人血浆高密度脂蛋白对大鼠内毒素血症的治疗及防护作用研究

目的:观察人血浆高密度脂蛋白(HDL)对大鼠内毒素血症的治疗和防护效果。方法:采用鲎试剂法和放射免疫分析法于3个时点动态测定对照组、治疗组和防护组大鼠血浆内毒素(ET)水平和肿瘤坏死因子(TNF)浓度并观察血压及存活时间。结果:①输注ET后对照组大鼠血压进行性下降(P<0.01);治疗组大鼠输注HDL后其血压虽也降低但下降程度明显弱于对照组(P<0.01);防护组大鼠在输注ET后血压无明显下降(P>0.05)。治疗组及防护组大鼠存活时间均明显长于对照组(P<0.01)。②3组大鼠血浆ET水平在各时点均无明显变化(P>0.05)。③治疗组及防护组大鼠血浆TNFα水平于第3时点均明显降低(P>0.05)。结论:人血浆HDL能减轻或抑制内毒素血症大鼠血压下降并明显延长其存活时间,对内毒素血症具有良好的治疗和防护作用,此作用可能与其抑制TNF释放有关。     

内毒素耐受研究进展

背景 细菌内毒素(endotoxin,ET)或细菌脂多糖(lipopolysaccharide,LPS)入血是大多临床全身性炎症综合征和感染性休克的首要原因,而ET或LPS耐受却对机体有一定保护作用.但有关ET耐受的机制还不完全清楚. 目的 综述近年来有关ET耐受的研究进展,为未来有关ET耐受机制的研究提供指导. 内容 主要从细胞水平、受体水平、信号通路水平、分子水平研究ET耐受机制的进展情况. 趋向 进一步研究ET耐受中的分子调控机制.     

The effect of activated protein C on plasma cytokine levels in a porcine model of acute endotoxemia

Objective To assess the anti-inflammatory effects of recombinant human activated protein C (rhAPC) in a porcine model of acute endotoxemia. Design and setting Animal randomized controlled study at the Laboratory of Clinical Institute, Aarhus University Hospital. Subjects Eighteen female landrace pigs (30 kg). Interventions By pairwise randomization, pigs were given either LPS or LPS and rhAPC. Both groups received a stepwise increasing LPS infusion for 30 min; whereafter the infusion continued at a lower rate (300 min LPS in both groups). The LPS+rhAPC group received rhAPC (100 μg/kg per hour) 15 min before the LPS infusion began and throughout the trial period. Results While rhAPC showed no modifying effects on peak plasma levels of pro- or anti-inflammatory cytokines (TNF-α, IL-6, IL-8, IL-10), TNF-α and IL-10 peaked significantly later in the rhAPC-treated animals. The profibrinolytic effects of rhAPC were confirmed by decreased plasminogen activator inhibitor 1 levels, while no differences were found in other coagulation markers, hemodynamic, metabolic, or leukocyte data between the two groups. Conclusions We found no significant effect of rhAPC on plasma levels of either pro- or anti-inflammatory cytokines in this porcine model of acute endotoxemia. However, TNF-α and IL-10 peaked significantly later in the rhAPC-treated animals.     

内毒素血症时大鼠脂多糖结合蛋白的变化及其意义

目的　探讨内毒素血症时大鼠肝组织中脂多糖结合蛋白mRNA的表达、血浆中脂多糖结合蛋白 (LBP)含量的变化及其意义。方法　经大鼠尾静脉注入内毒素 (5mg/kg)建立内毒素血症动物模型 ,检测不同时点模型鼠肝组织中LBPmRNA的表达 ,同时检测血浆中LBP、内毒素、TNF α及IL 6含量的变化 ,并与对照组相比较。另取肝组织在电镜下观察其病理学改变。结果　随着内毒素血症时间的延长 ,内毒素组大鼠肝组织LBPmRNA的表达明显增强 ,血浆中LBP、TNF α和IL 6含量也明显增加 ,与对照组比较差异有高度显著性 (P<0 .0 1)。电镜观察见肝细胞脂肪变 ,线粒体空化 ,枯否氏细胞数量增多、体积增大、吞噬功能增强。结论　内毒素血症时 ,大鼠肝组织中LBPmRNA表达明显增强 ,血浆中LBP含量也明显增加。由此提示 ,增高的LBP可能在脂多糖介导的枯否氏细胞激活及产生、释放各种炎性介质中可能起了重要作用。     

