Toll-like receptor 9 inhibition reduces mortality in polymicrobial sepsis

The high rate of mortality in patients with sepsis results from an inappropriately amplified systemic inflammatory response to infection. Toll-like receptors (TLRs) are important for the activation of innate immunity against microbial pathogens. We demonstrate a critical role of TLR9 in the dysregulated immune response and death associated with sepsis. Compared with wild-type (WT) mice, TLR9(-/-) mice exhibited lower serum inflammatory cytokine levels, higher bacterial clearance, and greater survival after experimental peritonitis induced by cecal ligation and puncture (CLP). Protection of TLR9(-/-) mice after CLP was associated with a greater number of peritoneal dendritic cells (DCs) and granulocytes than in WT controls. Adoptive transfer of TLR9(-/-) DCs was sufficient to protect WT mice from CLP and increased the influx of peritoneal granulocytes. Subsequent experiments with a depleting antibody revealed that granulocytes were required for survival in TLR9(-/-) mice. Remarkably, a single injection of an inhibitory CpG sequence that blocks TLR9 protected WT mice, even when administered as late as 12 h after CLP. Our findings demonstrate that the detrimental immune response to bacterial sepsis occurs via TLR9 stimulation. TLR9 blockade is a potential strategy for the treatment of human sepsis.     

Toll-like receptor 4 signaling leads to neutrophil migration impairment in polymicrobial sepsis

OBJECTIVE: We have documented an impaired neutrophil migration toward the infectious focus in severe sepsis. This phenomenon appears to be mediated by nitric oxide, the release of which is stimulated by circulating inflammatory cytokines released by immune cells after stimulation by bacteria and/or their products. Toll-like receptor 4 (TLR4) is the major recognition receptor for lipopolysaccharide, a component of Gram-negative bacterial cell walls. In the present study, we investigated whether TLR4 is involved in the failure of neutrophil migration in mice subjected to polymicrobial or Gram-negative sepsis. DESIGN: Controlled animal study. SETTING: University research laboratory. SUBJECTS: Male C3H/HeJ (TLR4-deficient) and C3H/HePas (TLR4-normal) mice. INTERVENTIONS: Mice were subjected to sublethal or lethal polymicrobial sepsis, both induced by cecal ligation and puncture or intraperitoneal polymicrobial inoculation, and subjected to sublethal Gram-negative sepsis induced by intraperitoneal Salmonella typhimurium inoculation (GNI). Survival was monitored for 5 days. In separate experiments, mice were killed 6 hrs after sepsis induction, and intraperitoneal neutrophil migration, bacteremia, lung neutrophil sequestration, and levels of cytokines, chemokines, and nitrate were evaluated. MEASUREMENTS AND RESULTS: TLR4-deficient (C3H/HeJ) mice presented incapacity to promote neutrophil recruitment to the infectious site after sublethal GNI, resulting in high mortality. However, TLR4 signaling is not essential to display neutrophil migration in sublethal polymicrobial sepsis induced by both cecal ligation and puncture and polymicrobial inoculation models, but surprisingly, it is crucial to establish the impairment of neutrophil migration in lethal polymicrobial sepsis, since TLR4-deficient mice that underwent lethal cecal ligation and puncture or polymicrobial inoculation did not present failure of neutrophil migration to infectious focus. As a consequence, these animals presented low bacteremia and a high survival rate and did not display systemic inflammation, determined by high levels of circulating cytokines and lung neutrophil sequestration and chemokine production. CONCLUSION: These results highlight the harmful role of TLR4 signaling in polymicrobial severe sepsis.     

The decrease of PKCalpha is associated with hepatic apoptosis at early and late phases of polymicrobial sepsis

The present study investigates the relationship between the PKC-alpha and hepatic apoptosis during sepsis. Cecal ligation and puncture- (CLP) induced animal model of polymicrobial sepsis was used, with early and late sepsis referring to those animals sacrificed at 9 and 18 h, respectively, after CLP. The expressions of PKCalpha and Bcl-2 family proteins as well as poly(ADP-ribose) polymerase (PARP) cleavage were quantified to evaluate the possible factors involved in the hepatic cell death during sepsis. The apoptosis of hepatocytes under septic condition or hepatocytes treated with PKCalpha antisense was evaluated by gel electrophoresis and/or flow cytometry after Annexin-V-Fluos and propidium iodide staining. The results indicated that (1) the protein expression of membrane-associated PKCalpha was decreased at early (P < 0.05) and late (P < 0.01) sepsis; (2) the protein expressions of Bcl-2 and Bcl-xL were decreased, whereas Bax expression was increased at late sepsis; (3) the percentage of PARP cleavage was increased at early (P < 0.05) and late (P < 0.01) sepsis; (4) severe DNA fragmentation was observed at late sepsis; (5) the apoptotic cell population was increased at early and late sepsis; and (6) the percentage of apoptotic cell population in PKCalpha antisense-treated cells was significantly higher than that in untreated cells. These results suggest that inactivation of PKCalpha may play an important role in modulating hepatic apoptosis during sepsis and the apoptosis is closely associated with the alterations of Bcl-2 family proteins.     

