Knockdown of macrophage migration inhibitory factor (MIF), a novel target to protect neurons from parthanatos induced by simulated post-spinal cord injury oxidative stress.

Parthanatos is a form of regulated cell death (RCD) that is closely linked to DNA damage, which is a common consequence of oxidative stress due to central nervous trauma, such as spinal cord injury (SCI). The mechanism by which apoptosis-inducing factor (AIF) mediates DNA strand breaks in parthanatos was not clear until the discovery of the nuclease function of MIF. A previous study suggested that observed results may not be reliable if the oxidative stress induced in cells observed under experimental pathological conditions does not accurately replicate the specific pathologies being studied. According to an earlier direct measurement of extracellular oxidative stress in a rat SCI model, post-SCI oxidative stress was approximately the same as exposure to 150 µM H2O2. However, this concentration has been reported as sublethal oxidative stress in other cell types related to senescence, apoptosis, and parthanatos. Using sublethal H2O2 concentrations to induce oxidative stress is equivocal. Also, different cell types have diverse tolerances and responses to oxidative stress, and, therefore, exposure to H2O2. To avoid these limitations, the present study explored the mechanism of neuronal death under this simulated post-SCI oxidative stress and determined the effects of MIF knockdown in parthanatos associated with SCI. Immunofluorescence and flow cytometry were used to reveal typical characteristics of parthanatos that were blocked by PARP-1 inhibitors but not caspase inhibitors. In addition to classic features like PARP-1 and caspase-3 cleavage that were absent, we determined that parthanatos instead of apoptosis played a major role in the cell death caused by oxidative stress following SCI. Flow cytometry analysis of cells transfected by adenovirus with MIF-shRNA then exposed to H2O2 showed a significant decrease in cell death for MIF knockdown cells, even after AIF nuclear translocation. The comet assay also displayed significantly fewer DNA strand breaks after MIF knockdown. This is the first study has verified that MIF knockdown enables to protect neurons from parthanatos under a simulated in vivo oxidative stress following SCI. It suggests that MIF knockdown is a promising therapy to rescue neurons suffering from oxidative stress-induced SCI pathology.

Effect of problem and scripting-based learning on spine surgical trainees' learning outcomes.

PURPOSE: To assess the impact of problem and scripting-based learning (PSBL) on spine surgical trainees' learning outcomes. METHODS: 30 spine surgery postgraduate-year-1 residents (PGY-1s) from the First Hospital of China Medical University were randomly divided into two groups. The first group studied spine surgical skills and developed individual judgment under a conventional didactic model, whereas the PSBL group used PBL and Scripted model. A feedback questionnaire and the satisfaction of residents were evaluated by the first assistant surgeon immediately following each procedure. At the end of the study, residents filled out questionnaires focused on identifying the strengths of each teaching method and took a multiple-choice theoretical examination. The results were analyzed by t tests. RESULTS: Significant difference was found between the two groups in total mean score of preparedness and performance feedback statement (P = 0.01) and the questionnaire by PGY-1's opinion on the effectiveness of the two teaching methods (P = 0.004). Compared with the non-PSBL group, the PSBL group had significantly higher mean score of pre-operative preparedness (P = 0.01), but there was no significant difference between the two groups in theoretical examination, intra-operative performance, and overall satisfaction with the PGY-1s. The residents found that PSBL could develop their judgment (P = 0.03) and provide greater satisfaction (P = 0.02), and would like to repeat the experience (P = 0.03). CONCLUSIONS: The PSBL method can activate spine residents' prior knowledge and building on existing cognitive frameworks, which is an important tool for improving pre-operative preparedness. We believe that PSBL is an important first step in training spine residents to become confident and safe spine surgeons.

MicroRNA-21 promotes proliferation, invasion and suppresses apoptosis in human osteosarcoma line MG63 through PTEN/Akt pathway.

