局灶性脑缺血再灌注时神经元、胶质细胞形态变化与TNF-α、c-Myc表达相关的实验研究

目的:探讨局灶性脑缺血再灌注时神经元、神经胶质细胞形态变化特点和TNF-α、c-Myc表达的相关性。方法: 采用线栓法大鼠大脑中动脉阻塞复制局部脑缺血再灌注模型,缺血2 h分别再灌注1 d、3 d、7 d,应用光镜和免疫组化法,观察缺血侧额顶叶皮质神经元,神经胶质细胞形态变化及TNF-α、c-Myc蛋白表达。结果: 局灶性脑缺血再灌注后,同侧额顶叶皮质梗死区神经元、小胶质细胞、星形胶质细胞出现变性、坏死,梗死灶周围小胶质细胞和星形胶质细胞增生,呈现时间相关性,变性、死亡以再灌注3 d最为显著,星形胶质细胞和小胶质细胞增生以再灌注7 d最为显著且位于梗死周围区。再灌注后,TNF-α、c-Myc阳性细胞表达也显著增加,以再灌注3 d最为显著,且主要表达于星形胶质细胞、小胶质细胞,少量表达于神经元。结论: 脑缺血再灌注后神经元、神经胶质细胞之间在损伤、抗损伤及修复中相互影响,而TNF-α、c-Myc蛋白表达的增加可能是联系不同细胞间相互作用的主要调节物质之一。     

小胶质细胞在大鼠暂时性局灶脑缺血再灌注后脑损伤区活化反应的初步研究

目的:探讨暂时性局灶脑缺血后小胶质细胞的反应规律,进一步探讨小胶质细胞在脑缺血损伤中的作用。方法:采用线栓法建立大鼠大脑中动脉阻塞(middle cerebral artery occlusion,MCAO)再灌注模型,应用组织学、免疫组化染色及免疫荧光双标技术,观察大脑中动脉阻塞30 min,再灌注0.5、3、6 h以及1、3、7、14 d和28 d后脑组织的损伤情况,小胶质细胞的形态学和数量变化。结果:组织学观察结果显示:MACO30 min再灌注0.5 h后,梗死区出现神经元肿胀,脑水肿;再灌注3 h和6 h,脑水肿加重,部分神经元出现核固缩,对侧脑组织也出现水肿。脑水肿和神经元固缩在再灌注1 d时最重。再灌注3 d开始,脑水肿程度逐渐减弱,缺血区浸润的小胶质细胞增多。再灌注7 d时,缺血灶小胶质细胞浸润最明显,伴胶质结节形成,再灌注14 d,胶质瘢痕逐渐减小。再灌注28 d,大多数动物梗死区仅存少量小胶质细胞,个别未能修复的坏死灶液化并形成囊腔。免疫组化和免疫荧光双标记结果显示:假手术组小胶质细胞的胞体小,突起细长柔和。脑缺血30 min再灌注0.5 h可见小胶质细胞的体积增大,突起少而短。缺血再灌注6 h,小胶质细胞的胞体增大,突起减少或消失。再灌注1 d和3 d,小胶质细胞的数量明显多于假手术组(P0.05)。再灌注7 d,细胞数量增加达到高峰。再灌注14 d以后,小胶质细胞的数量进一步减少,再灌注28 d后小胶质细胞的数量少于再灌注7 d,但仍多于假手术组和缺血再灌注3 d(P0.05)。结论:暂时性局灶脑缺血能够引起小胶质细胞活化和增生,经历损伤性、反应性、效应性和恢复性变化四个阶段。小胶质细胞在脑缺血损伤组织的清除和损伤修复等方面发挥重要作用。     

银杏叶提取物对局灶性脑缺血再灌注后GFAP表达的影响

目的研究银杏叶提取物(extract of Ginkgo biloba,EGB)对局灶性脑缺血再灌注后星形胶质细胞胶质纤维酸性蛋白(GFAP)表达的影响。方法大脑中动脉插线法制作大鼠局灶性脑缺血再灌注模型。75只Wistar大鼠随机分为假手术组、缺血再灌注组、EGB治疗组。缺血2h再灌注48h后,采用免疫组织化学法检测脑组织内GFAP蛋白的表达。结果缺血再灌注后可诱导脑组织GFAP表达增强,EGB可抑制缺血再灌注后GFAP的表达(P<0.05)。结论局灶性脑缺血再灌注后,可诱导脑组织GFAP表达增强,EGB可抑制脑缺血后星形胶质细胞GFAP的高表达,提示EGB可能对缺血诱导的星形胶质细胞活化具有抑制作用,这可能是EGB抗脑缺血损伤保护神经元作用的机制之一。     

