猴急慢性实验性变应性脑脊髓炎的病理研究

目的　探讨急、慢性猴 (猕猴类 )实验性变应性脑脊髓炎 (EAE)的病理特点。方法　从EAE猴病程不同阶段进行病理取材 ,制成切片 ,用HE、Bielschowsky改良法、Page法、Holzer法染色及间接免疫荧光法观察CD4、CD8和B淋巴细胞。结果　 ( 1)猴急性EAE脑组织炎症反应重 ,分布在小静脉周围形成血管套 ,以CD4淋巴细胞浸入为主。脱髓鞘病灶微小 ,分布弥散 ,轴突改变轻 ,无出血 ,类似急性播散性脑脊髓炎 (ADEM)。 ( 2 )猴慢性EAE脑组织炎症反应轻 ,分布在血管外周 ,以CD8和B细胞为主。脱髓鞘病灶较大 ,界线清晰 ,呈局灶性分布。病变部位轴突变性严重及轴突丧失 ,有胶质斑块形成 ,与慢性多发性硬化 (MS)的活动期病理改变有惊人的相似。结论　支持猴慢性EAE是MS的优秀模型。另外 ,用相同抗原诱导出不同病程的EAE提示ADEM和MS可能是同一疾病的不同病程 ,或可能是同一种病因 ,而致病程不同。     

多病程Wistar大鼠实验性变态反应性脑脊髓炎的病理研究

目的:在建立wistar大鼠多病程实验性变态反应性脑脊髓炎(EAE)的动物模型的基础上,进行病理学研究,探讨不同发病类型EAE的基本病理改变如炎细胞浸润、脱髓鞘和轴索损伤等方面的差别,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,进行常规HE染色、Weil髓鞘染色和改良的Bielschowsky,并行GFAP免疫组化染色,观察不同发病类型EAE的病理政变。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,急性型EAE炎症浸润明显,尤脱髓鞘改变,缓解-复发型和持续进展型EAE髓鞘脱失和轴索损伤更明显,且有陈旧病灶周围的星型胶质细胞增生,而新发病灶无此表现,良性型EAE则改变接近正常。结论:首次建立了Wistar大鼠多病程EAE,且病理证实不同类型EAE的炎细胞分布、髓鞘脱失及轴索损伤等基本病理改变是不同的,它具有人类MS的许多发病特点,其中多病程的发病形式和主要病理特点与MS极其相似,是理想的MS动物模型。     

Autoimmunity against myelin oligodendrocyte glycoprotein is dispensable for the initiation although essential for the progression of chronic encephalomyelitis in common marmosets

To elucidate the pathogenetic significance of myelin/oligodendrocyte glycoprotein (MOG)-specific autoreactivity in a genetically and immunologically heterogeneous nonhuman primate model of multiple sclerosis, we analyzed experimental autoimmune encephalomyelitis (EAE) in the outbred common marmoset (Callithrix jacchus). One sibling each of 5 bone marrow chimeric marmoset twins was immunized with myelin derived from wild-type (WT) C57BL/6 mice (WT myelin); the other sibling was immunized with myelin from MOG-deficient C57BL/6 mice (MOG -/- myelin). One twin pair developed acute EAE simultaneously; the 4 remaining twin siblings immunized with WT myelin developed chronic progressive EAE, whereas siblings of these 4 monkeys remained free of clinical disease signs. Many EAE-related abnormalities were identified in the CNS of both groups by magnetic resonance imaging and histologic analysis, but mean percentages of spinal cord demyelination were lower in monkeys immunized with MOG -/- myelin (8.2%) than in WT myelin-immunized animals (40.5%). There was a strong correlation between the development of overt clinical EAE and seropositivity for anti-MOG antibodies, but blood and lymph node T-cell proliferative responses showed no relationship to disease. These results indicate that the initiation of CNS inflammation and demyelination can take place in the absence of detectable autoimmunity against MOG, but the clinical progression and histopathologic severity depends on the presence of antibodies against MOG in this multiple sclerosis model.     

Chronic experimental allergic encephalomyelitis in rhesus monkeys and its modification by treatment.

