PFOS对BV-2细胞的炎性损伤及机制研究

目的：探讨环境内分泌干扰物全氟辛磺酸(perfluorooctane suifonate,PFOS)对小鼠小胶质瘤细胞BV-2的损伤作用及其炎性反应。方法：利用体外培养的小胶质细胞,给予不同浓度和作用时间的PFOS进行染毒,通过MTT法检测BV-2细胞活力;实时定量PCR的方法观察诱导型一氧化氮合酶（inducible nitric oxide synthesis,iNOS）、白介素（interleukin,IL）-6 和肿瘤坏死因子（tumor necrosis factor,TNF）-α mRNA的表达。ELISA法检测炎性因子IL-6,免疫蛋白印迹法检测核转录因子kappa B(nuclear factor-kappa B,NF-κB)等信号蛋白表达情况。结果：不同浓度PFOS对BV-2细胞染毒12、24 h后,细胞活力下降,引起明显的细胞损伤。ELISA结果显示, PFOS作用BV-2 24 h后,细胞炎性因子IL-6分泌增加。此外,PFOS还可引起iNOS、IL-6基因表达上调,而TNF-α表达有下降趋势。PFOS与细胞孵育后,炎性通路NF-κB明显激活,表现为磷酸化程度升高。且随染毒浓度的增加,p-NF-κB的表达有上升趋势;此外,随染毒时间的增加,p-NF-κB的表达亦有上升趋势。结论：PFOS可引起BV-2细胞活力降低,激活NF-κB通路,促进炎性因子的释放,该途径可为阐明PFOS引起的神经系统损伤的分子机制提供理论依据。     

Prevention of Acute Lung Allograft Rejection in Rat by CTLA4Ig

CTLA4 immunoglobulin (CTLA4Ig), which binds with a high affinity to B7-1 and B7-2, interrupts T-cell activation by inhibiting costimulatory signal. CTLA4Ig has been used in hopes of achieving antigen-specific tolerance induction in several solid organ transplants. In lung allograft rejection, however, its use has been controversial in terms of its effect on prevention of rejection. In the present study, the effect of murine CTLA4Ig on rat-lung allograft rejection was investigated. Rat left-lung transplantation was performed in an RT1 incompatible donor (Brown Norway; BN)-recipient (F344) combination. All allografts (n = 12) without any treatment were rejected within 7 days after transplantation. A single injection of murine form CTLA41g at a dose of 100 microg intraperitoneally (ip) or intravenously (iv) on day 1 post-transplantation achieved long-term graft survival (>90days) in 2/5 (40%) and 3/8 (38%), respectively. Moreover, 6/7 (86%) allografts in rats that received iv injection of 500 microg CTLA4Ig survived more than 90days. Allograft survival in the CTLA4Ig 500 microg iv recipient group was significantly longer than that in the no-treatment control or control immunoglobulin group (p <0.01). Four out of seven recipients bearing functional allografts for more than 90 days with the CTLA4Ig treatment accepted donor-specific skin grafts, whereas all third-party skin grafts (n=3) were rejected. Prevention of rat-lung allograft rejection could be achieved by intravenous administration of CTLA4Ig, resulting in long-term allograft survival with acceptance of donor-specific skin grafts.     

Mechanism of vascular smooth muscle cells activation by hydrogen peroxide: role of phospholipase C gamma.

