睫状神经营养因子对新生大鼠培养星形细胞胶质化的影响

在新生大鼠混合培养胶质细胞机械划伤模型上, 研究了睫状神经营养因子(CNTF)对反应性星形细胞胶质化的影响. 损伤后, 在损伤边缘可见典型的星形细胞胶质化过程, 表现为扁平型星形胶质细胞增生肥大, 其胞内GFAP表达增加, O-2A前体细胞向受损区域迁移, 并分化成为突起型星形胶质细胞. 向培养基加入外源性CNTF可促进损伤边缘的扁平型星形胶质细胞的增生及GFAP的表达. 结果提示CNTF可以加强损伤区的星形细胞胶质化.

脊髓损伤后bFGF和GFAP的变化及其意义

目的 研究脊髓损伤后碱性成纤维细胞因子和胶质纤维酸性蛋白的变化及其两者的相关性 ,探讨脊髓损伤后脊髓的自身保护机制以及星形胶质细胞在脊髓损伤中的作用。方法 用免疫组织化学、组织学染色和图象分析的方法检测损伤脊髓碱性成纤维细胞及胶质纤维酸性蛋白表达的动态变化。结果 脊髓损伤后 1d损伤脊髓中碱性成纤维细胞的表达明显增高 ,7d达到高峰 ,14d末回落 ;而胶质纤维酸性蛋白表达则在 1～ 14d内呈进行性增高趋势。两指标相关性显著 (r =0 .777,P =0 .0 0 1)。结论 脊髓损伤后反应性星形细胞胶质化对脊髓的再生和自身修复起着重要作用 ,提示脊髓本身存在自身保护机制。

SOX2/DRD2 signaling pathway facilitates astrocytic dedifferentiation in cerebral ischemic mice

Objective:To explore the effects of dopamine receptor D2(DRD2)on astrocytic dedifferentiation based on SOX2-regulated genes in neural stem cells(NSCs)and astrocytes.Methods:Immunofluorescence staining and SOX2-GFP mice were used to examine the lineage differentiation of SOX2-positive cells during the development of cerebral cortex.Primary NSCs/astrocytes culture,ChIP-seq and Western Blot were adopted to analyze and verify the expression of candidate genes.Pharmacological manipulation,neurosphere formation,photochemical ischemia,immunofluorescence staining and behavior tests were adopted to evaluate the effects of activating DRD2 signaling on astrocytic dedifferentiation.Results:Immunofluorescence staining demonstrated the NSC-astrocyte switch of SOX2-expression in the normal development of cerebral cortex.ChIP-seq revealed enrichment of DRD2 signaling by SOX2-bound enhancers in NSCs and SOX2-bound promoters in astrocytes.Western Blot and immunofluorescence staining verified the expression of DRD2 in NSCs and reactive astrocytes.Application of quinagolide hydrocholoride(QH),an agonist of DRD2,significantly promoted astrocytic dedifferentiation both in vitro and in vivo following ischemia.In addition,quinagolide hydrocholoride treatment improved locomotion recovery.Conclusion:Activating DRD2 signaling facilitates astrocytic dedifferentiation and may be used to treat ischemic stroke.

Effect of ciliary neurotrophic factor on activation of astrocytes in vitro

Objective To observe the activating effect of ciliary neurotrophic factor （CNTF） on astrocyte in vitro. Methods Astrocytes cultured purely from newborn rats. Cerebral cortex was raised in normal and serum deprivation condition with different concentrations （in ng/ml： 0, 2, 20, or 200） of CNTF. After cultured for 24 h, the shape and the cell cycle of astrocytes were examined by immunocytochemistry and flow cytometer, respectively. Results The immunoactivity of glial fibrillary acidic protein （GFAP） and the nuclear size of astrocytes were increased when CNTF was applied, whether cells were cultured in medium with or without serum. CNTF promoted astrocytes to enter the cell cycle in medium with serum, but had no this effect in medium without serum. Conclusion In medium without serum, astrocytes could differentiate into activated state ceils with CNTF application, but could not proliferate; in medium with serum, astrocytes could proliferate with aid of CNTF.

Human Cytomegalovirus Infection Inhibits the Differentiation of Human Hippocampus Neural Precursor Cells into Astrocytes

HCMV is a major cause of congenital brain disease in humans, and its neuropathogenesis is not yet fully understood. The objective of the present study is to investigate the effect of human cytomegalovirus (HCMV) infection on human hippocampus neural precursor cell (NPCs) differentiation in vitro. Fetal hippocampus tissue was dissociated mechanically and then cultured in proliferation medium with EGF and bFGF. The identification and purity of the NPCs were confirmed by using immunofluorescence to detect the expression of the NPCs marker-Nestin. To drive NPCs differentiation, bFGF and EGF were withdrawn from the medium and replaced with FBS (10%). HCMV AD169 (MOI=5) was added into the differentiation medium at the onset of the differentiation. After 7 days of differentiation, in order to confirm whether NPCs are permissive for HCMV infection, immunofluorescence was used to stain for the presence of immediate early (IE) and late (pp65) HCMV proteins in the infected cells. The effects of HCMV infection on NPCs’ differentiation was observed by detecting the ratio of nestin and GFAP positive cells with confocal microscopy and immunofluorescence. The data showed that 95%±8% of the cells (passage 4-8) cultured were Nestin positive which suggested that majority of the cells were NPCs. On day 7 postinfection, most of the infected cells were IE and PP65 positive. The percentage of Nestin-positive cells were 93%±10% and 50%±19% (t=6.03, p<0.01) and those of GFAP-positive cells were 55±17% and 81%±11% (t=3.77, p<0.01) in HCMV treated and control groups respectively. These findings indicate that NPCs are HCMV permissive cells and HCMV (AD 169) infection suppresses the differentiation of Hippocampus-genetic human NPCs into astrocytes. These effects may provide part of the explanation for the abnormalities in brain development associated with congenital HCMV infection.

Protective effects of parecoxib on rat primary astrocytes from oxidative stress induced by hydrogen peroxide

Objective： To investigate the protective effects of parecoxib from oxidative stress induced by hydrogen peroxide （H202） in rat astrocytes in vitro. Methods： All experiments included 4 groups： （1） negative control （NC） group, without any treatment; （2） H202 treatment group, 100 μmol/L H202 treatment for 24 h; （3） and （4） parecoxib pre- treatment groups, 80 and 160 μmol/L parecoxib treatment for 24 h, respectively, and then treated with 100 μmol/L H202. Several indices were investigated, and the expressions of Bax, Bcl-2, and brain-derived neurotrophic factor （BDNF） were quantified. Results： Compared to the NC group, exposure to H202 resulted in significant morphological changes, which could be reversed by pretreatment of parecoxib. In addition, H202 treatment led to loss of viability （P=0.026） and increased intracellular reactive oxygen species （ROS） levels （P〈0.001）, and induced apoptosis （P〈0.01） in the primary astrocytes relative to the NC group. However, in the parecoxib pretreatment groups, all the above changes reversed significantly （P〈0.05） as compared to the H202 treatment group, and were nearly unchanged when compared to the NC group. Mechanical investigation showed that dysregulated Bax, Bcl-2, and BDNF could be im- plicated in these changes. Conclusions： Our results indicated that parecoxib provided a protective effect from oxidative stress induced by exposure to H202.