黏附分子CD44在实验性自身免疫性脑脊髓炎中的作用

目的探讨黏附分子CD44在实验性自身免疫性脑脊髓炎(EAE)发病中的作用。方法将20只大鼠随机分为正常对照组及EAE组,EAE组采用粗制髓鞘碱性蛋白(MBP)抗原注入大鼠后足掌皮下(0. 2 ml/100 g)制作EAE模型,观察大鼠的发病情况及病理表现;并采用免疫组织化学法检测两组大鼠脑组织CD44的含量。结果正常对照组大鼠未发病,EAE组大鼠均有不同程度的发病。HE染色后,光镜下观察,正常对照组大鼠脑和脊髓无异常; EAE组大鼠可见脑及脊髓实质内小血管充血,小静脉周围有大量炎性细胞浸润,血管周围白质脱髓鞘改变。免疫组化显示,正常对照组大鼠脑和脊髓组织未发现CD44阳性细胞; EAE组大鼠中枢神经系统(CNS)白质及灰白质交界处可见大量CD44阳性细胞。结论 EAE模型中存在黏附分子CD44的高表达,其对EAE的发病可能起到促进作用。     

黏附分子CD44介导的雌激素对实验性变态反应性脑脊髓炎大鼠保护作用的研究

目的 探讨雌激素对实验性变态反应性脑脊髓炎（EAE）大鼠的保护作用及其与黏附分子CD44的关系。方法 将40只大鼠随机分为4个组：正常对照组、EAE组、大小剂量雌激素治疗组,每组10只。观察大鼠发病情况及脑组织病理变化,并采用免疫组织化学法检测各组大鼠脑组织CD44的含量。结果 EAE组及大小剂量雌激素治疗组大鼠均有不同程度的发病,但大小剂量雌激素治疗组EAE临床症状均较EAE组轻。免疫组织化学显示,EAE组及大小剂量雌激素治疗组大鼠中枢神经系统（CNS）白质及灰白质交界处可见不同程度的CD44阳性细胞表达。图像分析结果显示,与EAE组比较,大小剂量雌激素治疗组CNS白质CD44表达水平均明显降低（P<0.01）;与小剂量雌激素治疗组比较,大剂量雌激素治疗组CNS白质的CD44表达水平显著降低（P<0.01）。结论 多发性硬化动物模型EAE大鼠中存在黏附分子CD44的高表达,雌激素可能通过抑制黏附分子CD44的表达而发挥对EAE大鼠的保护作用。     

左旋咪唑对实验性自身免疫性脑脊髓炎大鼠脊髓内CD4 、CD8、CD28和CD152表达的影响

目的 探讨左旋咪唑（Levamisole,LMS）对实验性自身免疫性脑脊髓炎（experimental autoimmune encephalomyelitis，EAE）大鼠脊髓内单个核细胞CD4、CD8、CD28及CD152表达的影响及其意义。方法 采用临床症状评分、病理学检查和流式细胞术，观察LMS处理和非处理条件下豚鼠全脊髓匀浆诱导的Wistar大鼠EAE临床表现、病理改变及脊髓内单个核细胞CD4、CD8、CD28及CD152分子表达水平。结果 LMS同时给药促发组和预处理组EAE大鼠脊髓内单个核细胞CD4、CD28表达水平明显高于非LMS处理的EAE模型组（P〈0．01），病理变化更加明显。而CD8、CD152表达水平差异无统计学意义。结论 LMS可促进EAE大鼠脊髓内单个核细胞CD4、CD28的表达，提示LMS上调CD4、CD28的表达可能与LMS诱发炎性脱髓鞘白质脑病有关。     

实验性自身免疫性脑脊髓炎大鼠脑神经干细胞的增殖

目的通过建立实验性自身免疫性脑脊髓炎动物模型,检测EAE神经干细胞的增殖。方法以豚鼠脑脊髓匀浆加完全弗氏佐剂作为抗原．给予Wistar大鼠四足垫皮内注射,建立EAE模型,对正常组、免疫后7d组、EAE发病后3,7,14,21d组,分别进行5一溴脱氧尿嘧啶（BrdU）免疫组织化学染色,以观察正常大鼠脑内Brdu、EAE免疫损伤后BrdU的变化规律。结果在正常组大鼠,Brdu阳性细胞主要分布在室管膜下区（SVz）及海马齿状回的颗粒层（SGZ）;Brdu阳性细胞教在免疫后呈现先上升后下降的变化趋势,于发病后3d达高峰,21d恢复正常。结论EAE可以诱导大鼠脑内神经干细胞的增殖。     

