper limb, the survival rate of MNs, the oxidative stress levels in the ventral horn of the spinal cord, the morphology of abnormal musculocutaneous nerve fibers, the remyelination of axons in musculocutaneous nerves, and the degree of bicep atrophy. ART significantly increased TGT score, improved the survival of MNs, inhibited the oxidative stress, ameliorated the abnormal morphology of fibers in the musculocutaneous nerve, promoted the remyelination of axons, and alleviated muscle atrophy. Take together, ART can improve the survival of MNs and axonal remyelination to promote the motor function recovery via inhibiting oxidative stress, suggesting that ART may represent a new approach to the therapy of spinal root avulsion.

Bone marrow mesenchymal stem cells promote remyelination in spinal cord by driving oligodendrocyte progenitor cell differentiation via TNF\u03b1/RelB-Hes1 pathway: a rat model study of 2,5-hexanedione-induced neurotoxicity

BackgroundN-hexane, with its metabolite 2,5-hexanedine (HD), is an industrial hazardous material. Chronic hexane exposure causes segmental demyelination in the peripheral nerves, and high-dose intoxication may also affect central nervous system. Demyelinating conditions are difficult to treat and stem cell therapy using bone marrow mesenchymal stem cells (BMSCs) is a promising novel strategy. Our previous study found that BMSCs promoted motor function recovery in rats modeling hexane neurotoxicity. This work aimed to explore the underlying mechanisms and focused on the changes in spinal cord.MethodsSprague Dawley rats were intoxicated with HD (400 mg/kg/day, i.p, for 5 weeks). A bolus of BMSCs (5 × 107 cells/kg) was injected via tail vein. Demyelination and remyelination of the spinal cord before and after BMSC treatment were examined microscopically. Cultured oligodendrocyte progenitor cells (OPCs) were incubated with HD ± BMSC-derived conditional medium (BMSC-CM). OPC differentiation was studied by immunostaining and morphometric analysis. The expressional changes of Hes1, a transcription factor negatively regulating OPC-differentiation, were studied. The upstream Notch1 and TNFα/RelB pathways were studied, and some key signaling molecules were measured. The correlation between neurotrophin NGF and TNFα was also investigated. Statistical significance was evaluated using one-way ANOVA and performed using SPSS 13.0.Results The demyelinating damage by HD and remyelination by BMSCs were evidenced by electron microscopy, LFB staining and NG2/MBP immunohistochemistry. In vitro cultured OPCs showed more differentiation after incubation with BMSC-CM. Hes1 expression was found to be significantly increased by HD and decreased by BMSC or BMSC-CM. The change of Hes1 was found, however, independent of Notch1 activation, but dependent on TNFα/RelB signaling. HD was found to increase TNFα, RelB and Hes1 expression, and BMSCs were found to have the opposite effect. Addition of recombinant TNFα to OPCs or RelB overexpression similarly caused upregulation of Hes1 expression. The secretion of NGF by BMSC and activation of NGF receptor was found important for suppression of TNFα production in OPCs.Conclusions Our findings demonstrated that BMSCs promote remyelination in the spinal cord of HD-exposed rats via TNFα/RelB-Hes1 pathway, providing novel insights for evaluating and further exploring the therapeutical effect of BMSCs on demyelinating neurodegenerative disease.

Effects of Repetitive Transcranial Magnetic Stimulation (rTMS) and Treadmill Training on Recovery of Motor Function in a Rat Model of Partial Spinal Cord Injury.

BackgroundThis study aimed to investigate the effects of repetitive transcranial magnetic stimulation (rTMS) and treadmill training (TT) on motor function recovery in rats with partial spinal cord injury (SCI).Material/MethodsSixty rats with moderate partial SCI at the 9th thoracic vertebral level induced by a Louisville Injury System Apparatus impactor were randomly allocated to 5 groups: Sham surgery (Intact); Sham rTMS without TT (S-rTMS/Non-TT); Sham rTMS with TT (S-rTMS/TT); rTMS without TT (rTMS/Non-TT); and rTMS with TT (rTMS/TT). Interventions commenced 8 days after SCI and continued for 8 weeks. Outcomes studied were Basso, Beattie, and Bresnahan locomotor scale scores, grid walking test, and biochemical analysis of the brain-derived neurotrophic factor (BDNF), synapsin I (SYN), and postsynaptic density protein-95 (PSD-95) in the motor cortex and spinal cord.ResultsThe rTMS/TT contributed to greater Basso, Beattie, and Bresnahan scores compared with the S-rTMS/Non-TT (P<0.01), S-rTMS/TT (P<0.05), and rTMS/Non-TT (P<0.05), and showed obviously reduced numbers of foot drops compared with the S-rTMS/Non-TT (P<0.05). The rTMS/TT significantly increased the expressions of BDNF, SYN, and PSD-95 compared with the S-rTMS/Non-TT, both in the motor cortex (P<0.01, P<0.01, P<0.001, respectively) and spinal cord (P<0.001, P<0.01, P<0.05, respectively).ConclusionsIn a modified rat model of SCI, combined rTMS with TT improved motor function, indicating that this combined approach promoted adaptive neuroplasticity between the motor cortex and the spinal cord. A combined app roach to improving motor function following SCI requires further evaluation to determine the possible clinical applications.

