实验性自身免疫性脑脊髓炎大鼠小胶质细胞的变化

目的　观察活化的小胶质细胞 (表达主要组织相容性抗原 )在实验性自身免疫性脑脊髓炎 ( EAE)大鼠脊髓中的变化 ,探讨 EAE大鼠发病相关生物学机制。方法　采用免疫组化法观察豚鼠全脊髓匀浆诱导的 Wistar大鼠 EAE过程中脊髓内表达 MHC 、MHC 类抗原的小胶质细胞的变化情况。结果　对照组脊髓内未发现表达 MHC抗原细胞 ,实验组脊髓内表达 MHC 抗原细胞与表达 MHC 抗原细胞的分布和形态一致 ,小胶质细胞变化与 EAE大鼠的病程一致。动物临床症状评分 2分和 3分 EAE大鼠脊髓表达 MHC抗原的小胶质细胞比评分 1分大鼠明显增高 ( P <0 .0 1 ) ,恢复期 EAE大鼠表达 MHC抗原的小胶质细胞明显减少 ( P <0 .0 1 )。结论　活化小胶质细胞与 EAE大鼠的病情相关 ,提示其可能通过表达 MHC抗原在 EAE大鼠的发病机制中具有作用     

趋化因子MCP-1、MIP-1α在EAE小鼠脊髓中的表达

目的:研究单核细胞趋化蛋白(MCP)-1和巨噬细胞炎性蛋白(MIP)-1α与实验性自身免疫性脑脊髓炎(EAE)发病的关系。方法:用髓鞘少突胶质细胞糖蛋白_(35-55)多肽加福氏完全佐剂皮下注射免疫C57BL/6小鼠建立EAE模型,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MCP-1、MIP-1α的表达的变化,并通过免疫组化染色标记星形胶质细胞及小胶质细胞,判断MCP-1、MIP-1α的细胞来源。结果: MCP-1、MIP-1α在EAE小鼠发病初期脊髓中有少量表达,发病高峰期表达增高,而恢复期无表达,MCP-1主要由星形胶质细胞产生,MIP-1α主要由小胶质细胞产生;对照组小鼠脊髓中则没有MCP-1、MIP-1α表达。结论:趋化因子MCP-1、MIP-1α在EAE小鼠CNS不同胶质细胞中表达,是EAE发病早期募集免疫反应细胞向CNS浸润的重要致炎性因子。     

实验性变态反应性脑脊髓炎大鼠星形胶质细胞的变化

目的观察实验性变态反应性脑脊髓炎(EAE)大鼠脊髓中星形胶质细胞的变化,探讨EAE大鼠的发病相关生物学机制。方法采用免疫组化法,对豚鼠全脊髓匀浆诱导的Wistar大鼠EAE的过程中,脊髓内星形胶质细胞变化情况进行研究。结果EAE大鼠症状高峰期时星形胶质细胞开始激活,恢复期时激活达到高峰,而且活化的星形胶质细胞未见表达主要组织相容性抗原(MHC)。结论活化的星形胶质细胞可能与EAE大鼠的恢复有关。     

阿托伐他汀对实验性变态反应性脑脊髓炎大鼠TNF-α和iNOS表达的影响

目的应用阿托伐他汀干预实验性变态反应性脑脊髓炎(experiment allergic encephalom yelitis,EAE)大鼠,探讨药物对于疾病发病、炎性细胞浸润及TNF-α和iNOS表达的影响。方法采用豚鼠脊髓匀浆诱导Wistar大鼠建立EAE模型,口服给药干预,观察药物对大鼠发病、炎性细胞浸润情况及TNF-α和iNOS表达的影响。结果阿托伐他汀降低了大鼠发病率(P<0.05),改善了大鼠发病的严重程度(P<0.05),抑制了炎性细胞向脊髓组织的的浸润(P<0.05),降低了脊髓中iNOS的表达(P<0.05),但对于血清中TNF-α的水平没有影响(P>0.05)。结论阿托伐他汀降低了大鼠的发病率,减轻了实验性变态反应性脊髓炎大鼠发病的严重程度及炎性细胞的浸润、iNOS的表达。     