Rhesus monkeys were immunized with low doses of encephalitogenic mixture. Twenty two of 24 monkeys developed experimental allergic encephalomyelitis (EAE) lasting from 3 to 252 days. Fifteen of 22 monkeys developed chronic progressive EAE with remissions and relapses. In the early stages of EAE multiple perivascular foci of demyelination and lymphoid histiocytic infiltration were found within the central nervous system (CNS). In advanced disease these foci became confluent, developing foci of plaque type with demyelination and gliofibrosis. Eight affected monkeys received an emulsion of spinal cord with incomplete adjuvant; 6 of them showed a good therapeutic response. In the CNS of those monkeys 514 to 667 days later plaques of demyelination and gliofibrosis and minimal inflammatory lesions were detected. Two monkeys without clinical evidence of EAE had plaques of demyelination and gliofibrosis in the CNS 2 years after immunization. It is suggested that chronic EAE in monkeys may be considered an adequate model for multiple sclerosis (MS).     

Characterization of CD8-positive macrophages infiltrating the central nervous system of rats with chronic autoimmune encephalomyelitis

CD8+ macrophages appear in the central nervous system (CNS) under various pathological conditions such as trauma and ischemia. Furthermore, macrophages expressing CD8 were found in CNS lesions of chronic, but not acute, experimental autoimmune encephalomyelitis (EAE). To further characterize cells with this phenotype, we examined CD8+ macrophages/monocytes in the CNS and peripheral organs during the course of acute and chronic EAE that had been induced by immunization of rats with myelin basic protein and myelin oligodendrocyte glycoprotein, respectively. Counting CD8+ macrophages in CNS lesions revealed that their numbers increased reaching about 60% of total infiltrating macrophages in chronic EAE, while CD8+ macrophages remained less than 5% throughout the course of acute EAE. Unexpectedly, however, higher abundance of CD8+ monocytes/macrophages in the peripheral blood was found in both acute and chronic EAE. Real-time polymerase chain reaction analysis revealed no significant difference in the levels of chemokines and chemokine receptors of blood CD8+ monocytes between acute and chronic EAE. mRNA expression of perforin, a cytotoxic substance, was up-regulated in CD8+ monocytes compared with that of CD8- monocytes in both acute and chronic EAE. These findings suggest that activated CD8+ macrophages may play a cytotoxic role in chronic EAE lesions and that cells other than CD8+ monocytes/macrophages determined the difference in CNS pathology between acute and chronic EAE. Analysis of CD8+ monocytes/macrophages may provide useful information to permit further dissect the pathomechanisms of multiple sclerosis and to develop effective immunotherapies against autoimmune diseases in the CNS.     

Concomitant detection of changes in myelin basic protein and permeability of blood-spinal cord barrier in acute experimental autoimmune encephalomyelitis by electroimmunoblotting

An electroimmunoblotting technique was used with a monoclonal antibody to myelin basic protein (MBP) to assess demyelination in 3 defined regions of the spinal cord in rats with acute experimental autoimmune encephalomyelitis (EAE). A slight loss in MBP was detected only in the sacrococcygeal region of the spinal cord after the onset of clinical signs. In all 3 spinal cord regions studied, significantly elevated levels of albumin and IgG were detected during the course of EAE by the same technique. At the onset of clinical signs, the levels of IgG and albumin were highest in the more caudal regions of the spinal cord. As the clinical signs became more severe, IgG and albumin levels increased in the more cranial regions of the spinal cord. These changes thus correlated with the ascending progression of clinical signs typical of EAE in rats. These results provided added evidence that in rats affected with acute EAE, the clinical signs occur independently of demyelination and coincide with vasogenic edema.     

Serial analysis of peripheral blood T-cell phenotypes and myelin basic protein reactivity in experimental allergic encephalomyelitis

We have serially analyzed peripheral blood T-cell phenotypes and reactivity to myelin basic protein (MBP) during the course of acute experimental allergic encephalomyelitis (EAE) in the Lewis rat and have correlated changes with the onset of clinical disease. A reduction in total T cells (W3/13+), due primarily to a reduced helper/inducer (W3/25+) subpopulation, preceded the onset of EAE. Circulating MBP-reactive lymphocytes were only transiently present in the blood at the time EAE was clinically evident. Our findings demonstrate that in EAE, immunologic abnormalities in the peripheral blood are transient and can begin before clinical disease is evident.     

