Toll样受体4在CCI4诱导的大鼠慢性肝损伤过程中的表达

背景：Toll样受体4（TLR4）在内毒素的信号转导过程中具有重要作用。目的：动态观察在CCl4诱导的大鼠慢性肝损伤过程中。肝组织和Kupffer细胞TLR4基因表达的变化，探讨TLR4在肝损伤中的作用。方法：以CCl4诱导慢性肝损伤纤维化大鼠模型，分离肝Kupffer细胞。以逆转录聚合酶链反应（RT-PCR）检测肝组织和Kupffer细胞TLR4 mRNA的表达；将Kupffer细胞分别与不同浓度的脂多糖（LPS）孵育，以酶联免疫吸附测定（ELISA）检测细胞培养上清的肿瘤坏死因子（TNF）-α水平。以基质显色法测定大鼠血浆内毒素水平。结果：正常大鼠肝组织TLR4 mRNA表达水平较低，Kupffer细胞未检测到TLR4 mRNA表达；CCl4处理2～6周大鼠的肝组织和Kupffer细胞TLR4 mRNA表达水平显著增高（P〈0．05）。CCl4处理4周和6周大鼠Kupffer细胞的TNF-α基础分泌水平显著高于正常大鼠（P〈0．05）；在LPS的刺激下，TNF-α的分泌水平较基础值进一步增高（P〈0．05），呈浓度依赖性。大鼠血浆内毒素水平在肝损伤过程中逐渐增高，相关分析显示在慢性肝损伤的早、中期。肝组织和Kupffer细胞TLR4 mRNA的表达与血浆内毒素水平呈正相关。结论：在CCl4诱导的慢性肝损伤过程中，大鼠肝脏TLR4基因表达上调，与Kupffer细胞活化和肝脏的炎症损伤有关。     

库普弗细胞内毒素受体CD14在大鼠肝损伤中的变化

目的动态观察四氯化碳(CCl4)诱导大鼠肝损伤过程中库普弗细胞膜上脂多糖(LPS)受体CD14表达变化及其在细胞因子分泌中的作用。方法以CCl4皮下注射诱导大鼠肝损伤。采用联合酶灌注消化、不连续密度梯度离心法分离不同时期大鼠肝脏库普弗细胞。将库普弗细胞与不同浓度内毒素孵育6h,收集培养上清并抽提细胞RNA。ELISA检测细胞培养上清中肿瘤坏死因子(TNF)α水平。RTPCR法检测库普弗细胞CD14mRNA表达。偶氮基质显色法测定大鼠血浆内毒素水平。结果经CCl4处理4周和6周,大鼠库普弗细胞在体外培养时TNFα基础分泌量明显高于正常大鼠(P<0.05)。在LPS刺激下,CCl4处理2、4和6周库普弗细胞的TNFα分泌水平明显增加(P<0.05),呈浓度依赖方式。CCl4组大鼠库普弗细胞CD14mRNA表达从2周开始增加,6周时最明显,8周时恢复至正常水平。大鼠外周血内毒素浓度在肝损伤过程中升高。结论在CCl4诱导的大鼠慢性肝损伤早期过程中,库普弗细胞内毒素受体CD14表达上调,对内毒素敏感性增加。库普弗细胞是肝脏早期炎症反应中的一个重要效应细胞。     

四氯化碳诱导大鼠肝纤维化过程中TLR4的作用机制研究

目的 动态观察Kupffer细胞(KCs) Toll样受体4(TLR4)及其蛋白在四氯化碳(CCl4)致大鼠肝纤维化过程中的表达及作用.方法 用40％四氯化碳花生油溶液皮下注射建立肝纤维化模型,于第0、4、6、8、10周收集血液和肝脏组织.检测血清内毒素、Ⅳ型胶原(collagenⅣ,CⅣ)、转化生长因子β1(TGF-β1)水平,并检测KCsTLR4 mRNA表达水平,免疫组化SP法检测肝脏TLR4蛋白、核因子κB(nuclear factor-κB,NF-κB)蛋白和组织金属蛋白酶组织抑制剂-1(TIMP-1)蛋白表达.结果 大鼠4、6、8、10周组肝组织TLR4蛋白、NF-κB蛋白、纤维化积分和KCs TLR4 mRNA以及血清内毒素、TGF-β1、CⅣ型胶原水平明显升高,同0周组比较差异有统计学意义(P＜0.01).NF-κB蛋白、TLR4蛋白和KCs TLR4 mRNA在第10周时较第8周有轻度下降;肝KCs TLR4 mRNA的表达与血浆内毒素水平呈正相关(r=0.845,P＜0.01),与血清TGF-β1水平成正相关(r=0.665,P＜0.01).结论 在CCl4诱导的肝纤维化过程中,内毒素可上调Kupffer细胞TLR4的表达,其可能为通过TLR4信号途径在肝纤维化中起重要作用.     

