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At least 19 records

SU-E-J-85: The Effect of Different Imaging Modalities On the Delineation of the True Spinal Cord for Spinal Stereotactic Body Radiation Therapy

Purpose: SBRT allows the delivery of high dose radiation treatments to localized tumors while minimizing dose to surrounding tissues. Due to the large doses delivered, accurate contouring of organs at risk is essential. In this study, differences between the true spinal cord as seen using MRI and CT myelogram (CTM) have been assessed in patients with spinal metastases treated using SBRT. Methods: Ten patients were identified that have both a CTM and a MRI. Using rigid registration tools, the MRI was fused to the CTM. The thecal sac and true cord were contoured using each imaging modality. Images were exported and analyzed for similarity by computing the Dice similarity coefficient and the modified Hausdorff distance (greatest distance from a point in one set to the closest point in the other set). Results: The Dice coefficient was calculated for the thecal sac (0.81 ±0.06) and true cord (0.63 ±0.13). These two measures are correlated; however, some points show a low true cord overlap despite a high overlap for the thecal sac. The Hausdorff distance for structure comparisons was also calculated. For thecal sac structures, the average value, 1.6mm (±1.1), indicates good overlap. For true cord comparison, the average value, 0.3mm (±0.16), indicates very good overlap. The minimum Hausdorff distance between the true cord and thecal sac was on average 1.6mm (±0.9) Conclusion: The true cord position as seen in MRI and CTM is fairly constant, although care should be taken as large differences can be seen in individual patients. Avoidning the true cord in spine SBRT is critical, so the ability to visualize the true cord before performing SBRT to the vertebrae is essential. Here, CT myelogram appears an excellent, robust option, that can be obtained the day of treatment planning and is unaffected by uncertainties in image fusion.

60 APPLIED LIFE SCIENCES↗

FoxJ1 regulates spinal cord development and is required for the maintenance of spinal cord stem cell potential

Development of the spinal cord requires dynamic and tightly controlled expression of numerous transcription factors. Forkhead Box protein J1 (FoxJ1) is a transcription factor involved in ciliogenesis and is specifically expressed in ependymal cells (ECs) in the adult central nervous system. However, using FoxJ1 fate-mapping mouse lines, we observed that FoxJ1 is also transiently expressed by the progenitors of other neural subtypes during development. Moreover, using a knock-in mouse line, we discovered that FoxJ1 is essential for embryonic progenitors to follow a normal developmental trajectory. FoxJ1 loss perturbed embryonic progenitor proliferation and cell fate determination, and resulted in formation of adult ECs having impaired stem cell potential and an inability to respond to spinal cord injury in both male and female animals. Thus, our study uncovers unexpected developmental functions of FoxJ1 in cell fate determination of subsets of neural cells and suggests that FoxJ1 is critical for maintaining the stem cell potential of ECs into adulthood.

60 APPLIED LIFE SCIENCES↗

Phase 1 Study of Spinal Cord Constraint Relaxation With Single Session Spine Stereotactic Radiosurgery in the Primary Management of Patients With Inoperable, Previously Unirradiated Metastatic Epidural Spinal Cord Compression

We seek to establish the feasibility of using spine stereotactic radiosurgery (SSRS), allowing for spinal cord dose constraint relaxation, as the primary management of metastatic epidural spinal cord compression (MESCC) in inoperable patients.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

Bioactive scaffolds with enhanced supramolecular motion promote recovery from spinal cord injury

The signaling of cells by scaffolds of synthetic molecules that mimic proteins is known to be effective in the regeneration of tissues. Here, we describe peptide amphiphile supramolecular polymers containing two distinct signals and test them in a mouse model of severe spinal cord injury. One signal activates the transmembrane receptor β1-integrin and a second one activates the basic fibroblast growth factor 2 receptor. By mutating the peptide sequence of the amphiphilic monomers in nonbioactive domains, we intensified the motions of molecules within scaffold fibrils. This resulted in notable differences in vascular growth, axonal regeneration, myelination, survival of motor neurons, reduced gliosis, and functional recovery. Here, we hypothesize that the signaling of cells by ensembles of molecules could be optimized by tuning their internal motions.