Nonhematopoietic toll-like receptor 2 contributes to neutrophil and cardiac function impairment during polymicrobial sepsis

Toll-like receptor 2 (TLR2) has been implicated in neutrophil and cardiac dysfunction during sepsis. Here we tested the hypothesis that nonhematopoietic (parenchymal) and hematopoietic TLR2 play distinct roles in sepsis pathogenesis. To achieve this, we generated two groups of chimeric mice with TLR2 deletions either in nonhematopoietic cells (knockout [KO] mice with wild-type [WT] bone marrow [BM]) or in BM cells (WT mice with KO-BM). Polymicrobial sepsis was created by cecal ligation and puncture (CLP). Neutrophil functions, cytokine production, and bacterial clearance were investigated following CLP or sham procedures. Cardiac contractile function was measured in a Langendorff apparatus. Intracellular reactive oxygen species (ROS) were measured using redox-sensitive dye and flow cytometry. Cecal ligation and puncture mice had markedly increased peritoneal neutrophil recruitment compared with the sham-operated mice. Toll-like receptor 2 KO mice, regardless their TLR2 phenotypes (WT vs. KO) in their BM-derived hematopoietic cells, had markedly increased neutrophil migration as well as phagocytosis and reduced cytokine productions compared with TLR2 WT mice following polymicrobial peritonitis. These changes in the chimeric TLR2 KO mice were associated with enhanced blood bacterial clearance and markedly improved cardiac contractile function. Moreover, CLP induced a robust ROS production in the peritoneal leukocytes isolated from WT mice but not from TLR2 KO mice. Taken together, these data indicate that TLR2, particularly that of nonhematopoietic cells, plays a major role in sepsis pathogenesis by impairing neutrophil migratory and phagocytic function, promoting cytokine production, and mediating cardiac contractile dysfunction during polymicrobial sepsis. Toll-like receptor 2 also mediates critical ROS production during polymicrobial sepsis.     

Dehydroepiandrosterone decreases mortality rate and improves cellular immune function during polymicrobial sepsis

OBJECTIVE: Sepsis is associated with a marked depression of cellular immune function. The steroid hormone dehydroepiandrosterone (DHEA) is proposed to have immunoenhancing activities. We, therefore, investigated the effect of DHEA on the mortality rate and cellular immune functions in an experimental model of sepsis. DESIGN: Randomized animal study. SETTING: Level I trauma center, university research laboratory. SUBJECTS: Male NMRI mice. INTERVENTIONS: Mice were subjected to laparotomy (sham) or cecal ligation and puncture (CLP). Mice were treated with (sham/DHEA; CLP/DHEA) or without (sham; CLP) the steroid hormone DHEA (30 mg/kg sc). Animals were killed 48 hrs after the onset of sepsis. MEASUREMENTS AND MAIN RESULTS: The survival rate of septic mice was determined 24 and 48 hrs after onset of sepsis. Forty-eight hours after the septic challenge, a white blood cell count was performed and serum tumor necrosis factor (TNF)-alpha and interleukin (IL)-1beta concentrations were monitored using ELISA. Furthermore, the delayed type of hypersensitivity (DTH) reaction was evaluated on the basis of ear pinna swelling after dinitrofluorobenzene (DNFB) administration, and clinical variables (body weight, temperature, heart rate, fluid input/output, food intake) were monitored using metabolic cages. DHEA administration improved the survival rate (87% vs. 53% after 48 hrs; p <.001). This was accompanied by a restoration of the depressed DTH reaction and a reduction in TNF-alpha serum concentrations (20.7 +/- 1.4 pg/mL vs. 32.4 +/- 6.6 pg/mL). CONCLUSIONS: These results demonstrate that DHEA administration leads to an increased survival following a septic challenge. The immunoenhancing effect of DHEA is accompanied by a reduction of TNF-alpha release and an improved activity of T-cellular immunity. DHEA administration may, therefore, be beneficial in systemic inflammation.     

