电刺激治疗对脑梗死后运动功能及星形胶质细胞活性的影响

目的　观察电刺激治疗对大鼠脑梗死后运动功能和脑星形胶质细胞活性的影响 ,方法　易卒中型肾血管性高血压大鼠 (RHRSP)右侧大脑中动脉闭塞后 ,电刺激其瘫痪肢体的 4个穴位 ,以走横木试验 (BWT)评价大鼠的精细运动功能恢复情况 ,免疫组化法观察脑星形胶质细胞活性。结果　经电刺激治疗的大鼠 ,运动功能的恢复较对照组明显改善 (P<0 0 1) ;电刺激治疗组在坏死边缘区 (A区 )和远隔区 (B)星形胶质纤维酸性蛋白 (GFAP)表达均较对照组高 ;GFAP阳性细胞浆平均光密度值变化情况与GFAP表达变化基本相同。结论　电刺激可通过增强星形胶质细胞活性而促进瘫痪肢体功能恢复。脑梗死后星形胶质细胞在其修复中起了重要的作用。     

RNA干扰抑制马桑内酯诱导的大鼠星形胶质细胞Mdr1基因的表达

目的观察RNA干扰对培养的大鼠星形胶质细胞逆转P-糖蛋白介导的多药耐药现象的影响。方法用短发夹RNA表达载体p-SIREN shuttle质粒转染马桑内酯诱导表达P-糖蛋白的星形胶质细胞，荧光定量聚合酶链反应（PCR）测定Mdr1 mRNA的表达量，免疫细胞化学方法检测P-糖蛋白表达的变化，流式细胞术检测转染前后细胞罗丹明蓄积外排的变化。结果建立表达P-糖蛋白的星形胶质细胞模型，有效地将p-SIREN shuttle质粒转染该细胞模型。转染后实验组细胞Mdr1 mRNA水平被抑制达67．70％，P-糖蛋白表达明显低于对照组（P〈0．01），实验组P-糖蛋白作用底物罗丹明的细胞外泵出率（23．08％）明显低于对照组（78．35％，P〈0．01）。结论RNA干扰对马桑内酯诱导的星形胶质细胞Mdr1表达有明显抑制作用，并且在很大程度上逆转多药耐药蛋白的耐药作用。     

Connexin 43 regulates astrocytic migration and proliferation in response to injury

Marked alterations in astrocyte function are a universal response to disease or injury in the central nervous system. Affected astrocytes develop characteristic morphological changes known as “reactive astrogliosis”, characterized by increased expression of the intermediate filament proteins, glial fibrillary acidic protein and vimentin. Reactive astrocytes also display alterations in other proteins including a rapid up-regulation of the gap junction protein, Connexin 43. The present study tests whether Connexin 43 is directly involved in the astrocytic response to injury. We have down regulated Connexin 43 expression using a microRNA generating plasmid and investigated the functional consequences of this treatment on the response of astrocytes in primary culture to a well-characterized scratch wound injury. The treatment resulted in more than 70% transfection efficiency and a near complete depletion of Connexin 43 in transfected cells. Compared to cells transfected with non-targeting microRNA, the cells depleted of Connexin 43 showed a slower wound closure and fewer transfected cells in the wound area. These changes were associated with decreased proliferation of the Connexin 43-depleted cells as well as shorter processes extending into the wound area suggesting a direct impairment of migration. The effects were independent of gap junction conductivity as exposure to the gap junction blocker carbenoxolone did not affect the rate of wound healing. The findings directly indicate a role for Connexin 43 in the astrocytic response to injury and suggest that modification of Connexin 43 expression might provide a therapeutic target to alter potentially deleterious astrocytic responses.     