BACKGROUND: Hydrogen peroxide (H2O2) formation is a critical factor in processes involving ischaemia/ reperfusion. However, the precise mechanism by which reactive oxygen species (ROS) induce vascular damage are insufficiently known. Specifically, activation of phospholipase C gamma (PLCgamma) is a probable candidate pathway involved in vascular smooth muscle cells (VSMC) activation by H2O2. METHODS: The activation of human venous VSMC was measured as cytosolic free calcium mobilization, shape change and protein phosphorylation, focusing on the role of tyrosine phosphorylation-activated PLCgamma. RESULTS: The exposure of VSMC to exogenous H2O2 caused a rapid increase in cytosolic free calcium concentration ([Ca2+]i), and induced a significant VSMC shape change. Both effects were dependent on a tyrosine kinase-mediated mechanism, as determined by the blockade of short-term treatment of VSMC with the protein tyrosine kinase inhibitor, genistein. Giving further support to the putative role of phospholipase C (PLC)-dependent pathways, the [Ca2+]i and VSMC shape change response were equally inhibited by the specific PLC blocker, 1-(6-((17-beta-methoxyestra-1,3,5(10)trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione (U73122). In addition, U73122 had a protective effect against the deleterious action (24 h) of H2O2 on non-confluent VSMC. As a further clarification of the specific pathway involved, the exposure to H2O2 significantly stimulated the tyrosine phosphorylation of PLCgamma with a concentration- and time-profile similar to that of [Ca(2+)](i) mobilization. CONCLUSIONS: The present study reveals that H(2)O(2) activates PLCgamma on VSMC through tyrosine phosphorylation and that this activation has a major role in rapid [Ca(2+)](i) mobilization, shape-changing actions and damage by H(2)O(2) in this type of cells. These findings have direct implications for understanding the mechanisms of the vascular actions of H(2)O(2) and may help to design pharmacologically protective strategies.     

吸入麻醉药心肌预处理的信号转导机制

吸入麻醉药预处理有IPC样的心肌保护作用,其作用机制目前尚未完全阐明。吸入麻醉药预处理的信号转导机制可能与IPC的信号转导途径相似,吸入麻醉药可能刺激心肌产生触发因子,然后启动级联反应,激活效应因子,发挥预处理效应。目前为止,研究已证实ROS、G蛋白耦联受体、蛋白激酶、线粒体和肌膜KATP通道（Mito KATP and Sarc KATP）介导APC。现就吸入麻醉药心肌预处理信号转导机制方面的最新进展作一综述。     

DNA芯片技术筛选膀胱移行细胞癌信号转导相关基因

目的探讨人膀胱移行细胞癌信号转导相关基因的表达变化。方法使用人肿瘤基因表达谱芯片检测11例膀胱移行细胞癌组织基因表达谱的变化，以寻找与细胞信号转导相关的差异表达基因。结果以正常膀胱黏膜组织为对照，11例膀胱肿瘤组织中有87个基因表达明显下调，102个基因表达明显上调。其中与细胞信号转导相关的差异表达基因有35个，明显上调基因13个，明显下调基因22个。结论膀胱肿瘤的发生与发展与多种细胞信号转导相关基因的异常表达有关。     

C-jun氨基末端激酶(JNKs)与脑缺血性损伤

c-Jun氨基末端激酶（c-Jun N-terminal kinases,JNKs）为丝裂原活化蛋白激酶（mitogen activated protein kinase,MAPK）超家族之一,其参与胚胎发育、免疫反应、及细胞的生长、分化、增殖等多种生理过程,同时也参与了许多病理过程。近期研究表明其在脑缺血性损伤神经元死亡过程中起重要调控作用。现就其相关研究进展作一综述。     

颅内动脉狭窄栓子起源部位微栓子信号的特性研究

目的经颅多普勒超声(TCD)可以在脑动脉血流中监测到微栓子信号(MES),通过分析MES在频谱和声窗中的参数,比较来源于颅内动脉狭窄部位(栓子起源部位)和来源于颈动脉狭窄或机械性心瓣膜置换术患者(远距离栓子源)MES特点,描述在颅内动脉狭窄处微栓子起源部位MES的特点,分析产生这些特点的可能机制。方法研究了2000年1月～2005年10月,经TCD监测到的微栓子信号,研究组325个MES来自10例颅内动脉狭窄患者,其中大脑中动脉狭窄者8例,大脑后动脉狭窄者2例,在该狭窄动脉分布区均发现多发急性梗死灶。对照组56个MES来自8例颈内动脉或心脏。全部MES均脱机分析频谱和声窗信号。根据MES在频谱中频率的部位和分布将其分成3种类型:局限性频率信号(FFS):局限在某一频率范围;多频率信号(MFS):占据多个频率范围;基底频率信号(BFS):频率很低与基线几乎相连。结果研究组的325个MES中MFS 305个(占93．8%),FFS有11个(占3．4%),BFS有9个(占2．8%);对照组的56个MES中最多的是FFS 52个(占92．8%),BFS有2个(占3．6%), MFS有2个(占3．6%),两组间差异有显著性意义(P=0．001)。在颅内动脉狭窄中最常见的MFS在频谱中不仅占据多个频率范围,而且其低频部分往往是双向的,在声窗中也由多个不同频率组成,频率最高部分类似一个扭曲了的振幅-调节正弦波,低频部分的振幅在近端深度随时间的推移而降低,在远端深度则随时间的推移而增大,由于MFS在声窗中的起点和振幅最高点不明显,因此很难测量双深度间的时间差。对照组中最常见类型FFS在声窗内的信号表现为一个规整的振幅-调节正弦波(纺锤波),并且在双深度之间有明显的时间差。结论TCD在脑动脉中监测到的来自于远距离栓子源的MES具有局限性频率特点,但从颅内动脉狭窄栓子起源处监测到的MES具有多频且低频部分呈双向的特点,描述了一个振动的微栓子旋转滚动着从脱落的血管壁移动到血管中央的轨迹。     