Collagen nanomaterial in the recovery of motor ability of patients with peripheral nerve transection injury

Objective: The combination of neurotrophic factors and ordered collagen material can promote the regeneration of nerve fibres in the injured area, which has a good effect on the recovery of motor ability in patients with peripheral nerve transection. In this paper, the collagen composite scaffolds were used to repair peripheral nerve defects, and then the collagen scaffolds combined with neurotrophic factors were used to promote axon regeneration and motor function recovery in rats with total transection of peripheral nerve. The experimental results show that the fusion of neurotrophic factors with collagen binding domain can specifically bind to collagen-based biomaterials, prevent rapid diffusion of factors in vivo, thus maintaining a more uniform release efficiency in vivo, which can be widely used in the study of motor ability recovery of peripheral nerve transection patients.

Neuroprotective effect of immunomodulatory peptides in rats with traumatic spinal cord injury.

Several therapies have shown obvious effects on structural conservation contributing to motor functional recovery after spinal cord injury (SCI). Nevertheless, neither strategy has achieved a convincing effect. We purposed a combined therapy of immunomodulatory peptides that individually have shown significant effects on motor functional recovery in rats with SCI. The objective of this study was to investigate the effects of the combined therapy of monocyte locomotion inhibitor factor (MLIF), A91 peptide, and glutathione monoethyl ester (GSH-MEE) on chronic-stage spinal cord injury. Female Sprague-Dawley rats underwent a laminectomy of the T9 vertebra and a moderate contusion. Six groups were included: sham, PBS, MLIF + A91, MLIF + GSH-MEE, A91 + GSH-MEE, and MLIF + A91 + GSH-MEE. Two months after injury, motor functional recovery was evaluated using the open field test. Parenchyma and white matter preservation was evaluated using hematoxylin & eosin staining and Luxol Fast Blue staining, respectively. The number of motoneurons in the ventral horn and the number of axonal fibers were determined using hematoxylin & eosin staining and immunohistochemistry, respectively. Collagen deposition was evaluated using Masson's trichrome staining. The combined therapy of MLIF, A91, and GSH-MEE greatly contributed to motor functional recovery and preservation of the medullary parenchyma, white matter, motoneurons, and axonal fibres, and reduced the deposition of collagen in the lesioned area. The combined therapy of MLIF, A91, and GSH-MEE preserved spinal cord tissue integrity and promoted motor functional recovery of rats after SCI. This study was approved by the National Commission for Scientific Research on Bioethics and Biosafety of the Instituto Mexicano del Seguro Social under registration number R-2015-785-116 (approval date November 30, 2015) and R-2017-3603-33 (approval date June 5, 2017).

The promotive effect of activation of the Akt/mTOR/p70S6K signaling pathway in oligodendrocytes on nerve myelin regeneration in rats with spinal cord injury

