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Astrocytes (ASTs) and oligodendroglial lineage cells (OLGs) are major macroglial cells in the central nervous system. ASTs communicate with each other through connexin (Cx) and Cx-based network structures, both of which allow for quick transport of nutrients and signals. Moreover, ASTs interact with OLGs through connexin (Cx)-mediated networks to modulate various physiological processes in the brain. In this article, following a brief description of the infrastructural basis of the glial networks and exocrine factors by which ASTs and OLGs may crosstalk, we focus on recapitulating how the interactions between these two types of glial cells modulate myelination, and how the AST-OLG interactions are involved in protecting the integrity of the blood-brain barrier (BBB) and regulating synaptogenesis and neural activity. Recent studies further suggest that AST-OLG interactions are associated with myelin-related diseases, such as multiple sclerosis. A better understanding of the regulatory mechanisms underlying AST-OLG interactions may inspire the development of novel therapeutic strategies for related brain diseases.
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Humans , Myelin Sheath , Astrocytes , Oligodendroglia , Brain , Brain DiseasesABSTRACT
Oligodendrocytes are the major glial cells in the white matter of brain. Under normal circumstances, they form myelin sheaths around axons, which are conducive to rapid nerve conduction.After cerebral ischemia, the death of oligodendrocytes increases, leading to white matter dysfunction. White matter repair is associated with the ability of proliferation and mature differentiation of oligodendrocyte precursor cells. However, oligodendrocyte proliferation and differentiation may not be the only mechanism of white matter damage repair. Existing studies have shown that white matter repair requires synergistic action among neurons, glial cells and vascular endothelial cells in the whole neurovascular unit.
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Objective To analyze the clinical features and prognosis of adult optic neuritis patients with positive serum myelin oligodendrocyte glycoprotein antibody (MOG-ON) or aquaporin 4 antibody (AQP4-ON).Methods A retrospective study. From December 2015 to February 2018, in the Beijing Chaoyang Hospital of Capital Medical University and Chinese PLA General Hospital, 162 eyes of 132 patients with positive serum MOG antibody and AQP4 were included in the study. There were 42 MOG-ON patients (49 eyes, 31.8％), 90 AQP4-ON patients (113 eyes, 68.2％). The clinical features of optic neuritis (annual recurrence frequency, incidence of optic disc edema), brain and optic nerve enhanced MRI, serum autoimmune antibodies and cerebrospinal fluid test results were compared between MOG-ON and AQP4-ON patients. All patients were treated with intravenous methylprednisolone sodium succinate in the acute phase and then switched to oral prednisone acetate tablets. The average follow-up time was 15 months. The glucocorticoid dependence, visual prognosis, spinal cord symptoms, and myelitis at the last follow-up were comparatively analyzed between MOG-ON and AQP4-ON patients. The comparison of the count data was performed by χ2 test, and the measurement data were compared byt test.Results Compared with AQP4-ON patients, MOG-ON patients had higher annual recurrence frequency (t=3.760,P=0.005), higher incidence of optic disc edema (χ2=14.777,P<0.001), higher incidence of hormone dependence (χ2=25.496,P<0.001), and better visual prognosis (χ2=28.759, P<0.001). MOG-ON patients were more likely to involve the optic nerve, AQP4-ON patients were more likely to involve the optic chiasm and the optic tract. There was a significant difference in the location of lesions between MOG-ON and AQP4-ON patients (χ2= 5.447,P= 0.015). The proportion of AQP4-ON patients with autoimmune antibodies was significantly higher than that of MOG-ON patients (χ2 = 20.453,P<0.001). The results of cerebrospinal fluid test showed that the white blood cell count of patients with MOG-ON and AQP4-ON were within the normal range, but the IgG level of AQP4-ON patients was significantly higher than that of MOG-ON patients (t=8.669,P<0.001). At the last follow-up, there were 7 and 29 patients of myelitis in MOG-ON and AQP4-ON patients respectively (χ2=3.494,P=0.046).Conclusions The clinical characteristics of MOG-ON were different from AQP4-ON. The incidence of optic disc edema and recurrence rate were higher, but the proportion of autoimmune antibodies was lower. MOG-ON was more likely to show hormone dependence, but the visual prognosis was better. AQP4-ON was easily involved in optic chiasm and optic tract, and the incidence of myelitis was higher.
