CCK-8对LPS攻击小鼠IL-1β、IL-6、IL-4、IL-10表达的影响

目的： 观察LPS攻击小鼠IL-1β、IL-6、IL-4、IL-10的动态变化规律及八肽胆囊收缩素（CCK-8）对其表达的影响。方法: 将小鼠分为4组：对照组、LPS组（腹腔注射LPS）、LPS+CCK-8组（注射LPS前 30 min 腹腔注射CCK-8）及CCK-8组（单独注射CCK-8）。用ELISA及PT-PCR方法检测各组小鼠血清、肺组织中IL-1β、IL-6、IL-4、IL-10的含量及mRNA的表达情况。结果: LPS攻击可使小鼠血清及肺组织中 IL-1β、IL-6、IL-4、IL-10蛋白及mRNA的表达增加，预先注入CCK-8可显著抑制IL-1β、IL-6的表达，并使 IL-4、IL-10的表达进一步增加。结论: CCK-8可能通过抑制LPS攻击小鼠IL-1β、IL-6的表达和进一步增加 IL-4、IL-10的表达参与抗炎反应过程，从而减轻LPS引起的肺组织炎症反应。     

天抗(TK)对脂多糖诱导小鼠炎症模型的抗炎作用及其机制

目的研究天抗(TK)对脂多糖(LPS)诱导的小鼠炎症模型的抗炎作用及机制研究。方法将42只昆明小鼠随机分为正常对照(NC)组、模型对照(LPS)组、地塞米松(DXM)组、天抗低(TK-L)、中(TK-M)和高(TK-H)剂量组(0.2,0.8和3.2 g/kg)。各组分别灌胃给药7 d后,腹腔注射30 mg/kg的LPS诱导小鼠急性炎性模型,6 h后处死小鼠,检测小鼠脾脏指数,ELISA测定小鼠血清中IL-1β、IL-6和TNF-α的表达水平;生化法检测小鼠血清中SOD和MDA的表达;qRT-PCR检测小鼠脾脏TLR4、MyD88、TRAF6、p65、IL-1β、IL-6和TNF-αmRNA的表达水平;Western blot检测小鼠脾脏TLR4、MyD88、TRAF6、p-p65和p65蛋白表达水平。结果与LPS组相比,TK组小鼠的脾脏指数明显降低,血清和脾脏组织中IL-1β、IL-6、TNF-α和MDA水平显著下降,SOD水平明显升高,小鼠脾脏组织的TLR4、MyD88、TRAF6和p-p65等蛋白及mRNA表达水平均明显降低。结论天抗对LPS诱导的小鼠急性炎症模型具有抗炎作用,其作用机制可能是通过TLR4/MyD88/NF-κB(p-65)信号通路抑制炎症因子的释放。     

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。     

二甲双胍对脂多糖致炎性反应小鼠的抗炎作用

目的探究二甲双胍(Met)对脂多糖(LPS)致炎性小鼠的抗炎效应。方法 ICR小鼠分为对照组、LPS组、二甲双胍高、中和低剂量组(400, 200和100 mg/kg)。对照组和LPS组腹腔注射0.9%氯化钠溶液,其余3组注射不同剂量的二甲双胍;0.5 h后,除对照组外,其余4组腹腔注射等体积的LPS致小鼠炎性反应,6 h后测量小鼠的脾指数;ELISA检测小鼠血清中炎性因子IL-6、TNF-α和IL-10的表达;RT-PCR检测小鼠肝脏组织IL-6、TNF-α和IL-10 mRNA表达的变化;HE染色检测小鼠肝脏组织炎性反应变化。结果相对于LPS组,二甲双胍用药组小鼠的脾指数降低(P0.05);外周血IL-6和TNF-α及肝脏组织中IL-6和TNF-αmRNA的表达明显下降(P0.05);而外周血IL-10及肝脏组织中IL-10 mRNA显示上升(P0.05);二甲双胍高剂量组可明显减轻由LPS所致小鼠肝脏的炎性反应。结论二甲双胍对于LPS致炎性小鼠具有一定的抗炎活性。     