Osteosarcoma, which accounts for 5 % of pediatric tumor, remains the major cause of death among orthopedic malignancies. However, the factors associated with its malignant biological behavior are still poorly understood. MicroRNAs are a class of small noncoding RNAs, which have been considered to associate with malignant progression including cell differentiation, proliferation, apoptosis, invasion, and distant metastasis. In our research, we found that microRNA-21 (miR-21) was significantly overexpressed in human osteosarcoma cell line MG63 compared to human fetal osteoblastic cell line hFOB1.19 by using quantitative real-time polymerase chain reaction (qRT-PCR). Moreover, miR-21 overexpression in MG63 caused a significant raise in cell proliferation and invasion and a significant reduction in cell apoptosis. However, miR-21 underexpression in MG63 caused an opposite result. Western blotting displayed that proteins related with proliferation, apoptosis, and invasion were significantly changed in different groups, respectively. Furthermore, we demonstrated that PTEN may be a potential target of miR-21 in MG63 cells and miR-21 could activate PI3K/Akt pathway by suppressing PTEN expression. In summary, our findings suggested that miR-21 played an active role in osteosarcoma and it could predict the occurrence and development of osteosarcoma.

A meta-analysis of endoscopic discectomy versus open discectomy for symptomatic lumbar disk herniation.

PURPOSE: The purpose of this study was to systematically compare the effectiveness and safety of endoscopic discectomy (ED) with open discectomy (OD) for the treatment of symptomatic lumbar disc herniation (LDH). METHODS: A highly sensitive search strategy was used to identify all published randomized controlled trials up to August 2014. A criteria list taken from Koes et al. was used to evaluate the risk of bias of the included studies. The five questions that were recommended by the Cochrane Back Review Group were used to evaluate the clinical relevance. Cochrane methodology was used for the results of this meta-analysis. RESULTS: Nine relevant RCTs involving 1,092 patients were identified. Compared with OD, ED results in slightly better clinical outcomes which were evaluated by the Macnab criteria without clinical significance (ED group: 95.76 %; OD group: 80 %; OR: 3.72, 95 % CI: [0.76, 18.14], P = 0.10), a significantly greater patient satisfaction rate (ED group: 93.21 %; OD group: 86.57 %; OR: 2.19; 95 % CI: [1.09, 4.40]; P = 0.03), lower intraoperative blood loss volume (WMD: -123.71, 95 % CI: [-173.47, -73.95], P < 0.00001), and shorter length of hospital stay (WMD: -Table 2144.45, 95 % CI: [-239.54, -49.37], P = 0.003). CONCLUSIONS: From the existing outcomes, ED surgery could be viewed as a sufficient and safe supplementation and alternative to standard open discectomy. The cost-effectiveness analyses still remain unproved from the existing data. More independent high-quality RCTs using sufficiently large sample sizes with cost-effectiveness analyses are needed.

[Association between the expression of Aggrecan and the distribution of Aggrecan gene variable number of tandem repeats with symptomatic lumbar disc herniation].

OBJECTIVE: To study the expression of Aggrecan and the relationship between the variable number of tandem repeats (VNTR) of Aggrecan and lumbar disc herniation (LDH). METHODS: The disease group comprised of 74 patients already diagnosed with symptomatic LDH. The control group consisted of 15 patients restricted to spinal trauma and 113 healthy blood donors without symptoms of LDH who were not diagnosed with LDH. Disc tissue samples were obtained from surgical operations and blood samples were donated from all participants. The Aggrecan expression in isolated tissues was assessed by western blot using specific antibodies. The Aggrecan gene VNTR region was analyzed by PCR. RESULTS: The Aggrecan expression positive rate of control group was statistically and significantly higher (control group:86.67%, disease group:13.51%;χ(2) = 34.83, P < 0.05) than that of the disease group. Moreover, there was a statistically significant higher frequency of Allele 25 or Allele 21 in disease group compared to controls (A25disease group = 22.97%, A25control group = 12.11%, χ(2)A25 = 8.20, PA25 = 0.004; A21disease group = 6.76%, A21control group = 0.39%, χ(2)A21 = 14.35, PA21 = 0.000). Compared to the participants with 2 Alleles>25 repeats, subjects with 1 or 2 Alleles ≤ 25 repeats statistically and significantly over represented the disease group without the expression of Aggrecan (χ(2) = 5.69, P = 0.017). CONCLUSIONS: The findings suggest a relationship between Aggrecan and symptomatic LDH, where symptomatic LDH has a tendency of allele 21 and allele 25 repeats.In addition, an association between the distribution of Aggrecan gene VNTR polymorphism and the expression of Aggrecan is observed in symptomatic LDH.