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Objective To explore the expression level and possible reasons of Tau protein in Beagle dog model of ischemic cerebral white matter(WM) demylination.Methods Sixteen adult Beagle dogs were divided into the sham operation group(A) and observation group B,C and D according to the completely random mumber table method,4 cases in each group.Different.degrees of cerebral ischemia animal models were established by 4-vessel occlusion(4-VO) method.The bilateral ventricle edge white matter (WM) was selected.The oligodendrocyte precursors(OPCs) were labeled by NG2.The mature oligodendrocytes(Ols) were labeled by CNPase.Tau,NG2 and CNPase were detected by using the immunohistochemical method.The expression level was quantified by the mean optical value.The correlation among Tau,NG2 and CNGase was analyzed by adopting the Pearson linear correlation analysis.Results The HE staining showed obvious changes of WM demylination after chronic cerebral ischemic.The scores after LFB staining in the group A,B,C and D were(0.75 ± 0.71) points,(1.38 ± 0.06) points,(1.63 ± 0.52) points and (1.88 ± 0.64)points.Compared with the group A,the scores in the group B,C and D were much higher(P＜0.05).Compared with the group A,the expression levels of Tau protein and NG2 were significantly increased(P＜0.05),while the CNPase expression level was significantly decreased(P＜0.05).The Pearson correlation analysis showed that Tau expression level was positively correlated with the NG2 expression level(r=0.277,P=0.006);Tau and NG2 were negatively correlated with the CNPase level(r=-0.303,-0.402,P=0.003,0.001).Conclusion The increase of Tau expression in Beagle dog model of ischemic cerebral WM demylination may be related to the differentiation dysmaturity of OPCs.
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Objective To study the effects of ibuprofen on the growth and development of oligodendrocytes. Methods A total of 6 clean and healthy adult female SD (Sprague Dawley) rats were used for extracting and culturing of oligodendrocytes(OLs).Lysophosphatidic acid(LPA)was then added,and the morphological changes of OLs pre-treatment and post-treatment were observed. Then 6 newborn rats (born 24-48 h) were used for mixed glial cell extraction from the cortex, then the OPCs were inoculated into the culture plates and randomly divided into control group, ibuprofen group, lysophosphatidic acid(LPA)group and LPA+ibuprofen group.After the adhering of the cells in each group for three days, cell morphology was observed,and the drugs were added as interventions.The control group was treated with normal saline, and the other 3 groups were added with saline solution of ibuprofen(100 μmol/L),LPA(1.0 μmol/L)and the mixture of them. The cell morphological changes were observed after 7-day intervention.The morphology of OPCs and OLs were observed by immunofluorescence staining through OPCs'specific immune markers (platelet-derived growth factor receptor alpha, PDGFR-α)and OLs'specific immune markers(myelin basic protein,MBP)along with cell count of mature OLs.Western blot assay was used to detect the relative expression level of MBP in each group. Results After the treatment with LPA to the mature OLs,protrusions were shrinking and became very sparse.The morphology of cells developed well in each group after cell adhering for 3 days. After drug intervention for 7 days, more cell protrusions and branches were observed in ibuprofen group and LPA+ibuprofen group than those of the control group and LPA group.The results of cell count showed that the number of MBP positive cells was significantly higher in the ibuprofen group and LPA+ibuprofen group than that in the control group and LPA group(P<0.01).The results of Western blot assay showed that the MBP protein expression was significantly less in LPA group than the other three groups (P<0.01), and the expression was significantly higher in the ibuprofen group than that of LPA+ibuprofen group (P<0.01). Conclusion LPA has a toxic effect on the growth and development of OPCs, and it has an inhibitory effect on the normal growth of mature OLs. A certain concentration of ibuprofen can significantly inhibit the cytotoxicity of LPA on OPCs and OLs,and promote the formation and maintenance of mature OLs.