The effect of pentoxifylline on the healing of intestinal anastomosis in rats with experimental obstructive jaundice

The aims of this study were (1) to investigate the effect of experimental obstructive jaundice on the healing of intestinal anastomosis, and (2) to investigate the effect of pentoxifylline on the healing of intestinal anastomosis in rats with obstructive jaundice. Obstructive jaundice was induced in rats by the ligation and division of the common bile duct. Four days after this operation, either pentoxifylline or isotonic saline solution was administered intraperitoneally to these jaundiced rats and controls, and then intestinal anastomosis was performed. The concentrations of serum tumor necrosis factor α (TNF-α) and serum triglyceride of jaundiced and nonjaundiced rats were measured, and the quality of healing was evaluated by measuring the bursting preasure and hydroxyproline content of the anastomoses on the fifth and tenth days of anastomotic healing. Obstructive jaundice resulted in an impaired wound healing of the intestinal anastomosis in the rats. The administration of pentoxifylline to the jaundiced rats resulted in better anastomotic wound healing. The beneficial effects of pentoxifylline on anastomotic healing in rats with obstructive jaundice was attributed to its inhibitor effect on the endotoxin-induced TNF-α release from macrophages and monocytes, and the stabilizing effect on the neutrophils. Received: March 29, 1999 / Accepted: March 24, 2000     

Effect of acute endotoxemia on analog estimates of mean systemic pressure

Dynamic estimates of mean systemic pressure based on a Guytonian analog model (Pmsa) appear accurate under baseline conditions but may not remain so during septic shock because blood volume distribution and resistances between arterial and venous beds may change. Thus, we examined the effect of acute endotoxemia on the ability of Pmsa, estimated from steady-state cardiac output, right atrial pressure, and mean arterial pressure, to reflect our previously validated instantaneous venous return measure of mean systemic pressure (Pmsi), derived from beat-to-beat measures of right ventricular stroke volume and right atrial pressure during positive pressure ventilation. We studied 6 splenectomized pentobarbital-anesthetized close chested dogs. Right ventricular stroke volume was measured by a pulmonary arterial electromagnetic flow probe. Instantaneous venous return measure of mean systemic pressure and Pmsa were calculated during volume loading and removal (± 100-mL bolus increments × 5) both before (control) and 30 minutes after endotoxin infusion (endo). Cardiac output increased (2628 ± 905 vs 3560 ± 539 mL/min; P < .05) and mean arterial pressure decreased (107 ± 16 vs 56 ± 12 mm Hg; P < .01) during endo. Changes in Pmsi and Pmsa correlated during both control and endo (r² = 0.7) with minimal bias by Bland-Altman analysis (mean difference ± 95% confidence interval, 0.47 ± 5.04 mm Hg). We conclude that changes in Pmsa accurately tracts Pmsi under both control and endo.     

谷氨酰胺对内毒素血症幼年大鼠肾脏ERK以及p38表达的影响

目的：通过观察谷氨酰胺(glutamine, Gln)对内毒素血症幼年大鼠肾脏信号转导通路ERK-2、p38及其mRNA表达的影响,探讨谷氨酰胺在大鼠内毒素血症中通过干预肾脏ERK-2以及p38信号转导途径来保护肾脏的机制。方法：选健康18日龄Wistar大鼠121只,按腹腔注射药物不同分为：0 h对照组(生理盐水,n=11), 内毒素组（LPS,n=55）,谷氨酰胺组(Gln, n=55); 后两组又分为2,4,6,24及72 h共5个时间点,每个时间点11只,在各指定时间点分别将大鼠断头分离肾脏,8只用逆转录 聚合酶链反应（RT-PCR）方法测定ERK-2以及p38的mRNA的表达,另3只取肾组织后用甲醛固定,制成石蜡切片,用免疫组化方法确定ERK-2以及p38蛋白质的表达。结果：LPS组各时点ERK-2 mRNA, p38MAPK mRNA, ERK-2, p38MAPK表达均较对照组增强,最高点在 6 h,差异有显著性,P<0.01;Gln组各时点ERK-2 mRNA, p38MAPK mRNA, ERK-2, p38MAPK表达趋势与LPS组一致,但明显低于LPS组,P<0.05或P<0.01。结论：ERK及p38在内毒素血症表达均明显增强。谷氨酰胺可使其表达下调,从而减轻肾脏损伤。［中国当代儿科杂志,2009,11（4）：301-305］     