严重脓毒症患儿Toll样受体4水平及临床意义

目的 探讨Toll样受体4(TLR4)水平在严重脓毒症患儿中的临床意义.方法 采用前瞻性病例对照研究方法,选择儿科重症监护病房(ICU)住院且诊断符合严重脓毒症、脓毒性休克患儿14例(严重脓毒症组),以同期住院的支气管肺炎患儿(肺炎组)及健康体检儿童(健康对照组)各10例作为对照.取患儿入院时静脉血2 ml,用流式细胞仪检测TLR4水平,用酶联免疫吸附法(ELISA)测定血清白细胞介察(IL-6、IL-10)、肿瘤坏死因子-α(TNF-α)含量.结果 严重脓毒症组TLR4[(71.56±15.32)%]、IL-6[(1.98±1.55)ng/L]、IL-10[(88.20±61.23)ng/L]、TNF-α[(104.08±85.36)ng/L]水平均显著高于肺炎组[分别为(50.07±26.36)%、(0.93±0.16)ng/L、(41.42±7.02)ng/L、(48.96±6.40)ng/L]与健康对照组[分别为(39.43±17.43)%、(0.94±0.43)ng/L、(43.73±22.68)ng/L、(49.94±18.47)ng/L],差异均有统计学意义(均P＜0.05);而肺炎组与健康对照组间比较差异均无统计学意义(均P＞0.05).结论 TLR4是脓毒症发生与发展的启动点,其水平与促炎因子IL-6、TNF-α及抗炎因子IL-10水平一致;若将TLR4的变化与部分炎症介质水平相互结合,可作为脓毒症患儿早期诊断和病情严重程度的预测指标.     

Adrenal insufficiency during the late stage of polymicrobial sepsis

OBJECTIVES: Although studies have indicated that adrenal insufficiency occurs after severe trauma and hemorrhagic shock, it remains controversial whether adrenal function is depressed during the late stage of polymicrobial sepsis. DESIGN: Prospective, controlled animal study. SETTING: A university research laboratory. SUBJECTS: Male rats (275-325 g) were subjected to polymicrobial sepsis by cecal ligation and puncture (CLP) or sham operation followed by the administration of normal saline solution. MEASUREMENTS AND MAIN RESULTS: Systemic blood samples were taken at 20 hrs after CLP (i.e., a late stage of sepsis) or sham operation to measure plasma levels of corticosterone and corticotropin as well as adrenal contents of corticosterone. Additional groups of animals were utilized to examine corticotropin-stimulated plasma corticosterone release as well as adrenal levels of cyclic adenosine monophosphate (cAMP, the second messenger of corticotropin action). The results indicate that despite a 75% (p < .05) higher concentration in plasma corticotropin at 20 hrs after the onset of sepsis, plasma corticosterone levels were similar to those in sham-operated animals. In addition, adrenal contents of corticosterone were reduced by 42% (p < .05) in septic animals. Moreover, the plasma corticosterone and adrenal cAMP responses to corticotropin were reduced by 53% and 27% (p < .05), respectively, at 20 hrs after CLP. CONCLUSIONS: These findings suggest that, despite high plasma levels of endogenous corticotropin, adrenal dysfunction, as indicated by the reduction of corticotropin-induced plasma corticosterone release and adrenal contents of cAMP as well as the decreased adrenal levels of corticosterone, occurs during the late stage of polymicrobial sepsis. Therefore, the recognition of adrenal insufficiency and interventions to improve adrenal responsiveness may be beneficial in improving the outcome during late sepsis.     

Modulation of atherosclerosis in mice by Toll-like receptor 2

Epidemiologic evidence has established a relationship between microbial infection and atherosclerosis. Mammalian TLRs provide clues on the mechanism of this inflammatory cascade. TLR2 has a large ligand repertoire that includes bacterial-derived exogenous and possibly host-derived endogenous ligands. In atherosclerosis-susceptible low-density lipoprotein receptor-deficient (Ldlr-/-) mice, complete deficiency of TLR2 led to a reduction in atherosclerosis. However, with BM transplantation, loss of TLR2 expression from BM-derived cells had no effect on disease progression. This suggested that an unknown endogenous TLR2 agonist influenced lesion progression by activating TLR2 in cells that were not of BM cell origin. Moreover, with intraperitoneal administration of a synthetic TLR2/TLR1 agonist, Pam3CSK4, disease burden was dramatically increased in Ldlr-/- mice. A complete deficiency of TLR2 in Ldlr-/- mice, as well as a deficiency of TLR2 only in BM-derived cells in Ldlr-/- mice, led to striking protection against Pam3CSK4-mediated atherosclerosis, suggesting a role for BM-derived cell expression of TLR2 in transducing the effects of an exogenous TLR2 agonist. These studies support the concept that chronic or recurrent microbial infections may contribute to atherosclerotic disease. Additionally, these data suggest the presence of host-derived endogenous TLR2 agonists.     