Purpose Akt/mTOR/p70S6K signaling pathway promotes motor function recovery after spinal cord injury (SCI) in both neurons and astrocytes. But the role and mechanism of this pathway in oligodendrocytes during nerve repair following SCI has not been researched. This study aimed to investigate the effect and mechanism of this signaling pathway in oligodendrocytes on nerve myelin regeneration and motor function recovery in rats with SCI. Methods After inhibiting or activating this signaling pathway, Western blotting and double immunofluorescence labeling were used to determine the levels of the signaling molecules in this pathway and myelin formation-related proteins in the plane of the thoracic segment of the injured spinal cord. The level of motor function recovery was evaluated and the oligodendrocytes involved in nerve myelin regeneration were studied. Primary oligodendrocytes were isolated and cultured in vitro, then MBP, PLP, and MOG were measured with reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Results Akt/mTOR/p70S6K signaling pathway was activated after SCI compared with the sham-operated rats, prominently elevated levels of the pathway components were observed in the SC79-treated group. The activation of the signaling pathway significantly increased the expression levels of myelin formation-related proteins, including MBP, PLP, and MOG, and improved the Basso, Beattie, and Bresnahan (BBB) scores in the injured spinal cord. Conversely, rapamycin suppressed the expression of these signaling molecules and reduced the levels of myelin formation-related proteins. Conclusion Akt/mTOR/p70S6K signaling pathway activation can contribute to nerve myelin regeneration and has the potential to improve the regenerative environment and motor function, as well as the potential to promote repair of SCI.

Therapeutic effect of metformin on inflammation and apoptosis after spinal cord injury in rats through the Wnt/β-catenin signaling pathway

ObjectiveTo verify the effect of metformin on spinal cord injury (SCI) through Wnt/β-catenin signaling pathway. BackgroundSCI is a serious traumatic disease of the central nervous system. Wnt/β-catenin signaling pathway plays important roles in SCI. Metformin has been reported to exert neuroprotective effects in the central nervous system. Whether metformin could improve SCI through Wnt/β-catenin signaling pathway remains unclear. MethodsRats were divided into sham group, SCI group, SCI + metformin group, metformin + XAV939 group (XAV939 is an effective inhibitor of the Wnt/β-catenin signaling pathway), and methylprednisolone group. BBB scores were used to detect motor function recovery at different time points (0, 1, 3, 7, 14, 21, and 28 days) in SCI rats. Western blot analysis, immunofluorescence, TUNEL, HE and Nissl staining were used to observe the morphological characteristics of spinal cord tissue and the expression of inflammation and apoptosis in spinal cord neurons. ResultsMetformin(50 mg/kg) promoted motor functional recovery in rats after SCI, increased the expressions of β-catenin and brain derived neurotrophic factor (BDNF), inhibited neuron apoptosis and inflammatory response, and improved the recovery of pathological morphology at the injury site by activating the Wnt/β-catenin signaling pathway. ConclusionWe found a possible mechanism that metformin could reduce inflammation and apoptosis, and promote functional recovery of SCI rats through activating Wnt/β-catenin signaling pathway.

MiR-21-5p reduces apoptosis and inflammation in rats with spinal cord injury through PI3K/AKT pathway.

To explore the effect of micro ribonucleic acid (miR)-21-5p on spinal cord injury (SCI) in rats and its mechanism of action. The rat model of SCI was established, and the key miRNAs were screened using the microarray assay and miRNA-mRNA interaction network. After intrathecal injection of agomir-21 and antagomir-21, the effect of miR-21 expression on motor function recovery of rats was evaluated using the Basso-Beattie-Bresnahan (BBB) score. The expression level of miR-21 in spinal cord tissues was determined via quantitative reverse transcription-polymerase chain reaction (qRT-PCR), and the effect of miR-21 expression on apoptosis in spinal cord tissues was determined via terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay and Western blotting. Moreover, the effects of agomir-21 and antagomir-21 on SCI-induced expressions of inflammatory factors interleukin-8 (IL-8), IL-1β, IL-6 and tumor necrosis factor-α (TNF-α) in spinal cord tissues were detected through qRT-PCR. Finally, Western blotting was performed to detect the effects of agomir-21 and antagomir-21 on the phosphatidylinositol 3-hydroxy kinase (PI3K)/protein kinase B (AKT) signaling pathway and its downstream molecules in each group. The screening results of the microarray assay revealed that the mRNA and miRNA expression profiles in spinal cord tissues had significant differences in model group from those in sham group. The BBB score was significantly higher in agomir-21 group than that in model group. Compared with that in model group, the apoptosis of spinal cord tissues was obviously weakened in agomir-21 group, while it was obviously enhanced in antagomir-21 group. Agomir-21 group had evidently lower Bax/Bcl-2, and Caspase-3 and Caspase-9 protein expressions, while antagomir-21 group had evidently higher Bax/Bcl-2 and Caspase-3 protein expression than model group. Besides, the expressions of inflammatory factors IL-8, IL-1β, IL-6 and TNF-α were remarkably lower in agomir-21 group than those in model group, while they were remarkably higher in antagomir-21 group than those in model group. Finally, it was found that the protein expressions of phosphorylated PI3K (p-PI3K)/PI3K and p-AKT/AKT rose markedly, while the protein expressions of phosphatase and tensin homolog deleted on chromosome ten (PTEN) and endothelial nitric oxide synthase (eNOS) declined markedly in agomir-21 group compared with those in model group. However, the opposite results were observed in antagomir-21 group compared with those in model group. MiR-21-5p may reduce the apoptosis and inflammation in spinal cord tissues of rats through the PI3K/AKT pathway.