巴曲酶对脑缺血再灌注大鼠海马CA1区的影响

目的 通过观察大鼠局灶性脑缺血再灌注不同时段，巴曲酶对海马CAl神经元及星形胶质细胞数目、形态等方面的影响，从而探讨巴曲酶对局灶性脑缺血再灌注损伤的保护作用。方法 采用改良的线栓法制备大脑中动脉阻塞(MACO)2h、不同再灌注时间段(3h、6h、12h、24h、48h、72h、7d)的大鼠短暂局灶性脑缺血(transient focal cerebral isehemia)模型，随机设立巴曲酶组(Bat)、生理盐水对照组(N．S)、假手术组(sham-operated)，通过HE染色及胶质原纤维酸性蛋白(GFAP)和神经元特异核抗原(NeuN)的免疫组化染色，观测CAl区神经元和星形胶质细胞的形态、数目的动态变化。结果巴曲酶能显提高再灌注早期(6～24h)CAl区GFAP阳性细胞的数目，再灌注7d组存活锥体细胞的数量较盐水对照组有明显提高，提示局灶性脑缺血后早期反应性星形胶质细胞的增多对维持神经元的存活有积极意义，巴曲酶对短暂局灶性脑缺血再灌注引起的海马CAl区延迟性神经元坏死(DND)有一定的抑制作用。     

磷酸化细胞周期素依赖性激酶在局灶性脑缺血大鼠神经细胞中的表达

目的:观察磷酸化细胞周期素依赖激酶在大鼠局灶性脑缺血后神经元和星形胶质细胞的表达。方法:采用大脑中动脉阻塞（MCAO）方法制作大鼠局灶性脑缺血模型,应用免疫荧光技术检测缺血后1 d、3 d、7 d、14 d大鼠缺血侧病灶周围神经元和星形胶质细胞中磷酸化周期素依赖激酶2（CDK2）、磷酸化细胞分裂周期激酶2（CDC2）的表达。结果:在神经元中,与正常对照组相比,缺血后1 d、3 d组磷酸化CDK2的表达量明显增加（P<0.05）,磷酸化CDC2在正常组及缺血组均无明显表达;在星形胶质细胞中,缺血后1 d、3 d、7 d均出现明显的磷酸化CDK2、CDC2的表达,与对照组相比有显著差异（P<0.05）。结论:大鼠局灶性脑缺血后早期部分神经元再次进入细胞周期,细胞周期调控机制可能参与了大鼠局灶性脑缺血后神经元的凋亡及星形胶质细胞的分裂增殖。     

S100A9通过增加小鼠星形胶质细胞的谷氨酸分泌促进神经元损伤

目的:研究钙防卫蛋白S100A9刺激体外星形胶质细胞后细胞外谷氨酸浓度变化及其对神经元影响和调控机制。方法:分离培养新生C57BL/6小鼠大脑皮层星形胶质细胞和神经元；Amplite荧光法检测星形胶质细胞培养上清谷氨酸浓度；Real time RT-PCR和Western Blot分别检测星形胶质细胞谷氨酸转运体(GLT-1) mRNA和蛋白表达；Fluo-4荧光探针法检测星形胶质细胞胞内Ca²⁺浓度；转录组测序并结合KEGG分析筛选星形胶质细胞谷氨酸浓度变化的调控机制；S100A9刺激星形胶质细胞的培养上清(CS)干预神经元后，末端脱氧核苷酸转移酶标记法(TUNEL)检测神经元凋亡，CCK-8试剂盒检测神经元存活。结果:S100A9刺激星形胶质细胞后细胞外谷氨酸浓度增加，GLT-1 mRNA和蛋白表达减少，细胞内Ca²⁺浓度增加。差异表达基因KEGG富集在核因子-κB(NF-κB)信号通路、toll样受体(TLRs)信号通路和肿瘤坏死因子(TNF)信号通路等。培养上清组神经元凋亡率高于对照组。结论:S100A9可能通过激活TLR4/NF-κ...     