α-GalCer诱导急性肝损伤时肝内Kupffer细胞表型和功能的变化

背景:Kupffer细胞是肝内重要的免疫细胞,在天然免疫和适应性免疫中起重要作用。目的:研究α-GalCer诱导的急性肝损伤中肝内Kupffer细胞表型和功能变化。方法:将30只小鼠分为模型组和对照组,腹腔注射α-GalCer诱导小鼠急性肝损伤。行肝组织病理学检查,免疫组化法检测肝内F4/80阳性的Kupffer细胞的分布。胶原酶原位灌注、不连续密度梯度离心和选择性贴壁法分离正常和急性肝损伤小鼠的Kupffer细胞。real time-PCR法检测肝组织和Kupffer细胞肿瘤坏死因子(TNF)-α、于扰素γ(IFN-γ)、白细胞介素(IL)-10和Toll样受体(TLR)4mRNA表达。采用全自动生化仪测定血清ALT和AST水平。结果:α-GalCer腹腔注射引起小鼠局灶性肝细胞坏死、炎性细胞聚集,血清ALT、AST明显升高(P<0.05)。免疫组化法发现肝内F4/80阳性细胞明显增加、体积增大,并在肝组织炎症坏死处呈灶性聚集。胶原酶原位灌注分离的Kupffer细胞数量明显增加(P<0.01),肝组织和Kupffer细胞TNF-α、IFN-γ和IL-10 mRNA表达明显增加(P<0.05),而Kupffer细胞中TLR4 mRNA表达显著下降(P<0.05)。结论:在急性肝损伤中Kupffer细胞的抗炎因子IL-10表达增加和TLR4途径下调可能是Kupffer细胞维持机体免疫耐受、避免过度炎症的重要机制。     

Toll样受体4在D-氨基半乳糖/内毒素介导的急性肝损伤中的表达

目的研究D-氨基半乳糖(D-Gal)/内毒素介导的急性肝损伤模型中肝组织细胞Toll样受体4(TLR4)的表达变化,探讨TLR4在识别内毒素、启动炎性肝损伤中的作用.方法 BALB/C小鼠腹内注射D-Gal 900 mg/kg与内毒素(即脂多糖,LPS)10 μg/kg后0～7 h分别检测血清丙氨酸转氨酶(ALT)及天门冬氨酸转氨酶(AST)与血浆肿瘤坏死因子(TNF-α)含量以评价肝功能;另随机取10只小鼠给药后观察致死率.用半定量逆转录-聚合酶链反应(RT-PCR)和Tanon Gis 2.0软件分析不同时间点肝组织中TLR4 mRNA表达,并与血浆TNF-α含量进行相关分析;免疫组织化学观察肝组织TLR4蛋白的表达.实验数据用SAS软件分析.结果给药后4 h,血清转氨酶明显升高(与0h比较,P＜0.05);血浆TNF-α含量逐步上升,在2 h、5 h有两个分泌高峰;7 h小鼠开始死亡,10 h致死率达80%.正常小鼠肝组织少量表达TLR4 mRNA,给药后表达明显增强(与0 h比较,P＜0.05);免疫组织化学也显示TLR4蛋白有类似的变化,尤其肝窦内皮细胞、库普弗细胞表达更为显著.血浆TNF-α含量与肝组织TLR4 mRNA表达呈正相关.结论肝内细胞膜上表达的TLR4可能通过启动下游的炎性应答基因表达及细胞因子释放而诱导出肝组织对LPS的炎性应答.因此,调控TLR4表达可能是感染性疾病防治的一种新策略.     