36 MATERIALS SCIENCE↗

lncRNA-Map2k4 sequesters miR-199a to promote FGF1 expression and spinal cord neuron growth

Spinal cord injury (SCI) is a common critical illness in clinical practice. SCI prevention, treatment and rehabilitation have become important topics in today's medical profession. Studies have shown that long noncoding RNAs (lncRNAs) also play an important role in the pathology of SCI. The biology software analysis identified miR-199a binding sites in the lncRNA-Map2k4 and FGF1 sequences, which were confirmed by the subsequent dual luciferase reporter assay. When lncRNA-Map2k4 expression was down-regulated by siRNA, miR-199a expression in neurons was up-regulated and FGF1 expression was down-regulated. In turn, miR-199a up-regulation inhibited lncRNA-Map2k4 and FGF1 expression. But when lncRNA-Map2k4-m (a lncRNA-Map2k4 overexpression vector with mutated miR-199a binding sites) was co-transfected into neuronal cells with miR-199a mimics, lncRNA-Map2k4-m over-expression did not block the inhibition of FGF1 expression by miR-199a. Moreover, lncRNA-Map2k4 and FGF1 promoted the proliferation and inhibited the apoptosis of neuronal cells, whereas miR-199a down-regulated the aforementioned functions of lncRNA-Map2k4 and FGF1; however, lncRNA-Map2k4-m could not block the inhibitory action of miR-199a on proliferation. Thus, lncRNA-Map2k4 regulates neuronal proliferation and apoptosis through a miR-199a/FGF1 pathway. This finding provides more evidence for the role of lncRNAs in SCI. - Highlights: • lncRNA-Map2k4 is the target gene of miR-199a, and its down-regulation promotes miR-199a expression in neurons. • miR-199a targeted regulation of FGF1 expression in neurons. • Knockdown of lncRNA-Map2k4 inhibited the FGF1 expression by up-regulating miR-199a. • lncRNA-Map2k4 regulates neuron proliferation and apoptosis through an miR-199a/FGF1 pathway.

60 APPLIED LIFE SCIENCES↗

Intradiencephalon injection of histamine inhibited the recovery of locomotor function of spinal cord injured zebrafish

Human spinal cord injury (SCI) usually causes irreversible disability beneath the injured site due to poor neural regeneration. On the contrary, zebrafish show significant regenerative ability after SCI, thus is usually worked as an animal model for studying neuroregeneration. Most of the previous SCI studies focused on the local site of SCI, the supraspinal-derived signals were rarely mentioned. Here we showed that intradiencephalon injection of histamine (HA) inhibited the locomotor recovery in adult zebrafish post-SCI. Immunofluorescence results showed that intradiencephalon HA administration increased the activated microglia 3 days post injury (dpi), promoted the proliferation of radial glial cells at 7 dpi and affected the morphology of radial glial cells at 11 dpi. Furthermore, quantitative real-time polymerase chain reaction (qRT-PCR) results showed that intradiencephalon HA administration also reduced the expression of neurotrophic factors including brain-derived neurotrophic factor (BDNF) and insulin-like growth factor1 (IGF-1) at the lesion site, however, had no effect on the expression of pro-inflammatory factors such as TNF-alpha and IL-1 beta. Hence, our data suggested that exogenous intradiencephalon HA retarded locomotor recovery in spinal cord injured zebrafish via modulating the repair microenvironment. - Highlights: • A novel model to study the effect of supraspinal signals on repair of SCI zebrafish. • Exogenous HA administration suppresses the locomotor function recovery after SCI. • Exogenous HA administration modulates the repair microenvironment after SCI.

