溴氰菊酯对大鼠脑神经细胞凋亡及Caspase-3表达的影响

目的 研究Caspase-3在溴氰菊酯(deltamethrin,DM)诱导大鼠脑神经细胞凋亡机制中的作用。方法 成年雄性Wistar大鼠腹腔注射12.5 mg/kg的DM染毒,并分成不同时间观察组;以FACS420型流式细胞仪测定大鼠海马和皮层细胞凋亡率和Caspase-3蛋白的表达;以四肽化合物Ac-DEVD-pNa为底物测其神经细胞Caspase-3活力。结果 DM染毒后24 h、48 h、5 d组大鼠海马、皮层神经细胞凋亡率[海马:(8.45±1.02)％、(9.44±1.14)％、(7.58±0.75)％,皮层:(7.90±0.49)％、(8.01±0.87)％、(7.97±0.41)％]均高于对照组[海马:(2.97±0.36)％,皮层:(3.50±0.48)％],差异有统计学意义(P<0.01),而5 h组未见明显变化;DM染毒后5、24、48 h,大鼠海马、皮层神经细胞Caspase-3活力(A405nm吸光度值,海马:0.389±0.038、0.472±0.041、0.295±0.049,皮层:0.321±0.068、0.429±0.077、0.344±0.047)与5 d组大鼠海马Caspase-3活力(0.246±0.065)均明显高于对照组(海马:0.184±0.054,皮层:0.198±0.049),差异有统计学意义(P<0.05,P<0.01);DM染毒后5、24、48h,大鼠脑组织Caspase-3蛋白表达亦明显高于对照组,5 d组未见明显变化。结论DM可影响大鼠脑海马和皮层神经细胞凋亡率、Caspase-3活力及蛋白表达;Caspase-3活力及蛋白表达升高发生在神经细胞     

姜黄素通过新型蛋白激酶-θ亚型抑制大鼠海马神经元中通道的研究

目的探讨姜黄素对Ca2+通道电流的选择性抑制作用。方法使用10 mmol/L的钡离子作为电荷载体,利用膜片钳技术记录大鼠海马神经元的全细胞电流;免疫印迹法检测大鼠海马神经元中蛋白激酶C(PKC)的分型;进行全细胞膜片钳技术分析。结果姜黄素浓度依赖性抑制高电压门控Ca2+通道电流(IBa),姜黄素对Ca2+型通道的激活无显著影响,但能够使Ca2+通道的失活曲线向超极化方向移动;此外,在体外培养的大鼠海马神经元中,细胞内应用PKC-θ的抑制肽PKC-θ-IP,能消除黄素诱导抑制的作用;新型PKC-δ、PKC-ε和PKC-θ,但不包括PKC-η在神经元中内源性表达。结论姜黄素在大鼠海马神经元中通过新型的PKC-θ依赖途径抑制IBa,这个结论可能有利于证明姜黄素的神经保护作用。     

Cerebral complement C1q activation in chronic Toxoplasma infection

Exposure to the neurotropic parasite, Toxoplasma gondii, causes significant brain and behavioral anomalies in humans and other mammals. Understanding the cellular mechanisms of T. gondii-generated brain pathologies would aid the advancement of novel strategies to reduce disease. Complement factor C1q is part of a classic immune pathway that functions peripherally to tag and remove infectious agents and cellular debris from circulation. In the developing and adult brain, C1q modifies neuronal architecture through synapse marking and pruning. T. gondii exposure and complement activation have both been implicated in the development of complex brain disorders such as schizophrenia. Thus, it seems logical that mechanistically, the physiological pathways associated with these two factors are connected. We employed a rodent model of chronic infection to investigate the extent to which cyst presence in the brain triggers activation of cerebral C1q. Compared to uninfected mice, cortical C1q was highly expressed at both the RNA and protein levels in infected animals bearing a high cyst burden. In these mice, C1q protein localized to cytoplasm, adjacent to GFAP-labeled astrocytes, near degenerating cysts, and in punctate patterns along processes. In summary, our results demonstrated an upregulation of cerebral C1q in response to latent T. gondii infection. Our data preliminarily suggest that this complement activity may aid in the clearance of this parasite from the CNS and in so doing, have consequences for the connectivity of neighboring cells and synapses.     

β-淀粉样蛋白与老年痴呆症发生发展关系研究进展

老年痴呆症足一种常见的进行性神经系统退行性疾病，主要发生于中老年人群，并且其发病率在逐年升高，对AD发病机制的探讨和研究变得尤为重要。在探讨的过程中，出现了很多发病假说，本文主要围绕β-淀粉样蛋白假说介绍其发病机理和最新的研究进展。     