大鼠脑缺血后反应性星形胶质细胞异质性的形态学观察

星形胶质细胞异质性是指星形胶质细胞在形态结构、生理功能、胞质活性物质、对创伤的反应等方面存在的差异性。脑损伤后星形胶质细胞的活化是一种普遍现象,表现为星形胶质细胞胞体肥大、肿胀、突起增多延长、免疫组化染色GFAP表达增强等。为探讨脑缺血后不同脑区的星形胶质细胞的反应性变化的特征,本实验建立Wistar大鼠全脑缺血30分钟再灌注的模型,采用胶质纤维酸性蛋白(GFAP)单克隆抗体免疫组化方法观察了脑缺血再灌注1d、3d、5d、7d、10d后不同脑区内反应性星形胶质细胞的形态特征,结果如下:1脑缺血再灌注后第1～3d即可见轻度星形胶质…     

墨西哥钝口螈脊髓全切后胶质细胞的变化

背景：墨西哥钝口螈脊髓切断可以再生,再生过程伴随胶质细胞数目及分布的改变,研究墨西哥钝口螈脊髓全切后胶质细胞的变化,对进一步探讨其脊髓切断再生机制有重要意义。 目的：观察墨西哥钝口螈脊髓全切后小胶质细胞、星形胶质细胞及少突胶质细胞的变化。 方法：选用成年墨西哥钝口螈,分为脊髓全切组和对照组,利用免疫组织化学法观察脊髓全切后1,3和10 d的损伤脊髓及周围区cd11b标记的小胶质细胞、胶质细胞原纤维酸性蛋白标记的星形胶质细胞及髓鞘碱性蛋白标记的少突胶质细胞的变化。 结果与结论：脊髓全切后短期内cd11b染色阴性;脊髓损伤后胶质细胞原纤维酸性蛋白及髓鞘碱性蛋白阳性细胞染色强度,1 d组阳性细胞染色强度与对照组比较无显著差异,3及10 d组阳性细胞染色强度较对照组低。墨西哥钝口螈小胶质细胞染色阴性,可能存在不同于哺乳动物的标记蛋白;脊髓全切后3及10 d在损伤脊髓及周围区的胶质细胞原纤维酸性蛋白及髓鞘碱性蛋白阳性细胞染色强度较对照组低,提示钝口螈脊髓急性损伤早期未见星形胶质细胞及少突胶质细胞增生,无胶质瘢痕形成。     

肢体远程缺血后处理促进局灶性脑缺血再灌注大鼠皮质区热休克蛋白70的表达

目的　观察肢体远程缺血后处理（LRIP）对局灶性脑缺血再灌注损伤大鼠皮质梗死区周围神经元、血管内皮细胞以及星形胶质细胞热休克蛋白70（Hsp70）的表达变化,探讨LRIP发挥脑保护作用的可能分子机制。方法　健康成年SD大鼠,随机分为假手术组（sham）、局灶性脑缺血再灌注模型组（I/R）、LRIP组。实验采用线栓法建立局灶性大脑中动脉脑缺血(1h)再灌注模型(MCAO),大鼠脑缺血再灌注即刻行双下肢股动脉橡皮筋结扎10min,放松10min,重复3次建立LRIP组模型。于再灌注1d、3d分别断头取脑,Zea longa评分作为判断MCAO模型成功的标准,Garcia神经行为学评分方法检测大鼠神经损伤程度,TTC检测脑梗死体积,Western blotting检测Hsp70蛋白表达含量, 免疫组织化学和免疫荧光技术,用于检测皮质梗死区周围Hsp70阳性表达细胞的数目、部位以及类型。结果　应用LRIP后,LRIP组与I/R组比较,神经行为学评分明显增加（P<0.05）、脑梗死体积显著降低（P<0.05）,Hsp70蛋白表达明显增加,其中1d组无统计学意义（P>0.05）,3d组有显著统计学意义（P<0.01）,Hsp70阳性表达主要在梗死区周围神经元、血管内皮细胞和星形胶质细胞突起。结论　LRIP可明显改善脑缺血后神经行为学功能、降低脑梗死体积,根据本实验结果我们推测此作用可能与LRIP上调皮质梗死区周围神经元、血管内皮细胞和星形胶质细胞Hsp70表达有关。     