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Objective To analyze the clinical and histology characteristics of a patient with frontal lobe epilepsy diagnosed with mild malformation of cortical development with oligodendroglial hyperplasia, and to recognize the new neuropathological entity. Methods Clinical history, seizure types, neuroimaging, electroencephalography as well as macroscope, histology and immunohistochemistry characteristics were collected from a frontal lobe epilepsy patient and were compared with cases from literature. Results It was a female patient aged 16 years with 12 years history of epilepsy. The seizures manifested as episodes of conscious loss with automatism including grope and voice lasting for seconds. About 10 episodes a day were found and sometimes with secondary generalized tonic-clonic seizures. MRI showed blurring of grey-white matter interface in left orbital frontal cortex. Video-encephalography revealed left frontal lobe origin of seizures. So left prefrontal lobe was removed. Histology showed almost normal cortex neuropil and neurons. Blurring of grey-white interface in some area with patches of proliferation of oligodendrocytes in the corresponding sub-cortical white matter was found. The density of oligodendrocytes was significantly higher in sub-cortical than in deep white matter both shown in HE and Oligo-2 staining. Obvious oligodendrocytes increase and satellite phenomenon in deep cortical layer as well as increased ectopic neurons in sub-cortical white matter were found in the lesion. In proliferation area, there were some nuclei stained with Ki-67, but not as high as tumor. Subsequent follow up for two years proved the operation efficacy and benign prognosis. Conclusions There are special and undiscovered histopathological entities in epilepsy etiology. Although known as grey matter disease, white matter pathology plays an important role in epilepsy pathophysiology which needs further research.
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Toll-like receptor 2 (TLR2) is the most w idely expressed receptor in the Toll-like receptor family, and is also an important pattern recognition receptor of the innate immune system to pathogenic microorganisms. In addition, TLR2 can also identify endogenous risk signals and participate in non -pathogenic microbial inflammatory reaction in ischemic injury. The role of TLR2 and its signal transduction in ischemic cerebral w hite matter lesions have received more and more attention. This article reviews the relationship between TLR2 and ischemic cerebral white matter lesion.
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Objective:To explore whether different phospholipid peptides could induce different pathological features of EAE in Lewis rats.Methods:Lewis rats were immunized with myelin basic protein 82-99 (MBP82-99),MBP68-86,and myelin oligodendroglia glycoprotein 35-55 (MOG35-55),respectively,and evaluated everyday for neurological scores.The cerebrum,brain stem,cerebellum and spinal cord of every rat were removed and pathological features observed.Results: Rats immunized with the two MBP peptides exhibited neurological signs of EAE wherein the central nervous system had extensive inflammation infiltration.The number of infiltrates in spinal cords in the two MBP peptides groups was higher than that in the cerebrums,brain stems and cerebellums.In spinal cords, there was no statistical difference of infiltrates between MBP82-99 and MBP68-86 groups;however,the both groups had more infiltrates than MOG35-55 group.Inflammatory cells were observed only in spinal cords of animals immunized with MOG35-55.Conclusion:This study provides certain evidence for understanding the diversity of pathological manifestations of EAE in Lewis rats.
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BACKGROUND: Recently, we reported the antiapoptotic effect of ghrelin in spinal cord injury-induced apoptotic cell death of oligodendrocytes. However, how ghrelin inhibits oligodendrocytes apoptosis, is still unknown. Therefore, in the present study, we examined whether ghrelin inhibits microglia activation and thereby inhibits oligodendrocyte apoptosis. METHODS: Using total cell extracts prepared from BV-2 cells activated by lipopolysaccharide (LPS) with or without ghrelin, the levels of p-p38 phosphor-p38 mitogen-activated protein kinase (p-p38MAPK), phospho-c-Jun N-terminal kinase (pJNK), p-c-Jun, and pro-nerve growth factor (proNGF) were examined by Western blot analysis. Reactive oxygen species (ROS) production was investigated by using dichlorodihydrofluorescein diacetate. To examine the effect of ghrelin on oligodendrocyte cell death, oligodendrocytes were cocultured in transwell chambers of 24-well plates with LPS-stimulated BV-2 cells. After 48 hours incubation, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and terminal deoxynucleotidyl transferase 2'-deoxyuridine, 5'-triphosphate nick end labeling staining were assessed. RESULTS: Ghrelin treatment significantly decreased levels of p-p38MAPK, p-JNK, p-c-Jun, and proNGF in LPS-stimulated BV-2 cells. ROS production increased in LPS-stimulated BV-2 cells was also significantly inhibited by ghrelin treatment. In addition, ghrelin significantly inhibited oligodendrocyte cell death when cocultured with LPS-stimulated BV-2 cells. CONCLUSION: Ghrelin inhibits oligodendrocyte cell death by decreasing proNGF and ROS production as well as p38MAPK and JNK activation in activated microglia as an anti-inflammatory hormone.