氧葡萄糖剥夺-再恢复后抑制小胶质细胞TLR9激活对神经元的保护作用

目的:观察氧葡萄糖剥夺-再恢复(OGDR)后小胶质细胞BV-2 Toll样受体9(TLR9)激活对神经元凋亡的影响。方法:对BV-2细胞或TLR9-siRNA转染的BV-2细胞进行OGDR处理4 h后,将细胞上清添加至OGDR处理4 h的小鼠原代皮层神经元中,继续正常培养24 h后,倒置显微镜下观察神经元形态变化,TUNEL染色检测神经元凋亡,Western blotting检测神经元caspase-3蛋白的表达。实验分为正常BV-2组、negative control-siRNA组、TLR9-siRNA组、OGDR组、OGDR+NC-siRNA组、OGDR+TLR9-siRNA组和对照组(神经元OGDR后不添加BV-2细胞上清)。结果:OGDR后神经元胞体肿胀,折光性下降,出现空泡样变,轴突变细、扭曲、断裂。TUNEL染色各组均可见绿染凋亡小体。与对照组比较,其它组的caspase-3蛋白表达升高(P0.05);与正常BV-2组比较,OGDR组和TLR9-siRNA组的caspase-3蛋白表达升高(P0.05);OGDR+TLR9-siRNA转染组与TLR9-siRNA转染组和OGDR组比较,caspase-3蛋白表达下降(P0.05)。结论:OGDR后BV-2细胞TLR9激活致神经元凋亡增多,caspase-3蛋白表达升高;抑制TLR9表达后,神经元损伤减轻。     

Inhibition of insulin-like growth factor-I signaling by ethanol in neuronal cells

BACKGROUND: Ethanol inhibits insulin-like growth factor-I receptor (IGF-IR) activation. However, the potency of ethanol for inhibition of the IGF-IR and other receptor tyrosine kinases varies considerably among different cell types. We investigated the effect of ethanol on IGF-I signaling in several neuronal cell types. METHODS: IGF-I signaling was examined in SH-SY5Y neuroblastoma cells, primary cultured rat cerebellar granule neurons, and rat NG-108 neuroblastoma x glioma hybrids. The tyrosine phosphorylation of IGF-IR, IRS-2, Shc, and p42/p44 MAP kinase (MAPK), and the association of Grb-2 with Shc, were examined by immunoprecipitations and Western blotting. RESULTS: IGF-I-mediated tyrosine phosphorylation of MAPK was inhibited by ethanol in all cell lines. IGF-IR autophosphorylation was markedly inhibited by ethanol in SH-SY5Y cells, was only mildly inhibited in cerebellar granule neurons, and was unaffected in rat NG-108 cells. In vitro tyrosine autophosphorylation of immunopurified IGF-IR obtained from all cell lines was inhibited by ethanol. There was also differential ethanol sensitivity of IRS-2 and Shc phosphorylation, and the association of Shc with IRS-2, among the different cell types. CONCLUSIONS: The findings demonstrate that IGF-I-mediated MAPK activation is a sensitive target of ethanol in diverse neuronal cell types. The data are consistent with ethanol-induced inhibition of IGF-IR activity, although the extent of IGF-IR tyrosine autophosphorylation per se is a poor marker of the inhibitory action of ethanol on this receptor. Furthermore, despite uniform inhibition of MAPK in the different neuronal cell types, tyrosine phosphorylation of proximal mediators of the IGF-IR are differentially inhibited by ethanol.     

氟对原代培养大鼠海马细胞氧化应激及凋亡的影响

目的观察氟诱导的大鼠原代培养海马细胞氧化应激损伤和凋亡及活性氧在细胞凋亡中的作用。方法采用原代细胞培养的方法,将大鼠海马细胞暴露于20、40、80 mg／L氟化钠中,24 h后检测海马细胞存活率、活性氧(ROS)、丙二醛(MDA)及细胞凋亡。结果与对照组比较,各染氟组细胞存活率降低(9．1％、 12．2％、25．0％),但组间比较差异无统计学意义(F=106．8．P>0．05)。各染氟组MDA(5．06、7．66、 9_82 nmol／mg Pr)明显高于对照组(2．34 nmol／mg Pr),组间比较差异有统计学意义(F=7．151,P<0．05)。氟对海马细胞的损伤呈明显的剂量-效应关系,染氟40、80 mg／L组细胞内ROS和细胞凋亡率高于20 mg／L组和对照组,细胞凋亡率与ROS水平存在明显正相关关系(r=0．913,P<0．05)。结论氟可引起大鼠海马细胞发生氧化应激反应及凋亡,活性氧可能在氟诱导细胞凋亡中起重要作用。     

Type 1 metalloproteinase is selectively expressed in adult rat brain and can be rapidly up-regulated by kainate

The expression of metalloproteinase MMP-1 was traced in frontal sections of the rat brain in normal conditions and 4 h after an intraperitoneal injection of kainate. In the olfactory lobe, immunoreactivity was normally detected in the lateral olfactory tract. Kainate treatment led to the appearance of additional immunoreactivity in the neuropilar tracts. In the hippocampal part of brain, immunoreactive neurons were found exclusively after the kainate treatment in several hypothalamic and amygdalar nuclei, and in the restricted cortex areas (clusters of neurons in layers 3–4 of cortex, and a stripe of cells in layer 6). In the area between the hippocampus and cerebellum, MMP-1-like immunoreactivity was normally present in the entorhinal cortex, in the lateral periaqueductal gray, and in the pontine nucleus. After kainate treatment, the immunoreactive neurons were also found in the medial entorhinal cortex and in the dorsal raphe nucleus. In the brain stem, the immunoreactive cells were normally found in six nuclei. After kainate treatment, additional immunoreactivity appeared in the inferior olive neurons and in tracts supplying the cerebellar cortex. Thus, MMP-1 is present in several brain areas in normal conditions at a detectable level, and its expression increases after kainate-induced seizures.     