氧葡萄糖剥夺-再恢复后抑制小胶质细胞TLR9激活对神经元的保护作用

目的:观察氧葡萄糖剥夺-再恢复(OGDR)后小胶质细胞BV-2 Toll样受体9(TLR9)激活对神经元凋亡的影响。方法:对BV-2细胞或TLR9-siRNA转染的BV-2细胞进行OGDR处理4 h后,将细胞上清添加至OGDR处理4 h的小鼠原代皮层神经元中,继续正常培养24 h后,倒置显微镜下观察神经元形态变化,TUNEL染色检测神经元凋亡,Western blotting检测神经元caspase-3蛋白的表达。实验分为正常BV-2组、negative control-siRNA组、TLR9-siRNA组、OGDR组、OGDR+NC-siRNA组、OGDR+TLR9-siRNA组和对照组(神经元OGDR后不添加BV-2细胞上清)。结果:OGDR后神经元胞体肿胀,折光性下降,出现空泡样变,轴突变细、扭曲、断裂。TUNEL染色各组均可见绿染凋亡小体。与对照组比较,其它组的caspase-3蛋白表达升高(P0.05);与正常BV-2组比较,OGDR组和TLR9-siRNA组的caspase-3蛋白表达升高(P0.05);OGDR+TLR9-siRNA转染组与TLR9-siRNA转染组和OGDR组比较,caspase-3蛋白表达下降(P0.05)。结论:OGDR后BV-2细胞TLR9激活致神经元凋亡增多,caspase-3蛋白表达升高;抑制TLR9表达后,神经元损伤减轻。     

Upregulation of erbB receptors in rat brain after middle cerebral arterial occlusion

We have previously demonstrated that neuregulin-1 (NRG-1) is upregulated and is neuroprotective in ischemic brain injury, however the expression and localization of its receptors during ischemia has not been investigated. Therefore, we used a rat middle cerebral artery occlusion (MCAO) model to examine the distribution of erbB receptors following ischemic stroke. Like neuregulin-1, we observed a dramatic induction of erbB4 in the peri-infarct regions of the ipsilateral cortex 24 h following MCAO. Using Fluoro-Jade B (FJB) staining as a marker of neurodegeneration, erbB4 was upregulated in FJB-positive cells, suggesting that erbB receptors are induced in injured neurons. The increase in erbB receptors was seen in neurons and a subpopulation of macrophages/microglia. There was no erbB co-localization with GFAP-positive astrocytes. These results demonstrate that erbB receptors are upregulated in neurons and macrophages/microglia following ischemic stroke and may be involved in neuroprotection and repair.     

An immunohistochemical study of neuronal and glial cell reactions in retinae of rats with experimental glaucoma

Glaucoma is a common disease seen in the eye clinic, but its associated pathological processes, especially the role of glial cells in glaucomatous retinae, are still under debate. The aim of the present work was to study the responses of astrocytes, Müller cells and microglia in retinae of rats with experimental glaucoma. Glaucoma was induced in adult male Wistar rats by cauterizing limbal-derived veins and the changes in glial fibrillary acidic protein (GFAP), OX42, OX18, OX6 and EDI expression were studied by immunohistochemical staining. Neuronal cell viability was studied by immunostaining with the neuronal nuclei (NeuN) antibody. In the experimental glaucomatous eyes, a significant drop in the number of NeuN-positive neurons was observed from 7 days postoperation and beyond in both the ganglion cell layer and inner nuclear layer. The expression of GFAP and OX42 was increased during the first 2 months after operation and reduced in rats at 3 and 4 months. OX6 and OX18 immunoreactivity was induced in some microglia of both glaucomatous and sham-operated control eyes. Possible mechanisms of the reaction of astrocytes, Müller cells and microglia in neuronal degeneration following glaucoma are discussed.     

