银椴苷对激活的原代小胶质细胞极化及神经炎症的影响＊

目的 银椴苷（Tiliroside，Tle）是一种天然产物，存在于结香花（Edgeworthia chrysantha Lindl.）、金英（Galphimia gracilis）、和Phlomoides spectabilis等生物体中。本文主要探讨Tle对脂多糖（lipopolysaccharide，LPS）激活的原代小胶质细胞的M1/M2极化的转化作用及其抑制神经炎症反应的影响。方法 MTT检测各浓度Tle对LPS激活的原代小胶质细胞活性的影响；Griess试剂检测LPS激活的原代小胶质细胞的一氧化氮（Nitric oxide，NO）产物生成量的影响；ELISA法检测Tle对LPS激活的原代小胶质细胞的肿瘤坏死因子-α（Tumor necrosis factor-α，TNF-α）、白细胞介素-6（Interleukin-6，IL-6）蛋白水平的影响；qRT-PCR检测Tle对LPS激活的原代小胶质细胞的精氨酸酶-1（Arginase-1，Arg-1）和胰岛素生长因子-1（Insulin growth factor-1，IGF-1）的mRNA表达水平。结果 Tle（0-80 μmol·L^-1）对LPS激活的原代小胶质细胞活性没有明显影响；Tle显著降低LPS激活的原代小胶质细胞亚硝酸盐的含量，并对炎症因子IL-6、TNF-α蛋白水平有显著抑制作用，同时显著提高抗炎因子Arg-1和IGF-1的mRNA水平。结论 Tle能够通过促进LPS激活的原代小胶质细胞M1型向M2型转化从而抑制神经炎症反应，因此Tle具有一定的神经保护作用。     

D-Ribose-LCysteine attenuates manganese-induced cognitive and motor deficit,oxidative damage,and reactive microglia activation

Due to overexposure, manganese (Mn) accumulation in the brain can trigger the inhibition of glutathione synthesis and lead to increased generation of reactive oxygen species (ROS) and oxidative stress. D-Ribose-L-Cysteine (RibCys) has been demonstrated to effectively support glutathione synthesis to scavenge ROS and protect cells from oxidative damage. In the present study, we examined the effects of RibCys on weight changes, cognitive and motor associated activities, oxidative stress markers, striatal and cortical histology, and microglia activation following Mn exposure. Rats were exposed to either saline, Mn or/and RibCys for two weeks. The Mn exposed rats received RibCys either as pre-, co-, or post-treatments. Mn caused a significant decrease in weight, memory and motor activities, increased lactate dehydrogenase level, overexpression of IBA1 reflecting microglia activation, and distortion of the neuronal cytoarchitecture of the striatum and motor cortex, respectively. Interventions with RibCys mitigated Mn-induced neurotoxic events. Our novel study demonstrates that RibCys effectively ameliorates the neurotoxicity following Mn treatment and maybe a therapeutic strategy against the neurological consequences of Mn overexposurec     

Excess salt intake promotes M1 microglia polarization via a p38/MAPK/AR-dependent pathway after cerebral ischemia in mice

A high salt diet (HSD) is among the most important risk factors for many diseases. One mechanism by which HSD aggravates cerebral ischemic injury is independent of blood pressure changes. The direct role of HSD in inflammation after cerebral ischemia is unclear. In this research, after twenty-one days of being fed a high salt diet, permanent focal ischemia was induced in mice via operation. At 12 h and 1, 3 and 5 days postischemia, the effects of HSD on the lesion volume, microglia polarization, aldose reductase (AR) expression, and inflammatory processes were analyzed. We report that in mice, surplus dietary salt promotes inflammation and increases the activation of classical lipopolysaccharide (LPS)-induced microglia/macrophages (M1). This effect depends on the expression of the AR protein in activated microglia after permanent middle cerebral artery ligation (pMCAL) in HSD mice. The administration of either the AR inhibitor Epalrestat or a p38-neutralizing antibody blocked the polarization of microglia and alleviated stroke injury.In conclusion, HSD promotes polarization in pro-inflammatory M1 microglia by upregulating the expression of the AR protein via p38/MAPK, thereby exacerbating the development of ischemia stroke.     

Brain-derived neurotrophic factor and inflammation in depression: Pathogenic partners in crime?

Major depressive disorder is a debilitating disorder affecting millions of people each year. Brain-derived neurotrophic factor (BDNF) and inflammation are two prominent biologic risk factors in the pathogenesis of depression that have received considerable attention. Many clinical and animal studies have highlighted associations between low levels of BDNF or high levels of inflammatory markers and the development of behavioral symptoms of depression. However, less is known about potential interaction between BDNF and inflammation, particularly within the central nervous system. Emerging evidence suggests that there is bidirectional regulation between these factors with important implications for the development of depressive symptoms and anti-depressant response. Elevated levels of inflammatory mediators have been shown to reduce expression of BDNF, and BDNF may play an important negative regulatory role on inflammation within the brain. Understanding this interaction more fully within the context of neuropsychiatric disease is important for both developing a fuller understanding of biological pathogenesis of depression and for identifying novel therapeutic opportunities. Here we review these two prominent risk factors for depression with a particular focus on pathogenic implications of their interaction.     

miR-203 protects microglia mediated brain injury by regulating inflammatory responses via feedback to MyD88 in ischemia

Much evidence demonstrates that microglia mediated inflammatory responses play an important role in brain injury in ischemia. miRNA is the important factor in regulation of inflammation. However, the effect of miRNA in microglia mediated inflammatory responses has not been well studied. In the study, we demonstrate that miR-203 negatively regulates ischemia induced microglia activation by targeting MyD88, an important adapter protein involved in most Toll-like receptors (TLRs) and interleukin-1 receptor (IL-1R) pathways. Through negative feedback, enforced expression of miR-203 or MyD88 siRNA silencing inhibits downstream NF-κβ signaling and microglia activation, thereby alleviating neuronal injury. These findings reveal that miR-203 represents a novel target regulating neuroinflammation and brain injury, thus offering a new therapeutical strategy for cerebral hypoxic diseases.     