2-(2-苯并呋喃基)-2-咪唑啉对实验性自身免疫性脑脊髓炎小鼠小胶质细胞活化及氧化应激的影响

目的观察2-(2-苯并呋喃基)-2-咪唑啉(2-BFI)对实验性自身免疫性脑脊髓炎(EAE)小鼠CNS小胶质细胞活化及氧化应激的影响。方法将27只C57BL/6小鼠随机分为正常对照组、EAE组和2-BFI干预组,每组9只。采用MOG_(35-55)免疫法制作经典EAE模型。2-BFI干预组小鼠于EAE造模后当日起腹腔注射2-BFI 20 mg/kg,2次/d,连续14 d。正常对照组和EAE组以等量生理盐水代替。每日观察并记录动物的行为学变化、进行神经功能缺损评分。免疫后第20 d处死各组小鼠,采用HE染色和LFB染色观察组织学变化;免疫组化法测定诱导型小鼠CNS中一氧化氮合成酶(iNOS)蛋白和离子钙接头分子(Iba-1)的表达,比色法检测丙二醛(MDA)的含量;并对活化的小胶质细胞数量和iNOS蛋白表达水平进行线性相关分析。结果正常对照组小鼠未见神经系统受损的表现。与EAE组相比,2-BFI干预组日均神经功能缺损评分明显降低,CNS脊髓炎性细胞浸润明显减少,髓鞘脱失严重程度明显减轻,活化的小胶质细胞数量减少,iNOS蛋白表达明显减少,MDA含量降低(P0.05~0.01)。相关分析结果显示,iNOS表达水平与活化的小胶质细胞数量呈正相关(r=0.596,P0.01)。结论 2-BFI能减轻EAE小鼠临床症状和组织学改变,2-BFI对EAE小鼠的神经保护作用于小胶质细胞激活和减轻氧化应激相关。     

iNOS和OPN在EAE中动态表达及依达拉奉保护作用研究

目的研究诱导型一氧化氮合酶(iNOS)和骨桥蛋白(OPN)在实验性自身免疫性脑脊髓炎(EAE)中的动态表达以及依达拉奉治疗和保护作用机制的探讨。方法将EAE大鼠随机分为实验组和依达拉奉治疗组,根据发病时间又分为发病前组、高峰期组和缓解期组。光镜下观察脊髓HE染色炎性细胞浸润情况,观察免疫组化染色iNOS和OPN阳性细胞数目。结果依达拉奉治疗组与实验组比较,发病时间延迟、发病率降低及神经功能评分减低(P<0.05)。依达拉奉治疗组脊髓炎症细胞浸润较实验组减少。免疫组化染色iNOS和OPN阳性细胞在EAE发病前期上升,高峰期达到峰值,缓解期随疾病好转而下降,依达拉奉组均较同时期实验组阳性细胞表达数目减少(P<0.05)。结论依达拉奉可以减轻EAE大鼠临床发病程度和病理炎症损害,并降低不同发病时期iNOS和OPN表达程度。推测依达拉奉通过抗氧化和抗炎的双重机制发挥神经保护作用。     

