SD大鼠血液及某些组织过氧化脂质参考值的探讨

用SD大鼠检测正常血清及肝、肺和肠组织的黄嘌呤氧化酶(XOD)、还原谷光甘肽(GSH)和丙二醛(MDA)含量的变化,采用多指标测试的方法进行分析。通过上述指标检测．为大鼠有关过氧化脂质提供一些参考数据。     

Trilostane和地塞米松对内毒素血症大鼠血清氨基酸和肿瘤坏死因子的影响

用Trilostane将内毒素血症大鼠的血浆皮质酮维持在略高于对照大鼠的水平或给内毒素血症大鼠注射地塞米松,使血浆中糖皮质激素浓度进一步升高。结果发现,血清氨基酸总浓度和丙氨酸浓度与血浆皮质酮浓度正相关,而血清肿瘤坏死因子浓度则与血浆皮质酮浓度负相关。说明应激时糖皮质激素浓度的升高对于促进分解代谢,抑制细胞因子和炎症介质的释放是必需的。本文就应激时糖皮质激素分泌增多的生理意义以及激素治疗的作用机理作了讨论。     

抗重组人肿瘤坏死因子单克隆抗体对内毒素血症家兔氧提取功能的影响

本工作采用渐进性低氧法降低总氧运输量,从而观察抗重组人肿瘤坏死因子（rhTNFα）单克隆抗体对内毒素血症家兔氧提取功能的影响。结果表明,在DO2－VO2的关系中,抗体保护组类同于对照组,可清楚地分为"非依赖"与"依赖"两部分;无关抗体组类同于内毒素组,从呼吸空气开始从未出现坪区。抗体保护组的临界氧运输量（DO2c）和合并氧提取率分别为10．80±3．21ml／（min·kg）和0．690,与对照组（分别为10．18±1．69和0．730）无显著差异（P＞0．05）;无关抗体组合并氧提取率为0．408,显著低于抗体保护组（P＜0.05）。在血浆中TNFα浓度,无关抗体组在各时间点上均显著高于抗体保护组（P＜0.01）。实验结果表明,精确特异性的重组人TNFα单抗具有阻断或逆转内毒素血症氧提取障碍的病理过程。     

血必净注射液对梗阻性黄疸大鼠血清内毒素及肿瘤坏死因子-alpha水平的影响

目的：探究血必净注射液对梗阻性黄疸大鼠血清内毒素(ETX)及肿瘤坏死因子-alpha(TNF-alpha)水平的影响。方法：选取雄性SD 大 鼠60 只,随机分为假手术(A)组、梗阻性黄疸(B)组、血必净干预(C)组,每组20 只。A组不结扎胆总管,B、C两组结扎胆总管。术后 七天,C 组每日皮下注射血必净4 mL/Kg,A 组、B 组用等量生理盐水替代,持续用药一周。实验两周后,检测和比较各组大鼠血清 ETX、TNF-alpha、总胆红素(TBIL)及直接胆红素(DBIL)水平。结果：术后两周,A组血清TBIL、DBIL 水平显著低于B、C两组;B组血 清TBIL、DBIL 水平显著高于C 组,差异均有统计学意义(P<0.05)。B组血清ETX和TNF-alpha水平显著高于A、C 组,差异均有统计 学意义(P<0.05)。结论：血必净注射液可能通过降低血清ETX和TNF-alpha含量改善梗阻性黄疸。     

老年大鼠单核／巨噬细胞分泌和表达肿瘤坏死因子增多

为研究老年时肿瘤坏死因子（ＴＮＦ－α）分泌及表达的改变,在内毒素（ＬＰＳ）１．０μｇ／ｍｌ刺激大鼠单核／巨噬细胞后,用酶联免疫法（ＥＬＩＳＡ）测定培养液中ＴＮＦ－α含量,用半定量逆转录－聚合酶链反应（ＲＴ－ＰＣＫ）测定ＴＮＦ－αｍＲＮＡ。同时测定培养液中一氧化氮（ＮＯ）和前列腺素Ｉ２（ＰＧＩ２）的含量。结果显示：老年鼠ＴＮＦ－α分泌量及其ｍＲ－ＮＡ明显高于青年鼠。ＮＯ产量在老年鼠与青年鼠之间无明显差异。老年鼠ＰＧＩ２分泌明显低于青年鼠。由于ＰＧ能抑制ＴＮＦ－α释放,从而推测,ＰＧＩ２产生能力的降低可能是老年大鼠单核／巨噬细胞ＴＮＦ－α分泌量明显高于青年鼠的原因之一。     

