神经胶质细胞参与吗啡耐受机制及治疗的研究进展

 吗啡是临床上常用的强效镇痛药，然而长期应用会导致其镇痛效能降低，发生吗啡耐受。以往对吗啡耐受机制的研究主要集中在脊髓神经元敏化等中枢神经元机制，近年来越来越多的学者开始关注神经胶质细胞，特别是小胶质细胞和星形胶质细胞，在吗啡耐受形成中的作用。本文简要综述了神经胶质细胞参与吗啡耐受的作用机制及其治疗的研究进展，为解决临床上中重度疼痛治疗中的难点问题提供新的解决思路与依据。     

抑制细胞间缝隙连接通讯功能对星形胶质细胞缺氧/复氧损伤的保护作用

目的研究抑制细胞缝隙连接通讯功能对星形胶质细胞缺氧/复氧损伤的影响.方法原代培养的新生SD大鼠大脑皮层星形胶质细胞分为正常对照组、空白对照组及细胞缝隙连接抑制剂18-α-甘草次酸和油酸酰胺组.荧光示踪法检测星形胶质细胞的缝隙连接通讯功能; MTT法检测抑制缝隙连接通讯功能对缺氧/复氧损伤星形胶质细胞存活率的影响; Annexin V/碘化丙啶双染流式细胞术及Hoechst 33258荧光染色法检测抑制缝隙连接通讯功能对缺氧/复氧损伤星形胶质细胞凋亡的影响.结果与正常对照组相比, 空白对照组星形胶质细胞缝隙连接通讯功能明显增强( P＜0.01), 细胞存活率明显降低( P＜0.01), 细胞凋亡明显增加( P＜0.01);与空白对照组相比, 18-α-甘草次酸及油酸酰胺可显著降低星形胶质细胞缝隙连接通讯功能(均 P＜0.01), 减轻缺氧/复氧损伤引起的星形胶质细胞存活率的降低(均 P＜0.01), 且可减少缺氧/复氧损伤引起的星形胶质细胞凋亡(均 P＜0.01). 结论抑制细胞间缝隙连接通讯功能对星形胶质细胞缺氧/复氧损伤具有保护作用.     

针刺双向良性调控星形胶质细胞治疗脊髓损伤的研究进展＊

随着近年来交通和工业的快速发展，脊髓损伤患者也不断增加，现已成为严重的社会负担，但却一直没有理想的治疗方案。继发性损伤是脊髓损伤后分子和细胞发生的一系列复杂的级联反应。它是SCI的重要组成部分，阐明继发性损伤的机制，针对不同的机制采取不同的干预措施是主要的治疗策略。而星形胶质细胞作为中枢神经系统中数量最多的细胞，在脊髓损伤后发挥了重要作用，受到研究人员的广泛关注，许多研究证明针刺可通过调节星形胶质细胞而发挥治疗作用，故本文综述了星形胶质细胞在脊髓损伤后的作用，以及针刺对其的干预影响，并提出日后研究的展望。     

Downregulation of inflammatory markers by conjugated linoleic acid isomers in human cultured astrocytes

Objectives: Conjugated linoleic acid (CLA) isomers have been shown to possess anti-inflammatory activity in the central nervous system. In this study, we aimed to evaluate whether modulation of the fatty acid profile by the CLA isomers c9,t11 or t10,c12CLA was associated with changes in the expression of pro-inflammatory molecules in human astrocytes.

Methods: Cultured astrocytes were treated for 6 days with 100?µM fatty acids (c9,t11CLA or t10,c12CLA or oleic acid). Following the treatment, the fatty acid profile of the cell and pro-inflammatory molecule expression were assessed.

Results: Only the t10,c12CLA isomer induced a significant decrease in arachidonic acid and increased the ratio of docosahexaenoic acid/eicosapentaenoic acid, which constitutes indirect evidence of peroxisome proliferator-activated receptor alpha activation. Inhibition of tumour necrosis factor-α, interleukin-1β, and RANTES expression was observed in astrocytes treated with c9,t11CLA and t10,c12CLA.

Discussion: Current data demonstrate that CLA isomers, particularly t10,c12, may affect neuroinflammation by reducing the pro-inflammatory molecules in cultured astrocytes, suggesting a potential nutritional role of CLA isomers in modulating the astrocyte inflammatory response.     

