Astrocytes regulate glial scar formation in cerebral ischemic stroke / 中国组织工程研究

BACKGROUND:Cerebral ischemic stroke is one of the main fatal and disabling diseases in the clinic,but only a few patients benefit from vascular recanalization in time,so it is urgent to explore new and effective therapy.As one of the critical pathological changes of ischemic stroke,the glial scar formed mainly by astrocytes is one major cause that hinders axonal regeneration and neurological recovery at the late stage of stroke. OBJECTIVE:To elucidate the pathological process and crucial signal regulatory mechanism of astrocytes in the formation of glial scar after ischemic stroke,as well as the potential therapeutic targets,to provide a theoretical reference for intervening astrocytic scar formation against ischemic stroke effectively,and novel strategies for promoting post-stroke rehabilitation. METHODS:The relevant articles published in CNKI,PubMed and Web of Science databases from 2010 to 2022 were retrieved.The search terms were"Ischemic stroke,Brain ischemi*,Cerebral ischemi*,Astrocyt*,Astroglia*,Glial scar,Gliosis,Astrogliosis"in Chinese and English.Finally,78 articles were included after screening and summarized. RESULTS AND CONCLUSION:(1)Astrocytes play an important role in the maintenance of central nervous system homeostasis.After ischemic stroke,astrocytes change from a resting state to an active state.According to the different severities of cerebral ischemic injury,astrocyte activation changes dynamically from swelling and proliferation to glial scar formation.(2)Mature astrocytes are stimulated to restart the cell cycle,then proliferate and migrate to lesions,which is the main source of the glial scar.Neural stem cells in the subventricular zone,neuron-glial antigen 2 precursor cells and ependymal precursor cells in the brain parenchyma can also differentiate into astrocytes.Endothelin-1,aquaporin 4,ciliary neurotrophic factor and connexins are involved in this process.In addition,chondroitin sulfate proteoglycan,as the main component of the extracellular matrix,forms the dense glial scar barrier with proliferated astrocytes,which hinders the polarization and extension of axons.(3)Activation or inhibition of crucial signal molecules involved in astrocyte activation,proliferation,migration and pro-inflammation functions regulate the glial scar formation.Transforming growth factor beta 1/Smad and Janus kinase/signal transducer and activator of transcription 3 are classical pathways related to astrogliosis,while receptor-interacting protein 1 kinase and glycogen synthase kinase 3β are significant molecules regulating the inflammatory response.However,there are relatively few studies on Smad ubiquitination regulatory factor 2 and Interleukin-17 and their downstream signaling pathways in glial scar formation,which are worthy of further exploration.(4)Drugs targeting astrogliosis-related signaling pathways,cell proliferation regulatory proteins and inflammatory factors effectively inhibit the formation of glial scar after cerebral ischemic stroke.Among them,the role of commonly used clinical drugs such as melatonin and valproic acid in regulating glial scar formation has been verified,which makes it possible to use drugs that inhibit glial scar formation to promote the recovery of neurological function in patients with stroke.(5)Considering the protective effects of glial scar in the acute phase,how to choose the appropriate intervention chance of drugs to maintain the protective effect of the glial scar while promoting nerve regeneration and repair in the local microenvironment is the direction of future efforts.

Strategies and advance on stem cell transplantation for repair of spinal cord injury / 中国组织工程研究

BACKGROUND:Spinal cord injury not only causes serious physical and psychological injuries to patients but also brings a heavy economic burden to society.Spinal cord injury is initially triggered by mechanical trauma,followed by secondary injuries,and as the disease progresses,a glial scar develops. OBJECTIVE:To summarize the pathological process of spinal cord injury and strategies for stem cell transplantation to repair spinal cord injury,aiming to provide the best protocol for treating spinal cord injury. METHODS:Computer search was used to search PubMed and CNKI databases.Chinese search terms were"stem cell transplantation,spinal cord injury".English search terms were"stem cell,spinal cord injury,spinal cord,mesenchymal stem cells,neural stem cells,pathophysiology,clinical trial,primary injury,secondary injury".The literature was screened according to the inclusion and exclusion criteria.Finally,91 articles were included for review analysis. RESULTS AND CONCLUSION:(1)The strategies for repairing spinal cord injury through stem cell transplantation can be divided into exogenous stem cell transplantation and endogenous stem cell transplantation.The exogenous stem cell transplantation strategy for the treatment of spinal cord injury is divided into four kinds:injecting stem cells into the site of injury;transplantation of biomaterials loaded with stem cells;fetal tissue transplantation;transplantation of engineered neural network tissue or spinal cord-like tissue.(2)Compared with a single treatment method,combination therapy can more effectively promote nerve regeneration and spinal cord function recovery.(3)Microenvironment regulating the injury site,magnetic stimulation,electrical stimulation,epidural oscillating electric field stimulation,transcription factor overexpression and rehabilitation therapy can be combined with stem cell transplantation for combination therapy,thereby promoting the recovery of spinal cord function.