Suppression of acute and chronic experimental allergic encephalomyelitis in strain 13 guinea pigs: A clinical and pathological study

Adult inbred Strain 13 guinea pigs develop an acute, fatal form of experimental allergic encephalomyelitis (EAE) about 2 weeks after a single injection of isologous spinal cord in complete Freund's adjuvant (CFA), but similarly injected juveniles develop a delayed, rarely fatal chronic form. Thirty-seven sensitised adult Strain 13 animals were separated into 2 groups. One group was permitted to develop acute EAE. The other group was injected intramuscularly with 1 mg of guinea pig or bovine myelin basic protein (MBP) in incomplete Freund's adjuvant (IFA) on day 2, 7 or 10 post-inoculation (PI) followed by 0.2 mg in IFA every third day for a total of 10 doses. Animals in the unsuppressed group succumbed to acute EAE 13–16 days post-sensitisation. No animal in the suppressed group died during this period. Animals treated with MBP beginning 2 days PI showed no clinical signs, but mild clinical manifestations occurred in animals suppressed from days 7 and 10 PI. These signs remitted by 21 days post-sensitisation. One suppressed animal (out of 21) died during the fourth week postsensitisation. The other 20 suppressed animals appeared clinically normal towards the end of the course of MBP injections and remained so for the 6 months of study. Morphological examination revealed that CNS lesions occurred in all animals. In animals suppressed with MBP beginning on day 2 PI, lesions consisted only of a few meningeal inflammatory cells. Animals given MBP beginning on day 7 or 10 PI and sampled 1–2 weeks later, had lesions which could not be distinguished from those occurring in the non-suppressed acute EAE group. In time, the suppressed animals developed lesions which were typical of chronic EAE with remyelination as a predominant feature. Preliminary experiments on the suppression of chronic EAE in 5 juvenile Strain 13 guinea pigs have revealed that 3 MBP-injected animals failed to develop clinical disease over a 28-week period of study although lesions typical of chronic EAE were present. Simultaneously, 2 non-suppressed juvenile animals developed clinical signs by 12 weeks. These were associated with both acute inflammation and demyelination superimposed upon regions of chronic demyelinative activity.     

新西兰兔和SD大鼠实验性变态反应性脑脊髓炎模型的比较

目的比较两种不同种属的动物及不同免疫原诱发的实验性变态反应性脑脊髓炎（EAE）模型的各自特点及其适用的优缺点。方法应用兔脊髓匀浆（R-SCH）、SD大鼠脊髓匀浆（M-SCH）、异种牛大脑白质匀浆（C-SCH）为免疫原，分别免疫新西兰兔和SD大鼠制备EAE动物模型。观察比较模型的发病过程、临床评分、病理变化和病理组织学评分。结果新西兰兔EAE模型呈单相发病过程，发病时间长，发病率较低，但其病灶大且集中，MRI更易观察和定位。SD大鼠EAE模型则呈典型的双相病程，发病时间短，发病率高，复发率高，其发病更像人类多发性硬化的发病过程。同时发现同种免疫原诱发的EAE模型其发病过程更稳定，发病率也较异种免疫原高．其导致的模型病理变化也更明显，尤其是脱髓鞘更明显。结论不同的动物物种和不同的免疫原制备的EAE模型具有各自适用的优缺点和特点，可根据研究目的的不同选取所需的模型。     

Quantitation of myelin oligodendrocyte glycoprotein and myelin basic protein in the thymus and central nervous system and its relationship to the clinicopathologic features of autoimmune encephalomyelitis

There is controversy whether the amount of autoantigens expressed in the thymus regulates negative selection of autoreactive T cells and determine susceptibility or resistance to experimental autoimmune encephalomyelitis (EAE). In the present study, we have addressed this issue by quantifying neuroantigens in the thymus of two EAE-susceptible (LEW and LEW.1AV1) and one EAE-resistant (BN) rat strains. We further examined whether amounts of neuroantigens in various parts of the central nervous system (CNS) affect the clinical course and lesion distribution of acute and chronic EAE. Real-time PCR and histologic analyses showed that there was no significant difference in the amount and distribution of myelin oligodendrocyte glycoprotein and myelin basic protein in the thymus and CNS among the three strains and that both acute and chronic EAE lesions in the CNS were preferentially distributed in the area where neuroantigens were abundantly present. These findings suggest that susceptibility or resistance to EAE is not regulated by the amount of the neuroantigens expressed in the thymus. Furthermore, the lesion distribution, but not the clinical course, of EAE is related to the neuroantigen expression in the CNS.     