Alterations in tissue glucose uptake during the hyperglycemic and hypoglycemic phases of sepsis

The purpose of the present study was to characterize the alterations in tissue glucose uptake during the hyperglycemic, euglycemic, and hypoglycemic phases of peritonitis. Rats had vascular catheters implanted, and sepsis was induced by cecal ligation and puncture. Rates of whole-body glucose appearance (Ra), disappearance (Rd), and metabolic clearance (MCR) were determined by the constant infusion of 3H-glucose, and in vivo glucose uptake (Rg) by individual tissues was assessed by using 14C-deoxyglucose. During the hyperglycemic phase of sepsis (2 h), glucose Ra and Rd were increased, but glucose MCR was unaltered. In contrast, during the euglycemic phase (6 h), the sepsis-induced increase in glucose Ra and Rd was associated with an elevation in the MCR. Finally, during the hypoglycemic phase (24 h), sepsis decreased glucose Ra and Rd and the glucose MCR. The sepsis-induced changes in Rg for skeletal muscle and adipose tissue mimic those seen for the whole body at each time point. Rg for skin and intestine was elevated at 2 h and 6 h but was not different from control values at 24 h. In contrast, the Rg for liver, lung, and spleen was increased at all 3 time points. In a second study, there was no difference in Rg for any tissue between 2-h septic rats and control animals in which blood glucose and insulin levels were artificially elevated to the same degree. In a third study, the prevailing glucose and insulin levels in control animals were decreased, by injection of the gluconeogenic inhibitor 3-mercaptopicolinic acid, to levels seen in 24-h septic rats. There was no difference in the Rg for muscle and adipose tissue between 24-h septic rats and hypoglycemic insulinopenic control animals. However, the Rg for liver, lung, and spleen remained elevated in 24-h septic rats, compared with hypoglycemic insulinopenic control values. These data indicate that the increased tissue glucose uptake observed during the early phase of sepsis is a consequence of concomitant changes in plasma glucose and insulin. In contrast, during the euglycemic and hypoglycemic stages of sepsis, glucose uptake in macrophage-rich tissues remains elevated and is independent of changes in glucose and insulin.     

非重症及重症脓毒症患者外周血单核细胞炎性因子分泌及Toll样受体4表达的研究

目的 观察革兰阴性菌感染的非重症及重症脓毒症患者内毒素(LPS)刺激后外周血单核细胞炎性因子分泌及TLR4的表达.方法 以我院ICU革兰阴性菌感染所致脓毒症52例患者为研究对象,28例非重症脓毒症患者,24例重症脓毒症患者,选取30例健康对照者.所有人均晨起空腹采血,分离外周血单核细胞,将细胞加入1 μg/mL细菌LPS培养24 h后流式细胞仪检测单核细胞表面TLR4的表达,同时应用放射免疫法测定外周血单核细胞培养液中TNF-α、IL-10的浓度.结果 ①重症脓毒症患者单核细胞培养上清液中TNF-α的浓度低于非重症脓毒症患者及健康对照组(P<0.05),但IL-10浓度高于其他两组(P<0.05),IL-10/TNF-α比值明显高于非重症脓毒症患者及健康对照组(P<0.01).②三组患者外周血单核细胞LPS刺激后,细胞表面TLR4表达差异无统计学意义(P>0.05).结论 重症脓毒症患者外周血单核细胞体外给予LPS刺激后,促炎因子表达较非重症脓毒症组下降,且伴有抗炎因子表达的上调,IL-10/TNF-α比值明显升高,显示重症脓毒症患者存在更加严重的免疫抑制现象,但这种现象不能单纯用细胞膜表面TLR4的表达解释,其可能存在更复杂的机制.     