60 APPLIED LIFE SCIENCES↗

SU-F-T-113: Inherent Functional Dependence of Spinal Cord Doses of Variable Irradiated Volumes in Spine SBRT

Purpose: Spinal cord tolerance for SBRT has been recommended for the maximum point dose level or at irradiated volumes such as 0.35 mL or 10% of contoured volumes. In this study, we investigated an inherent functional relationship that associates these dose surrogates for irradiated spinal cord volumes of up to 3.0 mL. Methods: A hidden variable termed as Effective Dose Radius (EDR) was formulated based on a dose fall-off model to correlate dose at irradiated spinal cord volumes ranging from 0 mL (point maximum) to 3.0 mL. A cohort of 15 spine SBRT cases was randomly selected to derive an EDR-parameterized formula. The mean prescription dose for the studied cases was 21.0±8.0 Gy (range, 10–40Gy) delivered in 3±1 fractions with target volumes of 39.1 ± 70.6 mL. Linear regression and variance analysis were performed for the fitting parameters of variable EDR values. Results: No direct correlation was found between the dose at maximum point and doses at variable spinal cord volumes. For example, Pearson R{sup 2} = 0.643 and R{sup 2}= 0.491 were obtained when correlating the point maximum dose with the spinal cord dose at 1 mL and 3 mL, respectively. However, near perfect correlation (R{sup 2} ≥0.99) was obtained when corresponding parameterized EDRs. Specifically, Pearson R{sup 2}= 0.996 and R{sup 2} = 0.990 were obtained when correlating EDR (maximum point dose) with EDR (dose at 1 mL) and EDR(dose at 3 mL), respectively. As a result, high confidence level look-up tables were established to correlate spinal cord doses at the maximum point to any finite irradiated volumes. Conclusion: An inherent functional relationship was demonstrated for spine SBRT. Such a relationship unifies dose surrogates at variable cord volumes and proves that a single dose surrogate (e.g. point maximum dose) is mathematically sufficient in constraining the overall spinal cord dose tolerance for SBRT.

60 APPLIED LIFE SCIENCES↗

Management of Pediatric Spinal Cord Astrocytomas: Outcomes With Adjuvant Radiation

Purpose: Pediatric intramedullary spinal cord tumors are exceedingly rare; in the United States, 100 to 200 cases are recognized annually, of these, most are astrocytomas. The purpose of this study is to report the outcomes in pediatric patients with spinal cord astrocytomas treated at a tertiary care center. Methods and Materials: An institutional review board-approved retrospective single-institution study was performed for pediatric patients with spinal cord astrocytomas treated at our hospital from 1990 to 2010. The patients were evaluated on the extent of resection, progression-free survival (PFS), and development of radiation-related toxicities. Kaplan-Meier curves and multivariate regression model methods were used for analysis. Results: Twenty-nine patients were included in the study, 24 with grade 1 or 2 (low-grade) tumors and 5 with grade 3 or 4 (high-grade) tumors. The median follow-up time was 55 months (range, 1-215 months) for patients with low-grade tumors and 17 months (range, 10-52 months) for those with high-grade tumors. Thirteen patients in the cohort received chemotherapy. All patients underwent at least 1 surgical resection. Twelve patients received radiation therapy to a median radiation dose of 47.5 Gy (range, 28.6-54.0 Gy). Fifteen patients with low-grade tumors and 1 patient with a high-grade tumor exhibited stable disease at the last follow-up visit. Acute toxicities of radiation therapy were low grade, whereas long-term sequelae were infrequent and manageable when they arose. All patients with low-grade tumors were alive at the last follow-up visit, compared with 1 patient with a high-grade tumor. Conclusion: Primary pediatric spinal cord astrocytomas vary widely in presentation and clinical course. Histopathologic grade remains a major prognostic factor. Patients with low-grade tumors tend to have excellent disease control and long-term survival compared to those with high-grade tumors. This experience suggests that radiation therapy may enhance tumor control with an acceptably low risk of long-term sequelae in this sensitive patient population.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