Wistar大鼠实验性自身免疫性脑脊髓炎模型的建立

目的:建立Wistar大鼠实验性自身免疫性脑脊髓炎(experimental autoimmune encephalo-myelitis,EAE)模型,并检测可溶性血管细胞黏附分子-1(soluble vascular cell adhesion molecule-l,sVCAM-1)在EAE大鼠中的动态表达。方法:将豚鼠麻醉后,不用磷酸盐缓冲液(PBS)灌注,直接取新鲜豚鼠全脊髓制备匀浆(Guinea Pig Spinal Cord Homoge-nate,GPSCH)为抗原,免疫Wistar大鼠建立EAE的动物模型。观察其体重及神经功能评分的变化;取脑、脊髓组织石腊包埋,病理切片,光镜观察;采用双抗体夹心法酶联免疫吸附实验(ELISA)检测血清中sVCAM-1的表达。结果:Wist-ar大鼠在免疫后10天出现明显的神经系统体征,发病率达100%;脑脊髓组织可见血管周围炎细胞呈袖套样浸润;sV-CAM-1的表达与对照组比较有显著性升高(P<0.01)。结论:采用非灌注法制备的豚鼠全脊髓匀浆作为抗原,能够成功诱发Wistar大鼠的EAE模型,为研究多发性硬化(multiple sclerosis,MS)的发病机制及治疗奠定了一定的基础。     

实验性变态反应性脑脊髓炎的病理研究

目的　研究实验性变态反应性脑脊髓炎 (EAE)的病理变化。方法　利用光镜、电镜观察豚鼠 EAE模型的组织学改变。结果　光镜下可见脑实质及珠网膜下腔小血管充血 ,血管周围炎细胞浸润 ,呈“袖套”状改变 ,侧脑室旁白质及脊髓后联合、侧角出现髓鞘肿胀、崩解或消失。电镜下可见血管周围明显脱髓鞘 ,髓鞘呈松散状 ,部分区域斑块状脱落 ,明暗相间结构消失 ,轴突细胞器消失 ,神经元细胞尼 (氏 )小体消失 ,内质网扩张脱颗粒。结论　 EAE的病理改变主要为血管周围炎性浸润及白质脱髓鞘。     

热休克预处理对实验性自身免疫性脑脊髓炎神经细胞凋亡的影响及其机制研究

目的观察热休克预处理（HSP）后实验性自身免疫性脑脊髓炎（EAE）大鼠热休克蛋白70（HSP70）和核因子-KB（NF-KB）的表达及对神经细胞凋亡的影响，探讨其对EAE模型的神经保护作用。方法36只Wistar大鼠随机分为对照组（CON），EAE组和HSP组。EAE组制作成EAE模型；HSP组先给予HSP，24h后再制作成EAE模型；CON组不行特殊处理。观察大鼠神经症状．进行神经功能评分。于免疫后14-17d处死动物，取脊髓行HE染色，检测HSP70、NFKB免疫组化表达及神经细胞的凋亡。结果CON组大鼠没有发病。与EAE组大鼠比较，HSP组大鼠发病率显著降低，起病时间显著延迟，神经功能评分显著降低（均P〈0．05）。EAE组体重增加值较CON组明显减低，HSP后大鼠体重增加值较EAE组显著增加（p〈0．05）。脊髓病理显示HSP组炎性病灶数较EAE组显著减少（p〈0．05）。HSP组与EAE组相比，脊髓内HSP70阳性细胞数显著增加，NF-KB阳性细胞数显著减少，神经细胞凋亡显著抑制（均P〈0．01）。结论HSP对EAE大鼠具有一定的神经保护作用，其机理可能与HSP70表达增加，NF—KB表达受抑制从而导致神经细胞凋亡减少有关。     

Wistar大鼠实验性变态反应性脑脊髓炎的模型建立

目的:建立Wistar大鼠多病程实验性变态反应性脑脊髓炎(EAE)的动物模型,并进行病理学研究,为多发性硬化(MS)的研究提供实验依据。方法:以豚鼠全脊髓匀浆(GPSCH)为抗原免疫Wistar大鼠建立EAE的动物模型,并在光镜下观察不同发病类型EAE的病理改变。结果:根据病理和临床表现可将Wistar大鼠EAE模型分为5种发病形式:急性型、缓解-复发型、持续进展型、良性型和隐匿型。光镜下可见不同发病时期的EAE的病理改变有所不同,但都以血管"袖套"状改变、脑室周围及白质脱髓鞘改变为主,伴有神经元肿胀变性。结论:首次建立了Wistar大鼠多病程EAE,是研究多发性硬化的理想动物模型。     