Neuronal-glial Interactions Define the Role of Nitric Oxide in Neural Functional Processes

Nitric oxide (NO) is a versatile cellular messenger performing a variety of physiologic and pathologic actions in most tissues. It is particularly important in the nervous system, where it is involved in multiple functions, as well as in neuropathology, when produced in excess. Several of these functions are based on interactions between NO produced by neurons and NO produced by glial cells, mainly astrocytes and microglia. The present paper briefly reviews some of these interactions, in particular those involved in metabolic regulation, control of cerebral blood flow, axonogenesis, synaptic function and neurogenesis. Aim of the paper is mainly to underline the physiologic aspects of these interactions rather than the pathologic ones.     

两型星形胶质细胞基因表达谱差异的初步观察

目的:研究不同型别星形胶质细胞的基因表达谱,比较1型和2型星形胶质细胞基因表达谱之间的差异,以进一步研究两者的生物学特性及其功能。方法:原代培养新生SD大鼠大脑皮质混合胶质细胞,经振荡和差速消化纯化培养1型星形胶质细胞(T1A)和2型星形胶质细胞(T2A);应用基因芯片技术获取T1A和T2A的基因表达谱,并对两者的基因表达谱进行初步分析。结果:基因芯片上检测点4096个,共有差异表达基因267条,其中113条在T1A中高表达,154条在T2A中高表达。结论:本实验获得大鼠大脑T1A和T2A的基因表达谱,首次报道267条存在于T1A和T2A之间的差异表达基因。     

Expression of intercellular adhesion molecule (ICAM)-1 by a subset of astrocytes in Alzheimer disease and some other degenerative neurological disorders

Summary Intercellular adhesion molecule-1 (ICAM-1) was localized immunohistochemically in postmortem brain tissue of Alzheimer's disease (AD), progressive supranuclear palsy, amyotrophic lateral sclerosis, Pick's disease, and controls. In controls, only capillaries were stained for ICAM-1. In affected areas of neurologically disease brains, a subset of reactive astrocytes was also strongly stained. In addition, there were irregular, diffuse patches of positive staining in the tissue matrix. In AD, many of these patches had dense cores which corresponded with senile plaques. Double immunostaining for glial fibrillary acidic protein and ICAM-1 indicated that some reactive astrocytes at the periphery of senile plaques were positive for ICAM-1. Within such plaques, microglial aggregates were stained intensely for leukocyte function-associated antigen-1 (LFA-1), the adhesion molecule for ICAM-1. The LFA-1/ICAM-1 system appears to play an important role in the interaction of astrocytes and microglia in several neurological diseases.Supported by grants from the Foundation for Total Health Promotion (HA), the Sasakawa Research Foundation (HA), the Alzheimer Society of B.C. and the MRC of Canada, as well as donations from individual British Columbians     

Periventricular astrocytosis and acute necrotizing encephalitis

Summary A group of rats presented with acute necrotizing encephalitis. The histopathological picture was the same in all the animals yet the periventricular regions where no morphologically appreciable signs of necrosis or infection could be found, presented with a florid astrocytic response. This periventricular astrocytosis was undetected with standard morphological methods but well-demonstrated with histoenzymatic techniques. It is presumed that these astrocytes originated in the ependyma with a possible cellular contribution from the choroid plexus.This work was done while in tenure of a Clinical Research Fellowship of the Medical Research Council (England) in the Royal Postgraduate Medical School, Lodon.     

Identification of cell-surface antigens present exclusively on a sub-population of astrocytes in human foetal brain cultures

We have examined two monoclonal antibodies (McAbs; coded MI/N1 and 308) raised to human neuroblastoma cells for cell-type-specific reactivity in cultures of human neural tissues and in frozen sections of intact primate spinal cord. In dual-label immunofluorescence assays using established cell-type antigenic markers as positive controls, the reactivity patterns obtained with both McAbs MI/N1 and 308 were consistent with the detection of astrocyte-specific cell-surface antigens. No reactivity of the antibodies with other human neural cell-types, or with human muscle cells was detected. In cultures of human foetal brain a sub-population of astrocytic cells remained unlabeled by antibodies MI/N1 and 308. The significance of the latter observation has not yet been defined but may represent a developmental or functional division within the astrocytic cell lineage.