溶血磷脂酸对THP-1细胞Toll样受体4／核因子-κB信号通路的影响

目的观察溶血磷脂酸（lysophosphatidieacid,LPA）对人单核细胞株THP-1细胞Toll-样受体4（tolllikereceptor4,TLR4）／核因子-κB（nuclearfactorkappaB,NF-κB）信号通路的影响,探讨LPA致动脉粥样硬化的机制。方法以不同浓度水平LPA（0～10μM）刺激人THP-1细胞4h,或以LPA1μM处理THP-1细胞不同时间（0-8h）,荧光定量RT—PCR法测定TLR4mRNA表达,Westernblot检测TLR4蛋白、核蛋白NF-κBp65表达变化。结果IJPA以剂量依赖和时间依赖的方式上调THP-1细胞TLR4基因和蛋白的表达,并同步诱导THP-1细胞NF-κBp65活化。结论LPA可显著上调THP-1细胞TLR4表达及促进NF-κB的活化,LPA致粥样硬化作用可能部分是由TLR4／NF-κB信号途径介导的。     

Toll样受体4介导的MyD88信号通路在脑缺血损伤中的作用

脑缺血损伤发生机制十分复杂,目前有多种相关学说,大量研究表明炎症反应是脑缺血损伤主要机制之一,然而炎性瀑布反应触发后更加剧了脑损伤的发展,其中炎性受体发挥了重要作用。研究表明Toll样受体4(TLR4)在脑缺血的发生、发展和继发性脑损伤中起重要作用,髓样分化因子88(MyD88)是TLR4信号转导通路中关键的衔接蛋白,能够启动下游炎性因子的转导。对TLR4介导的MyD88信号通路在脑缺血损伤中的作用进展做一综述。     

Toll样受体4信号通路对脑缺血损伤影响的研究进展

Toll样受体4(TLR4)可以调节固有及获得性免疫反应应答,在多种疾病的发展机制中具有至关重要的作用。研究发现TLR4可通过多种途径参与脑缺血损伤,例如炎症反应、细胞凋亡、高迁移率族蛋白B1、热休克蛋白60、S100A蛋白、缺血预处理等。文中就TLR4对脑缺血损伤的作用机制研究做一综述。     

溶血磷脂酸对人单核细胞株基质金属蛋白酶-9和Toll样受体4表达的影响以及核因子-κB抑制剂的干预作用

目的 探讨溶血磷脂酸(LPA)对人单核细胞株(THP-1)基质金属蛋白酶(MMP)-9和Toll样受体4(TLR-4)表达的影响以及核因子(NF)-κB抑制剂的干预作用.方法 分别以0、0.1、0.5、1、5、10 μmol/L的LPA加入人THP-1细胞4 h,以及将NF-κB抑制剂咖啡酸苯乙酯(CAPE)20 mg/L预处理THP-1细胞1 h后,再加入LPA 1μmol/L4 h.应用酶联免疫吸附法测定细胞上清液的MMP-9含量,RT-PCR法测定TLR-4mRNA表达,Western Blot检测NF-κBp65活性.结果 LPA 0、0.1、0.5、1、5、10 μmol/L组细胞上清液MMP-9水平分别为(256.63±20.51)ng/ml、(296.57±10.92)ng/ml、(330.73±9.05)ng/ml、(367.8±6.4)ng/ml、(316.4±4.87)ng/ml及(303.00±6.45)ng/ml,各组间差异有统计学意义(均P＜0.01);各组TLR-4 mRNA表达的差异有统计学意义(均P＜0.01).CAPE干预组细胞上清液MMP-9含量、TLR-4 mRNA表达及NF-κBp65活性显著低于LPA 1μmol/L组(均P＜0.01).结论 LPA能促进THP-1细胞MMP-9和TLR-4的表达,NF-κB抑制剂预处理可以降低其表达水平.     

大鼠脑出血后核因子-κB的表达及黄芪多糖的干预作用

目的研究黄芪多糖（astragalus polysaccharide，APS）对大鼠脑出血（ICH）后血肿周围核因子-κB（nuclear factor-kappa B，NF-κB）蛋白表达的影响，并探讨APS抗炎的脑保护机制。方法采用Ⅶ型胶原酶注射至大鼠右侧苍白球诱导ICH模型并于造模术后2h行APS腹腔注射，分别于6h和1、3、5d4个时间点进行大鼠神经行为学评分，采用免疫组化方法检测血肿周围组织NF-κB表达的动态变化，采用透射电镜观察术后3d血肿周围神经元超微结构的变化。结果与模型组比较，APS干预后3d和5d大鼠神经行为学评分明显减少（P〈0．05），干预6h及1、3、5d时NF-κB阳性细胞数明显减少（P〈0．05），神经元超微结构改变亦比模型组减轻。结论APS可抑制NF—κB激活，减轻炎症反应，改善神经功能缺损症状。     