胞浆型磷脂酶A2在实验性自身免疫性脑脊髓炎小鼠脊髓中的表达

目的研究胞浆型磷脂酶A2（cPLA2）在实验性自身免疫性脑脊髓炎（EAE）小鼠发病不同时期的表达。方法8～10周龄的雌性C57BL／6小鼠30只随机分为2组，EAE组（n=20）以髓鞘少突胶质细胞糖蛋白（MOG）35-55多肽加福氏完全佐剂皮下注射诱发EAE，对照组（n=10）则用PBS液取代MOG35-55多肽。用免疫组织化学方法观察EAE小鼠发病后第0天（初期）、第7天（高峰期）及第30天（恢复期）脊髓中cPLA2的表达情况。结果cPLA2在EAE发病初期及高峰期脊髓内表达明显增多，初期在绝大多数血管内皮细胞中表达，高峰期时血管周围炎性细胞中表达相对增多，恢复期时表达下调；对照组小鼠脊髓中则没有cPLA2表达。结论cPLA2在EAE发病不同时期表达存在差异，可能与EAE发生及发展有密切联系。     

苦参素对实验性自身免疫性脑脊髓炎大鼠脑内神经干细胞增值的影响

目的观察苦参素对实验性自身免疫性脑脊髓炎(EAE)大鼠的治疗作用及对脑内神经干细胞标志物-巢蛋白Nestin、转录因子Sox-2表达的影响,探讨苦参素对EAE大鼠的治疗机制。方法将60只雌性Wistar大鼠随机分为正常组、模型组和治疗组,每组20只。用新鲜豚鼠全脊髓匀浆免疫诱导建立EAE模型,自免疫后第11天(发病初期)起,治疗组大鼠每日腹腔注射苦参素6.70 ml/kg(250 mg/kg),同时正常组与模型组注射等量生理盐水。每天观察并记录大鼠的体重变化及神经功能学评分。给药1 w后将大鼠处死,取脊髓和大脑,免疫组织化学法检测脑内Nestin的表达,RT-PCR法测定脑内SOX-2含量的变化。结果与模型组相比,治疗组大鼠神经功能评分明显降低,Nestin阳性细胞数和SOX-2的表达均显著增加(P0.05)。结论苦参素对EAE大鼠有治疗作用,其机制可能与增加中枢神经系统中神经干细胞的数量有关。     

Upregulation of β-1,4-Galactosyltransferase I in Rat Spinal Cord with Experimental Autoimmune Encephalomyelitis

Inflammatory infiltration has been recently emphasized in the demyelinating diseases of the central nervous system including multiple sclerosis. β-1,4-Galactosyltransferase I (β-1,4-GalT-I) is a major galactosyltransferase responsible for selectin–ligand biosynthesis, mediating rolling of the inflammatory lymphocytes. In the present study, Western blot showed that expression of β-1,4-GalT-I was low in normal or complete Freund’s adjuvant (CFA) control rats’ spinal cords, and it began to increase since early stage and peaked at E4 stage of experimental autoimmune encephalomyelitis (EAE) and restored approximately at normal level in the recovery stage. Immunohistochemisty revealed that upregulation of β-1,4-GalT-I was predominantly distributed in the white matter of spinal cord , while there was also some increased staining of β-1,4-GalT-I in the grey matter. Meanwhile, the expression of E-selectin, the substrate of β-1,4-GalT-I, was significantly increased, with a peak at E4 stage of EAE, and gradually decreased thereafter. Lectin blot showed that the protein bands with molecular weights of 65–25 kDa reacted a remarkable increase at the peak stage of EAE when compared with the normal and CFA control. Ricinus Communis Agglutinin-I (RCA-I) histochemistry revealed that RCA-Ι-positive signals were most intense in white matter of lumbosacral spinal cord at the peak stage of EAE (E4). Immunohistochemistry showed that β-1,4-GalT-I and CD62E, a marker for E-selectin stainings located in a considerable number of ED1 (+) macrophages in perivascular or in the white matter in EAE lesions, and a good co-localization of ED1 (+) cells with CD62E was observed. All these results suggest that β-1,4-GalT-I might serve as an inflammatory mediator regulating adhesion and migration of inflammatory cells in EAE, possibly through influencing the modification of galactosylated carbohydrate chains to modulate selectin–ligand biosynthesis and interaction with E-selectin.     