Effect of exosomes derived from mir-126-modified mesenchymal stem cells on the repair process of spinal cord injury in rats.

To investigate the effect of the micro ribonucleic acid (miR)-126-modified mesenchymal stem cell (MSC)-derived exosomes (MSC-exos) on the repair process of spinal cord injury (SCI) in rats. MiR-126-modified MSCs were cultured, the exosomes were extracted, and a rat model of SCI was established. The Quantitative Polymerase Chain Reaction (qPCR) was carried out to detect the expression of miR-126 in the injured spinal cord, and the Western blotting (WB) was adopted to detect the expressions of the exosome-related molecules. Subsequently, the motor function recovery of rats was examined via the Basso, Beattie and Bresnahan (BBB) locomotor rating scale. The effects of miR-126 exosomes on the injury volume and NeuN retention following SCI were evaluated via immunohistochemistry. MSCs were able to package miR-126 into exosomes secreted. After SCI, the recovery of the hind limb function of rats was remarkably improved by miR-126-modified MSC-exos relative to the control group. Treatment with miR-126-modified MSC-exos remarkably decreased the injury volume, retained the neuronal cells, and triggered the axon regeneration following SCI. Besides, the expression of Ras homolog gene family member A (RhoA), identified as the downstream gene of miR-126, was downregulated in the group with miR-126-modified MSC-exos. Moreover, miR-126-modified MSC-exos activated the extracellular regulated protein kinases 1/2 (ERK1/2) pathway. MiR-126-modified MSC-exos protect neurons of rats with SCI, stimulates axon regeneration, and improves the recovery of limb motor function after SCI.

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.

Ameliorative effects of echinacoside against spinal cord injury via inhibiting NLRP3 inflammasome signaling pathway

AimsThe activation of NLRP3 inflammasome, which initiates an inflammatory cascade and triggers inflammatory death, plays a crucial role in the pathogenesis of spinal cord injury (SCI). Echinacoside (ECH) is a phenylethanoid glycoside possessing prominent anti-inflammatory effects and various neuroprotective properties in the central nervous system, but the effect of ECH on SCI was rarely studied. Therefore, the purpose of this experiment was to look into the therapeutic effects of ECH on SCI and the underlying mechanisms. Main methodsBasso-Beattie-Bresnahan (BBB) locomotion scale, Nissl staining, and hematoxylin-eosin (HE) staining was employed to examine the therapeutic effects of ECH on SCI. In addition, reactive oxygen species (ROS) generation, mitochondrial membrane potential (MMP) in BV-2 cells stimulated with lipopolysaccharides and adenosine 5′-triphosphate were examined. The expression levels of proteins involving NLRP3 inflammasome-related pathway were measured. Key findingsThe in vivo experiment indicated that administration of ECH significantly enhanced the BBB scores, reduced the neuron loss, and ameliorated the tissue architecture after SCI. Additionally, ECH dramatically inhibited NLRP3 inflammasome activation in the rat SCI model. In vitro study indicated that ECH significantly reduced ROS level, improved the MMP, blocked activation of NF-κB, and inhibited the NLRP3 inflammasome signaling pathway. The effect of ECH on inhibition of NLRP3 inflammasome signaling pathway was partially governed by suppression of the generation of ROS and activation of NF-κB. SignificanceECH can accelerate motor function recovery in rats following SCI by inhibiting NLRP3 inflammasome-related signaling pathway, suggesting that ECH may serve as a potential therapeutic agent for treating SCI.

Effects of neural stem cell transplantation on the motor function of rats with contusion spinal cord injuries: a meta-analysis.

