Protective effects of lactoferrin in <Emphasis Type="Italic">Escherichia coli</Emphasis>-induced bacteremia in mice: Relationship to reduced serum TNF alpha level and increased turnover of neutrophils

Objective and Design:Previous studies demonstrated that lactoferrin (LF), given intravenously (i.v.), 24 h before lethal Escherichia coli (E. coli) infection, protects mice against mortality. The aim of this investigation was to determine whether downregulation of serum TNF alpha activity and increase of neutrophil number in the circulation and bone marrow by LF could contribute to the protective action of LF against E. coli-induced sepsis. Materials and subjects:CBA female mice, 10–12 week old, weight 20–22 g, were used. Treatment:Mice were given 10 mg LF i.v. either 2 h or 24 h before i.v. administration of lethal dose of E. coli (5 × 10⁸). Methods:Serum activities of TNF alpha and IL-1 were determined by bioassays 2 h following E. coli or LF injection. The blood and bone marrow smears were stained with Giemsa and May-Grünwald reagents and reviewed histologically. Results:LF given 24 h before E. coli caused a 60% reduction of TNF alpha released into circulation. However, pretreatment of mice with LF 2 h before bacterial challenge resulted in strong (15 fold) increase of TNF alpha serum level. Analysis of bone marrow cell composition revealed a significant increase in neutrophil lineage cell content (myelocytes, bands and mature neutrophils) following 24 h pretreatment with LF (51.8% of the total cell count), versus PBS control (32.7%) and 2 h LF pretreatment (35.8%). The percentage of neutrophils (bands and mature forms) in the peripheral blood rose to 47.4% versus 32% and 32%, respectively. Intravenous administration of LF increased also interleukin 1 (IL-1) concentration in the circulation of noninfected mice. Conclusions:This investigation has added more information regarding the mechanism of the protective action of LF in E. coli-induced bacteremia by revealing the phenomenon of accelerated neutrophil recruitment and down-regulation of E. coli-induced TNF alpha serum level.Received 22 September 2003; returned for revision 31 October 2003; accepted by M. J. Parnham 14 January 2004     

乳铁蛋白在大鼠坐骨神经慢性束缚损伤模型产生镇痛作用

目的:研究乳铁蛋白在大鼠坐骨神经慢性束缚损伤模型的镇痛作用。方法:30只成年SD大鼠被制作为坐骨神经慢性束缚损伤模型,用辐射热刺激法诱发鼠后腿回缩试验测定痛阈,实验动物分为5组,分别腹腔注射生理盐水及乳铁蛋白30mg/kg、100mg/kg、300mg/kg、1000mg/kg。药物效应以最大可能效应百分数(MPE%)表示。以t检验法分析乳铁蛋白各剂量组与对照组之间的差异。结果:腹腔注射乳铁蛋白剂量依赖性地延长大鼠后腿回缩潜伏期;乳铁蛋白的峰值作用时间在用药后60分钟;乳铁蛋白各剂量组的最大可能效应百分数与生理盐水组相比差异有显著性。结论:腹腔注射乳铁蛋白在大鼠坐骨神经慢性束缚损伤模型产生剂量依赖性镇痛作用。     

Cervical inflammatory cytokines and other markers in the cervical mucus of pregnant women with lower genital tract infection.

OBJECTIVE: To evaluate concentrations of interleukin (IL)-6, IL-8, lactoferrin (LF), and alpha defencine (alpha-DF) in the cervical mucus of pregnant women and analyze their relation to cervicitis and bacterial vaginosis (BV). METHODS: Cervical mucus samples were obtained from August 2003 through May 2004 from 157 women who were between the 6th and 36th week of an uncomplicated singleton pregnancy. All women were delivered at term, 69 without BV or cervicitis, 9 with BV, and 79 with cervicitis. RESULTS: Interleukin 8, LF, and mu-DF concentrations were higher in women with cervicitis (0.81 +/- 0.36 pg/mL, 14.8+/-12.3 microg/mL, and 0.60 +/- 0.49 microg/mL) than in women without BV or cervicitis (0.35 +/- 0.34 pg/mL, 8.0 +/- 11.0 microg/mL, and 0.15 +/- 0.12 microg/mL). Interleukin 6 concentration was higher in women with BV (0.26 +/- 0.32 pg/mL) than in women without BV or cervicitis (0.09 +/- 0.15 pg/mL) or in women with cervicitis (0.12 +/- 0.18 pg/mL). CONCLUSIONS: Higher levels of inflammatory cytokines in the cervical mucus of pregnant women may lead to early detection of lower genital tract infection.     