Effects of erythropoietin on glial cell development; oligodendrocyte maturation and astrocyte proliferation

We investigated the effects of erythropoietin (Epo) in glial cell development, especially the maturation of late stage immature oligodendrocytes and the proliferation of astrocytes. Epo mRNA level in oligodendrocytes was much more prominent than those in neurons or astrocytes, which were the same as those in the young adult kidney, while Epo receptor (Epo-R) mRNA level were almost the same among neural cells, kidney and liver tissues. On immunohistochemical examination, Epo-R expression was also detected in O4-positive immature oligodendrocytes and glial fibrillary acidic protein positive astrocytes. These results suggested that types of both glial cells are responsive to Epo. The numbers of mature oligodendrocytes, which are characterized by myelin basic protein and process development, were increased by treatment with recombinant human Epo (rhEpo) (0.001-0.1 U/ml). The maturation of oligodendrocytes was also enhanced by coculture with astrocytes in vitro. However, when mixed cultured cells (oligodendrocytes+astrocytes) were treated with anti-Epo antibody and/or soluble Epo-R, the differentiation of oligodendrocytes was partially inhibited. Interestingly, high dose rhEpo (1, 3, 10 U/ml) markedly enhanced the proliferation of astrocytes. These results suggested that Epo not only promotes the differentiation and/or maturation in oligodendrocytes, but also enhances the proliferation of astrocytes. It is generally accepted that astrocytes produce Epo, and therefore Epo might act on astrocytes in an autocrine manner. The astrocytes stimulated with Epo may further accelerate the maturation of oligodendrocytes. These comprehensive effects of Epo might also affect the ability of oligodendrocyte lineage cells to promote myelin repair in the normal and damaged adult central nervous system.     

Discrimination between different types of neuroglial cells in rat central nervous system using combined immuno- and enzyme-histochemical methods

The central nervous system (CNS) contains several types of neuroglial cells. In the present study, we characterized different types of glial cells in rat CNS by using single and combined immuno- and enzyme-histochemical methods, and immunofluorescence techniques. Two recently developed monoclonal antibodies (mAbs) against rat macrophages-associated antigens appeared to recognize a subpopulation of glial cells in the CNS of normal adult rats. These ED4- and ED8-positive glial cells were predominantly located in the white matter of adult rat CNS and shared morphological features with microglia. ED4 and ED8 were applied in a double staining combined with mAbs and an antiserum raised against galactocerebroside (GalC) to identify oligodendrocytes, or with anti-glial fibrillary acidic protein antiserum (GFA) to identify astrocytes. We also used a mAb against myelin basic protein (MBP) to identify oligodendrocytes. It appeared that ED4 and ED8 recognized a subpopulation of oligodendrocytes. MAbs against GalC and MBP recognized cells in an immunoperoxidase staining with a morphology identical to that of the ED8-positive cells and part of the ED4-positive cells. Frozen sections of Lewis rats CNS with acute experimental allergic encephalomyelitis (EAE) were investigated, where infiltrating brain macrophages could be found which stained positively with ED4 and ED8 as well as with the monocyte/macrophage mAbs ED1 and ED2. These brain macrophages did not stain when GalC, MBP and GFA markers were applied. Furthermore, ED4+GalC+ and ED8+GalC+ oligodendrocytes were present in the CNS white matter of EAE animals with similar appearance as in normal adult rats. With the currently used markers, we could not detect a third type of neuroglial cell, besides the astrocytes and oligodendrocytes. Thus, none of our anti-macrophage monoclonals recognized the presumptive microglia. Only under pathological conditions, e.g., in inflammatory infiltrates in the course of EAE, could brain macrophages be detected in the CNS parenchyma and only in the direct vicinity of blood vessels, indicating their hematogenous origin.     

The microglial cytoskeleton: vimentin is localized within activated cellsin situ

Summary Unlike astrocytes and oligodendrocytes, microglia are extremely plastic making them the chameleon among the glial cells in the CNS. This great mutability of the microglial cell shape suggests the presence of an elaborate cytoskeleton which is demonstrated here by applying a new ultrastructural method. Electron microscopic immunocytochemistry shows the presence of vimentin at intermediate filament sites in reactive microglia stimulated by rat facial nerve axotomy. It is suggested that vimentin-expression may serve as a marker for activated states of microglia, including brain macrophages.     