miR-146a-3p regulates astrocyte proliferation,migration and apoptosis by inhibiting insulin-like growth factor 1 expression / 中国组织工程研究

BACKGROUND:The alteration of miR-146a-3p level is a common event in the pathogenesis of most neurological diseases,and the specific mechanism of miR-146a-3p regulation of astrocytes has not been studied. OBJECTIVE:To verify that miR-146a-3p regulates astrocyte proliferation,migration and apoptosis through insulin-like growth factor 1. METHODS:12 SD rats were divided into a sham operation group and a spinal cord injury group,with six rats in each group.RNA sequencing analysis was performed on the spinal cord tissues of all groups 2 weeks after surgery to screen out the differential genes(log2FC>2),and to select spinal cord injury-related genes(Score>20)in the Genecards database,and then to predict the target genes of miR-146a-3p by Targetscan.The intersection of three gene sets was obtained to screen out insulin-like growth factor 1 as one of the important target genes.qPCR,western blot assay and immunohistochemistry were performed to analyze the expression level of insulin-like growth factor 1 in spinal cord tissues.The primary astrocytes were divided into NC group,NC-mimics group and miR-146a-3p mimics group.Annexin-V/PI staining was used to detect cell apoptosis.CCK-8 assay was used to detect cell proliferation.Transwell assay was used to detect cell migration ability. RESULTS AND CONCLUSION:The expression of miR-146a-3p in the spinal cord tissue of the spinal cord injury group was lower than that of the sham operation group(P<0.05).The expression of insulin-like growth factor 1 in the spinal cord tissue of the spinal cord injury group was higher than that of the sham operation group(P<0.05).Compared with the NC group and NC-mimics group,the apoptotic rate of astrocytes was increased(P<0.01);the proliferation of astrocytes was decreased(P<0.01)and the number of migration was decreased(P<0.01)in the miR-146a-3p mimics group.To conclude,the expression of miR-146a-3p decreased and the expression of insulin-like growth factor 1 increased in spinal cord tissue after spinal cord injury.miR-146a-3p targeted regulation of insulin-like growth factor 1 in astrocytes,inhibited the proliferation and migration of astrocytes and promoted their apoptosis.

Spatiotemporal Dynamics of the Molecular Expression Pattern and Intercellular Interactions in the Glial Scar Response to Spinal Cord Injury / 神经科学通报·英文版

Nerve regeneration in adult mammalian spinal cord is poor because of the lack of intrinsic regeneration of neurons and extrinsic factors - the glial scar is triggered by injury and inhibits or promotes regeneration. Recent technological advances in spatial transcriptomics (ST) provide a unique opportunity to decipher most genes systematically throughout scar formation, which remains poorly understood. Here, we first constructed the tissue-wide gene expression patterns of mouse spinal cords over the course of scar formation using ST after spinal cord injury from 32 samples. Locally, we profiled gene expression gradients from the leading edge to the core of the scar areas to further understand the scar microenvironment, such as neurotransmitter disorders, activation of the pro-inflammatory response, neurotoxic saturated lipids, angiogenesis, obstructed axon extension, and extracellular structure re-organization. In addition, we described 21 cell transcriptional states during scar formation and delineated the origins, functional diversity, and possible trajectories of subpopulations of fibroblasts, glia, and immune cells. Specifically, we found some regulators in special cell types, such as Thbs1 and Col1a2 in macrophages, CD36 and Postn in fibroblasts, Plxnb2 and Nxpe3 in microglia, Clu in astrocytes, and CD74 in oligodendrocytes. Furthermore, salvianolic acid B, a blood-brain barrier permeation and CD36 inhibitor, was administered after surgery and found to remedy fibrosis. Subsequently, we described the extent of the scar boundary and profiled the bidirectional ligand-receptor interactions at the neighboring cluster boundary, contributing to maintain scar architecture during gliosis and fibrosis, and found that GPR37L1_PSAP, and GPR37_PSAP were the most significant gene-pairs among microglia, fibroblasts, and astrocytes. Last, we quantified the fraction of scar-resident cells and proposed four possible phases of scar formation: macrophage infiltration, proliferation and differentiation of scar-resident cells, scar emergence, and scar stationary. Together, these profiles delineated the spatial heterogeneity of the scar, confirmed the previous concepts about scar architecture, provided some new clues for scar formation, and served as a valuable resource for the treatment of central nervous system injury.