Lactoferrin for prevention of common viral infections

Although lactoferrin has many biological functions, the host-protective effects against pathogenic microorganisms including bacteria, fungi, and viruses are regarded as one of the most important. Here, we review research on the protective role of lactoferrin administration against common viral infections. Many studies have shown the in vitro antiviral activity of lactoferrin against viral pathogens that cause common infections such as the common cold, influenza, gastroenteritis, summer cold, and herpes, where lactoferrin inhibits mainly viral attachment to the target cells. Recently, studies indicating the in vivo protective effects of lactoferrin by oral administration against common viral infections have been increasing. For instance, norovirus is an extremely important emerging human pathogen that causes a majority of gastroenteritis outbreaks worldwide that may be a target candidate for lactoferrin. Lactoferrin consumption reduced the incidence of noroviral gastroenteritis in children and a similar effect was observed in a wide range of ages in a preliminary survey. A recent in vitro study reported that lactoferrin inhibits both cellular attachment of the murine norovirus, a virus closely-related to the human norovirus, and viral replication in the cells by inducing antiviral cytokines interferon (IFN)-α/β. Lactoferrin administration also enhances NK cell activity and Th1 cytokine responses, which lead to protection against viral infections. In conclusion, lactoferrin consumption may protect the host from viral infections through inhibiting the attachment of a virus to the cells, replication of the virus in the cells, and enhancement of systemic immune functions.     

低密度脂蛋白受体抑制剂对低密度脂蛋白和脂蛋白(a)代谢的影响

应用低密度脂蛋白受体抑制剂乳酸肝褐质和受体结合蛋白经刺猬腋下静脉注入，２ｍｉｎ后注射１２５Ⅰ－低密度脂蛋白或１２５Ⅰ－脂蛋白（３），６ｈ后处死，测定血、肝、肾、脾、胆汁和肾上腺的放射活性。实验发现：乳酸肝褐质和受体结合蛋白均能抑制低密度脂蛋白受体活性，使各组织摄取低密度脂蛋白分别降低１５％～８６％以上，但乳酸肝褐质和全体结合蛋白对脂蛋白（ａ）的组织摄取不但无抑制作用，反而能使脂蛋白（ａ）进入组织量增加，激活率分别达４０％～１２６％。实验结果说明：脂蛋白（ａ）虽然与低密度脂蛋白结构相似，含有７０％载脂蛋白Ｂ１００，但由于与载脂蛋白（ａ）以二硫键的形式连接，改变了空间结构，失去了与低密度脂蛋白受体结合的能力，并且推测乳酸肝褐质和受体结合蛋白在抑制低密度脂蛋白受体的同时，可能激活了细胞膜的其它机制，从而利于脂蛋白（ａ）进入细胞内。     

环丙沙星与乳铁蛋白多肽嵌合体联用对铜绿假单胞菌生物膜及密度感知系统信号分子生成的抑制作用

目的 比较环丙沙星(CIP)、乳铁蛋白多肽嵌合体(LFchimera)单用及二者联用对铜绿假单胞菌生物膜及密度感知(QS)系统信号分子(AHL)生成的抑制作用.方法 以铜绿假单胞菌野生菌株PA01为实验菌株,分为对照组(未干预的铜绿假单胞菌野生菌株PA01)、CIP(0.04 μg·mL-1)组、LFchimera(0.25 μmol·L-1)组、LFchimera(1.00 μmol·L“)组、CIP(0.04 μg· mL-1)±LFchimera(1.00 μmol·L-1)组,分别定量测定并比较各组PA01生物被膜和QS系统信号分子表达.结果 与对照组PA01生物膜定量表达(A590) (1.511 3±0.031 8)及QS系统信号分子表达(A420) (0.502 5±0.028 3)比较,CIP(0.04 μ,g·mL-1)组(1.073 3±0.010 9,0.245 3±0.014 0)、LFchimera(0.25 μmol·L-1)组(1.065 5±0.011 4,0.235 9±0.010 7)、LFchimera(1.00 μmol·L-1)组(0.665 3±0.012 9,0.108 6±0.007 0)和CIP(0.04 μg·mL-1)± LFchimera(1.00 μmol·L-1)组(0.122 1 ±0.013 0,0.048 2±0.005 4)均下降(均P＜0.05);CIP(0.04 μg·mL-1)组和LFchimera(0.25 μmol·L-1)组比较,PAO1生物膜定量表达和QS系统信号分子表达差异无统计学意义(P＞0.05);LFchimera(1.00 μmol·L-1)组PA01的生物膜定量表达和QS系统信号分子表达较LFchimera(0.25 μmol·L-1)组和CIP(0.04 μg·mL-1)组均降低(均P＜0.05);CIP(0.04ug·mL-1)±LFchimera(1.00 μmol·L-1)组和各单独用药组比较,PAO1生物膜的定量表达和QS系统信号分子表达均下降(均P＜0.05).结论 亚抑菌浓度的CIP和LFchimera都对铜绿假单胞菌生物膜的形成和QS系统信号分子的生成有抑制作用,且提高LFchimera浓度可加强抑制作用;CIP与LFchimera联用能增强抑制作用,这种作用可能是通过抑制QS系统信号分子的生成实现.     