粘附分子在实验性变态反应性脑脊髓炎发生中的作用

目的 探讨粘附分子ＣＤ１１ａ，ＣＤ５４，ＣＤ６２在实验性变态反应性脑脊髓炎（ＥＡＥ）发生中的作用。方法 采用Ｗｉｓｔａｒ大鼠建立了ＥＡＥ动物模型，应用免疫荧光法检测下沉大鼠及ＥＡＥ动物周围血和脑组织中Ｔ细胞亚群及ＣＤ１１ａ，ＣＤ５４，ＣＤ６２的表达，结果 发病大鼠脑组织局灶周围大量淋巴细胞浸润，主要为ＣＤ４Ｔ细胞，发病大鼠周围血淋巴细胞上及大鼠脑组织粘附分子的表达明显升高，结论 粘附分子ＣＤ１１ａ     

Localization of the CD44 glycoprotein to fibrous astrocytes in normal white matter and to reactive astrocytes in active lesions in multiple sclerosis.

The CD44 antigen is a proteoglycan recently implicated in several adhesion events including that of lymphocytes to endothelium. The CD44 antigen, reactive with monoclonal antibody (MAb) 44D10, has been shown previously to be expressed in normal human white matter homogenates and to be found at higher concentrations in brain homogenates of victims of multiple sclerosis (MS). The cellular localization of CD44 in human brain of normal individuals and in those afflicted with MS has now been determined. Monoclonal antibody 44D10 reacted with astrocyte-like cells in 40 microns thick paraformaldehyde-fixed sections but not in thin (6 microns) fixed sections. A double labeling experiment performed on a frozen brain section with MAb 44D10 and rabbit anti-glial fibrillary acidic protein (GFAP), a cytoplasmic marker of astrocytes, confirmed the co-localization of these two antigens. The reactivity with brain tissue sections of a rabbit antiserum produced against lymphocyte-CD44 could be absorbed by a preparation of the CD44 glycoprotein, purified 2,100-fold from a white matter homogenate. The antiserum was shown by Western blot analysis to be specific for p80 glycoprotein in brain extracts derived from a normal and MS patients. This antibody reacted with fibrous astrocytes predominantly in white matter; staining was also noted in subependymal and subpial regions. Inhibition studies using a cellular radioimmunoassay indicated that the highest concentrations of CD44 in three MS victims were found in plaques, followed by periplaques and non-involved areas of white matter which were higher than normal white matter. Reactive astrocytes, identified in active lesions, expressed high levels of CD44 on their surfaces. Thus, CD44 is associated with astrocytes in human brain and the increased expression observed in MS brain may reflect activation and/or proliferation of astrocytes implicated in the pathogenesis of this disease.     

实验性自身免疫性脑脊髓炎小鼠脑内主要组织相容性复合体Ⅱ类抗原和分化群3ε的变化

目的观察实验性自身免疫性脑脊髓炎(EAE)小鼠脑内主要组织相容性复合体Ⅱ类抗原(MHC-Ⅱ)和分化群3ε(CD3ε)的变化。方法 25只C57BL/6小鼠随机分为EAE组(n=13)和正常对照组(n=12)。应用髓鞘少突胶质细胞糖蛋白35-55抗原诱导小鼠EAE模型。观察记录小鼠行为学变化;采用常规及髓鞘染色方法观察脊髓损伤和炎症细胞浸润程度;荧光定量PCR检测脑MHC-Ⅱ和CD3εmRNA的表达。结果 EAE组小鼠发病后EAE症状评分逐渐增加;脊髓炎症细胞浸润明显;髓鞘脱失较多;脑组织MHC-Ⅱ和CD3εmRNA表达显著高于正常对照组(均P<0.01),并与EAE症状评分呈正相关。结论 EAE小鼠脑内MHC-Ⅱ及CD3εmRNA表达水平增高与其病情严重程度一致。     

The subarachnoid space as a site for precursor T cell proliferation and effector T cell selection in experimental autoimmune encephalomyelitis