Objective:To judge the efficacies of neural stem cell (NSC) transplantation on functional recovery following contusion spinal cord injuries (SCIs).Data sources:Studies in which NSCs were transplanted into a clinically relevant, standardized rat model of contusion SCI were identified by searching the PubMed, Embase and Cochrane databases, and the extracted data were analyzed by Stata 14.0.Data selection:Inclusion criteria were that NSCs were used in in vivo animal studies to treat contusion SCIs and that behavioral assessment of locomotor functional recovery was performed using the Basso, Beattie, and Bresnahan lo-comotor rating scale. Exclusion criteria included a follow-up of less than 4 weeks and the lack of control groups.Outcome measures:The restoration of motor function was assessed by the Basso, Beattie, and Bresnahan locomotor rating scale.Results:We identified 1756 non-duplicated papers by searching the aforementioned electronic databases, and 30 full-text articles met the inclusion criteria. A total of 37 studies reported in the 30 articles were included in the meta-analysis. The meta-analysis results showed that transplanted NSCs could improve the motor function recovery of rats following contusion SCIs, to a moderate extent (pooled standardized mean difference (SMD) = 0.73; 95% confidence interval (CI): 0.47–1.00; P < 0.001). NSCs obtained from different donor species (rat: SMD = 0.74; 95% CI: 0.36–1.13; human: SMD = 0.78; 95% CI: 0.31–1.25), at different donor ages (fetal: SMD = 0.67; 95% CI: 0.43–0.92; adult: SMD = 0.86; 95% CI: 0.50–1.22) and from different origins (brain-derived: SMD = 0.59; 95% CI: 0.27–0.91; spinal cord-derived: SMD = 0.51; 95% CI: 0.22–0.79) had similar efficacies on improved functional recovery; however, adult induced pluripotent stem cell-derived NSCs showed no significant efficacies. Furthermore, the use of higher doses of transplanted NSCs or the administration of immunosuppressive agents did not promote better locomotor function recovery (SMD = 0.45; 95% CI: 0.21–0.70). However, shorter periods between the contusion induction and the NSC transplantation showed slightly higher efficacies (acute: SMD = 1.22; 95% CI: 0.81–1.63; subacute: SMD = 0.75; 95% CI: 0.42–1.09). For chronic injuries, NSC implantation did not significantly improve functional recovery (SMD = 0.25; 95% CI: –0.16 to 0.65).Conclusion:NSC transplantation alone appears to be a positive yet limited method for the treatment of contusion SCIs.

MiR-124 inhibits spinal neuronal apoptosis through binding to GCH1.

To explore the effect of micro ribonucleic acid (miR)-124 on the spinal neuronal apoptosis and to explore its related mechanism. The rat model of spinal cord injury (SCI) was established, agomir-124 was injected intrathecally and the effect of agomir-124 on motor function recovery of rats was evaluated using the Basso-Beattie-Bresnahan (BBB) score. The gene expression levels of miR-124 and GTP-cyclohydrolase 1 (GCH1) in spinal cord tissues were detected via quantitative Reverse Transcription-Polymerase Chain Reaction (qRT-PCR), and the correlation between them was detected using the Pearson correlation coefficient. Then, the direct interaction between miR-124 and GCH1 mRNA was detected using the TargetScan software and luciferase reporter assay. The changes in apoptosis in each group were examined via flow cytometry and Western blotting. Moreover, the changes in the tetrahydrobiopterin (BH4) content in each group were detected via high-performance liquid chromatography, and the changes in the nitrite level in the supernatant in each group were detected using the Griess reagent. Finally, the changes in the activity of the inducible nitric oxide synthase (iNOS) protein were detected using the iNOS kit. Compared with that in the model group, the BBB score was significantly increased in agomir-124 group at 21, 28, 35 and 42 d. In the agomir-124 group, the relative expression level of miR 124 in spinal cord tissues was significantly increased at 7-28 d and reached the peak at 21 d, while the mRNA level of GCH1 in spinal cord tissues declined and touched the bottom at 21 d. According to the Pearson correlation coefficient, there was a significant negative correlation between the expression of miR-124 and mRNA expression of GCH1 (r =- 0.87, p = 1.5e-6). It was found in the prediction using TargetScan software that GCH1 might be a potential target for miR-124, which was further verified by the luciferase reporter assay. The results of flow cytometry and Western blotting showed that miR-124 significantly reduced the LPS-induced primary spinal neuronal apoptosis, while the miR-124 inhibitor remarkably increased the primary spinal neuronal apoptosis. Moreover, it was also found that the knockout of GCH1 reduced the LPS-induced spinal neuronal apoptosis. In addition, the GCH1 overexpression assay revealed that miR-124 inhibited spinal neuronal apoptosis by suppressing the GCH1 expression. LPS + miR-124 remarkably decreased the BH4 content, nitrite level, and iNOS activity while LPS + miR-124 + GCH1 remarkably increased the BH4 content, nitrite level, and iNOS activity. MiR-124 inhibits neuronal apoptosis in SCI by binding to GCH1. The results in the present study may provide a new mechanism for the therapeutic effect of miR-124, and miR-124 may have a potential therapeutic value in the treatment of SCI in the future.