乳铁蛋白促进成骨细胞增殖的最佳浓度及促进分化的最佳时间

目的 探索乳铁蛋白促进大鼠成骨细胞增殖的最佳浓度及1000μg/mL乳铁蛋白对促进成骨细胞分化的最佳时间。方法 用混合酶消化法分离大鼠颅盖骨成骨细胞进行原代培养;不同浓度乳铁蛋白干预成骨细胞,浓度分别为0、0.1、1、10、100、200、400、600、800和1000μg/mL,在1、3、5、7d后分别采用CCK-8法测定细胞增殖;用1000μg/mL的乳铁蛋白干预成骨细胞7、14、21d后,采用碱性磷酸酶染色法检测细胞内碱性磷酸酶的活性。结果 1.CCK-8法测定细胞增殖结果显示,低于100μg/mL浓度乳铁蛋白组其OD值随着浓度的增高而增高,而高于100μg/mL浓度乳铁蛋白组其OD值随着乳铁蛋白浓度的增高而递减;2.碱性磷酸酶染色法结果显示,1000μg/mL的乳铁蛋白在干预第21天时碱性磷酸酶活性最高。结论 100μg/mL乳铁蛋白是促进大鼠成骨细胞增殖的最佳浓度;1000μg/mL的乳铁蛋白促进成骨细胞分化作用呈时间依赖性。     

粪便生物标记物检测对溃疡性结肠炎的诊断价值研究

目的研究两种粪便生物标记物乳铁蛋白、钙卫蛋白诊断溃疡性结肠炎(ulcerative colitis,UC)活动性的价值。方法选择确诊的UC患者72例作为研究组,60例经结肠镜检查均正常的患者作为对照组,留取结肠镜检查3 d内的粪便样本5~10 g,应用ELISA方法进行粪便乳铁蛋白、钙卫蛋白检测。结果粪便乳铁蛋白、钙卫蛋白水平在缓解组和对照组之间比较差异均无统计学意义(P0.05);活动组分别与缓解组和对照组比较差异均有显著统计学意义(P0.01);活动期各组之间相互比较差异均有统计学意义(P0.01)。粪便乳铁蛋白、钙卫蛋白水平与UC内镜分级标准呈正相关(r=0.873;0.891,P0.01)。结论粪便乳铁蛋白、钙卫蛋白检测能够较准确地诊断UC活动期和缓解期,对临床治疗有指导作用。     

载乳铁蛋白壳聚糖微球/nHA/Co复合材料的制备

目的:制备载乳铁蛋白壳聚糖微球/nHA/Co复合材料作为组织工程材料拟修复骨缺损。方法:通过乳化交联法法制备载乳铁蛋白壳聚糖微球,化学沉淀法制备纳米羟基磷灰石,改良酸酶法提取Ⅰ型胶原,应用京尼平交联制备复合材料,SEM检测材料的微观结构,测定壳聚糖微球对乳铁蛋白的载药率和包封率。结果:复合材料及各组成成份扫描电镜观察均具有较好的微观形态,壳聚糖微球对乳铁蛋白的载药率为(1.06±0.06)%,包封率为(88.2±2.9)%。结论:载乳铁蛋白壳聚糖微球/nHA/Co复合材料具有较好的微观形态。     

人血清与中性粒细胞中乳铁蛋白含量与中性粒细胞吞噬功能的关系

用ＥＬＩＳＡ测定了人血清及中性粒细胞（ＰＭＮ）中乳铁蛋白（ＬＦ）含量，并与ＰＭＮ的吞噬功能比较，证实血清中ＬＦ水平与ＰＭＮ吞噬功能不相关，ＰＭＮ中ＬＦ含量与其吞噬、杀菌功能有密切的正相关关系。