木犀草素对实验性自身免疫性脑脊髓炎大鼠SPH/SPHK1/S1P1通路及神经元凋亡的影响

目的 探讨木犀草素(Luteolin)对实验性自身免疫性脑脊髓炎(Experimental autoimmune encephalomyelitis,EAE)大鼠神经酰胺-鞘氨醇(Sphingosine,SPH)/鞘氨醇激酶1(Sphingosine kinase 1,SPHK1)/1-磷酸鞘氨醇受体1(Sphingosine-1-phosphate 1,S1P1)通路蛋白表达水平及神经元凋亡的影响。方法 取雌性Wistar大鼠,采用注射豚鼠脊髓免疫抗原法建立EAE模型,将造模成功的50只大鼠随机分为模型(EAE)组,Luteolin低(5mg/kg)、中(25 mg/kg)、高(50 mg/kg)剂量组,芬戈莫德(FTY720)阳性对照组(61.7 mg/kg),每组各10只; 另取10只雌性Wistar大鼠,注射等量生理盐水,作为空白对照(Control)组; 各组于造模15 d后开始给药,Luteolin低、中、高剂量组经腹腔注射相应剂量Luteolin药物,芬戈莫德(FTY720)阳性对照组灌胃给予相应剂量的FTY720,EAE组和Control组灌胃和腹腔注射等量生理盐水,各组连续给药14 d,2次/d; 各组大鼠于末次给药12 h后对大鼠EAE临床症状进行评分; 取脊髓组织,用苏木精-伊红染色(Hematoxylin eosin,HE)及固蓝(Luxol fast blue,LFB)染色法检测大鼠髓鞘组织病理表现及脱髓鞘面积; 原位缺口末端转移酶标记法(TdT-mediated dUTP nick and labeling,TUNEL)法检测髓鞘组织中神经元的凋亡情况并计算凋亡率; 以蛋白免疫印迹法(Western Blot)检测髓鞘组织中通路蛋白SPHK,SPH,S1P1及凋亡蛋白半胱氨酸天冬氨酸蛋白酶-12(Cystein-asparate protease-12,Caspase-12)蛋白相对表达水平。结果 与Control组比较,EAE组大鼠EAE临床症状评分、脊髓组织炎性细胞浸润和髓鞘脱失程度、神经元凋亡率、髓鞘组织中SPH,SPHK1,S1P1及Caspase-12蛋白表达水平均升高(P<0.05); 与EAE组比较,Luteolin低、中、高剂量组及芬戈莫德(FTY720)阳性对照组大鼠EAE临床症状评分、脊髓组织炎性细胞浸润和髓鞘脱失程度、神经元凋亡率、髓鞘组织中SPH,SPHK1,S1P1及Caspase-12蛋白表达水平均降低(P<0.05),且Luteolin各剂量组上述指标水平呈剂量依赖性; Luteolin高剂量组与芬戈莫德(FTY720)阳性对照组的上述指标水平均无明显差异(P>0.05)。结论 Luteolin可能通过抑制EAE模型大鼠髓鞘组织SPHK,SPH,S1P1蛋白表达来抑制EAE大鼠脱髓鞘病变及神经元凋亡。     

Efecto de la exposición a bajas dosis de ozono en la expresión de la interleucina 17A durante el proceso de neurodegeneración progresiva en el hipocampo de ratas

IntroductionChronic exposure to low doses of ozone causes oxidative stress and loss of regulation of the inflammatory response, leading to progressive neurodegeneration.ObjectiveWe studied the effect of chronic exposure to low doses of ozone on IL-17A concentration and expression in neurons, microglia, astrocytes, and T cells in the rat hippocampus.MethodsWe used 72 Wistar rats, divided into 6 groups (n = 12): a control group (no ozone exposure) and 5 groups exposed to ozone (0.25 ppm, 4 h daily) for 7, 15, 30, 60, and 90 days. We processed 6 rats from each group to quantify IL-17A by ELISA; the remaining 6 were processed for immunohistochemistry (against IL-17A and GFAP, Iba1, NeuN, and CD3).ResultsThe ELISA study data showed a significant increase in IL-17A concentrations in the 7-, 15-, 30-, and 60-day exposure groups, with regard to the control group (P < .05). Furthermore, they indicate that hippocampal neurons were the cells showing greatest immunoreactivity against IL-17A between 60 and 90 days of exposure to ozone; we also observed an increase in activated astrocytes in the 30- and 60-day exposure groups.ConclusionExposure to ozone in rats induces an increase in IL-17A expression, mainly in hippocampal neurons, accompanied by hippocampal astrocyte activation during chronic neurodegeneration, similar to that observed in Alzheimer disease in humans.