Heme oxgenase-1 is expressed in viable astrocytes and microglia but in degenerating pyramidal neurons in the kainate-lesioned rat hippocampus

The present study aimed to elucidate the distribution of heme oxygenase-1 (HO-1) in the hippocampus after intracerebroventricular injections of kainate. Very little or no staining of HO-1 was observed in the normal CA1, whilst moderate staining of dentate hilar neurons was observed in the dentate gyrus, in the normal hippocampus. At postinjection day 1, a slight increase in immunoreactivity in the neuropil of the lesioned CA fields and a marked increase in HO-1 immunoreactivity in glial cells of the stratum lacunosum moleculare of CA fields and the stratum moleculare of the dentate gyrus was observed. Electron microscopy showed that the glial cells had features of viable astrocytes. At postinjection day 3, glial cells in the dentate gyrus continued to express HO-1, whilst pyramidal neurons in the degenerating CA fields started to express intense HO-1 immunoreactivity in their cell bodies. At postinjection weeks 1–3, HO-1 was observed in glial cells in the center of the lesion, but also in neurons at the perifocal region of the glial scar. The glial cells were found to have features of viable astrocytes and microglia, whilst the neurons contained discontinuous cell membranes and nuclear outlines, and had features of degenerating neurons. Intense immunoreactivity was observed in the cytoplasm of the degenerating neurons. The density of staining was greater than that observed in astrocytes or microglia. Recent in vitro results on fibroblasts transfected with HO-1 cDNA showed that, despite cytoprotection with low (less than fivefold compared with untransfected cells) HO-1 activity, high levels of HO-1 expression (more than 15-fold) were associated with significant oxygen toxicity. These and the present observations suggest a destructive effect of increased expression of HO-1 in neurons, and possible novel therapeutic approaches involving overexpression of HO-1 must therefore be approached with caution. Electronic Publication     

Patterns of glial development in the human foetal spinal cord during the late first and second trimester

Summary Although the presence of radial glia, astrocytes, oligodendrocytes and microglia has been reported in the human foetal spinal cord by ten gestational weeks, neuroanatomic studies employing molecular probes that describe the interrelated development of these cells from the late first trimester through the late second trimester are few. In this study, immunocytochemical methods using antibodies to vimentin and glial fibrillary acidic protein were used to identify radial glia and/or astrocytes. An antibody to myelin basic protein was used for oligodendrocytes and myelin; and, an antibody to phosphorylated high and medium molecular weight neurofilaments identified axons. Lectin histochemistry usingRicinus communis agglutinin-I was employed to identify microglia. Vibratome sections from 35 human foetal spinal cord ranging in age from 9–20 gestation weeks were studied. By 12 gestational weeks, vimentin-positive radial glia were present at all three levels of the spinal cord. Their processes were easily identified in the dorsal two-thirds of cord sections, and reaction product for vimentin was more intense at cervical and thoracic levels than lumbosacral sections. By 15 gestational weeks, vimentin-positive processes were radially arranged in the white matter. At this time, glial fibrillary acidic protein-positive astrocytes were more obvious in both the anterior and anterolateral funiculi than in the dorsal funiculus, and the same rostral to caudal gradient was seen for glial fibrillary acidic protein as it was for vimentin. Myelin basic protein expression followed similar temporal and spatial patterns.Ricinus communis agglutinin-I labelling revealed more microglia in the white matter than in grey matter throughout the spinal cord from 10–20 gestational weeks. By 20 gestational weeks, the gradients of glial fibrillary acidic protein and vimentin expression were more difficult to discern. White matter contained more microglia than grey matter. These results suggest that astrocytes as well as oligodendrocytes follow anterior-to-posterior and rostral-to-caudal developmental patterns in the human foetus during middle trimester development.     