To characterize the phenotype of inflammatory cells in the central nervous system (CNS) in experimental autoimmune encephalomyelitis (EAE), Lewis rats were immunized with guinea pig myelin basic protein and frozen sections of the spinal cord with EAE were examined immunohistochemically using a panel of monoclonal antibodies against T cells and adhesion molecules. In addition, double immunostaining was performed with glial and T cells markers to examine the interaction between infiltrating T cells and reactive brain cells during the course of EAE. In the early stage of EAE, inflammatory cells first appeared in the subarachnoid space (SAS) and infiltrated the subpial region. The majority of inflammatory cells in SAS expressed TCRaβ and either CD4 or CD8 molecules. However, only CD4⁺ T cells infiltrated the parenchyma while the majority of CD8⁺ cells remained in SAS. A similar differential localization of T cells was observed with regard to CD45RC molecules. Inflammatory cells in SAS consisted of both CD45RC⁺ and CD45RC^- population, while those in the parenchyma were largely CD45RC˜. With regard to adhesion molecules, the leptomeninges constitutively expressed fibronectin (FN) and intercellular adhesion molecule 1 (ICAM-1). Most SAS inflammatory cells expressed very late activation antigen 4 (VLA-4) and, to lesser extent, lymphocyte function-associated antigen 1 (LFA-1) in the early stage of EAE. On the other hand, parenchyma! infiltrating cells expressed LFA-1 more strongly in the peak stage. Double staining for Vβ8.2 TCR and microglia demonstrated an increase in the number of microglia together with morphological changes into rod-shape cells in the vicinity of infiltrating T cells. Furthermore, these cells expressed adhesion molecules, such as LFA-1, ICAM-1 and CD4. These findings suggest that VLA-4/FN and LFA-1/ICAM-1 interactions between infiltrating cells and brain cells may be involved in the early and peak stages of EAE. Phenotype switching occurring in the process of inflammatory cell infiltration may be regulated by these adhesion molecules and factor(s) provided by the parenchyma, possibly by microglia.     

Nogo-A and Nogo-A receptor expression in periventricular white matter of experimental autoimmune encephalomyelitis rats

BACKGROUND:Previous studies have focused on the correlation between Nogo-A expression and multiple sclerosis or between Nogo-A receptor (NgR) expression and multiple sclerosis in the central nervous system. Expression patterns of Nogo-A and NgR remain poorly understood in rat models of experimental autoimmune encephalomyelitis (EAE).OBJECTIVE:To observe dynamic changes in Nogo-A and NgR protein expression, and to verify the correlation between Nogo-A and NgR protein, as well as expression patterns at various time points, in periventricular tissue of EAE rats.DESIGN, TIME AND SETrlNG:A neuroimmunological, randomized, controlled experiment was performed at the Clinical Institute of Hunan People's Hospital of China from September to November 2008.MATERIALS:Immunohistochemistry (streptavidin-biotin-peroxidase complex method) kit was purchased from Boster, China.METHODS:A total of 60 female, Wistar rats, aged 6-8 weeks, ware randomly assigned to EAE and control groups (n = 30, respectively). Guinea pig spinal cord homogenate, self-made complete Freund's adjuvant (0.2 mL/100 g), and pertussis vaccine (0.2 mL) were subcutaneously injected into the hindlimb foot pad of rats from the EAE group to create rat models of EAE. Complete Freund's adjuvant (0.2 mL) was infused into rats from the control group.MAIN OUTCOME MEASURES:Nogo-A and NgR protein expression was determined in periventricular white matter using immunohistochemical methods. Neurological scores ware determined in all rats.RESULTS:Rats from the EAE group developed acute-onset EAE following immunization. The pathogenetic symptoms reached a peak on day 15, and neurological scores ware also greatest at this time point. Neurological scores decreased with recovery of the illness. Nogo-A was shown to be expressed in neuronal cells and oligodendrocytes, and expression increased 11 days after immunization (P < 0.01), decreased by day 13 (P < 0.01), and then increased again by day 15. Nogo-A expression remained greater in the EAE group compared with the control group at day 30 (P < 0.01). In the EAE group, NgR protein was primarily expressed on the surface of neuronal bodies and axons. NgR expression increased 13-18 days after immunization (P < 0.01 or P < 0.05).CONCLUSION:Nogo-A and NgR protein expression altered with disease course in periventdcular white matter of EAE rats. Results suggested that Nogo-A and NgR were involved in EAE occurrence.     