乌司他丁对内毒素血症大鼠心肌TOLL样受体4表达的影响

目的 观察乌司他丁对脂多糖(Lipopolysaccharides,LPS)诱导心肌TOLL样受体4(TLR4)受体表达的影响及与炎症反应的关系.方法 选取8周龄的雄性SD大鼠32只,分成四组:正常对照组,内毒素血症组(LPS组),LPS+乌司他丁组,LPS+地塞米松组.除正常对照组以外,其余三组给予脂多糖8 mg/kg大鼠阴茎静脉注射,LPS+乌司他丁组与LPS+地塞米松组分别同时给予乌司他丁2.5万/kg、地塞米松5 mg/kg;正常对照组给予同量的生理盐水,3h后断头取血并取心肌液氮保存;ELISA法测血浆TNF-α的水平;放免法测定心肌组织中AngⅡ水平;RT-PCR法测定心肌组织TLR4 mRNA表达;免疫组化法和蛋白免疫印迹法测心肌组织TLR4含量.结果 (1)LPS组TNF-α、CRP、IL-6水平和心肌AngⅡ水平显著增高;与LPS组相比,乌司他丁组TNF-α 、CRP、IL-6和心肌AngⅡ显著降低(2)LPS可明显增加心肌中TLR 4 mRNA及蛋白表达,乌司他丁明显抑制心肌TLR4 mRNA及蛋白的表达.结论 乌司他丁能抑制LPS诱导大鼠心肌的炎症反应.乌司他丁能降低LPS诱导大鼠的心肌TLR4 mRNA及蛋白的表达.乌司他丁可能通过降低TLR4水平抑制LPS诱导的炎症反应.     

内毒素性肝衰竭大鼠TLR4mRNA表达、血清肿瘤坏死因子-α及肝细胞凋亡的动态变化

目的 观察急性内毒素性肝衰竭大鼠肝组织中TLR4mRNA表达变化规律及其与血清肿瘤坏死因子-α水平、肝细胞凋亡的关系。方法雌性Wistar大鼠给予D氨基半乳糖／脂多糖同时腹腔注射，计算动物死亡率及生存时间，动态观察给药后4、8、12h肝功能、血清肿瘤坏死因子-α、肝组织TLR4mRNA表达及病理变化，以TUNEL法检测原位细胞凋亡，计算凋亡指数。结果80％大鼠死于急性肝衰竭，平均生存时间15．6h±1．8h，病理表现为肝脏大块或亚大块坏死。给药后4、8、12h血清TNF—α增高含量及肝细胞凋亡均增加，血清TNF—α变化早于肝细胞凋亡指数的增加，肝组织TLR4mRNA的表达与血清TNF—α含量呈正相关（r=0．709，P=0．000）。结论 内毒素通过单核吞噬系统TLR4介导TNF—α大量产生，激活炎症级联反应并诱导肝细胞凋亡是内毒素性肝衰竭的重要病理机制之一，阻断肝内外单核吞噬系统TLR4介导的的生理学作用，可能会对内毒素性肝衰竭起到一定防治作用。     

TLR4在慢性支气管炎大鼠模型中对炎症损伤与黏液分泌的调控作用

目的观察TLR4在细菌内毒素(LPS)致慢性支气管炎大鼠模型中对气道炎症损伤与黏液分泌的调控作用。方法 SPF级雄性Wistar大鼠40只,随机分为正常对照组(NS组)、慢性支气管炎组(LPS组)、多粘菌素B干预组(LPS+PMB组)、多粘菌素B自身对照组(PMB组),每组10只。用气管内注入LPS 200μg/200μl及每日LPS溶液雾化吸入1 h的方法建立慢性支气管炎动物模型,3 w后收集支气管肺泡灌洗液(BALF)进行细胞学计数和白细胞分类检测,酶联免疫吸附实验(ELISA)法测定BALF中肿瘤坏死因子(TNF)-α含量,对大鼠肺脏进行病理学检查,肺组织阿先蓝过碘酸雪夫(AB-PAS)阳染面积,用免疫组化法观察黏蛋白Muc5AC、TLR4在支气管肺内的表达及荧光定量RT-PCR Muc5AC mRNA、TLR4 mRNA在肺内的表达。结果 LPS组大鼠BALF细胞总计数、中性粒细胞个数、TNF-α水平。AB-PAS阳染面积、Muc5AC、TLR4蛋白表达量及Muc5AC mRNA、TLR4 mRNA水平与LPS+PMB组比较有显著性差异(均P0.05),NS组和PMB无统计学差异(P0.05)。结论 TLR4介导LPS诱发的慢性呼吸道炎症反应可能导致Muc5AC蛋白与mRNA高表达。多粘菌素B可能通过抑制肺组织TLR4 mRNA及其蛋白的表达而抑制气道黏液高分泌。     