Neuroprotective effect of tetramethylpyrazine on mice after spinal cord injury / 中国中药杂志

This study aims to investigate the neuroprotective effect of tetramethylpyrazine on mice after spinal cord injury and its mechanism. Seventy-five female C57BL/6 mice were randomly divided into 5 groups, namely, a sham operation group, a model group, a tetramethylpyrazine low-dose group(25 mg·kg~(-1)), a tetramethylpyrazine medium-dose group(50 mg·kg~(-1)), and a tetramethylpyrazine high-dose group(100 mg·kg~(-1)), with 15 mice in each group. Modified Rivlin method was used to establish the mouse model of acute spinal cord injury. After 14 d of tetramethylpyrazine intervention, the motor function of hind limbs of mice was evaluated by basso mouse scale(BMS) and inclined plate test. The levels of inflammatory cytokines tumor necrosis factor-α(TNF-α), interleukin-6(IL-6), and interleukin-1β(IL-1β) in the spinal cord homogenate were determined by enzyme-linked immunosorbent assay(ELISA). Hematoxylin-eosin(HE) staining was used to observe the histology of the spinal cord, and Nissl's staining was used to observe the changes in the number of neurons. Western blot and immunofluorescence method were used to detect the expression of glial fibrillary acidic protein(GFAP) and C3 protein. Tetramethylpyrazine significantly improved the motor function of the hind limbs of mice after spinal cord injury, and the BMS score and inclined plate test score of the tetramethylpyrazine high-dose group were significantly higher than those of the model group(P<0.01). The levels of TNF-α, IL-6, and IL-1β in spinal cord homogenate of the tetramethylpyrazine high-dose group were significantly decreased(P<0.01). After tetramethylpyrazine treatment, the spinal cord morphology recovered, the number of Nissl bodies increased obviously with regular shape, and the loss of neurons decreased. As compared with the model group, the expression of GFAP and C3 protein was significantly decreased(P<0.05,P<0.01) in tetramethylpyrazine high-dose group. In conclusion, tetramethylpyrazine can promote the improvement of motor function and play a neuroprotective role in mice after spinal cord injury, and its mechanism may be related to inhibiting inflammatory response and improving the hyperplasia of glial scar.

Temporal dynamics of microglia-astrocyte interaction in neuroprotective glial scar formation after intracerebral hemorrhage / 药物分析学报

The role of glial scar after intracerebral hemorrhage(ICH)remains unclear.This study aimed to inves-tigate whether microglia-astrocyte interaction affects glial scar formation and explore the specific function of glial scar.We used a pharmacologic approach to induce microglial depletion during different ICH stages and examine how ablating microglia affects astrocytic scar formation.Spatial transcriptomics(ST)analysis was performed to explore the potential ligand-receptor pair in the modulation of microglia-astrocyte interaction and to verify the functional changes of astrocytic scars at different periods.During the early stage,sustained microglial depletion induced disorganized astrocytic scar,enhanced neutrophil infiltration,and impaired tissue repair.ST analysis indicated that microglia-derived insulin like growth factor 1(IGF1)modulated astrocytic scar formation via mechanistic target of rapamycin(mTOR)signaling activation.Moreover,repopulating microglia(RM)more strongly activated mTOR signaling,facilitating a more protective scar formation.The combination of IGF1 and osteopontin(OPN)was necessary and sufficient for RM function,rather than IGF1 or OPN alone.At the chronic stage of ICH,the overall net effect of astrocytic scar changed from protective to destructive and delayed microglial depletion could partly reverse this.The vital insight gleaned from our data is that sustained microglial depletion may not be a reasonable treatment strategy for early-stage ICH.Inversely,early-stage IGF1/OPN treatment combined with late-stage PLX3397 treatment is a promising therapeutic strategy.This prompts us to consider the complex temporal dynamics and overall net effect of microglia and astrocytes,and develop elaborate treatment strategies at precise time points after ICH.

Effects of delayed ramelteon treatment on neurological function and tissue repair after cryogenic traumatic brain injury / 中国药理学通报

:Aim To study the effects of continuous dai¬ly administration of ramelteon starting at the subacute period of cryogenic traumatic brain injury (cTBI) on neurological function and brain tissue repair in mice. Methods Thirty male C57BL/6 mice were randomly divided into sham group, vehicle group and ramelteon treatment groups. The right sensory-motor cortex was damaged by pressing a copper probe precooled by liq¬uid nitrogen onto the skull. Ramelteon ( 10 nig 'kg-1 • d"1) was administered by gavage every day starting at different time points after cTBI (1 h, 1 d,3 d) until sacrifice on day 14. Beam walking test and open field test were used to evaluate the motor function. Toluidine blue staining was used to measure the infarct volume. Immunofluorescence was used to detect the expression of GAP-43 and synaptophysin in peri-infarct area. Mi¬croglia activation was detected using Iba-1. The area and thickness of glial scars were analyzed by detecting GFAP positive areas. Results All three treatment ( 1 h - 14 d, 1 - 14 d, and 3 - 14 d) significantly im¬proved cTBI induced motor dysfunction, reduced the infarct volume, elevated the expression of GAP -43 and synaptophysin, and decreased the area and thick¬ness of glial scar and microglia activation. In addition, all ramelteon treatment groups had similar effects on the above indexes. Conclusions Delayed ramelteon treatment can improve neurological dysfunction after cTBI,and the therapeutic time window can be delayed for up to three days after cTBI. Inhibiting glial scar formation and microglia activation, and promoting ax- onal regeneration and synaptogenesis may contribute to the beneficial effects of ramelteon.