Molecular cloning and cellular expression of the cholesterol synthesizing enzymes during the prenatal development of the optic nerve in the dromedary camel (Camelus Dromedarius)

The Cholesterol-synthesizing proteins (HMGCS1 and HMGCS2) are mitochondrial enzymes that believed to catalyze the first reaction of ketogenesis, the process by which energy is provided from fats in the absence of carbohydrates. Typically, astrocytes developed from its progenitor cells in the embryonic optic nerve and enriched with HMGCS1 and 2. However, the detailed histomorphology of camel HMGCS1 and 2 remains to be clearly defined. Here, we investigated the changes that associate with astrocytes differentiation within the developing camel optic nerve. Firstly, we isolated cDNAs encoding HMGCS1 and 2 from the optic nerve. Then, we found that HMGCS1 shared high similarity to human, while HMGCS2 showed a lower similarity and was more diverse. Immunohistochemical studies revealed that distinct correlation of astrocytes differentiation with HMGCS1 and 2 expressions in the developing camel optic nerve. Both encoded proteins were localized throughout the cytoplasm, as well as the nuclei of the astrocytes. In addition, semi-quantitative PCR analysis and western analysis confirmed that both HMGCS1 and 2 were highly expressed in camel optic nerve as well as other tissue, but they were lower in both skeletal and heart muscles. Moreover, various stains such as Sudan black and florescence filipin stains were used to visualize the free cholesterol in the astrocytes, indicating the enzymatic activity of HMGCS1 and 2. Together, our study reported the first comprehensive investigation of the molecular cloning and cellular expression of HMGCS1 and 2 in the optic nerve of dromedary camel.     

Neuroprotective effect of omega-3 polyunsaturated fatty acids in the 6-OHDA model of Parkinson's disease is mediated by a reduction of inducible nitric oxide synthase

Objective: Parkinson's disease (PD) is characterized by deterioration of the nigrostriatal system and associated with chronic neuroinflammation. Glial activation has been associated with regulating the survival of dopaminergic neurons and is thought to contribute to PD through the release of proinflammatory and neurotoxic factors, such as reactive nitric oxide (NO) that triggers or exacerbates neurodegeneration in PD. Polyunsaturated fatty acids (PUFAs) exert protective effects, including antiinflammatory, antiapoptotic, and antioxidant activity, and may be promising for delaying or preventing PD by attenuating neuroinflammation and preserving dopaminergic neurons. The present study investigated the effects of fish oil supplementation that was rich in PUFAs on dopaminergic neuron loss, the density of inducible nitric oxide synthase (iNOS)-immunoreactive cells, and microglia and astrocyte reactivity in the substantia nigra pars compacta (SNpc) and striatal dopaminergic fibers.

Methods: The animals were supplemented with fish oil for 50 days and subjected to unilateral intrastriatal 6-hydroxydopamine (6-OHDA)-induced lesions as a model of PD.

Results: Fish oil mitigated the loss of SNpc neurons and nerve terminals in the striatum that was caused by 6-OHDA. This protective effect was associated with reductions of the density of iNOS-immunoreactive cells and microglia and astrocyte reactivity.

Discussion: These results suggest that the antioxidant and antiinflammatory properties of fish oil supplementation are closely related to a decrease in dopaminergic damage that is caused by the 6-OHDA model of PD.     

Propentofylline attenuates allodynia, glial activation and modulates GABAergic tone after spinal cord injury in the rat