PECAM-1 (CD31) expression in the central nervous system and its role in experimental allergic encephalomyelitis in the rat

The role of T cell activation associated adhesion molecules on lymphocyte traffic and the initiation of inflammation has received considerable attention. This study, using a new monoclonal antibody (mAb) TLD-3A12, describes the distribution of PECAM-1 (CD31), an Ig supergene family adhesion molecule thought to be important in leukocyte transmigration during inflammation, in rat lymphoid organs and spinal cord. PECAM expression within the CNS is confined to endothelial cells of the blood brain barrier (BBB). Induction of inflammation within the CNS using the adoptive transfer of myelin reactive CD4⁺ T cells results in the de novo expression of immune adhesion and accessory molecules in the spinal cord, while the level of PECAM appeared only mildly increased. The distribution of PECAM on CNS endothelial cells became more diffuse during EAE induction, possibly the result of endothelial cell activation. In vitro studies demonstrate a partial inhibition of antigen-specific CD4⁴ T cell proliferation following anti-PECAM mAb treatment. Treatment of Lewis rats with TLD-3A12 antibody prior to T cell injection and throughout EAE induction does not result in a delay in the onset of clinical signs or weight loss, nor does it decrease the incidence and severity of disease. These data suggest that the expression of PECAM by CNS endothelial cells is not a requirement for the initiation of inflammation and clinical signs of EAE following the adoptive transfer of encephalitogenic lymphocytes. Thus, cells requiring PECAM-1 to migrate and perform their pathogenic functions are not critical to the development of rat EAE. © 1996 Wiley-Liss, Inc.     

The developmental and aging changes of Down’s syndrome cell adhesion molecule expression in normal and Down’s syndrome brains

We studied the expression of Down’s syndrome cell adhesion molecule (DSCAM) in Down’s syndrome (DS) and control brains, using antisera against peptide fragments of DSCAM. On Western blots of human, mouse and rat brain homogenates, the antisera recognized a product at approximately 200 kDa. In the brain of a 2-year-old patient with DS, Western blotting revealed an overexpression of DSCAM compared to an age-matched control. Immunohistochemistry demonstrated DSCAM in the cerebral and cerebellar white matter of both control and DS subjects, in accordance with the temporal and spatial sequence of myelination. In DS brains, immunoreactivity for DSCAM, compared to that for controls, was enhanced in the Purkinje cells at all ages, and in the cortical neurons during adulthood. In demented DS patients, DSCAM immunoreactivity was observed in the core and periphery of senile plaques. The pattern of DSCAM expression suggests that it may play a role as an adhesion molecule regulating myelination. The overexpression of DSCAM may also play a role in the mental retardation and the precocious dementia of DS patients, although the mechanism of neuronal dysfunction is undetermined. Received: 13 December 1999 / Revised, accepted: 23 February 2000     

Lesional accumulation of RhoA(+) cells in brains of experimental autoimmune encephalomyelitis and multiple sclerosis

Aim: Infiltration of autoantigen-specific T cells and monocytes into the central nervous system is essential for the development of both experimental autoimmune encephalomyelitis (EAE) and multiple sclerosis (MS). RhoA is one of the best-known members of Rho GTPases, and inhibition of RhoA has been shown to attenuate the progression of EAE. The aim of this study was to investigate the expression of RhoA in brains of EAE rats and MS tissue. Methods: EAE was induced by immunization with the synthetic peptide gpMBP68-84 in rats, and clinical severity was scored. RhoA expression pattern was investigated in brains of EAE rats at different time points and in different lesions of brain tissue specimens from six MS brains and five neuropathologically unaffected controls by immunohistochemistry. Methods: In EAE rat brains, accumulation of RhoA⁺ cells reached maximal levels around Day 13, correlating to the clinical severity of EAE, and up-regulation lasted until the recovery stage of the disease. Double-labelling experiments showed that the major cellular sources of RhoA were reactive macrophages/microglia. While RhoA⁺ cells in normal human brain parenchyma were rarely observed, RhoA expression was found to be spatially associated with MS lesions, showing a marked decrease from active lesions via chronic stages to its near absence in normal-appearing white matter. In addition, major RhoA⁺ cells in brain parenchyma of MS were identified to be activated macrophages/microglia. Conclusion: Our present data indicated that RhoA may play an important role during the effector phase of EAE and MS. Therefore, RhoA inhibitors might be a therapeutic option for MS patients.