Salidroside promotes rat spinal cord injury recovery by inhibiting inflammatory cytokine expression and NF-κB and MAPK signaling pathways.

Spinal cord injury (SCI) is a public health problem in the world. The SCI usually triggers an excessive inflammatory response that brings about a secondary tissue wreck leading to further cellular and organ dysfunction. Hence, there is great potential of reducing inflammation for therapeutic strategies of SCI. In this study, we aim to investigate if Salidroside (SAD) exerts an anti-inflammatory effect and promotes recovery of motor function on SCI through suppressing nuclear factor-κB (NF-κB) and the mitogen-activated protein kinase (MAPK) pathways. In vitro, real-time polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA) were used to examine the inhibitory effect of SAD on the expression and release of interleukin-1β (IL-1β), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) activated by lipopolysaccharide (LPS) in astrocytes. In addition, SAD was found to inhibit NF-κB, p38 and extracellular-regulated protein kinases (ERK) signaling pathways by western blot analysis. Further, in vivo study showed that SAD was able to improve hind limb motor function and reduce tissue damage accompanied by the suppressed expression of inflammatory cytokines IL-1β, IL-6, and TNF-α. Overall, SAD could reduce the inflammatory response and promote motor function recovery in rats after SCI by inhibiting NF-κB, p38, and ERK signaling pathways.

Electroacupuncture and Curcumin Promote Oxidative Balance and Motor Function Recovery in Rats Following Traumatic Spinal Cord Injury.

Spinal cord injury (SCI) is a condition that puts the patient's life at risk in the acute phase and, during the chronic stage, results in permanent deficits in motor, sensory and autonomic functions. Isolated therapeutic strategies have not shown an effect on this condition. Therefore, this study aimed to evaluate the effects of electroacupuncture (EA) and curcumin, alone or combined, on the oxidative balance, motor function recovery and amount of preserved tissue following a traumatic SCI. Long-Evans rats were divided into five groups: SHAM, SCI, SCI + EA, SCI + Curcumin, and SCI + EA + Curcumin. Nitric oxide was significantly decreased in the Curcumin group; the EA, Curcumin and SCI + EA + Curcumin groups had significantly decreased hydroxyl radical and lipid peroxidation levels. Motor function recovery and the amount of preserved spinal cord tissue were significantly greater in the EA, Curcumin and EA + Curcumin groups. The results show that EA and Curcumin treatment alone or in combination decreased oxidative stress, improved functional motor recovery and increased the amount of preserved spinal cord tissue following a traumatic injury.

Effect of exogenous spastin combined with polyethylene glycol on sciatic nerve injury.