In this study, we evaluated whether propentofylline, a methylxanthine derivative, modulates spinal glial activation and GABAergic inhibitory tone by modulation of glutamic acid decarboxylase (GAD)₆₅, the GABA synthase enzyme, in the spinal dorsal horn following spinal cord injury (SCI). Sprague–Dawley rats (225–250 g) were given a unilateral spinal transverse injury, from dorsal to ventral, at the T13 spinal segment. Unilateral spinal injured rats developed robust bilateral hindlimb mechanical allodynia and hyperexcitability of spinal wide dynamic range (WDR) neurons in the lumbar enlargement (L4–L5) compared to sham controls, which was attenuated by intrathecal (i.t.) administration of GABA, dose-dependently (0.01, 0.1, 0.5 μg). Western blotting and immunohistochemical data demonstrated that the expression level of GAD₆₅ protein significantly decreased on both sides of the lumbar dorsal horn (L4/5) after SCI (p < 0.05). In addition, astrocytes and microglia showed soma hypertrophy as determined by increased soma area and increased GFAP and CD11b on both sides of the lumbar dorsal horn compared to sham controls, respectively (p < 0.05). Intrathecal treatment with propentofylline (PPF 10 mM) significantly attenuated the astrocytic and microglial soma hypertrophy and mechanical allodynia (p < 0.05). Additionally, the Western blotting and immunohistochemistry data demonstrated that i.t. treatment of PPF significantly prevented the decrease of GAD₆₅ expression in both sides of the lumbar dorsal horn following SCI (p < 0.05). In conclusion, our present data demonstrate that propentofylline modulates glia activation and GABAergic inhibitory tone by modulation of GAD₆₅ protein expression following spinal cord injury.     

Bone mesenchymal stem cell-conditioned medium decreases the generation of astrocytes during the process of neural stem cells differentiation

Objectives: The aim of this study was to investigate the effect of bone mesenchymal stem cell (BMSC) conditioned medium (CM) and Bone morphogenetic protein-4 (BMP-4) on the generation of astrocytes during the process of NSCs differentiation.

Design: Neural stem cells (NSCs) were grown under different culture conditions.

Setting: The First Affiliated Hospital of Anhui Medical University, Hefei, China.

Outcome Measures: The study consisted of four groups: NSCs cultured under control conditions (group 1) or with the addition of BMSC-CM (group 2);(BMP-4) (group 3) or both (group 4).The expression of glial fibrillary acidic protein (GFAP) was detected by immunocytochemical staining and Western blotting.

Results: The expression of GFAP was higher in Group3 and lower in Group 2 compared to that in Group 1. The expression of GFAP in Group 4 was intermediate between that of Group 2 and Group 3.

Conclusions: These results suggest that BMSC-CM can decrease the generation of astrocytes and that the inhibition of the (BMP-4) /Smad1/5/8 signaling pathway may be the underlying mechanism. This phenomenon may be mediated by increasing the expression of Smad6.     

抑制病理性疼痛相关胶质细胞活化药物的研究进展

背景 病理性疼痛的产生和持续机制十分复杂.近些年越来越多的研究者关注到脊髓胶质细胞在病理性疼痛中所发挥的作用,其中胶质细胞活化和增殖的抑制剂成为了研究的重点.目的 系统阐述胶质细胞在病理性疼痛中的作用和部分胶质细胞抑制剂的作用机制及研究进展.内容 胶质细胞不仅具有营养和支持作用,还参与了病理性疼痛,已有许多实验证实了应用胶质细胞抑制剂可以减弱胶质细胞的激活从而削弱疼痛反应.趋向 期望能为进一步的药物实验研究提供有价值的思路和借鉴.     

CNS: Not an immunoprivilaged site anymore but a virtual secondary lymphoid organ

The cardinal dogma of central nervous system (CNS) immunology believed brain is an immune privileged site, but scientific evidences gathered so far have overturned this notion proving that CNS is no longer an immune privileged site, but rather an actively regulated site of immune surveillance. Landmark discovery of lymphatic system surrounding the duramater of the brain, made possible by high resolution live imaging technology has given new dimension to neuro-immunology. Here, we discuss the immune privilege status of CNS in light of the previous and current findings, taking into account the differences between a healthy state and changes that occur during an inflammatory response. Cerebrospinal fluid (CSF) along with interstitial fluid (ISF) drain activated T cells, natural killer cells, macrophages and dendritic cells from brain to regional lymph nodes present in the head and neck region. To keep an eye on inflammation, this system hosts an army of regulatory T cells (CD25+ FoxP3+) that regulate T cell hyper activation, proliferation and cytokine production. This review is an attempt to fill the gaps in our understanding of neuroimmune interactions, role of innate and adaptive immune system in maintaining homeostasis, interplay of different immune cells, immune tolerance, knowledge of communication pathways between the CNS and the peripheral immune system and lastly how interruption of immune surveillance leads to neurodegenerative diseases. We envisage that discoveries should be made not only to decipher underlying cellular and molecular mechanisms of immune trafficking, but should aid in identifying targeted cell populations for therapeutic intervention in neurodegenerative and autoimmune disorders.