中药四毒清抑制LPS性肾脏损伤的机制研究

目的：研究中药复方四毒清防治内毒素性肾功能衰竭的作用机制。 方法： 将小鼠随机分成对照组、LPS组、四毒清防治组和四毒清组，用水（0.2 mL/10 g BW）或四毒清（1 000 g/L, 0.2 mL/10 g BW）灌胃3 d，每天2次, 第3 d灌胃后2 h，腹腔注射LPS(30 mg/kg，0.2 mL/10 g BW)或生理盐水（0.2 mL/10 g BW），腹腔注射后2 h，再用水或四毒清（0.2 mL/10 g）灌胃1次。测定各组小鼠血清肌酐（Cr）和尿素氮（BUN）的含量，观察肾脏超微结构，肾组织丙二醛(MDA)含量和超氧化物歧化酶(SOD)活性的变化， 并用半定量RT-PCR方法测定肾组织细胞间黏附分子-1(ICAM-1) mRNA的表达。 结果： LPS引起小鼠血清Cr和BUN含量明显升高，肾脏近曲小管出现明显病理改变。四毒清有效降低LPS攻击小鼠血清Cr和BUN的含量，明显减轻近曲小管的损伤。LPS组小鼠肾组织MDA含量和ICAM-1 mRNA的表达显著高于对照组，而四毒清防治组肾组织MDA含量和ICAM-1 mRNA的表达明显低于LPS组，四毒清处理能显著升高肾组织SOD的活性。 结论： 中药四毒清防治内毒素性肾功能衰竭的作用机制与其升高肾组织SOD的活性、减轻肾组织氧化损伤并抑制肾脏ICAM-1 mRNA的表达有关。     

淋巴细胞缺陷对内毒素血症小鼠腹腔巨噬细胞活化的影响

目的观察淋巴细胞缺陷对内毒素血症小鼠腹腔巨噬细胞活化的影响。方法采用腹腔注射脂多糖(LPS)建立Balb/c小鼠和T、B细胞缺陷的重症联合免疫缺陷(SCID)小鼠内毒素血症模型,ELISA检测2种小鼠腹腔灌洗液TNF-α和IL-10水平,实时荧光定量PCR检测腹腔巨噬细胞(peritoneal macrophage,PMa)TNF-α、IL-10及丝裂原蛋白激酶磷酸酶-1(mito-gen-activated protein kinase phosphatase-1,MKP-1)mRNA表达;ELISA检测Balb/c及SCID小鼠PMa体外刺激后细胞因子分泌情况。结果 LPS注射后1 h,SCID小鼠腹腔灌洗液TNF-α水平高于Balb/c小鼠,注射后3 h,IL-10水平低于Balb/c小鼠;LPS注射前及注射后,SCID小鼠PMa TNF-αmRNA表达高于Balb/c小鼠PMa,IL-10 mRNA表达低于Balb/c小鼠PMa;体外实验LPS刺激下,SCID小鼠PMa较Balb/c小鼠PMa分泌更多的TNF-α,IL-10的分泌却偏少。LPS注射前及注射后,Balb/c小鼠PMa MKP-1 mRNA表达均明显高于SCID小鼠。结论淋巴细胞缺陷导致内毒素血症小鼠腹腔巨噬细胞活性的增加,淋巴细胞抑制巨噬细胞的活化并可能调控其发育及成熟;MKP-1表达的减少可能是淋巴细胞缺陷导致腹腔巨噬细胞活性增加的分子机制之一。     

Wortmannin对急性肺损伤小鼠肺组织IL-1β和TNF-α表达的影响

目的研究Wortmannin对急性肺损伤模型小鼠肺组织白介素-1β(IL-1β)和肿瘤坏死因子-α(TNF-α)表达的影响。方法 30只昆明小鼠随机分为正常对照组、急性肺损伤组和Wortmannin处理组。采用腹腔注射LPS(10 mg/kg)建立小鼠急性肺损伤模型,对照组腹腔注射同体积的生理盐水,Wortmannin处理组则于造模前2 h腹腔注射Wortmannin(1.4 mg/kg)。LPS注射后6 h处死大鼠,计算肺组织湿/干重(W/D)比值,Western blot方法检测三组小鼠肺组织内IL-1β和TNF-α蛋白的表达变化,RT-PCR方法检测三组小鼠肺组织内IL-1βmRNA和TNF-αmRNA的表达变化。结果急性肺损伤组小鼠肺组织IL-1β和TNF-α蛋白及mRNA表达水平显著上升,显著高于正常对照组(0.05);相比于急性肺损伤组小鼠,Wortmannin处理组小鼠肺组织IL-1β和TNF-α蛋白及mRNA表达水平显著降低(0.05)。结论 Wortmannin能抑制急性肺损伤小鼠肺组织IL-1β和TNF-α表达。     