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Apoptosis , Blotting, Western , Cell Death , Cell Extracts , DNA Nucleotidylexotransferase , Ghrelin , JNK Mitogen-Activated Protein Kinases , Microglia , Oligodendroglia , Phosphotransferases , Protein Kinases , Reactive Oxygen Species , Spinal CordABSTRACT
Objective To investigate the alterations in oligodendrocyte and microglia and changes in neurobehavior after human umbilical cord mesenchymal stem cells (HUcMSCs) intervention on the newborn rat model of white matter damage (WMD) induced by hypoxia-ischemia.Methods After the operation of left common carotid artery ligation and 4 h hypoxia (6％ O2 and 94％ N2),twelve three-day-old Sprague-Dawley rats died and the remaining sixty rats were randomly divided into the experimental group and the control group.The first day was 0 to 24 h after birth.Rats of the experimental group were intraperitoneally injected the fourth generation HUcMSCs 1 × 106 (0.05 ml) on the third,fourth and fifth day respectively.At the same time,rats of the control group were intraperitoneally injected phosphate buffer (0.05 ml).Eight rats of each group were executed on the tenth and twenty first day respectively to detect the number of cells positive for myelin basic protein (MBP) and ectodermal dysplasia-1 (ED-1) staining by immunohistochemistry.Three rats of each group were executed on the tenth and twenty first day respectively to detect MBP and ED-1 expression by western blot.Eight rats of each group were weighed and underwent the neurobehavioral evaluation on the twenty eighth day.Data were analyzed using t test.Results On the tenth and twenty first day,the numbers of MBP-positive cells in the experimental group (11.8 ± 4.1 and 23.8± 8.1) were significantly higher than those in the control group (6.7±3.1 and 11.5 ± 5.8,t=-2.81 and 3.49,both P＜0.05) ; and the numbers of ED-1 positive cells in the experimental group (20.8 ± 3.4 and 19.1 ± 2.8) were significantly lower than those in the control group (32.8±4.2 and 29.5±5.2,t=6.23 and 4.93,both P＜0.01).On the tenth and twenty first day,MBP expressions in the experimental group (1.3 ± 0.1 and 1.1 ± 0.1) were higher than those in the control group (0.8±0.0 and 0.6±0.1,t=-7.53 and 6.68,both P＜0.01) ; and the ED-1 expressions in the experimental group (0.6±0.1 and 0.4±0.1) were lower than those in the control group (1.0±0.1 and 0.8±0.1,t=3.09 and 4.90,both P＜0.01).Weight on the seventh,tenth,fourteenth,twenty first and twenty eighth day in the experimental group [(15.0± 1.2),(16.6±0.9),(27.0± 1.6),(44.2±2.3) and (68.1 ±4.2) g] was significantly higher than that in the control group [(12.7 ± 1.6),(13.5 ± 2.0),(23.6 ± 1.9),(38.4± 0.9) and (60.0± 4.2) g,t=-3.11,-3.97,3.67,-6.52 and-3.72,all P＜0.05].On the twenty eighth day,the score of open field test in the experimental group was significantly higher than that in the control group (36.5 ± 2.9 vs 24.3 ± 3.6,t=7.36,P＜0.01).So was the hanging test (3.6± 1.0 vs 2.0±0.7,t=3.53,P＜0.01).In Cylinder test,the ratio of left/both and right/both forefeet in the experimental group were similar [(49.8± 13.3) ％ vs (41.4±5.9) ％,t=0.86,P＞0.05],but the ratio of left/both forefeet in the control group was higher than right/both [(49.5 ± 11.3) ％ vs (31.2±3.2) ％,t=4.38,P＜0.01].Conclusions HUcMSCs are able to enhance the number of oligodendrocytes while weaken the activity of microglias in the WMD newborn rat model,and to promote the physical development and improve the rat neurobehavior.