咪唑克生对实验性自身免疫性脑脊髓炎大鼠小胶质细胞激活和白介素17、肿瘤坏死因子α表达的影响

目的观察咪唑克生对实验性自身免疫性脑脊髓炎(EAE)大鼠脑组织中小胶质细胞、白介素17(IL-17)、肿瘤坏死因子α(TNF-α)表达的影响。方法 SD大鼠30只随机分成3组:EAE-咪唑克生组(免疫当日开始给予咪唑克生2 mg·kg~(-1),腹腔注射,连续14 d)、EAE-生理盐水组(给予相同剂量生理盐水)和空白对照组。用豚鼠全脊髓匀浆免疫诱导制作EAE大鼠模型。每天观察评估各组大鼠神经功能变化;苏木精-伊红染色观察病理学改变;免疫组化法检测小胶质细胞(Iba1阳性)的激活与表达水平;酶联免疫吸附试验(ELISA)法检测发病高峰期(免疫后15 d)脑组织中IL-17,TNF-α表达水平。结果与EAE-生理盐水组比较,EAE-咪唑克生组(1)日均神经功能评分降低(P0.05),最大临床症状评分显著降低(P0.01);(2)苏木精-伊红染色:中枢炎症细胞浸润减少(P0.05);(3)免疫组化:Iba1阳性细胞表达减少(P0.05);而EAE-生理盐水组大鼠腰髓内Iba1阳性细胞表达较空白对照组明显升高(P0.01);(4)ELISA:炎性细胞因子IL-17和TNF-α表达明显降低(P0.01)。结论咪唑克生能够减缓大鼠EAE病情,其机制可能与抑制中枢神经系统小胶质细胞激活,下调中枢神经系统炎症因子IL-17和TNF-α的表达,扰乱中枢神经系统内炎症因子的平衡有关。     

二甲双胍通过调节Treg细胞反应治疗实验性自身免疫性脑脊髓炎

目的给予实验性自身免疫性脑脊髓炎(EAE)小鼠应用二甲双胍(MET)干预性治疗。观察MET对EAE小鼠发病情况及体内Treg细胞反应的作用。方法将雌性C57BL/6小鼠随机分为正常对照组、EAE模型组和MET治疗组,采用髓鞘少突胶质细胞糖蛋白MOG35-55免疫小鼠建立EAE模型。自身免疫后第1天开始,按100mg·kg~(-1)·d~(-1)给予MET治疗组腹腔注射。正常对照组及EAE模型组小鼠给予等量的生理盐水每日腹腔注射作为对照。应用Knoz评分观察小鼠的神经功能评分,流式细胞学检测方法检测小鼠脾细胞中Treg细胞比例,ELISA方法检测脾细胞培养上清及血清中IL-10、TGF-β含量。qPCR方法检测小鼠脾及脊髓中Treg细胞转录因子Foxp3 mRNA表达水平。结果与EAE模型组相比,MET治疗组发病程度减轻(P0.01);脾细胞中Treg细胞比例增高(P0.01),脾细胞培养上清及血清中IL-10、TGF-β含量增加(P0.01);脾组织中Foxp3mRNA表达水平升高(P0.01);脊髓组织中Foxp3mRNA表达水平升高(P0.01)。结论 MET通过提高外周免疫器官及中枢神经系统的Treg细胞数量,增加抑制炎症因子的表达而达到对EAE模型小鼠的保护作用。     