Spinal Cord Dose Tolerance to Stereotactic Body Radiation Therapy

Spinal cord tolerance data for stereotactic body radiation therapy (SBRT) were extracted from published reports, reviewed, and modelled. For de novo SBRT delivered in 1 to 5 fractions, the following spinal cord point maximum doses (D{sub max}) are estimated to be associated with a 1% to 5% risk of radiation myelopathy (RM): 12.4 to 14.0 Gy in 1 fraction, 17.0 Gy in 2 fractions, 20.3 Gy in 3 fractions, 23.0 Gy in 4 fractions, and 25.3 Gy in 5 fractions. For reirradiation SBRT delivered in 1 to 5 fractions, reported factors associated with a lower risk of RM include cumulative thecal sac equivalent dose in 2 Gy fractions with an alpha/beta of 2 (EQD2{sub 2}) D{sub max} ≤70 Gy; SBRT thecal sac EQD2{sub 2} D{sub max} ≤25 Gy, thecal sac SBRT EQD2{sub 2} D{sub max} to cumulative EQD2{sub 2} D{sub max} ratio ≤0.5, and a minimum time interval to reirradiation of ≥5 months. Larger studies containing complete institutional cohorts with dosimetric data of patients treated with spine SBRT, with and without RM, are required to refine RM risk estimates.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

Magnetic Resonance Imaging Assessment of Spinal Cord and Cauda Equina Motion in Supine Patients With Spinal Metastases Planned for Spine Stereotactic Body Radiation Therapy

Purpose: To assess motion of the spinal cord and cauda equina, which are critical neural tissues (CNT), which is important when evaluating the planning organ-at-risk margin required for stereotactic body radiation therapy. Methods and Materials: We analyzed CNT motion in 65 patients with spinal metastases (11 cervical, 39 thoracic, and 24 lumbar spinal segments) in the supine position using dynamic axial and sagittal magnetic resonance imaging (dMRI, 3T Verio, Siemens) over a 137-second interval. Motion was segregated according to physiologic cardiorespiratory oscillatory motion (characterized by the average root mean square deviation) and random bulk shifts associated with gross patient motion (characterized by the range). Displacement was evaluated in the anteroposterior (AP), lateral (LR), and superior-inferior (SI) directions by use of a correlation coefficient template matching algorithm, with quantification of random motion measure error over 3 separate trials. Statistical significance was defined according to P<.05. Results: In the AP, LR, and SI directions, significant oscillatory motion was observed in 39.2%, 35.1%, and 10.8% of spinal segments, respectively, and significant bulk motions in all cases. The median oscillatory CNT motions in the AP, LR, and SI directions were 0.16 mm, 0.17 mm, and 0.44 mm, respectively, and the maximal statistically significant oscillatory motions were 0.39 mm, 0.41 mm, and 0.77 mm, respectively. The median bulk displacements in the AP, LR, and SI directions were 0.51 mm, 0.59 mm, and 0.66 mm, and the maximal statistically significant displacements were 2.21 mm, 2.87 mm, and 3.90 mm, respectively. In the AP, LR, and SI directions, bulk displacements were greater than 1.5 mm in 5.4%, 9.0%, and 14.9% of spinal segments, respectively. No significant differences in axial motion were observed according to cord level or cauda equina. Conclusions: Oscillatory CNT motion was observed to be relatively minor. Our results support the importance of controlling bulk patient motion and the practice of applying a planning organ-at-risk margin.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

O-GlcNAc glycosylation of p27{sup kip1} promotes astrocyte migration and functional recovery after spinal cord contusion