镉负荷大鼠一氧化氮和肿瘤坏死因子-α释放在介导多器官机能活动障碍中的作用

选择健康SD雄性成年大鼠36只,随机分成对照组(C组)、镉负荷中剂量组(M组)、镉负荷高剂量组(H组).将分析纯CdCl2·2.5H2O用生理盐水稀释成含镉0.4 mg/ml浓度的注射溶液,高压灭菌.M组和H组大鼠每天分别按含镉0.5和1.0 mg/kg体重腹腔注射染毒,C组用同样方法注射与H组同等剂量的生理盐水,进行急性镉负荷实验,连续观察7 d.研究急性镉负荷对大鼠血液及几种组织中一氧化氮(NO)自由基、肿瘤坏死因子-α(TNF-a)变化的影响及作用.结果显示在整个实验期内,镉负荷大鼠体重与对照组比较明显下降;睾丸、心脏和肝脏组织中的镉含量极显著上升,并随镉负荷剂量和时间而增加;血浆NO水平M组虽高于对照组,但差异不显著,而H组极显著高于对照组,M和H组血浆TNF-α明显高于对照组;在整个实验期内,镉负荷大鼠睾丸、心脏和肝脏组织匀浆中NO较对照组高或明显高于对照组,睾丸和心脏组织匀浆中TNF-a也均高于或明显高于对照组,但肝脏中的TNF-a三组间没有差异.结果提示,镉负荷诱发NO、TNF-α大量释放在导致大鼠多种器官机能活动障碍发生过程中可能起重要作用.     

运动和低脂膳食对胰岛素抵抗大鼠肿瘤坏死因子α表达的影响

目的：研究长期运动和低脂膳食等生活方式的干预对胰岛素抵抗大鼠肿瘤坏死因子α（TNF-α）表达的影响。方法：130只大鼠随机分为：CON组,10只,低脂膳食喂养;HFD组,120只,高脂膳食喂养。喂养8周后,选取HFD组体重上游1/3的大鼠作为肥胖大鼠。进行一次口服葡萄糖耐量试验（OGTr）和胰岛素释放试验。整体胰岛素敏感性以葡萄糖一胰岛素指数评价。将肥胖的HFD大鼠再分为以下4组,每组10只,喂养8周：HFD-SED：高脂膳食;IHFD-EX：高脂膳食,跑台运动;LFD-sED：低脂膳食;LFD-EX：低脂膳食,跑台运动。CON组继续低脂膳食喂养。再进行一次OGTr和胰岛素释放试验。以ELISA技术分析脂肪组织和比目鱼肌中TNF-α。结果：I-IFD组葡萄糖．胰岛索指数显著大于CON组。8周干预后,HFD-SED组葡萄糖一胰岛素指数显著大于CON组。3个干预组葡萄糖．胰岛素指数均显著小于HFD-SED组。HFD-SED组脂肪组织和比目鱼肌中TNF-α含量显著大于CON组,3个干预组均显著小于HFD-SED组。结论：运动和低脂膳食干预均能降低胰岛素抵抗大鼠组织中TNF-α的表达,从而缓解炎症应激,改善胰岛素抵抗。     

肿瘤坏死因子和氧自由基在老龄大鼠多器官衰竭的变化

肿瘤坏死因子和氧自由基在老龄大鼠多器官衰竭的变化＊范利常润英王士雯金道山余颂涛高宇红（解放军总医院老年心脏科老年医学研究所,北京１００８５３）内毒素血症导致的老年多器官功能衰竭（以下简称ＭＯＦ）在临床上极为常见。本文通过对内毒素所致的老龄大鼠ＭＯＦ模...     