载脂蛋白E拟肽对实验性变态反应性脑脊髓炎小鼠基质金属蛋白酶-9和基质金属蛋白酶组织抑制因子-1表达的影响

目的探讨载脂蛋白E(Apo E)拟肽对实验性变态反应性脑脊髓炎(EAE)小鼠基质金属蛋白酶-9(MMP-9)和基质金属蛋白酶组织抑制因子-1(TIMP-1)表达的影响。方法将30只雌性C57BL/6J小鼠随机分为Apo E拟肽组、EAE组和正常组,每组10只小鼠。EAE模型通过以髓鞘少突胶质细胞糖蛋白多肽35-55为抗原诱导。Apo E拟肽组在免疫后第2 d到30 d每隔2 d按5 mg/(kg·d)背部皮下注射Apo E拟肽。EAE组和正常组均以等体积生理盐水替代。免疫后第0~35 d每日对小鼠进行神经功能评分。免疫后第35d解剖小鼠,分离大脑和脊髓并行HE染色。采用免疫组化染色法检测各组小鼠大脑、脑干和脊髓的MMP-9和TIMP-1的表达。结果正常组小鼠均未发病。Apo E拟肽组、EAE组的小鼠全部发病,但各有1只小鼠发病后死亡。Apo E拟肽组与EAE组的发病潜伏期差异无统计学意义(P=0.72)。Apo E拟肽组的神经功能评分在峰值和慢性期(第35 d)均明显低于EAE组(均P0.05)。HE染色示,正常组未见炎症细胞浸润;EAE组小鼠大脑、脑干和脊髓均有不同程度的炎性细胞浸润,以脑干和脊髓较为明显;Apo E拟肽组小鼠CNS炎性细胞浸润相对于EAE组明显减少。EAE组小鼠大脑、脑干和脊髓的MMP-9表达均高于正常组(均P0.05)。Apo E拟肽组小鼠大脑和脊髓的MMP-9表达要明显低于EAE组(均P0.05),其中Apo E拟肽组小鼠中脑和脊髓的MMP-9表达与正常组相比无明显差异(均P0.05)。正常组小鼠脊髓TIMP-1的表达明显高于EAE组和Apo E拟肽组(均P0.05)。而Apo E拟肽组与EAE组小鼠大脑、脑干和脊髓TIMP-1表达的差异均无统计学意义(均P0.05)。结论 Apo E拟肽能通过抑制大脑和脊髓MMP-9的表达改善EAE小鼠的症状。     

慢性间断性缺氧后一氧化氮和诱导型一氧化氮合酶的表达及维生素E和左旋丁基苯酞对其影响

目的 研究慢性间断性缺氧后一氧化氮 (NO)和诱导型一氧化氮合酶 (iNOS)在皮层和海马的表达及不同剂量维生素E(VitE)和左旋丁基苯酞 (L NBP)对其影响。方法 将 6 0只SD大鼠随机分成 6组 ,建立慢性间断性缺氧模型 ,并给予大、小剂量L NBP和VitE。其中 ,大剂量VitE和L NBP的剂量为 5 0mg/kg。小剂量VitE和L NBP的剂量为 2 5mg/kg。用免疫组织化学方法和生化方法分别检测皮层iNOS的表达和海马NO的水平。 结果对照组可检测到微弱的iNOS阳性染色。缺氧组大脑iNOS阳性染色显著增加 (P <0 .0 1)。与缺氧组相比 ,各治疗组阳性细胞均明显减少 (均P <0 .0 1)。与对照组相比 ,缺氧组NO的生成显著增多 (P <0 .0 1)。各治疗组与缺氧组相比 ,VitE大剂量组与缺氧组相比NO的生成无显著性差异 (P >0 .0 5 )。L NBP大剂量与L NBP小剂量及VitE小剂量组的NO含量均显著减少 (P <0 .0 1)。结论　 慢性间断性缺氧后iNOS表达增多 ,同时NO的合成增多。治疗性给予L NBP和VitE能够显著抑制iNOS表达。治疗性给予大、小剂量L NBP和小剂量VitE能够显著抑制NO的合成。大剂量VitE对于NO的合成无影响。     

实验性过敏性脑脊髓炎豚鼠中枢神经系统一氧化氮合酶的表达

目的探讨诱导型一氧化氮合酶（ｉＮＯＳ）在中枢神经系统脱髓鞘疾病中的作用。方法采用硫辛胺脱氢酶染色和抗诱导型一氧化氮合酶（抗ｉＮＯＳ）抗体的免疫组化方法，对髓鞘碱性蛋白诱导豚鼠产生的实验性过敏性脑脊髓炎（ＥＡＥ）病程中，脑和脊髓的一氧化氮合酶（ＮＯＳ）和ｉＮＯＳ表达情况进行研究。结果在ＥＡＥ的急性期主要为血管、血管周围细胞、浸润细胞和小胶质细胞显示ｉＮＯＳ免疫反应阳性，在恢复期星形细胞则出现免疫反应阳性。结论提示一氧化氮是ＥＡＥ早期血脑屏障破坏以及进展期髓鞘和少突胶质细胞破坏的重要介导物质。     