Glial scar formation derived from astrocyte proliferation and migration influences the functional recovery after spinal cord injury. Cyclin-dependent kinase inhibitor p27{sup kip1}, whose activity is closely related to its phosphorylation state, reportedly regulates astrocyte proliferation and migration. In this study, we reported that p27{sup Kip1} undergoes O-GlcNAc modification at Ser 2, Ser 110 and Thr 197. Inhibiting O-GlcNAcylation on Ser 2 by gene mutation (S2A) attenuated the phosphorylation of Ser 10, and vice versa. Interestingly, compared with wild type p27{sup Kip1}, S2A p27{sup Kip1} displayed a decreased interaction with CRM1 and reduced nuclear export following serum starvation and release. In addition, the interaction between stathmin and S2A p27{sup Kip1} was also decreased. Cytoskeletal proteins microtubules appeared high density in astrocytes transfected with S2A p27{sup Kip1} especially at the leading edge of the scratch wound. Accordingly, scratch-wound assay revealed that the motility of astrocytes transfected with S2A p27{sup Kip1} was faster than that of control. Finally, we injected lentiviral vectors immediately after spinal cord contusion, and found the lesion volume of the rat injected with S2A p27{sup Kip1} was smaller than that of rat injected with wild type p27{sup Kip1}. Besides, the BBB and CBS behavioral tests showed greater functional recovery in S2A p27{sup Kip1} treated rats. Taken together, our findings revealed a novel function of O-GlcNAc modification of p27{sup Kip1} in mediating astrocytes migration and functional recovery after spinal cord contusion. - Highlights: • This is the first article about the O-GlcNAc glycosylation of p27{sup kip1}. • We searched the effect of O-GlcNAc modification of p27{sup kip1} on the migration of astrocytes. • We first report the influence of O-GlcNAc modification of p27{sup kip1} on the recovery after spinal cord injury.

60 APPLIED LIFE SCIENCES↗

Nanog interact with CDK6 to regulates astrocyte cells proliferation following spinal cord injury

Previous research had reported transcription factors Nanog expressed in pluripotent embryonic stem cells (ESCS) that played an important role in regulating the cell proliferation. Nanog levels are frequently elevated in ESCS, but the role in the spinal cord was not clear. To examine the biological relevance of Nanog, we studied its properties in spinal cord injury model. The expression of Nanog and PCNA was gradually increased and reached a peak at 3 day by western blot analysis. The expression of Nanog was further analyzed by immunohistochemistry. Double immunofluorescent staining uncovered that Nanog can co-labeled with PCNA and GFAP in the spinal cord tissue. In vitro, Nanog can promote the proliferation of astrocyte cell by Fluorescence Activating Cell Sorter (FACS) and CCK8. Meanwhile, the cell-cycle protein CDK6 could interact with Nanog in the spinal cord tissue. Taken together, these data suggested that both Nanog may play important roles in spinal cord pathophysiology via interact with CDK6.

60 APPLIED LIFE SCIENCES↗

Small GTPase R-Ras participates in neural tube formation in zebrafish embryonic spinal cord

Ras related (R-Ras), a small GTPase, is involved in the maintenance of apico-basal polarity in neuroepithelial cells of the zebrafish hindbrain, axonal collapse in cultured murine hippocampal neurons, and maturation of blood vessels in adult mice. However, the role of R-Ras in neural tube formation remains unknown. Using antisense morpholino oligonucleotides (AMOs), we found that in the spinal cord of zebrafish embryos, the lumen was formed bilaterally in rras morphants, whereas it was formed at the midline in control embryos. As AMO can cause off-target effects, we generated rras mutant zebrafish lines using CRISPR/Cas9 technology. Although these rras mutant embryos did not have a bilateral lumen in the spinal cord, the following findings suggest that the phenotype is unlikely due to an off-target effect of rras AMO: 1) The rras morphant phenotype was rescued by an injection of AMO-resistant rras mRNA, and 2) a bilaterally segregated spinal cord was not observed in rras mutant embryos injected with rras AMO. The results suggest that the function of other ras family genes may be redundant in rras mutants. Previous research reported a bilaterally formed lumen in the spinal cord of zebrafish embryos with a mutation in a planar cell polarity (PCP) gene, van gogh-like 2 (vangl2). In the present study, in cultured cells, R-Ras was co-immunoprecipitated with Vangl2 but not with another PCP regulator, Pricke1. Interestingly, the interaction between R-Ras and Vangl2 was stronger in guanine-nucleotide free point mutants of R-Ras than in wild-type or constitutively active (GTP-bound) forms of R-Ras. R-Ras may regulate neural tube formation in cooperation with Vangl2 in the developing zebrafish spinal cord.