严重创伤患者血浆TNF、IL-6、IL-8和内毒素的变化

本研究选择１７例严重创伤患者，根据ＩＳＳ计分将患者分为两组（即ＩＳＳ１６－２５（Ⅰ组）和ＩＳＳ＞２５组（Ⅱ组）），动态观察伤后两周内血浆ＴＮＦ、ＩＬ－６和ＩＬ－８及内毒素水平的变化，并分析其相关性。研究结果显示，创伤后，患者血浆细胞因子水平可相继明显升高，其中血浆ＴＮＦ水平升高较早，血浆ＩＬ－６、ＩＬ－８较晚，Ⅱ组血浆细胞因子水平明显高于Ⅰ组，且三种血浆细胞因子均值分别与ＩＳＳ计分呈显著正相关。血浆内毒素水平在创伤早期也明显升高，其均值分别与ＩＳＳ计分和血浆细胞因子水平也呈显著正相关。研究结果提示，严重创伤能引起明显的细胞因子反应及内毒素血症，创伤后早期内毒素大量侵入可能是创伤后细胞因子产生、释放增加的重要机制之一。     

小檗碱和育亨宾对内毒素血症小鼠脾脏TLR4信号通路中相关基因表达的影响

目的: 观察小檗碱和α₂肾上腺素能受体拮抗剂育亨宾对内毒素血症小鼠脾脏Toll样受体4(TLR4)信号通路84种基因表达的影响,并初步探讨其作用机制。方法: 雄性BALB/c小鼠随机分为对照组、脂多糖(LPS)组、小檗碱+LPS组、小檗碱+育亨宾+LPS组、育亨宾+LPS组、小檗碱组、小檗碱+育亨宾组和育亨宾组。分别用蒸馏水、小檗碱(50 mg/kg)、小檗碱+育亨宾(50 mg/kg+2 mg/kg) 和育亨宾(2 mg/kg)灌胃,每天1次,连续3 d,第3 d灌胃1 h后,腹腔注射LPS(20 mg/kg)或生理盐水。腹腔注射1 h后,用RT² Profiler^TM PCR Array分析技术检测小鼠脾脏TLR4信号通路84种基因mRNA的表达;用Western blotting分析小鼠脾脏TLR4信号通路的抑制分子细胞因子信号抑制物(SOCS)1、SOCS3和白细胞介素-1受体相关激酶(IRAK)-M蛋白的表达。结果: LPS可上调小鼠脾脏TLR4信号转导通路中相关炎症因子的mRNA表达,包括CXCL10、TNF-α、IL-1α、IL-1β、IL-6、IFN-γ和IFN-β。小檗碱能显著下调下调髓样分化因子(MyD88)依赖信号通路下游TNF-α、IL-1α、IL-1β和IL-6 mRNA的表达,也能MyD88非依赖信号通路下游基因IFN-β和CXCL10 mRNA的表达(P<0.05)。育亨宾能显著下调内毒素血症小鼠脾脏IL-1α、IL-1β 和IFN-β mRNA的表达(P<0.05),但对TNF-α、IL-6和CXCL10 mRNA表达的下调作用与LPS组相比没有显著差异(P>0.05)。小檗碱与育亨宾合剂能显著下调内毒素血症小鼠脾脏IFN-β和CXCL10 mRNA的表达,但不能显著下调内毒素血症小鼠脾脏IL-1α、IL-1β、TNF-α 和IL-6 mRNA的表达。LPS攻击后1 h,小檗碱和(或)育亨宾均不能增强内毒素血症小鼠脾脏SOCS1、SOCS3和IRAK-M蛋白的表达。结论: 小檗碱和育亨宾均能抑制LPS诱导的MyD88依赖和非依赖信号通路下游部分基因的表达,这种抑制作用的机制与SOCS1、SOCS3和IRAK-M蛋白无关。