槐定碱抑制TLR4/NF-κB通路的激活和机制研究

目的观察脑缺血-再灌注损伤后TLR4/NF-κB通路的活性变化,并探讨槐定碱的调控机制。方法采用改良线栓法制备大脑中动脉缺血-再灌注模型。实验采用Western blot和qR-T PCR观察TLR4、NF-κB基因和蛋白变化,比较各组脑梗死体积、患侧脑水肿和神经功能。结果脑缺血-再灌注后TLR4、NF-κB表达明显上调。槐定碱通过抑制TLR4/NF-κB通路的激活,明显改善神经功能缺失,减轻脑水肿,减小脑梗死体积。结论 TLR4/NF-κB通路参与了槐定碱的脑保护作用,为其临床应用提供了理论基础。     

参附注射液对大鼠全脑缺血再灌注时核转录因子-κB表达的影响

目的探讨参附注射液（Shenfu Injection）对大鼠全脑缺血再灌注时核转录因子-κB（nuclearfac—torkappaB，NF-κB）表达的影响及其治疗作用。方法采用四血管阻塞的方法复制出大鼠全脑缺血再灌注模型，采用免疫组化法、原位杂交法和原位末端标记法分别检测假手术组（A组）、全脑缺血再灌注组（B组）、参附注射液治疗组（C组）海马CA1区NF-κB、肿瘤坏死因子-amRNA（TNF-amRNA）表达及细胞凋亡数的变化。结果与假手术组比较，全脑缺血再灌注组海马CAl区NF-κB和TNF-amRNA的表达及细胞凋亡数明显增加（P〈0．01）；NF-κB和TNF-amRNA的表达分别于再灌注6h和12h达到高峰，并持续到48h；细胞凋亡数随再灌注时间的延长而逐渐增多（P〈0．01）。参附注射液治疗后NF-κB和TNF-amRNA的表达下降，细胞凋亡数减少（P〈0．01）。结论在脑缺血再灌注救治过程中参附注射液可能通过抑制NF-κB与TNF-amRNA的表达，进而减少细胞凋亡而发挥脑保护作用。     

脑组织TOLL样受体2的激活与大鼠局灶性脑缺血再灌注损伤的关系

目的 探讨TOLL样受体2(TLR2)的激活与脑组织缺血再灌注损伤的关系.方法 线栓法制造局灶性脑缺血再灌注损伤大鼠模型,采用免疫组织化学法观察TLR2和核因子-κB(NF-κB)在不同再灌注时间点缺血脑组织的分布和表达量,同时应用酶联免疫方法检测肿瘤坏死因子-α(TNF-α)在不同再灌注时间点缺血脑组织内浓度,并分析其表达相关性.结果 大鼠局灶性脑缺血再灌注损伤过程中,TLR2蛋白在缺血半影区及皮质区、纹状体区有表达,且在灌注早期(即1h)即有增强表达,在3 h即达高峰;皮质区和纹状体区NF-κB表达从6 h开始逐渐增强,于再灌注24 h达高峰;缺血侧半球皮质内TNF-α变化规律与NF-κB相似,但表达高峰在再灌注12 h;TLR2蛋白的表达与NF-κB和TNF-α表达呈正相关.结论 TLR2在脑缺血再灌注过程中被激活,可能通过NF-κB导致炎性因子TNF-α等的大量表达介导参与了脑缺血再灌注损伤的过程.     

氢气抑制核因子-κB通路对糖尿病周围神经病变的保护作用

目的观察氢气对链脲霉素致糖尿病周围神经病变模型大鼠坐骨神经功能和疼痛行为学的影响,并探讨其可能的作用机制。方法腹腔注射链脲霉素(65 mg/kg)建立糖尿病大鼠模型,6周后腹腔注射富氢生理盐水(5 ml/kg),连续治疗2周后观察不同处理组大鼠坐骨神经功能和疼痛行为学变化,并检测坐骨神经炎性因子[肿瘤坏死因子α(TNFα)和白细胞介素6(IL 6)]及核因子κB(NFκB)p65亚基表达变化。结果 (1)与正常对照组相比,模型制备成功第8周时模型组大鼠体质量降低、血糖水平升高(均P=0.000);与模型组相比,氢气治疗组大鼠体质量和血糖水平无明显改善(均P>0.05)。(2)与正常对照组相比,模型制备成功第8周时模型组大鼠坐骨神经传导速度减慢、热痛阈和机械性痛阈降低(均P=0.000);而与模型组相比,氢气治疗后大鼠坐骨神经传导速度增加、热痛阈和机械性痛阈提高(均P=0.000)。(3)经氢气治疗后,大鼠坐骨神经TNFα和IL 6表达水平降低(均P=0.000),NFκB p65亚基阳性细胞数目减少(P=0.000)。结论糖尿病周围神经病变与炎症反应有关,而氢气可以通过抑制NFκB及其下游炎性因子的表达而发挥对糖尿病周围神经损害的保护作用。     