Further evidence for a role of nitric oxide in experimental allergic encephalomyelitis: aminoguanidine treatment modifies its clinical evolution

The role of nitric oxide (NO) in inflammatory/demyelinating diseases is undergoing extensive investigation as a potential target for therapeutic intervention. However, interference with NO production has resulted in contrasting effects on the development of experimental allergic encephalomyelitis (EAE), the most widely used experimental model for multiple sclerosis (MS). Purpose of this paper was both the analysis of the individual clinical evolution of EAE induced in Lewis female rats by active immunisation and the evaluation of the effect of treatment with aminoguanidine, a selective inhibitor for the inducible isoform of nitric oxide synthase (iNOS). In our experimental model, relapse occurred in 66% of animals. Aminoguanidine treatment, started 3 days before immunisation, guaranteed a complete recovery from the acute phase and a delayed, milder relapse. Moreover, 79 days after immunisation inflammatory cellular infiltrates in the spinal cord were reduced. These data further support the involvement of NO in EAE evolution.     

Experimental allergic encephalomyelitis in the rat is inhibited by aminoguanidine, an inhibitor of nitric oxide synthase

This study assessed the role of de novo nitric oxide (NO) production in the pathogenesis of experimental allergic encephalomyelitis (EAE) by using aminoguanidine (AG), an inhibitor of nitric oxide synthase (NOS). which preferentially inhibits the cytokine- and endotoxin-inducible isoform of NOS versus the constitutive isoforms consisting of endothelial and neuronal NOS. The maximum clinical severity of EAE and the duration of illness were significantly reduced or totally inhibited by twice daily subcutaneous injection of 100 mg/kg body weight AG. Histochemical staining for NADPH diaphorase, which detects enzymatic activity of NOS, revealed positive reactivity in untreated EAE rats both in parenchymal blood vessel walls and in anterior horn cell neurons, while normal rats and rats with EAE treated with AG showed predominantly the neuronal positivity. Moreover, this NADPH staining pattern was further supported by the immunohistochemical findings that endothelial NOS (eNOS) expression was increased in blood vessels in the inflamed lesions of untreated EAE rats and that inducible NOS (iNOS) was detected in some infiltrating inflammatory cells, while treatment with AG could significantly reduce both iNOS and eNOS production. These results suggest that: (i) both iNOS and eNOS are upregulated in inflamed areas of the rat central nervous system in EAE; (ii) increased NO production plays a role in the development of clinical signs in EAE; and (iii) selective inhibitors of iNOS and/or eNOS may have therapeutic potential for the treatment of certain autoimmune diseases.     

凝血酶诱导的小胶质细胞激活促进多巴胺能神经元变性

目的探讨凝血酶（Thrombin）诱导小胶质细胞（Micoglia）激活与黑质多巴胺能神经元变性的关系。方法采用立体定向术注射凝血酶至大鼠黑质,在不同时间点观察酪氨酸羟化酶（tyrosine hydroxylase,TH）神经元的表达及小胶质细胞的激活情况;同时检测黑质NO量及iNOS mRNA表达。结果（1）凝血酶注入大鼠黑质导致明显的黑质多巴胺能神经元变性,呈时间依赖性,TH阳性细胞数在第3d开始下降,第7d有大量的TH阳性细胞丢失,与对照侧相比下降达约53％（P〈0．01）;高倍镜下可见胞体皱缩、突起明显缩短或减少;14d时细胞数下降至21％,30d时下降至12％（P〈0．01）。（2）凝血酶注射入黑质4h后小胶质细胞开始呈现为“灌木丛样”或少量呈现“阿米巴样”：12h后小胶质细胞数目明显增加且绝大部分呈现“阿米巴样”;24h后细胞已完全激活,“阿米巴样”细胞达高峰;3d维持高峰;14d后小胶质细胞染色变淡,体积变小,“阿米巴样”细胞数目下降。（3）与对照组相比,iNOSmRNA表达明显上调及NO合成增加（P〈0．05）,并且有iNOS在小胶质细胞表达。结论凝血酶对多巴胺能神经元具有一定的损毁作用,小胶质细胞的激活先于多巴胺能神经元变性,其激活后释放的NO有可能参与多巴胺能神经元变性。     