Matrix metalloproteinase-9 is up-regulated by CCL19/CCR7 interaction via PI3K/Akt pathway and is involved in CCL19-driven BMSCs migration.

C-C chemokine receptor 7 (CCR7) and its ligands CCL19 contributes to the directional migration of certain cancer cell lines, but its role in the migration of BMSCs remains vague. The aim of this study was to determine the possible interaction between CCL19-induced conditions and matrix metalloproteinases-9 (MMP9) expression in BMSCs. Cell migration using Transwell assay indicated that activation of CCR7 by its specific ligand, exogenous chemokine ligand 19 (CCL19), was associated with a significant linear increase. Western blot and real-time PCR indicated that CCL19/CCR7 significantly upregulated expression of MMP9, which is related to metastasis-associated genes. The CCL19/CCR7 interaction significantly enhanced phosphorylation of Akt, as measured by Western blot. P-Akt and MMP9 protein expression exhibited a time-dependent pattern, and the peak was at 48h. LY294002 significantly abolished the effects of exogenous CCL19. These results suggest that CCL19/CCR7 contributes to the migration of BMSCs by upregulating MMP9 potentially via the PI3K/Akt pathway.

CIP2A is overexpressed in osteosarcoma and regulates cell proliferation and invasion.

Cancerous inhibitor of protein phosphatase 2A (CIP2A) is a newly characterized oncoprotein involved in a variety of malignant tumors. However, its expression pattern and biological functions in osteosarcoma remain unclear. In the present study, CIP2A expression was analyzed in 51 human osteosarcoma specimens using immunohistochemistry. CIP2A siRNA was used in the MG-63 cell line, and the effect of CIP2A depletion on cell proliferation and invasion was evaluated. We found that CIP2A was overexpressed in 76.5 % (39/51) of osteosarcoma tissues, while normal bone tissues showed negative CIP2A expression. In addition, the positive rate of CIP2A expression was higher in stage IIB osteosarcoma than stage IIA cases. Knockdown of the CIP2A expression significantly reduced osteosarcoma cell proliferation and invasion, with decreased c-Myc expression and p-AKT expression. CIP2A depletion also facilitated apoptosis and inhibited MMP9 mRNA expression. Taken together, our data identified CIP2A as a critical oncoprotein involved in cell proliferation and invasion, which could serve as a therapeutic target in osteosarcoma.

A new anterior-posterior surgical approach for the treatment of cervical facet dislocations.

STUDY DESIGN: The preliminary results from a new anterior-posterior surgical approach are reported. OBJECTIVE: To report a novel surgical approach, which was successfully applied to treat 8 cervical facet dislocation patients. SUMMARY OF BACKGROUND DATA: The combined anterior-posterior surgical procedure is used as a common approach in the treatment of cervical facet dislocations. However, some problems may arise during the application of this approach, and as a result, surgeons must change the initial surgical plan to anterior-posterior-anterior approach. METHODS: Between December 2011 and June 2012, 8 patients had facet dislocations were surgically treated by the new anterior-posterior approach. After anterior discectomy, a peek frame cage containing autologous iliac bone particles or tricalcium phosphate bone substitute was inserted in the interspace and fixed with a peek composite buttress plate screwed into the inferior vertebral body. Then, the anterior wound was closed and the patient was turned prone. Through a posterior midline approach, the posterior elements were exposed and the reduction was gradually achieved by posteriorly translating the superior segment and progressively positioning the patient's neck into extension. Then lateral mass or pedicle screws and titanium rods were placed in a favorable and satisfactory position, which was demonstrated by the intraoperative plain radiographs. A posterolateral fusion was performed and the posterior wound was closed. RESULTS: With the use of this new approach, all the patients had obtained successful reduction and satisfactory anatomic sagittal alignment. No instances of neurological deterioration and instrument failure occurred, no complications were owing to the use of this technique, and 4 patients existed neurological functional recovery at the most recent follow-up visit. CONCLUSIONS: This reported surgical approach is an efficient and safe way for the treatment of traumatic cervical facet dislocations.