Research on cellular damages and astrocyte activation after cerebral ischemia and reperfusion / 中国药理学通报

Aim To observe cellular damage and astrocyte activation at different time points of cerebral ischemia and reperfusion. Methods The middle cerebral artery of male SpragueDawley rats was occluded for 90 min followed by different time points of reperfusion. Eighty-five SPF male SD rats were randomly divided into control group (Sham), IR3, 6, 12, 24 and IR48h (MCAO followed by 48 h of reperfusion) group. Cerebral ischemia and reperfusion injury was observed by HE staining, and the structure of astrocytes was estimated with transmission electron microscopy (TEM). GFAP expression was detected by immunofluorescence staining and Western blot. Results Cerebral ischemia following by different time points of reperfusion led to different degrees of cellular damage, which was the most serious at 24 h of reperfusion. TEM showed destruction of astrocytes structure, swollen organelles and broken mitochondrial ridge. After cerebral ischemia-reperfusion, the expression levels of GFAP were significant up-regulated in the ischemic penumbra cortex and the highest was at 48 h of reperfusion, indicating astrocytes were activated. In addition, the results showed the gradual decrease in GFAP expression in the infarct core. Conclusions After cerebral ischemia-reperfusion, cellular damage is aggravated, and astrocytes are gradually activated in the ischemic penumbra. With the extension of reperfusion time, the boundaries of infarct area and ischemic area are gradually clear, and scarring may occur.

The activation of hippocampal pericytes and glial scar formation in rats with status epilepticus / 国际儿科学杂志

Objective:To explore the perivascular activation of reactive pericytes after status epilepticus(SE), and the relationship between pericytes and glial cells in proliferation and function.Methods:Eighty rats were randomly divided into control group( n=16) and model group( n=64, 16 for each group in SE1d, SE3d, SE7d, SE28d). The SE model was induced by intraperitoneal injection of lithium chloride and pilocarpine, and hematoxylin-eosin staining was performed on brain tissue sections to observe basic pathological changes.Use immunohistochemistry and Western blot to detect(neuron-glial antigen 2, NG2) expression, and use immunofluorescence technology to double stain NG2 and(glial fibrillary acidic protein, GFAP) to observe their relationship. Results:In the model group, the neurons were arranged disorderly, losing the ribbon structure, and the neurons appeared degeneration and necrosis.It was observed that the nuclei of the neurons were blurred, and the cytoplasm was agglomerated.There were more glial cells proliferation.Compared with the control group, it was found in model group that NG2 showed a dynamic high expression after SE( P<0.05). The number of pericytes increased significantly, reaching a peak at 7d, and the results of Western blot were consistent with the results of histochemistry( P<0.05). The aggregation of glial cells were induced in the surrounding area, and pericytes participated in the signal transduction of glial cells. Conclusion:Pericytes can induce the aggregation of glial cells and participate in the repairment in the form of glial scars after SE brain injury.

Effect of electroacupuncture on the formation of glial scars in cerebral cortex of rats with focal cerebral ischemia/reperfusion / 解剖学报

Objective To observe the effect of electroacupuncture on the formation of glial scars in the cerebral cortex of rats with focal cerebral ischemia/reperfusion( I /R) . Methods The focal cerebral ischemia/reperfusion model was established by thread method, and "Baihui" ( GV 20) and left "Siguan" (Hegu LI 4/Taichong LR 3) were selected as acupoints points. Seventy-eight male SD rats were randomly divided into sham group ( sham) , focal cerebral ischemia/ reperfusion ( I/R) , focal cerebral ischemia/reperfusion + electroacupuncture group ( I/R + EA ) . Seven days after reperfusion, modified neurological severity score ( mNSS) was used to evaluate neurological deficit, HE staining was used to observe the degree of ischemic cerebral cortex. Immunofluorescencte was used to observe glial fibrillary acidic protein (GFAP) /neurocan, GFAP/phosphacan positive cells in the ischemic cerebral cortex. The average immunofluorescent intensity of GFAP, neurocan and phosphacan, and the levels of GFAP, neurocan and phosphacan mRNA in the ischemic cerebral cortex were analyzed by Real-time PCR, respectively. Results Compared with the I/R group, mNSS score in I/R+EA group decreased significantly (P<0. 01) , and the degree of brain tissue damage reduced obviously. There were very few GFAP+/neurocan+ cells and GFAP+/phosphacan+ cells in the sham group. The astrocytes in I/R group were Irypertroplry, increasing and thickened protrusions, more GFAP+/neurocan+ cells and GFAP+/phosphacan+ cells weredectected as well. While the count of GFAPVneurocan+ cells and GFAP+/phosphacan+ cells in I/R + EA group were significantly lower than those in I /R group. In addition, the average immunofluorescence intensity of GFAP, neurocan and phosphacan in I/R+EA group, and mRNA content of above mentioned indicators were significantly lower than those in I/R group ( P < 0. 05 ) . Conclusion Electroacupuncture promotes the recovery of neurological function in rats with focal cerebral I /R and reduce brain tissue damage, which may be related to the inhibition of glial scar fonnation in cerebral cortex.