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Quantitative studies to date on the effects of opioid consumption and abstinence on the nervous system using modern stereological methods have not received enough attention. In addition, they have yielded controversial results. The present study was conducted to investigate the effects of morphine, with or without abstinence, on the neurons and oligodendrocytes of the medial prefrontal cortex (MPFC) in rats using quantitative stereological methods. The male rats were divided into four groups: the first (saline [SAL]) and second (morphine [MOR]) groups were treated with saline and an escalating dose of morphine (5-20 mg/kg) for 30 days, respectively; the third (SAL+abstinence [ABS]) and fourth (MOR+ABS) groups were treated in the same manner as the previous groups plus they had a 30-day abstinence period. The results showed that the volume of the MPFC and its subdivisions decreased by approximately 15% in the MOR group compared with that in the SAL group (P<0.05). In addition, the volume decreased by approximately 24% in the MOR+ABS group compared with that in the SAL+ABS group (P<0.05). The number of neurons in the MOR and MOR+ABS groups decreased by approximately 44% and 35%, respectively, compared with that in their corresponding control groups. Moreover, the number of the oligodendrocytes in the MOR and MOR+ABS groups decreased by approximately 41% and 37%, respectively. No significant difference was noted in the number of cells in the MOR and MOR+ABS groups. In conclusion, morphine consumption leads to a permanent reduction in the number of neurons and oligodendrocytes, and no additional neuron and oligodendrocyte loss occurs after abstinence.
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Animals , Humans , Male , Rats , Morphine , Nervous System , Neurons , Oligodendroglia , Prefrontal CortexABSTRACT
Objective To observe whether immature Brain Derived Neurotrophic Factor (proBDNF)can affect the activities of OPCs in the fields of cell proliferation and migration after SCI,and to investigate the relationship between proBDNF and p75NTR signal pathway on OPCs.Methods OLN-93 cell line was cultured and maintained for in vitro experiments.Immunofluorescence were used to check the expression of endogenous proBDNF,p75NTR and sortilin on OPCs.MTT assay was used to illustrate the inhibitory effect of proBDNF.The effects of anti-proBDNF was also observed by BrdU staining to find a probably signal pathway for proBDNF on OPCs.The Sprague-Dawley rats were administered for T9 spinal cord injury animal model.BBB score was applied to observe the situation of functional recovery after treated by anti-proBDNF.BrdU staining was managed to observe the situation of OPCs proliferation and migration after SCI.Results Endogenous proBDNF inhibited proliferation and migration of OPCs after SCI.BrdU staining showed that population of proliferative OPCs in lesion site of spinal cord was less in proBDNF in treated group than that in control group and anti-proBDNF group.While anti-proBDNF could inhibit proBDNF specifically and might induced a better functional recovery which was illustrated by BBB scores.The in vitro experiments found the inhibitory effect of proBDNF is dose-dependent and can be neutralized by anti-proBDNF properly.Moreover,the expression levels of p75NTR and sortilin are down regulated by proBDNF antibody treated group.This indicated that proBDNF may inhibit OPCs via p75NTR pathway.Conclusion Endogenous proBDNF can inhibit cell proliferation of OPCs after SCI and can be neutralized by specific antibodies of proBDNF.This kind of detrimental effect may be induced by p75NTR-sortilin pathway.Furthermore,proBDNF antibody treatment is effective to block proBDNF and promote the functional recovery.
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Objective To investigate correlation between demyelination and caspase-12 expression alteration after compressed spinal cord injury (CSCI) so as to discuss mechanism of demyelinating lesion after CSCI.Methods Seventy-five adult SD rats were randomly divided into five groups,ie,normal group,control group,compression 1 d,3 d and 7 d groups,with 15 rats per group.Models of spinal cord compression were established with a self-made device.Ultrastructure of the demyelinated nerve fibers was observed by electronic microscope and oligodendrocyte apoptosis was detected by TUNEL staining and double labeling immunofluorescence.Immunoblotting was used to defect caspase-12 that was related to cell apoptosis.Results Demyelination of nerve fiber occurred after CSCI and was aggravated with time.Apoptosis of oligodendrocytes was found after CSCI,and showed significant difference between compression 7 d group and normal group (P ＜ 0.05).Caspase-12 was also upregulated with extension of compression time.Conclusion Caspase-12 mediating oligodendrocyte apoptosis is one of the mechanisms of nerve fiber demyelination after CSCI.
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Endothelin (ET)-1 and its receptors (ETA and ETB receptor) are present in the central nervous system. ET exerts biological effects on gliogenesis and glial cell functions. In order to define a possible mechanism of ETA receptor signaling, the distribution of the ETA receptor in developing oligodendrocytes and the effects of ET-1 on the myelination of oligodendrocytes were examined. ETA receptor immunoreactivity was confined to the perivascular elements of the blood vessels during early postnatal development. However later in development, ETA receptor immunoreactivity was no longer observed in the vessels but became localized to the myelinating oligodendrocytes of the primitive corpus callosum of the white matter, apart from the vessels. ET-1 induced myelin basic protein (MBP) in primary oligodendrocyte precursor cell culture though the ETA receptor and was blocked by an ETA receptor antagonist. In addition, ET-1 evoked the release of Ca2+ which is a central regulator of oligodendrocyte differentiation. Our results provide a link between ET-1 and its ETA receptor and myelination during oligodendrocyte differentiation.