百草枯诱导小鼠脑小胶质细胞的炎症反应

目的观察百草枯(PQ)诱导小鼠脑小胶质(BV2)细胞株的炎症反应。方法取处于对数生长期的BV_2细胞,分别暴露于终浓度为0(阴性对照)、20、40、80μmol/L的PQ溶液继续培养6、12、24、48 h。检测细胞活性和炎症因子[肿瘤坏死因子α(TNF-α)、白细胞介素-6(interleukin 6,IL-6)、IL-1β及活性氧(ROS)]水平。结果与阴性对照组比较,各剂量PQ染毒组BV_2细胞TNF-α、IL-1β、IL-6和ROS的水平及细胞抑制率均较高,差异均有统计学意义(P0.05);与染毒6 h比较,染毒12、24、48 h时BV_2细胞TNF-α、IL-1β、IL-6和ROS的水平及细胞抑制率均较高,差异均有统计学意义(P0.05)。且随着PQ染毒剂量的升高和染毒时间的延长,BV_2细胞的抑制率及TNF-α、IL-1β、IL-6和ROS水平均呈上升趋势。结论PQ能活化小鼠小胶质细胞,使其分泌炎症因子,同时诱导氧化损伤,加重细胞毒性作用。     

小胶质细胞极化在热损伤介导的早期神经损伤中的相关研究

目的观察小胶质细胞在热损伤介导的早期神经损伤中的极化状态并探讨其可能机制。 方法通过建立Beagle犬热射病动物模型，按随机数字表法将18只Beagle犬分为正常对照组（A组）9只，根据热损伤后不同时间点（1、6、24 h）分为B、C、D组各3只，B~D组置于动物体温维持仪的电热毯上，温度设置为40℃±0.5℃，每5 min监测1次直肠温度直至达到40℃。建模成功后转移到26℃±0.5℃温度和60%±0.5%湿度的环境。4组18只Beagle犬均取下丘脑进行Western blot检测，检测小胶质细胞特异性标志物CD45、iNOS及Arginase、CD206分别在4组小胶质细胞中的表达。进一步免疫组织荧光共定位观察CD45、Arginase表达。 结果A组检测出少许CD45及iNOS蛋白，B、C组两种蛋白标志物均显著高于A组（P<0.05），而D组较A组差异无统计学意义（P>0.05）；A组检测出少许Arginase及CD206蛋白，B、C、D组两种蛋白标志物均高于A组，差异有统计学意义（P<0.05）。免疫组织荧光共定位CD45、Arginase，分别在热损伤后6 h和24 h荧光光密度显著增强，差异有统计学意义（P<0.001）。 结论热射病后Beagle犬脑组织可见小胶质细胞极化活跃，中枢神经系统损伤早期1~6 h小胶质细胞活化主要以M1型为主，6 h后则转化为M2为主，热射病后24 h M2型占优势。M1/M2极化趋势与热射病早期脑损伤的相互关系可能成为热射病中枢神经损伤关键。     

针刺干预对肌萎缩侧索硬化症模型小鼠脑及脊髓中IBA-1和TNF-α表达的影响

目的:探讨电针治疗肌萎缩侧索硬化症(ALS)的机制。方法:将SOD1^G93A转基因小鼠随机分为正常组、模型组、针刺组及利鲁唑治疗组,每组各8-10只。小鼠日龄30 d后,针刺组选取双侧天枢穴(ST25)及足三里穴(ST36)予以电针治疗。利鲁唑治疗组按照30 mg/(kg·d)的剂量予以90 d日龄小鼠灌胃治疗,1次/d。模型组及对照组常规饲养,不予干预。于小鼠电针治疗前及治疗后分别对4组进行体质量记录及行为学观察。采用免疫组化法检测各组小鼠脑干及脊髓中IBA-1和TNF-α表达变化。结果:正常组小鼠精神状态及运动功能良好,针刺组及利鲁唑组小鼠较模型组精神状态及运动功能明显改善; 转棒实验结果显示针刺组及利鲁唑组小鼠潜伏期较模型组延长; 免疫组化检测结果表明在模型组脑干IBA-1阳性细胞表达高于正常组(P<0.05); 而利鲁唑组IBA-1阳性细胞表达虽有降低,但组间无统计学差异(P>0.05)。该结果与IBA-1阳性细胞在脊髓L_4-5节段表达趋于一致(P<0.05)。针刺治疗后脊髓中促炎因子TNF-α表达明显减少(P<0.05),但利鲁唑组较模型组无统计学差异(P>0.05)。结论:电针治疗及利鲁唑灌胃治疗均可以改善小鼠运动功能及生存质量,但早期针刺干预明显减少脑干及脊髓中小胶质细胞的活化,抑制促炎因子TNF-α释放,表明电针治疗ALS有效,其机制可能与针刺抑制神经炎症产生有关。