Toll样受体4在猪急性坏死性胰腺炎肠道组织中的表达及其意义

目的:探讨猪急性坏死性胰腺炎(acute necrotizing pancreatitis,ANP)回肠组织中Toll样受体4(Toll-like receptor4,TLR4)的表达及其意义.方法:选择太湖梅山猪,随机分成对照组(C,n=4)、急性坏死性胰腺炎组(ANP,n=4).诱导制备ANP模型.用分光光度法检测血清及回肠组织匀浆中二胺氧化酶(DAO)活性;动态比浊法检测血浆内毒素水平;RT-PCR检测回肠黏膜组织TLR4、TNF-α及IL-6mRNA表达.结果:ANP组回肠组织DAO水平明显低于C组,血清中DAO明显升高(P<0.05).ANP组血浆内毒素水平较C组明显升高(P<0.05);回肠黏膜组织TLR4、TNF-α、IL-6mRNA在C组表达非常低,ANP组表达明显增加;TLR4mRNA表达水平与肠黏膜DAO水平呈负相关(r=-0.762,P=0.028),与血浆内毒素呈正相关(r=0.778,P=0.023).结论:ANP时回肠组织内TLR4mRNA表达上调,可能与ANP肠黏膜屏障功能障碍有关;其可能机制与TLR4介导激活核转录因子NF-αB信号转导途径有关.     

SOCS-1在内毒素血症及耐受小鼠肝组织中的表达变化及意义

目的:观察内毒素血症及内毒素耐受模型小鼠对LPS刺激的反应性,以及肝组织中SOCS-1表达的变化,试图从机体水平探讨SOCS-1与内毒素耐受状态之间的关系.方法:通过脂多糖(LPS)预处理建立内毒素血症及内毒素耐受动物模型,并与对照组进行比较.分时点用酶联免疫吸附试验(ELISA)检测细胞培养液中TNF-α水平,逆转录聚合酶联反应(RT-PCR)检测肝组织中TNF-αmRNA的表达水平以及肝组织中SOCS-1mRNA的表达,并观察肝组织病理改变及超微结构改变,免疫组织化学检测SOCS-1在肝脏的表达.结果:在LPS刺激后,LPS组血清TNF-α水平、TNF-αmRNA、SOCS-1mRNA均在1h开始升高,至3h时达到峰值,随后又逐渐下降正常水平;PBS组血清TNF-α水平及TNF-αmRNA表达几乎没有明显变化,且无SOCS-1mRNA表达,与LPS组比较有统计学意义(P<0.01);但是耐受组(ETT)的3h血清TNF-α水平较非耐受组(NETT)低(693.38ng/L±95.2ng/Lvs1110.24ng/L±164.33ng/L,P<0.01);3h肝组织TNF-αmRNA表达峰值较NETT组低(97.96±19.67vs139.14±31.17,P<0.05);而肝组织SOCS-1mRNA表达峰值较NETT组高(91.58±12.94vs 52.82±6.96,P<0.01);肝组织可见脂肪变性、坏死等病理改变,超微结构表现为Kupffer细胞激活,吞噬功能增强;免疫组织化学可见肝组织中SOCS-1的表达.结论:内毒素耐受状态下,肝组织中的SOCS-1mRNA表达却明显增强,肝组织中的SOCS-1mRNA表达、Kupffer细胞的激活以及机体的内毒素耐受状态三者间可能有着紧密的联系.     

Synthesis and antitumor activity of 4-demethoxyadriamycin and 4-demethoxy-4' -epiadriamycin

Two new analogs of adriamycin have been obtained by chemical synthesis, 4-demethoxyadriamycin and 4-demethoxy-4' -epiadriamycin. Both compounds were highly effective against experimental mouse tumors at doses about ten times lower than those effective for adriamycin. At the optimal dose, 4-demethoxyadriamycin displayed antitumor activity similar to that of adriamycin in solid Sarcoma 180 (S180), L1210, P388, and Gross leukemias, and mammary carcinoma, while it did not markedly inhibit the growth of Moloney sarcoma virus-induced sarcoma in mice treated before the virus infection. At the optimal dose, 4-demethoxy-4' -epiadriamycin was as active as adriamycin against L1210, P388,and Gross leukemias, and less active against solid S180. The results show that anthracycline derivatives characterized by the absence of the methoxyl group at the C-4 position are markedly more potent than the parent compound, and may exhibit a differential antitumor effect on a number of mouse tumors.     