60 APPLIED LIFE SCIENCES↗

Carbon Ion Irradiation of the Rat Spinal Cord: Dependence of the Relative Biological Effectiveness on Linear Energy Transfer

Purpose: To measure the relative biological effectiveness (RBE) of carbon ions in the rat spinal cord as a function of linear energy transfer (LET). Methods and Materials: As an extension of a previous study, the cervical spinal cord of rats was irradiated with single doses of carbon ions at 6 positions of a 6-cm spread-out Bragg peak (16-99 keV/μm). The TD{sub 50} values (dose at 50% complication probability) were determined according to dose-response curves for the development of paresis grade 2 within an observation time of 300 days. The RBEs were calculated using TD{sub 50} for photons of our previous study. Results: Minimum latency time was found to be dose-dependent, but not significantly LET-dependent. The TD{sub 50} values for the onset of paresis grade 2 within 300 days were 19.5 ± 0.4 Gy (16 keV/μm), 18.4 ± 0.4 Gy (21 keV/μm), 17.7 ± 0.3 Gy (36 keV/μm), 16.1 ± 1.2 Gy (45 keV/μm), 14.6 ± 0.5 Gy (66 keV/μm), and 14.8 ± 0.5 Gy (99 keV/μm). The corresponding RBEs increased from 1.26 ± 0.05 (16 keV/μm) up to 1.68 ± 0.08 at 66 keV/μm. Unexpectedly, the RBE at 99 keV/μm was comparable to that at 66 keV/μm. Conclusions: The data suggest a linear relation between RBE and LET at high doses for late effects in the spinal cord. Together with additional data from ongoing fractionated irradiation experiments, these data will provide an extended database to systematically benchmark RBE models for further improvements of carbon ion treatment planning.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

Decreased expression of LATS1 correlates with astrogliosis after spinal cord injury

Large tumor suppressor kinase 1 (LATS1) is a serine/threonine kinase of the AGC kinase family in mammals and involved in various biological processes, it is a key regulator of cell cycle progression. However, the role of LATS1 in central nervous system trauma is still unknown. In present study, we performed an acute spinal cord injury (SCI) model in adult rats and investigated the dynamic changes of LATS1 expression in the spinal cord. We found that LATS1 protein levels were significantly decreased at day 1 after injury. Meanwhile, double immunofluorescence staining showed these changes were striking in astrocytes, which were largely proliferated after SCI. In vitro, LATS1 overexpression inhibited astrocyte proliferation. Conversely, LATS1 depletion by siRNA promoted cell proliferation in primary astrocyte. Moreover, LATS1 overexpression reduced cyclin D1 expression and increased the expression of p27{sup kip1}. In addition, LATS1 overexpression also promoted yes-associated protein 1 (YAP) phosphorylation. Our data suggested that LATS1 might play an important role in spinal cord injury and suppress astrogliosis through regulating the expression of cyclin D1, p27{sup kip1} and p-YAP.

60 APPLIED LIFE SCIENCES↗

Impact of holmium fibre laser radiation (λ = 2.1 μm) on the spinal cord dura mater and adipose tissue

The impact of holmium fibre laser radiation on the samples of biologic tissues (dura mater of spinal cord and adipose tissue with interlayers of muscle) is studied. The experimental results are evaluated by the size of carbonisation and coagulation necrosis zones. The experiment shows that in the case of irradiation of the spinal cord dura mater samples the size of carbonisation and coagulation necrosis zones is insignificant. In the adipose tissue the carbonisation zone is also insignificant, but the region of cellular structure disturbance is large. In the muscle tissue the situation is opposite. The cw laser operation provides clinically acceptable degree of destruction in tissue samples with a minimal carbonisation zone. (laser applications in medicine)

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

Downregulation of miR-199b promotes the acute spinal cord injury through IKKβ-NF-κB signaling pathway activating microglial cells