Resveratrol inhibits inflammation after spinal cord injury via SIRT-1/NF-κB signaling pathway.

Spinal cord injury (SCI) can cause severe trauma to the central nervous system. Resveratrol has been widely studied for several of its medicinal properties, including anti-inflammatory, anti-aging and anti-oxidative effects. The regulation of SIRT-1 is thought to be related to the effects of resveratrol. As a downstream component of SIRT-1, NF-κB is one of the important signaling pathways that regulate the inflammatory response. Herein, we explored how treatment with resveratrol promoted recovery of motor function after SCI by activating the SIRT-1/NF-κB signaling pathway and inhibiting inflammation in rat models. Recovery of hind limb function was observed using the Basso, Beattie, and Bresnahan locomotor rating scale at different time points after SCI. Western blot analysis, immunofluorescence, Nissl staining and HE staining were utilized to observe the morphological characteristics of spinal cord tissue, as well as the expression of SIRT-1, NF-κB, TNF-α, IL-1ß, IL-6 and brain-derived neurotrophic factor. Resveratrol treatment promoted motor function recovery, increased the expression of brain-derived neurotrophic factor, and reduced loss of motor neurons and lesion size among rats after SCI. Meanwhile, inflammatory response was inhibited as the SIRT-1/NF-κB signaling pathway was modulated. These results suggest that resveratrol can help achieve neuroprotective effect by inhibiting inflammation, regulated by the SIRT-1/NF-κB signaling pathway.

Accurate simulation of the herniated cervical intervertebral disc using controllable expansion: a finite element study.

Expansions were carried out in finite element (FE) models of disc hernia including symmetric (median, lateral, paramedian) and asymmetric types. In all models, lubricous disk bulging that applied a linear compression to the anterior part of the cord was observed at the posterior surfaces of the expansion zone, respectively. The shape and position of protrusions varyed with the temperature, magnitude, and location of expanding elements. The geometric deformation and stress distribution of the spinal cord increased as the extent of compression grew. This method is in possession of enormous potential in promoting further individualized research of cervical spondylotic myelopathy.

The interaction between aggrecan gene VNTR polymorphism and cigarette smoking in predicting incident symptomatic intervertebral disc degeneration.

An association between the aggrecan variable number of tandem repeat (VNTR) polymorphism and the disc degeneration has been previously reported in Finnish men, and smoking had previously been suspected of causing disc degeneration. However, the interaction between aggrecan gene VNTR polymorphism and smoking in symptomatic intervertebral disc degeneration (IDD) has not been well studied. To examine the interaction between aggrecan gene VNTR and smoking in the susceptibility of symptomatic IDD of Chinese Han in northern China, intervertebral discs of 132 participants were evaluated on magnetic resonance imaging, using decreased signal intensity. After harvesting the blood samples, the aggrecan gene VNTR region was analyzed using polymerase chain reaction (PCR). The data indicated that between the two groups, participants carrying one or two alleles ≤25 repeats who did not smoke showed a 1.102-fold increased risk for symptomatic IDD (p= 0.855; 95% confidence interval 0.389-3.119), and participants carrying two alleles >25 repeats who smoked more than 1 pack-year showed a 1.013-fold higher risk (p = 0.982; 95% confidence interval 0.333-3.084), whereas participants carrying one or two alleles ≤25 repeats who smoked more than 1 pack-year showed a 4.5-fold increased risk for symptomatic IDD (p = 0.005; 95% confidence interval 1.589-12.743). Overall, we observed an underlying additive and multiplicative interaction between the aggrecan gene VNTR polymorphism and smoking in symptomatic IDD.

Role of Smad3 inhibitor and the pyroptosis pathway in spinal cord injury.

The aim of the present study was to investigate the role of Smad3 inhibitors and the pyroptosis pathway in spinal cord injury, and to determine the underlying mechanism. The pyroptosis signaling pathway may be involved in spinal cord injury during the recovery period. Smad3 inhibitor may serve a role in alleviating spinal cord injury by reducing the pyroptosis of neurons, which is induced by caspase-1, absent in melanoma-2 or NOD-like receptors protein-1 during the recovery period of spinal cord injury. In the present study, spinal cord injury was alleviated by caspase-1 and Smad3 inhibitors. Therefore, a Smad3 inhibitor could relieve spinal cord injury in mice by directly downregulating caspase-1 and reducing neuron pyroptosis following spinal cord injury during the recovery period.