The significance of the inflammatory reactions for the development of clinical signs in multiple sclerosis and acute experimental autoimmune encephalomyelitis as assessed by means of the spontaneous chemiluminescence activity of peripheral blood monocytes

We found that the course of the chemiluminescence activity (CL-A) of peripheral blood monocytes of Lewis rats with acute experimental autoimmune encephalomyelitis (EAE) correlates well with the clinical course of this autoimmune disease and that only a reduction in T helper cells caused a reduction in CL-A. However, in multiple sclerosis (MS) patients the CL-A increased when clinical improvement started. The serum of these patients contained at least two stimulatory substances. More than 50% of the stimulatory effect could be blocked by antibodies to interferon-γ.     

Severe T-cell depletion from the PALS leads to altered spleen composition in common marmosets with experimental autoimmune encephalomyelitis (EAE)

Recent data suggest that the spleen is a crucial component of the immune system in the development of experimental autoimmune encephalomyelitis (EAE) in marmoset monkeys. Using immunohistochemistry, we investigated changes in the distribution of leukocytes in the spleen associated with clinical symptoms of EAE. Animals without EAE displayed well-developed T- and B-cell areas, germinal centers and red pulp. In contrast, a marked depletion of periarteriolar T cells with preservation of other elements was found in animals with clinical EAE. These findings suggest that immune responses within the spleen are impaired during a paralysing inflammatory process in the central nervous system.     

Exacerbation of experimental autoimmune encephalomyelitis after withdrawal of phenytoin and carbamazepine

OBJECTIVE: In vitro observations and studies in murine experimental autoimmune encephalomyelitis (EAE) have shown protective effects of sodium channel blockers on central nervous system axons and improved clinical status when treatment is continued throughout the period of observation. Several clinical studies of sodium channel blockers are under way in patients with multiple sclerosis. Here we asked whether a protective effect would persist after withdrawal of a sodium channel blocker. METHODS: We studied a mouse model of myelin oligodendrocyte glycoprotein-induced EAE treated with phenytoin or carbamazepine. RESULTS: Both phenytoin and carbamazepine significantly improved the clinical course of the disease. Withdrawal of phenytoin resulted in acute exacerbation, accompanied by a significantly increased inflammatory infiltrate within the central nervous system and the death of nearly 60% of EAE mice. There were no clinical worsening or deaths in control mice after withdrawal of phenytoin. Withdrawal of carbamazepine led to acute worsening of EAE symptoms, increased inflammatory infiltrate, and was associated with the death of 8% of mice. INTERPRETATION: These results, together with results showing effects of sodium channel blockers in immune cells, raise questions about the long-term effects of sodium channel blockers in neuroinflammatory disorders, and suggest that clinical studies of sodium channel blockers in these disorders should be planned carefully.     

The suppression of T cell apoptosis influences the severity of disease during the chronic phase but not the recovery from the acute phase of experimental autoimmune encephalomyelitis in mice

The elimination of T cells by apoptosis is considered to be one of the regulatory factors in experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis. To address further the role of apoptotic T cell death in EAE, we investigated myelin oligodendrocyte glycoprotein (MOG)-induced EAE in transgenic mice overexpressing the anti-apoptotic gene, bcl-2, in T cells. During the acute phase of EAE, no significant difference was observed in the clinical course, pathology and T cell response to MOG between bcl-2 transgenic mice and wild-type littermates. While the recovery from the first attack of EAE was not impaired in the bcl-2 transgenic mice, a more severe disease was observed during the chronic phase of the disease even though T and B cell responses to MOG were comparable to those of wild-type littermates. A flow cytometric analysis by Annexin V showed a significant decrease of apoptotic T cells in the central nervous system (CNS) of the bcl-2 transgenic mice with EAE compared with controls during the chronic as well as the acute phase of disease. These results suggest that while T cell apoptosis in the CNS may play a regulatory role in EAE, the spontaneous recovery from acute EAE cannot solely be explained by T cell apoptosis.     