肿瘤坏死因子α对大鼠成骨样细胞增殖与甲状旁腺素受体表达的影响

大鼠成骨样细胞ROS17／2．8经肿瘤坏死因子α处理后,发现其c－myc,c－fos,c－jun等原癌基因mRNA的表达降低,细胞增殖明显受到抑制;同时,其PTH受体的表达以及PTH受体经刺激后引起的胞内cAMP的增加也受到抑制．提示TNFα可抑制大鼠成骨样细胞ROS17／2．8的增殖和分化．     

The effect of a single dose of tumor necrosis factor alpha inhibitor on gut permeability in rats during exposure to a heat stress

Heat stroke is a life threatening illness characterized by a core body temperature of >40 °C, delirium and convulsions, and often results in multi-organ dysfunction, due to the release of endotoxin through the intestinal wall into the circulation. While playing a major role in the gastrointestinal tract permeability changes seen in Crohn's disease, it is not clear whether tumor necrosis factor alpha (TNF-α) mediates the increase in intestinal permeability and the release of endotoxin into the circulation in heat stroke. The aim of the present study was to determine the acute effects of a single dose of TNF-α antibody on gut permeability in rats during heat stress. Fifty-five Sprague-Dawley rats (28 male and 27 female) were treated with either saline or infliximab (a monoclonal antibody to TNF-α), anesthetized with pentobarbitone (50 mg kg⁻¹) and then exposed to either normothermic conditions or an ambient temperature of between 41 and 42 °C for 70 min. Fluorescent isothiocyanate labeled dextrans (FITC-dextrans) were administered intragastrically as a marker of intestinal permeability. Liver enzymes, endotoxin and TNF-α were analyzed in the blood. Exposure to a heat stress significantly increased intestinal permeability to FITC-dextrans compared to the controls (P<0.05). Infliximab did not have an effect on the intestinal permeability to the FITC-dextrans. Heat stress had no significant effect on liver enzymes or endotoxin concentration versus controls (P>0.05). TNF-α was not detectable in any of the samples. TNF-α did not mediate the release of endotoxin into the circulation after an acute bout of heat stroke.     

Interleukin-6 is a better marker of lethality than tumor necrosis factor in endotoxin treated mice

Abstract We established a mouse model to differentiate between a lethal and non-lethal presentation of endotoxic shock. The model involved injecting different amounts of Escherichia coli LPS into C3H/HeN mice which had been 'primed' with BCG. We found that the mice receiving non-lethal and lethal doses of LPS could not be differentiated in terms of their physical symptoms for the first 8 h post-injection. Tumour necrosis factor (TNF) was detected at concentrations 2–9-fold greater in mice receiving lethal doses of LPA when compared with non-lethally injected mice. However, given that (i) the successful detection of this differential was dependent on the time of sampling and (ii) that TNF was only detected in the first 3–4 h post LPS challenge, we suggest that TNF may not be very useful as a prognostic marker in endotoxic shock. In contrast, circulating IL-6 appeared to mirror the symptoms of the endotoxic mice. The relative disappearance of IL-6 after 10 h in the non-lethally injected mice corresponded with their symptomatic recovery, while IL-6 continued to circulate up to the time of death in the lethally injected mice. Furthermore, there appeared to be a good correlation between the levels of injected LPS and the levels of IL-6 induced into the circulation. Our results suggest that IL-6, rather than TNF, may serve as a prognostic marker for endotoxic shock.     

The potential biological and clinical significance of the soluble tumor necrosis factor receptors

The role of TNF receptors (TNF-Rs) is not limited to signal transduction but includes extracellular regulatory functions affecting systemic TNF bioavailability. This review summarizes the regulation of TNF-R shedding and its kinetics, the complex interaction between the soluble receptors and their ligand in vitro and in vivo, and the potential diagnostic, prognostic and therapeutic value of the soluble receptors in malignant, inflammatory, infectious and autoimmune disorders.     