Fingolimod inhibits proliferation and epithelial-mesenchymal transition in sacral chordoma by inactivating IL-6/STAT3 signalling.

PURPOSE: To explore the sensitivity of the immunosuppressive agent fingolimod (FTY720) in chordoma and determine whether it can serve as an appropriate alternate treatment for unresectable tumours in patients after incomplete surgery. METHODS: Cell viability assays, colony formation assays and EdU assays were performed to evaluate the sensitivity of chordoma cell lines to FTY720. Transwell invasion assays, wound healing assays, flow cytometry, cell cycle analysis, immunofluorescence analysis, Western blotting analysis and enzyme-linked immunosorbent assays (ELISAs) were performed to evaluate cell invasion, epithelial-mesenchymal transition (EMT) and activation of related pathways after treatment with FTY720. The effect of FTY720 was also evaluated in vivo in a xenograft model. RESULTS: We found that FTY720 inhibited the proliferation, invasion and metastasis of sacral chordoma cells (P < 0.01). FTY720 also inhibited the proliferation of tumour cells in a xenograft model using sacral chordoma cell lines (P < 0.01). The mechanism was related to the EMT and apoptosis of chordoma cells and inactivation of IL-6/STAT3 signalling in vitro and in vivo. CONCLUSIONS: Our findings indicate that FTY720 may be an effective therapeutic agent against chordoma. These findings suggest that FTY720 is a novel agent that can treat locally advanced and metastatic chordoma.

miR­329­3p regulates neural stem cell proliferation by targeting E2F1.

Neural stem cells (NSCs) are a class of self­renewing and undifferentiated progenitor cells that retain the ability to differentiate to neurons, astrocytes and oligodendrocytes. MicroRNAs (miRNAs) are small noncoding RNAs that serve crucial roles in regulating a number of cellular processes, including cell proliferation, differentiation and apoptosis. Our previous GeneChip data indicated that the expression of miR­329­3p was increased in neurons compared with NSCs. However, whether miRNA­329­3p participates in regulating NSC function remains to be elucidated. In the present study, it was identified that the expression of miR­329­3p was upregulated in NSCs during neuronal differentiation, whereas expression of transcription factor E2F1 (E2F1), a putative target gene of miR­329­3p, was downregulated. Using luciferase reporter assays, it was confirmed that miR­329­3p regulated E2F1 expression. As differentiation has been demonstrated to limit the proliferative capacity of NSCs, the effects of miR­329­3p and E2F1 modulation on NSC proliferation were examined. Forced overexpression of miR­329­3p or RNA­mediated silencing of E2F1 inhibited NSC proliferation, and overexpression of miR­329­3p also inhibited E2F1 expression. Notably, ectopic expression of E2F1 reversed the inhibition of NSC proliferation induced by miR­329­3p overexpression. These results indicated that miR­329­3p may serve crucial roles in regulating the proliferation of NSCs, at least in part via inhibition of E2F1 expression. These data improve the understanding of the microRNA­mRNA regulatory network that controls NSC proliferation.

Neuregulin­1 impacting bone marrow mesenchymal stem cell migration is conducive to functional recovery following spinal cord injury.

The present study was designed to investigate the effect of neuregulin­1 (NRG1) on the migration of rat bone marrow mesenchymal stem cells (BMSCs) and evaluate the role of NRG1 in the functional recovery following spinal cord injury (SCI). Firstly, the effect of NRG1 on the mRNA expression of Snail in the BMSCs was detected by reverse transcription­quantitative polymerase chain reaction (RT­qPCR) analysis; secondly, the BMSCs were transfected with a Snail­overexpression plasmid (pBabe­puro­Snail) and the expression levels of Snail and matrix metalloptoreinase­2 (MMP­2) were detected by RT­qPCR and western blot analyses; thirdly, the cell proliferation and migration of BMSCs modified with pBabe­puro­Snail were detected by methyl thiazolyl tetrazolium and migration assays, respectively; finally, functional recovery of SCI was assessed using the Basso, Beattie, and Bresnahan rating scales. The results showed that NRG1 concentration­dependently promoted the expression of Snail with a peak at 40 ng/ml and 48 h; NRG1 enhanced the promoting effect of Snail on the expression of MMP­2; the overexpression of Snail did not enhance the cell growth of the BMSCs. The NRG1­modified BMSCs promoted the functional recovery of SCI. These results suggested that NRG1 significantly promoted the expression of MMP­2 by upregulating the expression of Snail, and enhanced cell migration of the BMSCs conducive to the functional recovery of SCI.