Endothelins-1/3 and endothelin-A/B receptors expressing glial cells with special reference to activated microglia in experimentally induced cerebral ischemia in the adult rats

We reported previously that amoeboid microglial cells (AMC) in the developing brain exhibited endothelins (ETs) expression which diminished with advancing age and was undetected in microglia in the more mature brain. This study sought to explore if microglia in the adult would be induced to express ETs in altered conditions. By immunofluorescence microscopy, ETs and endothelin (ET)-B receptor were undetected in microglial cells in sham-operated and normal control rats. However, in adult rats subjected to middle cerebral artery occlusion (MCAO), lectin labeled activated microglia which occurred in large numbers in the marginal zones in the ischemic cortex at 3 days and 1 week intensely expressed ETs specifically endothelin (ET)-1 and ET-B receptor; ET-3 and ET-A receptor were absent in these cells. By RT-PCR and ELISA, ET-1 and -3 mRNA and protein expression level was progressively increased in the ischemic cerebral cortex after MCAO compared with the controls. ET-A and ET-B receptor mRNA and protein levels were concomitantly up-regulated. It is suggested that increased release of ET-1 following MCAO by massive activated microglia can exert an immediate constriction of local blood vessels bearing ET-A receptor. ET-1 may also interact with activated microglia endowed with ET-B receptor via an autocrine manner that may be linked to chemokines/cytokines production. ET-1, ET-3 and ET-B receptor were also localized in reactive astrocytes along with some oligodendrocytes. We conclude that activated microglia together with other glial cells in the marginal zone after MCAO are the main cellular source of ETs that may be involved in regulation of vascular constriction and glial chemokines/cytokines production. However, dissecting the role of individual component of the endothelin system in the various glial cells, notably activated microglia, would be vital in designing of an effective therapeutic strategy for clinical treatment of stroke in which microglial cells have been implicated.     

PGRN阳性神经细胞在新生大鼠大脑皮层内的分布

目的:观察颗粒蛋白(progranulin,PGRN)阳性细胞在新生大鼠大脑皮层内的分布和PGRN在新生鼠大脑皮层神经元、星形胶质细胞和少突胶质细胞中的表达情况,探讨PGRN在新生鼠早期神经发育中的作用。方法:制备新生SD大鼠(1、7 d)脑组织切片,采用PGRN多克隆抗体进行免疫荧光组织化学染色法检测PGRN在新生鼠脑内的表达部位,免疫荧光组织化学双标法检测PGRN在新生鼠皮层内不同细胞中的定位。结果:新生鼠大脑皮质、侧脑室周围、胼胝体及海马中均表达PGRN。PGRN主要在新生鼠皮层内神经元中表达,而在星形胶质细胞和少突胶质细胞中几乎不表达。结论:新生鼠脑内表达PGRN,在大脑皮层内不同细胞表达模式有所不同,提示PGRN可能参与大鼠神经发育早期过程。     

Effect of pitavastatin against expression of S100beta protein in the gerbil hippocampus after transient cerebral ischaemia

AIM AND METHODS: We investigated the immunohistochemical alterations of S100beta-, S100-, glial fibrillary acidic protein (GFAP)- and isolectin B4-positive cells in the hippocampus after 5 min of transient cerebral ischaemia in gerbils. We also examined the effect of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitor pitavastatin against neuronal damage in the hippocampal CA1 sector after ischaemia. RESULTS: Severe neuronal damage was observed in the hippocampal CA1 pyramidal neurons from 5 days after ischaemia. GFAP-positive cells increased gradually in the hippocampus from 5 days after ischaemia. Five and 14 days after ischaemia, significant increases in the number of GFAP-positive cells and isolectin B4-positive cells were observed in the hippocampal CA1 and CA3 sector. Mild increases in the number of S100 and S100beta-positive cells were observed in the hippocampal CA1 sector from 1 h to 2 days after ischaemia. Thereafter, S100beta-positive cells increased in the hippocampal CA1 sector after ischaemia, whereas S100-positive cells decreased in this region. In our double-labelled immunostainings, S100 and S100beta immunoreactivity was found in GFAP-positive astrocytes, but not in isolectin B4-positive microglia. Pharmacological study showed that HMG-CoA reductase inhibitor, pitavastatin, can protect against the hippocampal CA1 neuronal damage after ischaemia. This drug also prevented increases in the number of GFAP-positive astrocytes, isolectin B4-positive microglia, S100-positive astrocytes and S100beta-positive astrocytes after ischaemia. CONCLUSION: The present study demonstrates that pitavastatin can decrease the neuronal damage of hippocampal CA1 sector after ischaemia. This beneficial effect may be, at least in part, mediated by inhibiting the expression of astrocytic activation in the hippocampus at the acute phase after ischaemia. Thus the modulation of astrocytic activation may offer a novel therapeutic strategy of ischaemic brain damage.