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Animals , Mice , Rats , Brain/pathology , Calcium/metabolism , Calcium Signaling , Cells, Cultured , Endothelin-1/metabolism , Mice, Inbred ICR , Myelin Basic Protein/genetics , Myelin Sheath/physiology , Oligodendroglia/cytology , Rats, Sprague-Dawley , Receptor, Endothelin A/metabolismABSTRACT
Objective To study the clinical,pathological characteristics and diagnosis of multiple system atrophy(MSA).Methods Among 4 cases of MSA,2 of them were from clinical data,the other 2were frum pathological data.Two cases verified by autopsy were investigated using Hematoxylin-eosi,Kltiver.Barrera and Gallvas-Braak silver staining and confirmed by immunohistochemistry using ubiquitin,α-synuclein staining.Results All 4 patients were male.aged 51-76.Case No.1 wag diagnosed as Parkinson's svndrome.Case No.2 was diagnosed as spinal ataxia cerebella,and the other two eases were diagnosed as MSA.The following changes were found by pathological studies.Macroscopic atrophies were presented in pens and cerebella.as well as putamen,globus pallidus and substantia nigra.Cerebral ventricles were dilated.Neuronal lOSS and gliosis could be seen at cerebral cortex.nigrostriatal.globus pallidus,pontine nuclei,subslantia innominata,inferior olives,doral motor nucleus of vagus,cerebellum antl intermediolateral column of the spinal cord.In the white matter of these regions cytoplasmic inclusions bodies were extensively present in oligodendrocytes.Conclusions Olivopontocerebellar atrophy mainly shows the,clinical symptoms of pens,cerebellum,and autonomic nerves damage;Shy-Drager syndrome presents mainly with the erecting hypotenstion symptom,while striatonigral degeneration mainly involves extrapyramidal system.As these three diseases share the common basic pathological changes,they are preferred to be classified as the subtype of MSA.
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The use of cyclosporine (CsA) has shown to induce an increase in the density of oligodendrocytes near remyelinating areas following the injection of ethidium bromide (EB), a demyelinating agent, in the rat brainstem. This study was designed in order to evaluate if CsA has the capacity of increasing remyelination. In this context, a comparison between the final balance of myelin repair in CsA treated and non-treated rats was assessed using a semi-quantitative method developed for documenting the extent and nature of remyelination in gliotoxic lesions. Wistar rats were submitted to intracisternal injection of 10 microliters of 0.1 percent EB. Some were treated during 31 days with CsA (group III - 10 mg/kg/day by 7 days and, thereafter, 3 times a week, with a minimal interval of 48 hours) by intraperitonial route. Others were not treated with CsA (group I). A control group was planned receiving into the cisterna pontis 10 microliters of 0.9 percent saline solution and following after that the same CsA administration protocol (group II). Results clearly demonstrate that in vivo administration of CsA after EB-demyelinating lesions stimulated oligodendrocyte remyelination (mean remyelination scores of 3.72±0.25 for oligodendrocytes and 1.04±0.39 for Schwann cells) compared to non-treated animals (3.13±0.71 and 1.31±0.62, respectively), although the mechanisms by which this positive CsA effect occurs are unclear.
O uso de ciclosporina (CsA) mostrou induzir um aumento na densidade de oligodendrócitos próximos a áreas de remielinização após injeção de brometo de etídio (EB), um agente desmielinizante, no tronco encefálico de ratos. Este estudo foi desenvolvido a fim de avaliar se a CsA possui a capacidade de acelerar a remielinização. Neste contexto, foi feita uma comparação entre o balanço final de reparo mielínico em ratos tratados ou não com CsA usando-se um método semiquantitativo desenvolvido para documentação da extensão e natureza da remielinização em lesões gliotóxicas. Ratos Wistar foram submetidos à injeção intracisternal de EB a 0,1 por cento. Alguns foram tratados durante 31 dias com CsA (grupo III - 10 mg/kg/dia por 7 dias e, após, 3 vezes por semana, com um intervalo mínimo de 48 horas entre as aplicações) por via intraperitoneal. Outros não foram tratados com CsA (grupo I). Um grupo controle foi desenvolvido recebendo, na cisterna pontina, 10 microlitros de solução salina e seguindo após o mesmo protocolo de administração de CsA (grupo II). Os resultados mostram claramente que a administração in vivo de CsA após lesões desmielinizantes induzidas pelo EB estimulou a remielinização por oligodendrócitos (escores médios de remielinização de 3,72±0,25 para oligodendrócitos e 1,04±0,39 para células de Schwann) em comparação aos animais não-tratados (3,13±0,71 e 1,31±0,62, respectivamente), embora os mecanismos pelos quais este efeito positivo da CsA ocorre sejam desconhecidos.