Advance in mechanisms of glial scarring after stroke and intervention of traditional Chinese medicine / 中国中药杂志

When ischemia or hemorrhagic stroke occurs, astrocytes are activated by a variety of endogenous regulatory factors to become reactive astrocytes. Subsequently, reactive astrocytes proliferate, differentiate, and migrate around the lesion to form glial scar with the participation of microglia, neuron-glial antigen 2(NG2) glial cells, and extracellular matrix. The role of glial scars at different stages of stroke injury is different. At the middle and late stages of the injury, the secreted chondroitin sulfate proteoglycan and chondroitin sulfate are the main blockers of axon regeneration and nerve function recovery. Targeted regulation of glial scars is an important pathway for neurological rehabilitation after stroke. Chinese medicine has been verified to be effective in stroke rehabilitation in clinical practice, possibly because it has the functions of promoting blood resupply, anti-inflammation, anti-oxidative stress, inhibiting cell proliferation and differentiation, and benign intervention in glial scars. This study reviewed the pathological process and signaling mechanisms of glial scarring after stroke, as well as the intervention of traditional Chinese medicine upon glial scar, aiming to provide theoretical reference and research evidence for developing Chinese medicine against stroke in view of targeting glial scarring.

Effect and mechanism of glycyrrhizin on glial scar formation after spinal cord injury in rats / 中国修复重建外科杂志

Objective: To explore the effect and potential mechanism of glycyrrhizin (GL) by inhibiting high mobility group box 1 (HMGB1) on glial scar formation after spinal cord injury (SCI) in rats. Methods: Seventy-two female Sprague Dawley rats were randomly divided into sham group ( n=12), SCI model group (SCI group, n=36), GL intervention group (SCI+GL group, n=12), and nuclear factor κB (NF-κB) inhibitor [pynolidine dithiocarbamate (PDTC)] intervention group (SCI+PDTC group, n=12). The SCI models of SCI group, SCI+GL group, and SCI+PDTC group were made by modified Allen's method, the sham group was only exposed the spinal cord without any injury. First of all, Basso-Beattie-Bresnahan (BBB) score of hind limbs and slope test were performed in SCI group at 1, 2, and 3 weeks after operation; Western blot was used to detect the expressions of glial fibrillary acidic protein (GFAP) and HMGB1 proteins. Compared with the sham group, the most significant time point in the SCI group was selected for subsequent experiment, in which the most significant glial scar was formed. Then, behavioral tests (BBB score of hind limbs and slope test), histological observation of spinal cord tissue structure, Western blot detection of HMGB1, GFAP, and NF-κB proteins, and immunohistochemical staining observation of GFAP and chondroitin sulfate proteoglycan (CSPG) were used to explore the effect of GL on the formation of glial scar after SCI and its potential mechanism. Results: The BBB score and slope angle of the SCI group increased gradually with time, which were significantly lower than those of the sham group at each time point ( P<0.05). Western blot detection showed that the relative expressions of HMGB1 and GFAP proteins in the SCI group at 1, 2, and 3 weeks after operation were significantly higher than those in sham group ( P<0.05). The change was most obvious at 3 weeks after SCI, therefore the spinal cord tissue was selected for subsequent experiments at this time point. At 3 weeks after operation, compared with the SCI group, BBB score and slope angle of SCI+GL group significantly increased ( P<0.05); the relative expressions of HMGB1, GFAP, and NF-κB proteins detected by Western blot and the expressions of GFAP and CSPG proteins detected by immunohistochemical staining significantly decreased ( P<0.05); the disorder of spinal cord tissue by HE staining improved, inflammatory cell infiltration reduced, and glial scar formation decreased. At 3 weeks after operation, the expressions of NF-κB, GFAP, and CSPG proteins of the SCI+PDTC group significantly reduced when compared with the SCI group ( P<0.05); and the expression of NF-κB protein significantly decreased and the expressions of GFAP and CSPG proteins significantly increased when compared with the SCI+GL group ( P<0.05). Conclusion: After SCI in rats, the application of GL to inhibit the expression of HMGB1 can reduce the expression of GFAP and CSPG in the injured spinal cord, then reduce the formation of glial scars and promote the recovery of motor function of the hind limbs, and GL may play a role in inhibiting glial scar through HMGB1/NF-κB pathway.