Polyethylene glycol can connect the distal and proximal ends of an injured nerve at the cellular level through axonal fusion to avoid Wallerian degeneration of the injured distal nerve and promote peripheral nerve regeneration. However, this method can only prevent Wallerian degeneration in 10% of axons because the cytoskeleton is not repaired in a timely fashion. Reconstruction of the cytoskeletal trunk and microtubule network has been suggested to be the key for improving the efficiency of axonal fusion. As a microtubule-severing protein, spastin has been used to enhance cytoskeletal reconstruction. Therefore, we hypothesized that spastin combined with polyethylene glycol can more effectively promote peripheral nerve regeneration. A total of 120 male Sprague-Dawley rats were randomly divided into sham, suture, polyethylene glycol, and polyethylene glycol + spastin groups. In suture group rats, only traditional nerve anastomosis of the end-to-end suture was performed after transection of the sciatic nerve. In polyethylene glycol and polyethylene glycol + spastin groups, 50 μL of polyethylene glycol or 25 μL of polyethylene glycol + 25 μL of spastin, respectively, were injected immediately under the epineurium of the distal suture. Sensory fiber regeneration distance, which was used to assess early nerve regeneration at 1 week after surgery, was shortest in the suture group, followed by polyethylene glycol group and greatest in the polyethylene glycol + spastin group. Behavioral assessment of motor function recovery in rats showed that limb function was restored in polyethylene glycol and polyethylene glycol + spastin groups at 8 weeks after surgery. At 1, 2, 4 and 8 weeks after surgery, sciatic functional index values and percentages of gastrocnemius muscle wet weight were highest in the sham group, followed by polyethylene glycol + spastin and polyethylene glycol groups, and lowest in the suture group. Masson staining was utilized to assess the morphology of muscle tissue. Morphological changes in skeletal muscle were detectable in suture, polyethylene glycol, and polyethylene glycol + spastin groups at 1, 2, 4, and 8 weeks after surgery. Among them, muscular atrophy of the suture group was most serious, followed by polyethylene glycol and polyethylene glycol + spastin groups. Ultrastructure of distal sciatic nerve tissue, as detected by transmission electron microscopy, showed a pattern of initial destruction, subsequent disintegration, and gradual repair in suture, polyethylene glycol, and polyethylene glycol + spastin groups at 1, 2, 4, and 8 weeks after surgery. As time proceeded, axonal ultrastructure gradually recovered. Indeed, the polyethylene glycol + spastin group was similar to the sham group at 8 weeks after surgery. Our findings indicate that the combination of polyethylene glycol and spastin can promote peripheral nerve regeneration. Moreover, the effect of this combination was better than that of polyethylene glycol alone, and both were superior to the traditional neurorrhaphy. This study was approved by the Animal Ethics Committee of the Second Military Medical University, China (approval No. CZ20170216) on March 16, 2017.

Testing Pathological Variation of White Matter Tract in Adult Rats after Severe Spinal Cord Injury with MRI.

The purpose of this study was to assess the pathological variation in white matter tracts in the adult severe thoracic contusion spinal cord injury (SCI) rat models combined with in vivo magnetic resonance imaging (MRI), as well as the effect of spared white matter (WM) quantity on hindlimb motor function recovery. 7.0T MRI was conducted for all experimental animals before SCI and 1, 3, 7, and 14 days after SCI. The variation in the white matter tract in different regions of the spinal cord after SCI was examined by luxol fast blue (LFB) staining, NF200 immunochemistry, and diffusion tensor imaging (DTI) parameters, including fraction anisotropy, mean diffusivity, axial diffusion, and radial diffusivity. Meanwhile, Basso-Beattie-Bresnahan (BBB) open-field scoring was performed to evaluate the behavior of the paraplegic hind limbs. The quantitative analysis showed that spared white matter measures assessed by LFB and MRI had a close correlation (R2 = 0.8508). The percentage of spared white matter area was closely correlated with BBB score (R2 = 0.8460). After SCI, spared white matter in the spinal cord, especially the ventral column WM, played a critical role in motor function restoration. The results suggest that the first three days provides a key time window for SCI protection and treatment; spared white matter, especially in the ventral column, plays a key role in motor function recovery in rats. Additionally, DTI may be an important noninvasive technique to diagnose acute SCI degree as well as a tool to evaluate functional prognosis. During the transition from nerve protection toward clinical treatment after SCI, in vivo DTI may serve as an emerging noninvasive technique to diagnose acute SCI degree and predict the degree of spontaneous functional recovery after SCI.

Multimodal Rehabilitation Program Promotes Motor Function Recovery of Rats After Ischemic Stroke by Upregulating Expressions of GAP-43, SYN, HSP70, and C-MYC