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Animals , Rats , Cyclosporine/therapeutic use , Demyelinating Diseases/drug therapy , Immunosuppressive Agents/therapeutic use , Myelin Sheath/drug effects , Nerve Regeneration/drug effects , Oligodendroglia/drug effects , Brain Stem/drug effects , Disease Models, Animal , Demyelinating Diseases/chemically induced , Demyelinating Diseases/pathology , Ethidium , Myelin Sheath/physiology , Rats, Wistar , Time FactorsABSTRACT
Objective To induce experimental allergic encephalomyelitis (EAE) in female C57BL/6 mice with the extracellular domain of myelin oligedendroglia glycoprotein(MOG~(Igd)). Percentages of CD4~+ CD25~+ T cell (Tr) were tested , and also normalized expressions of Foxp3. Methods Molecular cloning technology was used to produce MOG~(Igd) fusion protein. The MOG~(Igd)-TrxA fusion protein and TrxA protein were purified by metal chelate affinity chromatography (MCAC). Mice were injected s. c. in the flank with 300 μg MOG~(Igd) in complete Frcund's adjuvant (CFA) supplemented with 4 μg/μl Mycobacterium tuberculosis. H37Rv. Mice received 0.4 ml emulsion of spinal cord homogenate of guinea pigs (GPSCH) in positive control group, and the same volume emulsiom of TrxA in negative control group, while mice served as normal control received only saline/adjuvant. Mice were monitored two times a day for continuously 30 days by double bind. Clinical scores and histopathology were evaluated. Then, mice were sacrificed. The spinal cord and brain were removed and fixed in buffered formalin. Horizontal sections taken from the central nervous system(CNS) were stained with haematoxylin and eosin (HE), and Kluver-Barrera staining. Also, immunohistochemistry was performed. Percentages of CD4~+ CD25~+ T cells were tested through flow cytometric analysis, and real-time PCR was performed to test normalized expressions of Foxp3 mRNA. Then, correlations between the two were performanced. Results Mice in both MOG group and GPSCH group shew chronic non-remitting course. The onset of disease, time when the most severe clinical symptoms happened and the clinical score between the two groups shew no significant differnces (P>0.05). However, neither in TrxA treated group nor in normal control group did animals exhibit clinical signs of EAE. Histologic sections of the brain and spinal cord taken from affected animals shew perivascular infiltration of mononuclear cells, gliosis, and multifocal demyelination. Lesions scattered throughout the CNS including brainstem, spinal cord, cerebellum, and penventricular white matter. There were significant differences between MOG group and TrxA group in the level of lesion-ceutric AQP-4 expression showing up by immunohistochemistry (P<0.05). Percentages of CD4~+ CD25~+ T cells in MOG group and GPSCH group were (4.71±1.61) % and (1.44±0.65) %, respectively, both of which were significantly lower than those in the normal control group or TrxA treated group (P<0.01). And the difference between MOG group and GPSCH group also reached statistics meaning (P<0.01). Normalized expression of Foxp3 mRNA in MOG group was 2.26± 1.97, and was not significantly higher than the 1.44±1.20 level in GPSCH group (P>0.05). However, they beth were statistically lower than that in the negative control group, namely 8.58±3.34 (P<0.01). Percentages of CD4~+ CD25~+ T cells was statistically correlated with expressions of Foxp3 mRNA (P< 0.05). Conclusion EAE induced in C57BL/6 mice with MOG~(Igd) is reproduceable. It shares the similar clinial signs and pathologic features with human multiple sclerosis(MS). Thus, we find a good way to further study the immune mechanisms of MS and also to search for the effective treatments.