Glycine attenuates hepatocellular depression during early sepsis and reduces sepsis-induced mortality

OBJECTIVES: To determine whether administration of glycine, a nonessential amino acid, early after the onset of polymicrobial sepsis has any beneficial effects on hepatocellular function and the survivability of septic animals and, if so, whether the beneficial effects of glycine are associated with down-regulation of proinflammatory cytokine tumor necrosis factor-alpha production. DESIGN: Prospective, controlled, and randomized animal study. SETTING: A university research laboratory. SUBJECTS: Male adult rats were subjected to polymicrobial sepsis by cecal ligation and puncture or sham operation followed by the administration of normal saline solution. MEASUREMENTS AND MAIN RESULTS: At 1 hr after cecal ligation and puncture, glycine (0.6 mmol/kg) or vehicle (normal saline solution) was administered intravenously over 15 mins. At 5 hrs after cecal ligation and puncture (i.e., early stage of sepsis), hepatocellular function (i.e., the maximal velocity and efficiency of in vivo indocyanine green clearance) was determined and hepatocyte injury was assessed by measuring plasma concentrations of alpha-gluthathione S-transferase. Serum tumor necrosis factor-alpha was measured by enzyme-linked immunosorbent assay. In additional animals, the necrotic cecum was excised at 20 hrs after cecal ligation and puncture, the peritoneal cavity was irrigated with saline, and the midline incision was closed in layers. Mortality was monitored for 10 days thereafter. The results indicate that hepatocellular function was depressed in the early stage of sepsis (i.e., 5 hrs after cecal ligation and puncture) as indicated by significant decreases in both maximal velocity and transport efficiency of in vivo indocyanine green clearance. Plasma concentrations of alpha-gluthathione S-transferase and tumor necrosis factor-alpha were elevated significantly at that interval after cecal ligation and puncture. Administration of glycine 1 hr after cecal ligation and puncture, however, increased maximal velocity and maximal efficiency by 60% and 101% (p <.05), respectively. Glycine administration in septic animals decreased alpha-gluthathione S-transferase and tumor necrosis factor-alpha by 43% and 80% (p <.05). In addition, glycine treatment decreased the mortality rate from 50% to 0% (p <.05) at 10 days after cecal ligation and puncture and cecal excision. CONCLUSIONS: It appears that the beneficial effect of glycine on hepatocyte function and integrity in sepsis may be mediated via down-regulation of tumor necrosis factor-alpha. Because administration of glycine attenuated hepatocellular depression and injury during early sepsis and decreased sepsis-induced mortality rates, this amino acid appears to be a useful adjunct for maintaining cellular functions and preventing lethality from polymicrobial sepsis.     

Splenectomy inactivates the cholinergic antiinflammatory pathway during lethal endotoxemia and polymicrobial sepsis

The innate immune system protects against infection and tissue injury through the specialized organs of the reticuloendothelial system, including the lungs, liver, and spleen. The central nervous system regulates innate immune responses via the vagus nerve, a mechanism termed the cholinergic antiinflammatory pathway. Vagus nerve stimulation inhibits proinflammatory cytokine production by signaling through the alpha7 nicotinic acetylcholine receptor subunit. Previously, the functional relationship between the cholinergic antiinflammatory pathway and the reticuloendothelial system was unknown. Here we show that vagus nerve stimulation fails to inhibit tumor necrosis factor (TNF) production in splenectomized animals during lethal endotoxemia. Selective lesioning of the common celiac nerve abolishes TNF suppression by vagus nerve stimulation, suggesting that the cholinergic pathway is functionally hard wired to the spleen via this branch of the vagus nerve. Administration of nicotine, an alpha7 agonist that mimics vagus nerve stimulation, increases proinflammatory cytokine production and lethality from polymicrobial sepsis in splenectomized mice, indicating that the spleen is critical to the protective response of the cholinergic pathway. These results reveal a specific, physiological connection between the nervous and innate immune systems that may be exploited through either electrical vagus nerve stimulation or administration of alpha7 agonists to inhibit proinflammatory cytokine production during infection and tissue injury.     