Anti-inlfammatory properties of lipoxin A4 protect against diabetes mellitus complicated by focal cerebral ischemia/reperfusion injury

Lipoxin A4 can alleviate cerebral ischemia/reperfusion injury by reducing the inlfammatory reaction, but it is currently unclear whether it has a protective effect on diabetes mellitus complicated by focal cerebral ischemia/reperfusion injury. In this study, we established rat models of diabetes mellitus using an intraperitoneal injection of streptozotocin. We then induced focal cerebral ischemia/reperfusion injury by occlusion of the middle cerebral artery for 2 hours and reperfusion for 24 hours. After administration of lipoxin A4via the lateral ventricle, infarction volume was reduced, the expression levels of pro-inlfammatory factors tumor necrosis factor alpha and nuclear fac-tor-kappa B in the cerebral cortex were decreased, and neurological functioning was improved. These ifndings suggest that lipoxin A4 has strong neuroprotective effects in diabetes mellitus complicated by focal cerebral ischemia/reperfusion injury and that the underlying mech-anism is related to the anti-inlfammatory action of lipoxin A4.     

Temporal pattern of Toll-like receptor 9 upregulation in neurons and glial cells following cerebral ischemia reperfusion in mice

Purpose: The family of Toll-like receptors (TLRs) has recently been reported to play a role in ischemic injury, but the time course and cell types of the post-stroke TLR9 upregulation remain unclear. In this study, we investigated the dynamic changes of TLR9 expression and the expression of TLR9 in neurons and glial cells after cerebral ischemia reperfusion in mice. Methods: Focal cerebral ischemia was induced by middle cerebral artery occlusion for 90 min in male C57BL/6 mice. The TLR9 expression levels in the tissue surrounding the infarct were detected by Western Blot at 6 h, 3 d, 7 d, 14 d, 21 d, and 28 d after reperfusion. The expression of TLR9 in neurons and glial cells was observed by immunofluorescence staining. Results: The expression of TLR9 protein first increased and then decreased, with the peak observed at 14 d–21 d. Only small punctate intracellular TLR9 was occasionally observed in the neurons at each time point, and the TLR9-positive rate showed no difference at different time points. By contrast, the activated microglia gathered at the margin of the infarct, and the intracellular TLR9 changed from scattered small punctate to coarse and lumpy. The TLR9-positive rate of microglia was first increased and then decreased with time, with the peak observed at 3 d. No positive TLR9 staining was found in the astrocytes and oligodendrocytes. Conclusions: TLR9 expression showed dynamic changes for a long period of time and microglias were the main brain cells to express TLR9 after cerebral ischemia and reperfusion.     

大鼠脑缺血再灌注后血小板活化因子及其受体的病理作用

目的探讨血小板活化因子(PAF)及其受体(PAFR)在大鼠缺血再灌注后的病理性神经毒性作用及其可能的干预方法。方法选用SD大鼠建立一侧大脑中动脉缺血再灌注模型,于缺血再灌注后3h、6h、12h用高效薄层层析法测定大脑皮质缺血侧和缺血对侧PAF含量、RT-PCR检测PAFR基因表达。使用原代野生型小鼠皮质神经元细胞培养系统,将体外培养的神经元分为空白对照组、PAF组和PAF 拮抗剂组,应用碘化物/钙黄绿素染色分别检测各组细胞凋亡情况。结果缺血侧的大鼠皮质在缺血再灌注后3h、6h、12h PAF含量(单位为ng/g)分别为13·71±1·23、17·90±1·14和17·89±1·54;PAFR基因表达(单位为密度)分别为0·5892±0·1222、2·0512±0·1519、2·0168±0·1653,缺血再灌注6h、12h组缺血侧皮质PAF含量及PAFR基因表达与缺血对侧、再灌注3h比较差异有极显著性(均P<0·01);在进一步的体外小鼠皮质神经元细胞培养中,PAF组、PAF 受体拮抗剂组细胞凋亡率分别为(41·92±1·39)%和(18·94±1·18)%,与空白对照组[(10·23±0·59)%]比较差异有极显著性(均P<0·01),PAF 受体拮抗剂组细胞凋亡率与PAF组比较明显降低(P<0·01)。结论缺血性神经损伤作用是由PAF及其受体介导,用PAFR拮抗剂进行干预,对缺血缺氧性神经元损伤具有保护作用。     

Puerarin protects brain tissue against cerebral ischemia/reperfusion injury by inhibiting the inflammatory response

Puerarin, a traditional Chinese medicine, exerts a powerful neuroprotective effect in cerebral ischemia/reperfusion injury, but its mechanism is unknown. Here, we established rat models of middle cerebral artery ischemia/reperfusion injury using the suture method. Puerarin(100 mg/kg) was administered intraperitoneally 30 minutes before middle cerebral artery occlusion and 8 hours after reperfusion. Twenty-four hours after reperfusion, we found that puerarin significantly improved neurological deficit, reduced infarct size and brain water content, and notably diminished the expression of Toll-like receptor-4, myeloid differentiation factor 88, nuclear factor kappa B and tumor necrosis factor-α in the ischemic region. These data indicate that puerarin exerts an anti-inflammatory protective effect on brain tissue with ischemia/reperfusion damage by downregulating the expression of multiple inflammatory factors.     