Efficacy of tumor necrosis factor α and eicosanoid inhibitors in experimental models of neonatal sepsis

Abstract The potential role of tumor necrosis factor α (TNFα) and eicosanoids in the pathogenesis of experimental neonatal sepsis models was investigated. Lethality was induced in neonatal rats by administration of heat killed group B streptococci (GBS, 7 mg kg⁻¹ intracardially) or Salmonella enteritidis endotoxin (0.35 mg kg⁻¹ intracardially). The relative efficacy of six compounds with putative TNFα and eicosanoid inhibitory actions were tested. These were: ibuprofen (3 and 20 mg kg⁻¹), a cyclo-oxygenase inhibitor; CGS85515 (30 mg kg⁻¹), a lipoxygenase inhibitor; LY203647 (30 mg kg⁻¹), a leukotriene D₄ receptor antagonist; pentoxifylline (10, 50 and 100 mg kg⁻¹), a TNF inhibitor; cloricromene (2 and 10 mg kg⁻¹), a thromboxane A₂ synthetase inhibitor with TNFα inhibitory actions; and SKF86002 (2.5, 5, 10 and 20 mg kg⁻¹), a dual cyclo-oxygenase/lipoxygenase inhibitor with TNFα inhibitory activity. Pentoxifylline, cloricromene and SKF86002, when given intraperitoneally 2 h before challenge, produced 45, 52 and 61% reductions, respectively, in plasma levels of TNFα at 2.5 h post-injection with killed GBS ( P < 0.05). On the contrary, pretreatment with ibuprofen, CGS85515 or LY203647 did not significantly affect TNFα levels. All compounds significantly attenuated the lethality by killed GBS and S. enteritidis endotoxin. These data suggest that TNFα and eicoisanoids contribute to the pathogenesis of shock induced by killed GBS and endotoxemia.     

Purification of rabbit tumor necrosis factor

Rabbit tumor necrosis factor (TNF) was purified and shown by SDS-PAGE to be a single protein of 18 kDa. TNF in 355 ml rabbit serum was precipitated with ammonium sulfate, and purified by repeated DEAE-Sephadex and Sephacryl S-200 chromatographies, and the final fractionation on Blue-Sepharose 6B. By this procedure its yield was 22% and its specific activity was 2.4 × 10⁷ U/mg protein. The sequence of the N-terminal 20 amino acids was determined.     

Synergistic induction of endothelial tissue factor by tumor necrosis factor and vascular endothelial growth factor: functional analysis of the tumor necrosis factor receptors

Tissue factor expression on the surface of endothelial cells can be induced by tumor necrosis factor (TNF) and vascular endothelial growth factor (VEGF) in a synergistic manner. We have investigated the role of the two different TNF receptors for this synergy. Firstly, stimulation of the 60 kDa TNF receptor (TNFR60) by a mutant of TNF specific for TNFR60 induced responses comparable to wild-type TNF. In contrast, stimulation of TNFR80 by a TNFR80-specific TNF mutein did not result in enhancement of tissue factor expression even in the presence of a suboptimal TNFR60 triggering. Secondly, we tested neutralizing TNF receptor antibodies for inhibition of tissue factor synthesis induced by VEGF and TNF. A TNFR60-specific antibody inhibited tissue factor production over a broad range of TNF concentrations, indicating an essential role of TNFR60 in the TNF/VEGF synergy. In contrast, blocking of TNF binding to TNFR80 strongly inhibited TNF-induced tissue factor expression at low, but less pronounced at high, TNF concentrations. In conclusion, these data are in agreement with a model in which TNFR80 participates in the synergy between VEGF and low concentrations of soluble TNF by passing the ligand to the signalling TNFR60.     