Buyang Huanwu Decoction () Attenuates Glial Scar by Downregulating the Expression of Leukemia Inhibitory Factor in Intracerebral Hemorrhagic Rats / 中国结合医学杂志

OBJECTIVE@#To evaluate the effect of Buyang Huanwu Decoction (, BYHWD) on glial scar after intracerebral hemorrhage (ICH) and investigate the underlying mechanism.@*METHODS@#Collagenase type VII (0.5 U) was injected stereotaxically into right globus pallidus to induce ICH model. One hundred and twenty Sprague-Dawley rats were randomly divided into 3 groups according to a random number table, including normal group (n=40), ICH model group (n=40) and BYHWD group (n=40), respectively. After ICH, the rats in the BYHWD group were intragastrically administered with BYHWD (4.36 g/kg) once a day for 21 days, while the rats in ICH group were administered with equal volume of distilled water for 21 days, respectively. Double immunolabeling was performed for proliferating cell nuclear antigen (PCNA)/glial fibrillary acidic protein (GFAP) nuclei. The expression of GFAP and leukemia inhibitory factor (LIF) was evaluated by immunohistochemistry and quantitative real-time reverse transcription-polymerase chain reaction (RT-PCR).@*RESULTS@#The astrocytes with hypertrophied morphology around the hematoma was observed on day 3 after ICH. The number of GFAP positive cells and GFAP mRNA levels increased notably on day 3 and reached the peak on day 14 post-ICH (P<0.01). PCNA+/GFAP+ nuclei were observed around the hematoma and reached the peak on day 14 post-ICH (P<0.01). In addition, LIF-positive astrocytes and LIF mRNA level in the hemorrhagic region increased significantly till day 14 post-ICH (P<0.01). However, BYHWD not only reduced the number of PCNA/GFAP nuclei, but also decreased GFAP and LIF levels (P<0.05).@*CONCLUSIONS@#BYHWD could attenuate ICH-induced glial scar by downregulating the expression of LIF in the rats.

Role and Mechanism of Ski in Glial Scar Formation post Spinal Cord Injury (review) / 中国康复理论与实践

Ski is an evolutionary conserved protein, which is involved in diverse cellular processes such as proliferation, differentiation, transformation and tumor progression. In spinal cord injury, the activation of astrocytes and reactive astrocyte hyperplasia are important factors affecting the formation of glial scar after spinal cord injury. Ski is highly expressed after spinal cord injury, and acts on astrocytes through transforming growth factor-beta, mitogen-activated protein kinase and other signaling pathways, and regulates their activation, proliferation, migration and glial scar formation, providing a new therapeutic direction for the treatment of spinal cord injury.

Neuroprotective effects of saffron on chronic focal cerebral ischemia through inhibiting glial scar formation in rats / 中国药理学与毒理学杂志

OBJECTIVE To explore the neuro-protective effects of saffron (Crocus satius L.) on chronic focal cerebral ischemia in rats.METHODS SD rats were randomly divided into 6 groups:sham control group,MCAO group,edaravone group and saffron 30,100,300 mg·kg-1groups.Focal cerebral ischemia was induced by middle cerebral artery occlusion(MCAO).Saffron was administered orally by once daily from 2 h to 42 d after ischemia. At 42 d after cerebral ischemia, neurological deficit score, spontaneous activity test,elevated plus maze test,marble burying test and novel objective recognition test were used to evaluate the effects of saffron on the behevioural change. Infarct volume, survival neuron density, activated astrocyte number, and the thickness of glial scar were also detected. GFAP expression and inflammatory cytokine contents in ischemic peripheral region were detected by Western blot and ELISA,separately.RESULTS Saffron(100,300 mg·kg-1)improved the body weight decrease, neurological deficit and spontaneous activity. Saffron (30-300 mg·kg- 1) increased the traveled distance ratio and total time in open arm, decreased the buried marble number, which indicated that saffron could ameliorate anxiety- and depression-like behaviors. Saffron (100, 300 mg·kg-1)improved the learning and memory function,which manifested by increased discrimination ratio(DR)and discrim-ination index (DI) in T2test. The results of toluidine blue found saffron treatment (100, 300 mg·kg-1) decreased the infarct volume and increased the neuron density in cortex and hippocampal.The activated astrocyte number,the thickness of glial scar and GFAP expression in ischemic peripheral region decreased after saffron. Saffron (100, 300 mg·kg-1) decreased the contents of IL-6 and IL-1β, increased the content of IL-10 in ischemic peripheral region.CONCLUSION Saffron exerted neuro-protective effects on chronic focal cerebral ischemia,which could be related with inhibiting the activation of astrocyte and glial scar,following with the decrease of inflammatory reaction.