MEG3 inhibits proliferation and invasion and promotes apoptosis of human osteosarcoma cells.

Osteosarcoma is known as a malignant tumour with a high mortality rate in orthopaedic settings; however, the factors associated with its degree of malignancy and the biological response remains to be elucidated. Although the essential role of the long noncoding RNA (lncRNA) maternally expressed 3 (MEG3) has been recently reported, its biological functions and regulatory mechanism in osteosarcoma cells have not yet been reported. In the present study, reverse transcription-quantitative polymerase chain reaction analysis revealed that the expression of MEG3 in MG63 cells was lower compared with in hFOB1.19 cells. Furthermore, it was observed that overexpressing MEG3 in MG63 cells resulted in a decline in the proliferation and invasion, and a marked increase in apoptosis. Additionally, western blotting was used to detect the changes in expression of p53 and MDM2 proto-oncogene, which may be regulated by MEG3, and proteins that associated with cell proliferation, invasion and apoptosis. It was demonstrated that the upregulation of MEG3 significantly increased the transactivation of p53 and induced downstream changes in protein expression. In conclusion, these experiments have demonstrated that MEG3 serves an essential regulatory role in the biological processes of human osteosarcoma cells, and imply that MEG3 may be a marker for predicting the occurrence and development of osteosarcoma.

Overexpression of HIPK2 attenuates spinal cord injury in rats by modulating apoptosis, oxidative stress, and inflammation.

HIPK2 is considered to be a tumor suppressor. It also has been implicated in several functions such as apoptosis and inflammation that are linked to spinal cord injury (SCI). However, whether HIPK2 ameliorates the neurological pain of SCI remains unclear. Here, we investigated the effects of HIPK2 on neurological function, oxidative stress, levels of inflammatory cytokines and expression of Bcl-2/Bax in an SCI model. Firstly, we evaluated the therapeutic effects of HIPK2 on neurological pain in the SCI rat using the Basso, Beattie and Bresnahan scores and H & E staining. Overexpression of HIPK2 significantly elevated the levels of brain-derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF), and reduced the mRNA expression of Nogo-A and RhoA in SCI rats. Furthermore, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assays showed that overexpression of HIPK2 significantly reduced the number of apoptotic cells. Overexpression of HIPK2 also decreased expression of Bax and Caspase-3 and elevated expression of Bcl-2 in the SCI model, indicating that HIPK2 exhibited its protective activity by inhibiting SCI-induced apoptosis. Then, we measured the serum concentrations of malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-PX). We also determined the mRNA and protein levels of nuclear factor-κB p65 unit, tumor necrosis factor-α (TNF-α), and interleukin (IL)-1ß. HIPK2 overexpression reduced oxidative stress and the levels of inflammatory cytokines compared with SCI control animals. Additionally, acetylation of HIPK2 was reduced in SCI rats. Overexpression of HIPK2 could enhance autophagy by elevating the expression of Beclin-1 and LC3-II while autophagy is regarded as a beneficial regulator to improve spinal cord injury. Together, overexpression of HIPK2 improved contusive SCI induced pain by modulating oxidative stress, Bcl­2 and Bax signaling, and inflammation, and also regulating autophagy.

A Meta-Analysis on the Clinical Significance of Redundant Nerve Roots in Symptomatic Lumbar Spinal Stenosis.