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Central nervous system (CNS) injury, including brain injury and spinal cord injury, has higher disability and mortality. Therefore, CNS injury repair has been a research emphasis and focus in the field of neuroscience. The limited neurons intrinsic regenerative capacity in adult mammalians is one of the reasons of regeneration difficulties after CNS injury. However, the more important reason is the formation of inhibitive glial microenvironment at the local lesion sites. This article reviews the roles of all types of cells, such as astrocyte, microglia, taxi oligodendroglia in gtial microenvironment in CNS injury repair.
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Objective To expore the mechanism of low-dose interfone-γ(IFN-γ) influences on differentiation of oligodendrocyte precursor cell. Methods The cerebral cortex samples were obtained from one day old SD rats to form mixed single cell suspensions. After culturing in full medium for 7 to 10 days, succession and differential velocity adherent technique were performed to acquire oligodendrocyte precursor cell and cultured in serum-free medium. IFN-γ, AG490 and Fludarabine were added during the culture of oligodendrocyte precursor cell and reverse transcription-polymerase chain reaction, Western blot and flow cytometry were performed to evaluate the expression of intracellular P27kip1 and its influence on the differentiation of oligodendrocyte precursor cell. Results (1)The expression of P27kip1 mRNA and protein was lower in IFN-γ group than in control group (t=85. 535, P<0. 05;t= 12. 481, P<0. 05), while the expression of P27kip1 mRNA and protein in IFN-γ+AG490 group and IFN-γ+Fludarabine group were both higher than those in IFN-γ group (P<0. 05). (2) The phosphorylation levels of JAK2/STAT1 in INF-γ group were higher than that in the other three groups (P<0. 05). (3) The percentage of myelin basic protein positive cells was (68. 42 ± 2. 53)% in IFN-γ group, lower than that in control group [(88.21 ± 1.97)%](t=10.682, P < 0.05). Myelin basic protein positive cells in IFN-γ + AG490 group were (57. 63 ±2. 75) %, lower than those in the IFN-γ group. The same figure in IFN-γ+Fludarabine group were (79. 53±4. 15)% , higher than those in IFN-γ group (t = 3.957, P<0.05). Conclusions Low-dose IFN-γ can regulate the expression of intracellular P27kip1 through JAK2/STAT1 signal transduction pathway and Fludarabine may participate in this process and improve the differentiation and maturation of oligodendrocyte precursor cell.
ABSTRACT
The ethidium bromide-demyelinating model (EB) was used to study remyelination in the brainstem under the use of cyclosporine (CsA). Wistar rats were submitted to intracisternal injection of 0.1 percent EB or 0.9 percent saline solution, and others were taken as histologic controls (group I). Within those injected with EB, some have not received immunosuppressive treatment (II); some were treated by intraperitonial route with CsA (III.E - 10 mg/kg/day). Rats from group III.C were injected with saline solution and treated with CsA. The animals were perfused from 15 to 31 days post-injection collecting brainstem sections for light and transmission electron microscopy studies. After EB injection it was noted the presence of macrophages and non-degraded myelin debris, demyelinated axons, oligodendrocyte or Schwann cell remyelinated axons, groups of infiltrating pial cells, hypertrophic astrocytes and few lymphocytes. Tissue repair of EB-induced lesions in group III.E was similar to that of group II, but with the presence of a higher density of oligodendrocytes near remyelinating areas.
Empregou-se o modelo desmielinizante do brometo de etídio (BE) com o objetivo de estudar a remielinização no tronco encefálico frente ao uso de ciclosporina (CsA). Foram utilizados ratos Wistar, submetidos à injeção de BE a 0,1 por cento ou de solução salina na cisterna pontina, assim como controles histológicos (grupo I). Dos animais injetados com BE, alguns não receberam tratamento imunossupressor (II); outros foram tratados por via intraperitoneal com CsA (III.E - 10 mg/kg/dia). O grupo III.C incluiu animais injetados com salina e tratados com CsA. Os animais foram perfundidos dos 15 aos 31 dias pós-injeção, com colheita de material do tronco encefálico para estudos de microscopia de luz e eletrônica de transmissão. Após injeção de BE, foram observados macrófagos e restos de mielina não-degradada, axônios desmielinizados ou remielinizados por oligodendrócitos e por células de Schwann, grupos de células piais infiltrantes, astrócitos hipertróficos e poucos linfócitos. O processo de reparo das lesões no grupo III.E apresentou-se similar ao do grupo II, porém com maior densidade de oligodendrócitos próximos às áreas de remielinização.