Advance in Glial Scar Formation after Spinal Cord Injury (review) / 中国康复理论与实践

After spinal cord injury, the formation of glial scar related to the hypertrophy, proliferation and migration of astrocytes, and the increased expression of glial fibers acidic protein, vimentin and nestin, etc., and it may also inhibit the growth of neuron axon.

The role of glial scar on axonal regeneration after spinal cord injury / 中国修复重建外科杂志

The 'glial scar' has been widely studied in the regeneration of spinal cord injury (SCI). For decades, mainstream scientific concept considers glial scar as a 'physical barrier' to impede axonal regeneration after SCI. Moreover, some extracellular molecules produced by glial scar are also regarded as axonal growth inhibitors. With the development of technology and the progress of research, multiple lines of new evidence challenge the pre-existing traditional notions in SCI repair, including the role of glial scar. This review briefly reviewed the history, advance, and controversy of glial scar research in SCI repair since 1930s, hoping to recognize the roles of glial scar and crack the international problem of SCI regeneration.

Benefícios da condroitinase abc associada a células-tronco mesenquimais na lesão espinhal aguda em ratos / Benefits of chondroitinase abc associated with mesenchymal stem cells in acute spinal cord injury in rats

Com o objetivo de estudar o efeito da condroitinase associada às células-tronco mesenquimais na lesão aguda da medula espinhal, utilizaram-se 50 ratos Lewis, distribuídos igualmente nos grupos: controle negativo (CN), tratamento com placebo (PLA), condroitinase (CDN), células-tronco mesenquimais (CTM) e condroitinase mais células-tronco mesenquimais (CDN+CTM). Todos os animais tiveram a medula espinhal exposta por laminectomia, e os grupos PLA, CDT, CTM e CDT+CTM sofreram também trauma medular compressivo. Após sete dias, procedeu-se à reexposição da medula espinhal, quando os grupos PLA e CTM receberam 4µL de líquido cefalorraquidiano artificial via intralesional, e os grupos CDT e CDT+CTM receberam o mesmo líquido contendo 2,2U de condroitinase. Após 14 dias da cirurgia inicial, todos os animais receberam 0,2mL de PBS via endovenosa, contudo, nos grupos CTM e CDT+CTM, esse líquido continha 1x106 CTM. Avaliou-se a capacidade motora até o 28o dia pós-trauma e, posteriormente, as medulas espinhais foram analisadas por RT-PCR, para quantificação da expressão gênica para BDNF, NT-3, VEGF, KDR e PECAM-1, e por imunoistoquímica, para detecção das células-tronco GFP injetadas (anti-GFP), quantificação dos neurônios (anti-NeuN) e da GFAP e vimentina, para avaliação da cicatriz glial. As análises estatísticas foram realizadas com o auxílio do Prism 5 for Windows, com o nível de significância de 5%. Não houve diferença entre os grupos quanto à capacidade motora. O grupo CDT+CTM apresentou maior imunoexpressão de neurônios viáveis do que o placebo. No CTM, houve maior expressão dos fatores neurotróficos BDNF e VEGF. E no CDT, houve menor imunoexpressão de vimentina. Concluiu-se que a associação CDT+CTM favorece a viabilidade neuronal após o trauma, que o tratamento com CTM promove aumento na expressão dos fatores tróficos BDNF e VEGF e que o tratamento com condroitinase é efetivo na redução da cicatriz glial.(AU)