Bone marrow-derived versus parenchymal sources of inducible nitric oxide synthase in experimental autoimmune encephalomyelitis

The role of nitric oxide (NO) in central nervous system (CNS) inflammation is uncertain. Whereas experimental autoimmune encephalomyelitis (EAE) is exacerbated in mice deficient in inducible nitric oxide synthase (iNOS), inhibitor studies have suggested a pro-inflammatory role for NO. These discrepancies may reflect balance between immunoregulatory and neurocytopathologic roles for NO. We investigated selective effects of bone marrow-derived versus CNS parenchymal sources of iNOS in EAE in chimeric mice. Chimeras that selectively expressed or ablated iNOS in leukocytes both showed significant delay in disease onset, with no difference in disease severity. We conclude that bone marrow-derived and CNS parenchymal sources of iNOS-derived NO both play a regulatory role in EAE.     

Minocycline and fluorocitrate suppress spinal nociceptive signaling in intrathecal IL‐1β–induced thermal hyperalgesic rats

We previously demonstrated that intrathecal IL‐1β caused thermal hyperalgesia in rats. This study was conducted to examine the effects and cellular mechanisms of glial inhibitors on IL‐1β–induced nociception in rats. The effects of minocycline (20 μg), fluorocitrate (1 nmol), and SB203580 (5 μg) on IL‐1β (100 ng) treatment in rats were measured by nociceptive behaviors, western blotting of p38 mitogen‐activated protein kinase (MAPK) and inducible nitric oxide synthase (iNOS) expression, cerebrospinal fluid nitric oxide (NO) levels, and immunohistochemical analyses. The results demonstrated that intrathecal IL‐1β activated microglia and astrocytes, but not neurons, in the dorsal horn of the lumbar spinal cord, as evidenced by morphological changes and increased immunoreactivity, phosphorylated p38 (P‐p38) MAPK, and iNOS expression; the activation of microglia and astrocytes peaked at 30 min and lasted for 6 h. The immunoreactivities of microglia and astrocytes were significantly increased at 30 min (6.6‐ and 2.7‐fold, respectively) and 6 h (3.3‐ and 4.0‐fold, respectively) following IL‐1β injection, as compared with saline controls at 30 min (all P < 0.01). IL‐1β induced P‐p38 MAPK and iNOS expression predominantly in microglia and less in astrocytes. Minocycline, fluorocitrate, or SB203580 pretreatment suppressed this IL‐1β–upregulated P‐p38 MAPK mainly in microglia and iNOS mainly in astrocytes; minocycline exhibited the most potent effect. Minocycline and fluorocitrate pretreatment abrogated IL‐1β–induced NO release and thermal hyperalgesia in rats. In conclusion, minocycline, fluorocitrate, and SB203580 effectively suppressed the IL‐1β–induced central sensitization and hyperalgesia in rats. © 2012 Wiley Periodicals, Inc.     