过敏性紫癜患儿外周血单核细胞TLR2、TLR4、TLR6及与Treg相关细胞因子的表达

背景：Toll样受体介导的信号通路转导及调节性T细胞异常活化在过敏性紫癜发病中的作用不清楚。目的：研究Toll样受体TLR2、TLR4、TLR6在过敏性紫癜患儿外周血单核细胞的表达及调节性T细胞（Treg）的免疫应答,探讨TLR及Treg活化在敏性紫癜发病机制中的作用。方法：选择处于过敏性紫癜急性期的患儿42例为观察对象,另选取15名门诊健康查体儿童为正常对照组。采用流式细胞术检测外周血单核细胞的TLR2、TLR4、TLR6的蛋白表达量;应用反转录-聚合酶链反应（RT-PCR）及实时荧光定量PCR检测外周血单核细胞TLR信号途径分子MyD88 mRNA的基因相对表达量;ELISA法测Treg细胞分泌的转化生长因子β、白细胞介素10的血浆水平;两组间比较采用独立样本t或t’检验,相关性分析采用Pearson相关检验。结果与结论：过敏性紫癜患儿外周血单核细胞的TLR2、TLR4、TLR6蛋白的表达及MyD88 mRNA基因的相对表达量均显著高于对照组（P〈0.01）;过敏性紫癜患儿血浆中转化生长因子β、白细胞介素10均高于对照组（P〈0.05）;过敏性紫癜患儿TLR2、TLR4、TLR6的蛋白表达量与Myd88 mRNA的基因相对表达量呈正相关（P〈0.01）,与血浆白细胞介素10、转化生长因子β水平无明显相关（P〉0.05）。提示TLR2、TLR4、TLR6活化后可能通过MyD88依赖的途径参与敏性紫癜的发病,而过敏性紫癜急性期Treg代偿性活化可能为机体的保护性免疫应答。     

高氧致大鼠急性肺损伤Toll样受体2和4的变化及意义

目的 探讨Toll样受体(TLRs)在高氧致急性肺损伤(ALI)发病过程中的作用.方法 将32只SD大鼠按随机数字表法分为空气对照组和高氧暴露24、48、72 h组,每组8只.分别于相应时间点活杀8只大鼠,取肺组织标本,测定肺湿/干重(W/D)比值并行肺组织病理评分,用实时荧光定量逆转录-聚合酶链反应(RT-PCR)测定肺组织TLR2和TLR4的mRNA表达,用蛋白质免疫印迹法(Western blotting)测定肺组织TLR2和TLR4的蛋白表达,用酶联免疫吸附法(ELISA)测定肺组织匀浆中白细胞介素-6(IL-6)含量.结果 各高氧暴露组肺W/D比值均较空气对照组明显增高(P均<0.01).高氧暴露48 h、72 h肺组织病理评分[(2.69±0.53)分,(3.94±0.62)分]均明显高于空气对照组[(0.41±0.38)分,P均<0.01].RT-PCR结果显示,高氧暴露组肺组织TLR2和TLR4 mRNA表达均明显高于空气对照组(0.67±0.15和0.63±0.19),并均于24 h达高峰(1.82±0.33,1.35±0.26,P均<0.05).Western blotting结果显示,高氧暴露组TLR2和TLR4蛋白表达均较空气对照组[(7.20±0.51)%和(14.26±0.19)%]明显增高,分别于48 h、72 h达峰值[(28.12±0.24)%,(81.35±0.82)%,P均<0.05].ELISA结果显示,高氧暴露组肺组织匀浆IL-6含量较空气对照组[(639.38±95.24)pg/L]明显增高,于72 h达高峰[(1 300.58±442.24)pg/L,P<0.05].结论 在高氧引起的ALI中,TLR2和TLR4在肺组织炎症启动和维持中起重要作用.     

乌司他丁对严重脓毒症患者外周血单核细胞Toll样受体4表达的影响

目的 观察乌司他丁(UTI)对严重脓毒症患者外周血单核细胞Toll样受体4(TLR4)表达的影响,从而进一步了解UTI抑制炎症反应的作用机制.方法 70例严重脓毒症患者随机分为对照组(30例)和UTI组(40例),UTI组在对照组常规治疗基础上加用UTI(质量分数5%葡萄糖250 ml+UTI 600 kU)静脉滴注,每日2次,连用3 d.分别在治疗前及治疗后1、2、3 d采集动脉血,用流式细胞仪检测TLR4表达,用酶联免疫吸附法(EuSA)检测血浆肿瘤坏死因子-α(TNF-α)和白细胞介素-6(L-6)浓度.结果 两组治疗后单核细胞表面TLR4表达及血浆TNF-α、IL-6浓度均较治疗前显著增加(P均<0.05);UTI组各指标值均较对照组上升幅度低(P均<0.05).结论 UTI可有效抑制单核细胞表面TLR4表达,抑制炎症因子释放,对严重脓毒症患者有一定的保护作用.