The aim of this work was to study the effect of chondroitinase associated with mesenchymal stem cells in acute spinal cord injury. Therefore, 50 Lewis rats were distributed in the following groups: negative control (NC), treatment with placebo (PLA), chondroitinase (CDT), mesenchymal stem cells (MSC), and chondroitinase associated with mesenchymal stem cells (CDT + MSC). All animals had their spinal cord exposed by laminectomy, and the groups named PLA, CDT, MSC and CDT + MSC also suffered compressive spinal cord trauma. After seven days, the spinal cord was re-exposed, when the PLA and MSCs groups received 4uL of artificial cerebrospinal fluid through the lesion, and the CDT group and CDT + MSC received the same fluid containing 2,2U of chondroitinase. 14 days after the first surgery, all animals received 0.2ml of PBS intravenously; however, the MSC and CDT + MSC groups received the same liquid also containing 1x106 MSCs. The motor skills were evaluated up to 28 days post-injury and, subsequently, the spinal cords were analyzed by RT-PCR for BDNF, NT-3, VEGF, PECAM-1 and KDR gene expression quantification, immunohistochemistry to detect injected stem cells GFP (anti-GFP), to quantify neurons (anti-NeuN), GFAP and detect vimentin in order to evaluate the glial scar. Statistical analyzes were performed by Prism 5 for Windows using a 5% level of significance. There was no difference between groups with regarding motor capacity. The CDT + MSC group showed increased immunoreactivity of viable neurons than placebo. In MSC, there was a greater expression of neurotrophic factors BDNF and VEGF. Also, there was less vimentin immunostaining in group CDT. It was concluded that CDT + MSC association promotes neuronal viability after trauma, in which treatment with MSC promotes increased expression of BDNF and VEGF trophic factors, and also that treatment with chondroitinase is effective in reducing the glial scar.(AU)

Effect of combined treatment of brain-derived neurotrophic factor with chondroitin ABC on neurological function and glial scar in spinal cord injury rats / 中华神经医学杂志

Objective To evaluate the effect of brain-derived neurotrophic factor (BDNF) combined with chondroitin ABC (chABC) on neurological function recovery and partial glial scar formation in rats with spinal cord injury (SCI).Methods Eighty SD rats were randomly divided into sham-operated group,saline treatment group,BDNF treatment group,chABC treatment group and BDNF combined with chABC treatment group (n=16);rats in the later 4 groups were established SCI rat models;immediately after SCI,10 μL saline,20 μL BDNF,6 μL chABC and 6 μL chABC+20 μL BDNF were given,and rats in the sham-operated group did not give any treatment.One,7,14 and 28 d after SCI,HE and Nissl stainings were employed to observe the glial scar formation;immunohistochemical staining was used to detect the glial fibrillary acidic protein (GFAP) expression.Results One d after SCI,HE staining and Nissl staining showed that obvious hemorrhage in the grey matter and aggregated inflammatory cells were observed in the SCI center,and Nissl substance began to break up into dust particles from speckle;7 d after SCI,Nissl substance broke up into dust particles from speckle,and died neurons,activated astrocytes and infiltrated inflammatory cells were observed;14 and 28 d after SCI,glial scars were formed,activated astrocytes were noted,Nissl substance recovered from dust particles into maculosus,and number of colored neurons increased;the recovery of Nissl substance and number of neurons in the BDNF treatment group,chABC treatment group and BDNF combined with chABC treatment group were better than those in the saline treatment group,and BDNF combined with chABC treatment group enjoyed the best recovery.One d after SCI,GFAP positive expression began in the rats of the later 4 groups,and peaked 14 d after SCI;7 d after SCI,GFAP positive labeling areas in the BDNF combined with chABC treatment group were smaller than those in the saline treatment group;14 and 28 d after SCI,GFAP positive labeling areas in the BDNF treatment group,chABC treatment group and BDNF combined with chABC treatment group were significantly smaller than those in the saline treatment group (P＜0.05);28 d after SCI,GFAP positive labeling areas in the BDNF combined with chABC treatment group were significantly smaller than those in the saline treatment group,BDNF treatment group and chABC treatment group (P＜0.05).Conclusion BDNF combined with chABC has neuroprotective and neurotrophic effects,which can reduce the proliferation of astrocytes and glial scar formation and inhibit the GFAP expression;combined effect is better than single application.

Changes of Ski expression levels in rat activated astrocytes / 中国病理生理杂志

AIM:To explore the time-dependent change of Ski protein expression in normal and activated astrocytes in rats.METHODS:The astrocytes were obtained from rat cerebral cortex and cultured in vitro.The astrocytes were treated with LPS and scratch injury for activation.Western blot analysis was used to determine glial fibrillary acidic protein (GFAP) and Ski protein levels in activated astrocytes at a series of time points.The indirect immunofluorescence staining method was performed to detect the location of Ski protein in the astrocytes.RESULTS:The protein of GFAP was naturally expressed in the astrocytes, beginning to increase after treated with LPS and scratch injury.Little protein expression of Ski in the normal astrocytes was observed.The Ski protein expression began to increase after treated with 1 mg/L LPS, peaked at 4 d (P<0.05) and then deceased, but was stills higher than that in the normal cells.The protein expression level of Ski after scratch injury was highly consistent with above mentioned.Ski was mainly observed in the nucleus of the normal cells and the cells treated with LPS for 6 d, while it was observed in the cytoplasm 2 and 4 d after treated with LPS.CONCLUSION:The protein of Ski is expressed in the astrocytes, and the expression level is increased in activated astrocytes,mainly located in the nucelus.Ski may plays an essential roles in the processes of activation and proliferation of astrocytes.