OBJECTIVE: Symptomatic lumbar spinal stenosis (LSS), which leads to severe socioeconomic consequences and places a heavy burden on global healthcare system, is a relatively frequent spine disorder. Redundant nerve roots (RNRs) are a relatively common finding in which slender, serpiginous, or tortuous nerve roots are found in the subarachnoid space of the lumbar spine. Previous studies that evaluated the prognostic assessment of RNRs in patients with symptomatic LSS are composed of doubtful results. Therefore, the clinical significance of RNRs in symptomatic LSS is still uncertain. The aim of this meta-analysis is a systematic assessment of the clinical significance of RNR syndrome in symptomatic LSS. METHODS: This study used a highly sensitive search strategy to identify all published studies in multiple databases up to January 1, 2017. All identified trials were systematically evaluated using specific inclusion and exclusion criteria. Cochrane methodology was also applied to the results of this study. RESULTS: This study identified 4 relevant studies involving 297 patients. Compared with a non-RNR group, the RNR group results included worse clinical outcomes that were assessed using the Japanese Orthopedic Association scores after surgery (weighted mean difference [WMD], -0.78; 95% confidence interval [CI], -1.26 to -0.29; P = 0.002; I2 = 0%), for recovery rate (WMD, -9.87; 95% CI, -15.07 to -4.67; P = 0.0002; I2 = 0%), and for older age (WMD, 2.51; 95% CI, 0.45-4.57; P = 0.02; I2 = 43%). CONCLUSIONS: RNR is an entity in association with symptomatic LSS, which may be viewed as a potentially powerful prognostic indicator of worse postoperative functional recovery for symptomatic LSS.

MicroRNA-21 promotes bone mesenchymal stem cells migration in vitro by activating PI3K/Akt/MMPs pathway.

MicroRNA-21 (miR-21) contributes to anti-apoptosis in bone marrow mesenchymal stem cells (BMSC), but its role in the migration of BMSCs remains vague. The aim of this study was to determine the possible effect of miR-21 on regulating BMSCs directional migration and the expression of MMP-2/MMP-9 in BMSCs in vitro. BMSCs were successfully infected with miR-21-up lentivirus. Cell migration using Transwell assay indicated that upregulated expression of miR-21 could significantly promote BMSCs migration. Western blot analysis indicated that miR-21 significantly upregulated the expression of MMP-2 and MMP-9, which were related to metastasis-associated genes. GM6001, the specific MMPs inhibitor, abrogated the upregulated expression of MMP-2/MMP-9 and abolished the positive effect of miR-21 on promoting BMSCs migration. Meanwhile, miR-21 significantly enhanced Akt phosphorylation, as measured by Western blot analysis. LY294002, an inhibitor of Akt activation, abrogated the phosphorylation of Akt and abolished the positive effect of miR-21 on promoting BMSCs migration and upregulating MMP-2/MMP-9 expression. These results suggest that miR-21 contributes to BMSCs migration by upregulating MMP-2/MMP-9, potentially via the PI3K/Akt pathway.

Effects of Reactive Oxygen Species on Differentiation of Bone Marrow Mesenchymal Stem Cells.

BACKGROUND The low differentiation rates for transplanted stem cells are challenging problems in spinal cord injury (SCI) treatment. Studies have demonstrated that the inhibition of the Notch1 pathway in bone marrow mesenchymal stem cells (BMSCs) contributed to the differentiation of these cells. Research findings that certain antioxidants induce BMSCs to differentiate into neuronal cells suggest that BMSC differentiation is related to the level of reactive oxygen species (ROS) in cells. This study aimed to define the effect of ROS on the differentiation of BMSCs. MATERIAL AND METHODS In this study, after BMSCs were induced with the antioxidant ß-mercaptoethanol (ß-ME), related proteins were analyzed by Western blotting and immunofluorescence. In order to find the role of ROS in the differentiation, DCFH-DA was used to detect ROS levels in antioxidant-treated BMSCs, H2O2-treated BMSCs, and normal BMSCs, and the expression levels of Notch1 and its downstream transcriptional suppressor Hes1 were analyzed. RESULTS Induced with ß-ME, Western blotting and immunofluorescence revealed gradual increases in the expression of Nestin (a neural stem cell-specific protein) and neuron-specific enolase (NSE) but decreases in Notch1 expression. The expression levels of Notch1 and Hes1 were positively correlated with changes in ROS level. CONCLUSIONS These data suggest that the antioxidant-induced differentiation of BMSCs into neurons may be related to ROS-based regulation of the Notch1 signalling pathway.