Accelerated cerebral ischemic injury by activated macrophages/microglia after lipopolysaccharide microinjection into rat corpus callosum

In cerebral ischemic insults, activated inflammatory cells such as microglia and macrophages may be implicated in the pattern and degree of ischemic injury by producing various bioactive mediators. In the present study, we provide the evidence that activated microglia/macrophages accelerate cerebral ischemic injury by overexpression of inducible nitric oxide synthase (iNOS). To activate microglia/macrophages, a potent inflammation inducer lipopolysaccharide (LPS, 5 microg/5 microl) was microinjected into rat corpus callosum. Isolectin B4-positive microglia/macrophages were abundantly observed in ipsilateral hemisphere at 1 day after LPS injection. RT-PCR showed that LPS injection induced iNOS mRNA expression mostly in microglia/macrophages, peaking in intensity at 15 h after LPS injection. While ischemic injury was little evoked in control rats by 2-h middle cerebral artery occlusion (MCAO) followed by 3-h reperfusion, it was markedly increased in rats pre-injected with LPS 1 day before MCAO. However, no significant difference between control and LPS-pretreated groups was observed after 24-h reperfusion. The increased ischemic injury in LPS-treated rats was well correlated with iNOS level expressed over 3 orders of magnitude than in LPS-untreated rats. Immunohistochemical studies showed that iNOS- and nitrotyrosine (a peroxynitrite marker)-positive cells were prominent throughout the infarct area. NOS inhibitors aminoguanidine or N(G)-nitro-L-arginine, simultaneously injected with LPS, reduced the iNOS immunoreactivity and infarct volume, especially in penumbra regions. Total glutathione levels in ischemic regions were decreased more in LPS pre-injected rats than in control ones. Further defining the role of NO in cerebral ischemic insults would provide the rationale for new therapeutic strategies based on modulation of microglial and macrophageal NO production in the brain.     

Mechanisms of recovery from experimental allergic encephalomyelitis induced with myelin basic protein peptide 68-86 in Lewis rats: a role for dendritic cells in inducing apoptosis of CD4+ T cells.

Spontaneous remission of experimental allergic encephalomyelitis (EAE) is usually associated with prominent apoptosis. The mechanisms behind apoptosis are unknown. We examined the functions of dendritic cells (DC) from Lewis rats with EAE induced by immunization with myelin basic protein peptide 68-86 (MBP68 - - 86). Recovery from EAE was associated with three major functional changes of freshly prepared DC: (1) elevated proliferation, (2) increased nitric oxide (NO) production, and (3) augmented IFN-gamma secretion. In Freund's complete adjuvant (FCA)-immunized control rats, no increase of proliferation, NO production or IFN-gamma secretion was observed on day 21 post-immunization (p.i.), i.e., recovery from EAE. In vitro effects of IFN-gamma, TNF-alpha, TGF-beta1, IL-4 and IL-10 on DC were examined. IFN-gamma enhanced proliferation and NO production by DC, while TNF-alpha and IL-4 induced only slight DC proliferation. DC from recovering EAE rats (day 21 p.i.) suppressed MBP68 - - 86-induced T cell proliferation compared to DC obtained at other time points in EAE and FCA-immunized rats. DC-derived NO induced apoptosis of CD4+ T cells, thereby inhibiting autoreactive T cell responses. Besides IFN-gamma stimulation, NO production by DC was mainly induced in an antigen-dependent manner when DC were co-cultured with T cells. The results suggest that spontaneous recovery from EAE is associated with augmented DC functions. Overproduction of NO by DC results in apoptosis of autoreactive CD4+ T cells, thereby decreasing autoreactive T cell reactivities. The existence of such a NO negative feedback loop may contribute to remission of EAE.     

Nitric oxide and TNFalpha effects in experimental autoimmune encephalomyelitis demyelination

The involvement of inducible nitric oxide synthase (iNOS), which plays various roles in the progression of autoimmune diseases, was studied in iNOS knockout (KO) mice and wild-type (WT) controls with respect to experimental autoimmune encephalomyelitis (EAE). The iNOS (KO) mice presented a less severe form of the disease than the WT control mice. Although the levels of TNFalpha decreased in the periphery in both groups, an increase in the number of TNFalpha-positive cells was detected in the central nervous system during the acute phase of EAE in the WT mice, but not in the KO mice. These findings suggest that NO and TNFalpha contribute to the pathogenesis of acute EAE.