BackgroundDespite the intense efforts devoted to preventing and treating cerebral ischemia, some individuals will continue to have completed infarctions. Failure of prevention or intervention does not, however, preclude therapeutic approaches to enhance recovery. Our study aims to explore the effect of multimodal rehabilitation program on the motor function recovery of rats with ischemic stroke. MethodsRat models of ischemic stroke were established using clean-grade adult male Sprague-Dawley rats. Motor function of rats was scored by the Bederson neurological function, balance beam test, and screen test. Nissl staining was conducted for morphological and structural changes of nerve cells in the arteriae cerebri anterior zone. Immunohistochemistry was applied to detect the expressions of growth-associated protein (GAP-43), synaptophysin (SYN) and Caspase-3, terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) staining was carried out in the corpus striatum 21 days after operation; reverse transcription quantitative polymerase chain reaction and Western blot analysis were conducted for testing messager RNA (mRNA) and protein expressions of heat shock protein 70 (Hsp70) and MYC proto-oncogene (c-Myc). ResultsRats receiving multimodal rehabilitation program had lower Bederson neurological function, balance beam, and screen test scores on the 7th, 14th and 21st days after operation; more number of neurons surviving in the arteriae cerebri anterior zone at each time point after operation, higher GAP-43 expression on the 7th and 14th days after operation, and higher SYN expression on the 14th and 21st days after operation, on the 7th, 14th and 21st days after operation, higher mRNA and protein expressions of HSP70 and C-MYC, lower Caspase-3 positive expression and TUNEL positive stained cells. ConclusionsMultimodal rehabilitation program could promote motor function recovery of rats after ischemic stroke by upregulating GAP-43 and SYN expressions at arteriae cerebri anterior zone and upregulating HSP70 and C-MYC expressions in the brain tissues.

Promotion of transplanted collagen scaffolds combined with brain-derived neurotrophic factor for axonal regeneration and motor function recovery in rats after transected spinal cord injury

To evaluate the effect of the combination of collagen scaffold and brain-derived neurotrophic factor (BDNF) on the repair of transected spinal cord injury in rats. Thirty-two Sprague-Dawley rats were randomly divided into 4 groups: group A (sham operation group), T 9, T 10 segments of the spinal cord was only exposed; group B, 4-mm T 9, T 10 segments of the spinal cord were resected; group C, 4-mm T 9, T 10 segments of the spinal cord were resected and linear ordered collagen scaffolds (LOCS) with corresponding length was transplanted into lesion site; group D, 4-mm T 9, T 10 segments of the spinal cord were resected and LOCS with collagen binding domain (CBD)-BDNF was transplanted into lesion site. During 3 months after operation, Basso-Beattie-Bresnahan (BBB) locomotor score assessment was performed for each rat once a week. At 3 months after operation, electrophysiological test of motor evoked potential (MEP) was performed for rats in each group. Subsequently, retrograde tracing was performed for each rat by injection of fluorogold (FG) at the L 2 spinal cord below the injury level. One week later, brains and spinal cord tissues of rats were collected. Morphological observation was performed to spinal cord tissues after dehydration. The thoracic spinal cords including lesion area were collected and sliced horizontally. Thoracic spinal cords 1 cm above lesion area and lumbar spinal cords 1 cm below lesion area were collected and sliced coronally. Coronal spinal cord tissue sections were observed by the laser confocal scanning microscope and calculated the integral absorbance ( IA) value of FG-positive cells. Horizontal tissue sections of thoracic spinal cord underwent immunofluorescence staining to observe the building of transected spinal cord injury model, axonal regeneration in damaged area, and synapse formation of regenerated axons. During 3 months after operation, the BBB scores of groups B, C, and D were significantly lower than those of group A ( P<0.05). The BBB scores of group D at 2-12 weeks after operation were significantly higher than those of groups B and C ( P<0.05). Electrophysiological tests revealed that there was no MEP in group B; the latencies of MEP in groups C and D were significantly longer than that in group A ( P<0.05), and in group C than in group D ( P<0.05). Morphological observation of spinal cord tissues showed that the injured area of the spinal cord in group B extended to both two ends, and the lesion site was severely damaged. The morphologies of spinal cord tissues in groups C and D recovered well, and the morphology in group D was closer to normal tissue. Results of retrograde tracing showed that the gray matters of lumbar spinal cords below the lesion area in each group were filled with FG-positive cells; in thoracic spinal cords above lesion sites, the IA value of FG-positive cells in coronal section of spinal cord in group A was significantly larger than those in groups B, C, and D ( P<0.05), and in groups C and D than in group B ( P<0.05), but no significant difference was found between groups C and D ( P>0.05). Immunofluorescence staining results of spinal cord tissue sections selected from dorsal to ventral spinal cord showed transected injured areas of spinal cords which were significantly different from normal tissues. The numbers of NF-positive axons in lesion center of group A were significantly larger than those of groups B, C, and D ( P<0.05), and in groups C and D than in group B ( P<0.05), and in group D than in group C ( P<0.05). The combined therapeutic approach containing LOCS and CBD-BDNF can promote axonal regeneration and recovery of hind limb motor function after transected spinal cord injury in rats.