肿瘤相关钙信号传导蛋白-2基因对人乳腺癌细胞黏附和侵袭力的影响

目的 观察肿瘤相关钙信号传导蛋白-2(TROP-2)基因小干扰RNA (siRNA)对乳腺癌细胞黏附和侵袭力的影响.方法 培养人乳腺癌Bcap-37、LCC1、MCF-7、MDA-MB-231、MDA-MB-435、MDA-MB-468及ZR75-1细胞株,以荧光实时定量聚合酶链反应(PCR)方法检测TROP-2基因mRNA表达;筛选出TROP-2表达最高者.采用TROP4基因siRNA转染乳腺癌细胞,分别以荧光实时定量RT-PCR和免疫荧光方法观察TROP-2基因mRNA和蛋白水平,然后以噻唑蓝(MTT)比色法检测细胞黏附性,以Transwell方法检测癌细胞侵袭能力.结果 人乳腺癌Bcap-37、LCC1、MCF-7、MDA-MB-231、MDA-MB-35、MDA-MB-468及ZR75-1细胞株TROP-2 mRNA分别是1.362±0.057、2.207±0.056、2.997±0.052、0.136±0.045、0.122±0.025、0.194±0.028和2.706±0.039,以MCF-7细胞最高;以TROP-2 siRNA转染乳腺癌MCF-7细胞后,癌细胞TROP-2基因mRNA和蛋白水平明显下降,且呈浓度依赖性;黏附实验结果显示,5、10、20 nmol/L siRNA组黏附率分别为(52.9±2.5)％、(25.6±2.3)％、(12.8±2.2)％(P＜0.01);Transwell实验结果显示,5、10和20 mol/L siRNA组穿过滤膜的细胞分别为78±17、39±15、19±16,而对照组分别为136±25、139±21(P＜0.01).结论 TROP-2基因在乳腺癌细胞黏附和侵袭中发挥着重要作用;以siRNA转染乳腺癌细胞,可抑制乳腺癌细胞黏附和侵袭能力.     

N-cadherin、 β-连环素在肝癌组织中的表达及与Wnt信号途径的关系

目的 观察肝癌(HCC)中N-cadherin分子是否调控β-连环素(β-catenin)的表达及Wnt信号途径的活化。方法 免疫组织化学分析64例肝癌组织中N-cadherin及β-catenin的表达及相互关系。调控肝癌细胞株HCCLM3、SMMC-7721中N-cadherin表达并检测β-catenin的表达及Wnt信号途径的活化。结果 64例肝癌中,N-cadherin表达缺失34例;β-catenin在细胞膜上表达,无细胞核内聚集,且13例细胞膜表达缺失;细胞膜上β-catenin表达缺失与N-cadherin表达缺失呈正相关(P＜0.05)。下调HCCLM3细胞或上调SMMC-7721细胞中的N-cadherin表达导致细胞膜上β-catenin表达减弱或增强,但均未导致Wnt信号途径的活化。结论 在肝癌中,N-cadherin表达与细胞膜上β-catenin的表达水平呈正相关,但N-cadherin分子并不参与Wnt信号途径的调控。