Neuroprotective effect of angiotensin Ⅱ type 2 receptor during cerebral ischemia/reperfusion

Angiotensin Ⅱ type 2 receptor(AT2R) activation has been shown to protect against stroke,but its precise mechanism remains poorly understood.We investigated whether the protective effect of AT2 R against ischemia/reperfusion injury is mediated by the suppression of immune and inflammatory responses.Rat models of middle cerebral artery occlusion were intraperitoneally injected with physiological saline,the AT2 R agonist CGP42112(1 mg/kg per day) or antagonist PD123319(1 mg/kg per day).In the CGP42112 group,AT2 R expression increased,the infarct area decreased,interleukin-1β and tumor necrosis factor-α expression decreased,and interleukin-10 expression increased compared with the saline group.Antagonisin AT2 R using PD123319 produced the opposite effects.These results indicate that AT2 R activation suppresses immune and inflammatory responses,and protects against cerebral ischemia/reperfusion injury.     

双黄连注射液抑制病毒性脑炎模型小鼠脑组织核因子κB的表达：具有时间和剂量的依赖性

有研究认为双黄连注射液的抗病毒作用可能与抑制核因子κB的活性有关。实验观察柯萨奇病毒B3病毒性脑炎模型小鼠脑组织中核因子κB的表达,发现腹腔注射双黄连注射液检测模型小鼠脑组织中核因子κB基因和蛋白表达明显降低,随着干预时间延长和治疗剂量增加,抑制效应更显著。证实双黄连注射液以剂量和时间依赖形式降低病毒性脑炎模型小鼠脑组织中核因子κB的表达。     

Effect of propofol on brain-derived neurotrophic factor and tyrosine kinase receptor B in the hippocampus of aged rats with chronic cerebral ischemia

We intraperitoneally injected 10 and 50 mg/kg of propofol for 7 consecutive days to treat a rat model of chronic cerebral ischemia. A low-dose of propofol promoted the expression of brain-derived neurotrophic factor, tyrosine kinase receptor B, phosphorylated cAMP response element binding protein, and cAMP in the hippocampus of aged rats with chronic cerebral ischemia, but a high-dose of propofol inhibited their expression. Results indicated that the protective effect of propofol against cerebral ischemia in aged rats is related to changes in the expression of brain-derived neurotrophic factor and tyrosine kinase receptor B in the hippocampus, and that the cAMP-cAMP responsive element binding protein pathway is involved in the regulatory effect of propofol on brain-derived neurotrophic factor expression.     

小鼠局灶性脑缺血再灌注后IL-33及其受体的时程表达

目的检测白细胞介素-33(IL-33)及其膜受体ST2和可溶型受体sST2在小鼠局灶性脑缺血再灌注后不同时程的表达特征。方法利用线栓法闭塞大脑中动脉(MCAO)30 min诱导建立小鼠可逆性局灶性脑缺血再灌注损伤模型,通过半定量RT-PCR检测脑缺血再灌注后6 h、24 h和3 d缺血脑组织中IL-33及其膜受体ST2、凋亡相关蛋白Caspase-8和Caspase-3的mRNA表达水平,并通过免疫组织化学染色观察了IL-33在不同缺血脑区(运动皮质、感觉皮质、海马和纹状体)的时程表达情况;ELISA法检测了小鼠MCAO模型再灌注后不同时间点血清中IL-33及其可溶型受体sST2的表达水平。结果 IL-33 mRNA在缺血后6 h和3 d表达减少,但在24 h无明显改变;凋亡相关蛋白Caspase-3和Caspase-8在缺血后3个时间点均显著增高,且Caspase-3在6 h和3 d的mRNA表达水平较24 h高;ST2 mRNA在缺血后6 h无减少,但在24 h和3 d有明显减少;除了MCAO 24 h组运动皮质和纹状体阳性染色增加外,IL-33阳性细胞数在缺血后不同时程各脑区均有不同程度减少;缺血后外周血中IL-33的表达量无明显升高或降低,而sST2的表达水平在缺血后6 h即已显著升高。结论脑缺血再灌注后IL-33/ST2信号通路被下调,其与sST2表达增多的效应发挥和神经元凋亡有关。