Loss of astrocyte connexins 43 and 30 does not significantly alter susceptibility or severity of acute experimental autoimmune encephalomyelitis in mice

We showed previously that mice deficient in astrocyte gap junctions Cx43 and Cx30 exhibit white matter vacuolation and hypomyelination. In this study we tested the hypothesis that loss of astrocytic gap junction proteins leads to exacerbation of the primary demyelinating diseases, using experimental autoimmune encephalomyelitis (EAE) as a model system. To test for this, Cx43 floxed mice were crossed with GFAP:Cre, Cx30 null mice to generate mice lacking astrocytic expression of both Cx43 and Cx30 (dKO). EAE was induced using myelin oligodendrocyte glycoprotein (MOG(35-55)) peptide, and mice were monitored for acute expression of disease. No statistically significant difference in clinical or pathological expression of EAE was observed. Lesion load and susceptibility of different areas of the CNS to inflammation were similar in all genotypes. Moreover, no differences were noted in blood-brain barrier (BBB) permeability, tissue wet weight, axonal pathology, gliosis or demyelination during acute disease. These data show that loss of the astrocytic connexins, Cx43 and Cx30, and the white matter pathology observed in these mice does not statistically affect clinical or pathological expression of EAE and show that astrocyte gap junctions do not regulate autoimmune inflammation and associated BBB disruption in acute EAE.     

Electrophysiological follow-up of acute and chronic experimental allergic encephalomyelitis in the Lewis rat

Summary Cortical somatosensory evoked potentials (c-SEP) and flash visual evoked potentials (f-VEP) were serially recorded in acute monophasic and chronic relapsing experimental allergic encephalomyelitis (EAE) in the Lewis rat. In acute EAE, a significantly delayed latency and broadened peak of the c-SEP were observed corresponding to the clinical onset, and then returned to normal with the disappearance of clinical signs. In chronic EAE, the c-SEP showed the same changes as in acute EAE, also reflecting the first attack, remission and relapsing phase. However, chronic EAE, when paralysis had recovered in the relapsing phase, showed c-SEP abnormalities suggestive of subclinical active lesions. In contrast, the f-VEP showed no obvious abnormalities in acute or chronic EAE. These findings suggest that the c-SEP is an objective and sensitive index for detecting clinical and pathological changes in acute and chronic EAE in the Lewis rat.     

Modulation of experimental allergic encephalomyelitis in Lewis rats by monoclonal anti-T cell antibodies

The effect of monoclonal antibodies to different T lymphocyte populations of the rat on the induction and the course of experimental allergic encephalomyelitis (EAE) was investigated. EAE was induced by injection of guinea pig spinal cord in adjuvant. Subcutaneous injections of monoclonal antibodies to all peripheral T lymphocytes (W3/13) abrogated or prevented the development of clinical EAE. Similar results were obtained in animals injected with monoclonal antibodies to T helper cells (W3/25) mixed with monoclonal antibodies to T nonhelper cells (OX8). Animals treated with either W3/25 or OX8 developed clinical EAE as the control rats (subcutaneous injected with normal mouse serum). Histological examination after the acute stage revealed no significant differences between rats treated prophylactically with W3/13, W3/25 or OX8 and rats injected with normal mouse serum. Animals treated prophylactically with a mixture of W3/25 and OX8 developed, on the whole, EAE with less histological severity compared to the control animals. Treatment of rats after the onset of the first clinical symptoms of EAE (tail flaccidity) with W3/13 resulted in a less fatal course of the disease. Compared to surviving rats injected with mouse serum (controls) the number of infiltrates were reduced in these rats treated therapeutically.     

Attenuation of experimental autoimmune encephalomyelitis by Compound 48/80 in Lewis rats

The appearance of increased levels of histamine in the central nervous system (CNS) concomitant with the development of clinically significant acute experimental autoimmune encephalomyelitis (EAE) in male Lewis rats suggests that CNS-associated mast cells may mediate acute EAE in Lewis rats. We now report that, compared to controls, rats with acute EAE exhibit fewer detectable mast cells in their dura mater and velum interpositum. In addition, intracisternal, but not intraperitoneal administration of Compound 48/80 just prior to the appearance of clinical signs of acute or recurrent EAE in male and female rats, respectively, significantly attenuates the clinical severity of both forms of EAE. These results further support the hypothesis that CNS-associated, but not peripheral mast cells are mediators or modulators of acute and recurrent EAE in Lewis rats.     

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。