Inflammatory response played an important role in the progression of spinal cord injury (SCI). Several miRNAs were associated with the pathology of SCI. However, the molecular mechanism of miRNA involving in inflammatory response in acute SCI (ASCI) was poorly understood. Sprague-Dawley (SD) rats were divided into 2 groups: control group (n=6) and acute SCI (ASCI) group (n=6). The expression of miR-199b and IκB kinase β-nuclear factor-kappa B (IKKβ-NF-κB) signaling pathway were evaluated by quantitative reverse transcription-PCR (qRT-PCR) in rats with ASCI and in primary microglia activated by lipopolysaccharide (LPS). We found that downregulation of miR-199b and activation of IKKβ/NF-κB were observed in rats after ASCI and in activated microglia. miR-199b negatively regulated IKKβ by targeting its 3′- untranslated regions (UTR) through using luciferase reporter assay. Overexpression of miR-199b reversed the up-regulation of IKKβ, p-p65, tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) in LPS-treated BV2 cells assessed by western blotting analysis. In addition, BMS-345541 reversed the up-regulation effects of miR-199b inhibitor on the expression of TNF-α and IL-1β. In the SCI rats, overexpression of miR-199b attenuated ASCI and decreased the expression of IKKβ-NF-κB signaling pathway and TNF-α and IL-1β. These results indicated that miR-199b attenuated ASCI at least partly through IKKβ-NF-κB signaling pathway and affecting the function of microglia. Our findings suggest that miR-199b may be employed as therapeutic for spinal cord injury. - Highlights: • Downregulation of miR-199b and activation of IKKβ/NF-κB were observed in rat after SCI. • miR-199b negatively regulated IKKβ by targeting its 3′-UTR. • miR-199b overexpression reversed the increasing IKKβ, p-p65, TNF-α and IL-1β in LPS-treated BV2. • BMS-345541 reversed the up-regulation of TNF-α and IL-1β induced by miR-199b inhibitor. • Overexpression of miR-199b attenuated ASCI and decreased the expression of IKKβ-NF-κB in rats.

60 APPLIED LIFE SCIENCES↗

Ozone (O{sub 3}) elicits neurotoxicity in spinal cord neurons (SCNs) by inducing ER Ca{sup 2+} release and activating the CaMKII/MAPK signaling pathway

Ozone (O{sub 3}) is widely used in the treatment of spinal cord related diseases. Excess or accumulation of this photochemical air can however be neurotoxic. In this study, in vitro cultured Wister rat spinal cord neurons (SCNs) were used to investigate the detrimental effects and underlying mechanisms of O{sub 3}. Ozone in a dose-dependent manner inhibited cell viability at a range of 20 to 500 μg/ml, with the dose at 40 μg/ml resulting in a decrease of cell viability to 75%. The cell death after O{sub 3} exposure was related to endoplasmic reticulum (ER) calcium (Ca{sup 2+}) release. Intracellular Ca{sup 2+} chelator, ER stabilizer (inositol 1,4,5-trisphosphate receptor (IP3R) antagonist and ryanodine receptor (RyR) antagonist) and calcium/calmodulin-dependent protein kinase II (CaMKII) antagonist could effectively block Ca{sup 2+} mobilization and inhibit cell death following 40 μg/ml O{sub 3} exposure. In addition, ER Ca{sup 2+} release due to O{sub 3} exposure enhanced phospho-p38 and phospho-JNK levels and apoptosis of SCNs through activating CaMKII. Based on these results, we confirm that ozone elicits neurotoxicity in SCNs via inducing ER Ca{sup 2+} release and activating CaMKII/MAPK signaling pathway. Therefore, physicians should get attention to the selection of treatment concentrations of oxygen/ozone. And, approaches, such as chelating intracellular Ca{sup 2+} and stabilizing neuronal Ca{sup 2+} homeostasis could effectively ameliorate the neurotoxicity of O{sub 3}. - Highlights: • Exposure to O{sub 3} can reduce the viability of SCNs and cause the cell death. • Exposure to O{sub 3} can trigger RyR and IP3R dependent intracellular Ca{sup 2+} release. • Exposure to O{sub 3} can enhance the phospho-CaMKII, phospho-JNK and phospho-p38 levels.

60 APPLIED LIFE SCIENCES↗