Expressions of 2H4 and 4B4 antigens on ATL cells

We studied the expression of 2H4 and 4B4 on the surfaces of leukemia cells from 17 patients with adult T-cell leukemia (ATL) as well as of cells belonging to 2 T-cell lines derived from ATL patients. The effects of the supernatants obtained from culture fluids of the ATL cells and the T-cell lines on IgG production of a human B-cell line, CESS cells, were also examined. On the surfaces of the ATL cells from 15 out of 17 cases and of the cells of 2 T-cell lines 4B4 obviously existed at higher percentage than 2H4 and more than 80% of ATL cells from 16 out of these 17 cases showed the expression of T4 (CD4). These findings revealed that the most of ATL cells had a helper-inducer phenotype. Supernatants (Sups) of culture fluids of ATL cells from 4 patients and those of 2 T-cell lines were added at various concentrations to the CESS cells. In only 1 Sup from ATL patient enhanced the IgG production of the CESS cells at lower concentration. However, other 5 Sups suppressed the IgG production of the CESS cells in proportion to the increase of Sup added. These results showed that phenotypical type of ATL cells does not always correspond to their functions, and the ATL cells may produce humoral factors that regulate B cell functions.     

Interleukin-4

Summary Since its discovery in 1982, numerous biological activities of interleukin-4 (IL-4) have been described. Like other cytokines, IL-4 is highly pleiotropic, both with respect to the number of different target cells that are responsive to it and with respect to the number of different biological responses it elicits. Interleukin-4 was initially described as a costimulant for the proliferation of B lymphocytes stimulated with anti-IgM antibody. Synonyms for this cytokine are B cell growth factor-1 (BCGF-1) and B cell stimulatory factor-1 (BSF-1). After cloning of both the murine and human IL-4, the use of recombinant IL-4 enabled detailed studies of its biological functions. Many cell types, mainly of hematological origin, express receptors for IL-4. Accordingly, effects of IL-4 have been described on B lymphocytes, T lymphocytes, NK cells, mononuclear phagocytes, mast cells, fibroblasts and hematopoietic progenitor cells (Fig. 1). Currently, there are three major areas in which IL-4 appears to play an important role: 1) regulation of B cell growth and of antibody isotype expression. In this context, a possible role for IL-4 in allergic reactions is of special interest. 2) Stimulation of T cell growth and the generation of cytotoxic T lymphocytes. In addition to the suppressive effects on the induction of non HLA-restricted cellular cytotoxicity by natural killer- (NK) and lymphokine-activated killer (LAK) cells, this suggests a role for IL-4 in the regulation of cellular immune responses. 3) Regulation of the growth and differentiation of hematopoietic bone marrow stem cells. IL-4 itself does not induce proliferation of hematological progenitor cells but it can modulate the growth-factor dependent proliferation of these cells. In this review the biological functions of IL-4, reported until present, are discussed.Abbreviations CSF colony stimulating factor - EPO erythropoietin - IFN interferon - IL interleukin - G-CSF granulocyte-CSF - GM-CSF granulocyte-macrophage-CSF - M-CSF macrophage-CSF - LAK lymphokine activated killer - NK natural killer - SA Staphylococcus aureus strain Cowan I - TIL tumor infiltrating lymphocyte - TNF- tumor necrosis factor alpha - tPA tissue plasminogen activator     

DNA A-tract bending in three dimensions: solving the dA4T4 vs. dT4A4 conundrum

DNA A-tracts have been defined as four or more consecutive A.T base pairs without a TpA step. When inserted in phase with the DNA helical repeat, bending is manifested macroscopically as anomalous migration on polyacrylamide gels, first observed >20 years ago. An unsolved conundrum is why DNA containing in-phase A-tract repeats of A(4)T(4) are bent, whereas T(4)A(4) is straight. We have determined the solution structures of the DNA duplexes formed by d(GCAAAATTTTGC) [A4T4] and d(CGTTTTAAAACG) [T4A4] with NH(4)(+) counterions by using NMR spectroscopy, including refinement with residual dipolar couplings. Analysis of the structures shows that the ApT step has a large negative roll, resulting in a local bend toward the minor groove, whereas the TpA step has a positive roll and locally bends toward the major groove. For A4T4, this bend is nearly in phase with bends at the two A-tract junctions, resulting in an overall bend toward the minor groove of the A-tract, whereas for T4A4, the bends oppose each other, resulting in a relatively straight helix. NMR-based structural modeling of d(CAAAATTTTG)(15) and d(GTTTTAAAAC)(15) reveals that the former forms a left-handed superhelix with a diameter of approximately 110 A and pitch of 80 A, similar to DNA in the nucleosome, whereas the latter has a gentle writhe with a pitch of >250 A and diameter of approximately 50 A. Results of gel electrophoretic mobility studies are consistent with the higher-order structure of the DNA and furthermore depend on the nature of the monovalent cation present in the running buffer.