Lack of cell-cycle-specific effects of recombinant tumor necrosis factor in vivo

Several in vitro studies have demonstrated that tumor cells arrested in the G2 and M phases of the cell cycle expressed an increased sensitivity to the tumor necrosis factor (TNF). The scope of the present study was to investigate whether this cycle dependence of TNF effects also exists in vivo. The experiments were performed by using the Lewis lung carcinoma (LLC), which had been allotransplanted to nude mice. In order to induce delays of the tumor cell cycle in G2, the animals were treated with etoposide (40 mg/kg body weight i.p.) or with local radiation (15 Gy), each increasing the G2 fraction of the LLC from 10% to 35% and 50% respectively. For combination therapy with recombinant (r)TNF, the tumor was transplanted to four groups of six mice each, one of them serving as a control group the others being treated either with a G2 inductor alone, with rTNF alone, or with rTNF and a G2 inductor combined. Administration of rTNF (125 or 250 g/kg body weight i.v.) was always carried out 24 h after therapy with etoposide or radiation when the maximum of G2 accumulation had developed. The growth behavior of the treated tumors revealed that the response of the LLC to rTNF in vivo was not improved by pretreatment with a G2 inductor and, thus, obviously lacked cell-cycle specificity. It is supposed that direct interactions of TNF with the tumor cells, which are a basic requirement for cell-cycle-linked phenomena, play a minor role in the therapeutic outcome of the LLC under in vivo conditions.     

Monocyte tumoricidal activity and tumor necrosis factor production in patients with malignant brain tumors

Summary Monocyte-mediated tumoricidal activity, tumor necrosis factor (TNF) secretion and gene expression were examined in astrocytoma patients, patients with other types of brain tumors (primary or metastatic), and normal individuals. The spontaneous monocyte-mediated tumoricidal activity of either patient group against an astrocytoma cell line was significantly greater than normal. There was no difference between patient groups. When monocytes were stimulated with lipopolysaccharide in vitro, tumoricidal activity increased in all patient groups. Patient monocyte activity tested shortly (48 h) after surgery was not different from that before surgery. Both spontaneous and stimulated monocyte cytocidal activities were tumor-cell-restricted: melanoma and astrocytoma cells were equally susceptible but non-neoplastic glial cells were not affected. Examination of monocyte TNF secretion and mRNA expression indicated that patient activity was comparable to or greater than normal. These results demonstrate that, despite steroid therapy, circulating monocytes in astrocytoma and other brain tumor patients retain intact functional activity.Supported in part by grant CA-49 950 from the National Cancer Institute (B.P.B) and grant 1454-HL from the National Institutes of Health (M.L.E.)     

Down-regulation of tumor necrosis factor expression by pentoxifylline in cancer patients: A pilot study

The wasting syndrome (cachexia) characterized by anorexia, malaise, and weight loss is observed in many patients with cancer or chronic infection. The excessive levels of tumor necrosis factor- (TNF)/cachectin reported in 50% of cancer patients exhibiting clinically active disease may therefore mediate, at least in part, the cachexia associated with malignancy. Pentoxifylline, a substituted methylxanthine approved for treatment of intermittent claudication, has been shown in preclinical studies to down-regulate TNF RNA expression as well as TNF activity. We report that pentoxifylline suppressed TNF RNA levels on all three occasions in patients with initially elevated levels of TNF RNA. Pentoxifylline did not suppress TNF RNA to subnormal levels in all five patients with initially normal TNF RNA levels. Four patients reported an increased sense of well-being, improved appetite and ability to perform the activities of daily living. Two of these five patients with normal TNF levels each had a weight gain of more than 5% after 3 weeks of pentoxifylline therapy suggesting that, although TNF may be important in the pathogenesis of cancer cachexia, other anorexia-producing cytokines that are potentially affected by pentoxifylline may also be involved. No severe adverse effects were observed. Taken together these findings suggest that pentoxifylline can down-regulate TNF expression and improve the sense of well-being in cancer patients. A larger study with a randomized, double-blind, placebo-controlled design and more sophisticated estimates of quality of life will be needed to confirm these observations.This study was supported in part by a grant from Hoechst-Roussel Pharmaceuticals Inc., Somerville, N. J. to Dr. Dezube and by a fellowship from Aid for Cancer Research of Boston, Mass., to Dr. Fridovich-Keil. Part of this work has been presented at a workshop: Pentoxifylline, leukocytes and cytokines, held in Scottsdale, Arizona, 8–10 March 1991