右美托咪啶减轻急性肺损伤的机制研究

目的探讨右美托咪啶(Dex)对小鼠急性肺损伤(ALI)的影响及潜在作用机制。方法将32只C57BL/6雄性小鼠随机分为空白对照组(Sham组)、右美托咪啶组(Dex组)、脂多糖组(LPS组)和药物干预组(LPS+Dex组)。LPS组和LPS+Dex组小鼠通过腹腔注射LPS(10 mg/kg)构建小鼠ALI模型,Dex组及LPS+Dex组小鼠腹腔注射Dex(40μg/kg),Sham组和LPS组注射等剂量生理盐水。LPS注射12 h后,采用HE染色比较各组小鼠肺损伤状况;qRT-PCR检测各组小鼠肺组织中促炎性细胞因子IL-1β、TNF-α、IL-6和MCP-1 mRNA的表达;Western blot检测各组小鼠肺组织中GPX4、COX2和转录因子红系2相关因子2(Nrf2)蛋白的表达。结果与Sham组相比,LPS组小鼠肺损伤评分明显升高(P0.05),促炎性细胞因子IL-1β、TNF-α、IL-6和MCP-1mRNA表达水平均明显升高(P0.05),肺组织铁死亡标志物GPX4蛋白表达水平明显降低(P0.05),COX2蛋白表达水平则明显升高(P0.05),肺组织中Nrf2蛋白表达水平明显降低(P0.05)。与LPS组相比,LPS+Dex组小鼠肺损伤评分明显降低(P0.05),IL-1β、TNF-α、IL-6和MCP-1 mRNA表达水平明显降低(P0.05),GPX4的蛋白表达水平明显升高(P0.05),COX2蛋白表达水平则明显降低(P0.05),Nrf2的蛋白表达水平也明显升高(P0.05)。结论 Dex可能通过激活Nrf2抑制小鼠肺组织铁死亡,进而发挥肺保护作用。     

LPS上调大鼠HIF-1和GLUT表达

目的 探讨脂多糖(LPS)致大鼠内毒素血症早期,葡萄糖转运体(GLUT)家族在脑、心和肝组织等表达水平及低氧诱导因子-1(HIF-1)调控的相关性.方法 雄性SD大鼠分为对照组(腹腔注射0.9％氯化钠注射液)和给药组(腹腔注射2 mg/kg LPS),每组6只.测定给药后0～24h体温.ELISA法检测血清IL-1水平.RT-PCR法测定GLUT家族mRNA表达.Western blot法检测GLUT1和HIF-1蛋白表达.结果 在大鼠脑、心及肝等组织中,GLUT1和GLUT4均有表达;GLUT2在脑和肝组织中有表达;GLUT3仅在脑组织特异性表达.LPS作用24h可引起大鼠体温升高,血清IL-1水平上调(P＜0.05).LPS可上调脑组织GLUT1 mRNA水平和蛋白翻译水平(P＜0.01);同时LPS可促进脑组织HIF-1蛋白稳定表达(P＜0.001).结论 LPS促进大鼠HIF-1稳定表达,上调GLUT1表达及调控糖代谢.     

小檗碱预防脂多糖性肝损伤的机制研究

目的： 观察小檗碱对脂多糖性肝损伤的防治效果及其作用机制。 方法： 将雄性昆明小鼠随机分成4组：① 对照组：用蒸馏水灌胃（0.01 mL/g），每天1次，共5 d，第5 d灌胃后1 h，腹腔注射生理盐水（0.02 mL/g）；②小檗碱组：用5 g/L中性硫酸小檗碱灌胃（0.01 mL/g），每天1次，共5 d，第5 d灌胃后1 h，腹腔注射生理盐水（0.02 mL/g）； ③ 脂多糖（LPS）组：除腹腔注射LPS（0.02 mL/g，28 mg/kg）外，其余处理同①；④小檗碱防治组：除腹腔注射LPS（0.02 mL/g，28 mg/kg）外，其余处理同②。腹腔注射后2 h和10 h去眼球取血，分别检测各组小鼠血清中TNF-α的含量以及丙氨酸氨基转移酶（ALT）和天冬氨酸氨基转移酶（AST）的活性；另于腹腔注射后24 h取肝组织标本，观察各组小鼠肝脏的组织学和超微结构的变化,同时测定肝组织MDA的含量及SOD的活性。 结果： LPS组小鼠血清ALT、AST活性明显高于对照组（P＜0.01），而小檗碱防治组小鼠血清ALT和AST活性明显低于LPS组（P＜0.05）。腹腔注射LPS后2 h，LPS组小鼠血清中TNF-α含量明显高于小檗碱防治组。组织学检查发现，LPS组小鼠肝细胞水肿、变性、坏死，肝窦充血；电镜下可见，肝细胞核溶解、部分核膜不完整，线粒体肿胀、嵴消失。小檗碱防治组小鼠肝脏的病理变化明显轻于LPS组。此外，LPS组肝脏组织中MDA的含量明显高于对照组（P＜0.01），而小檗碱防治组肝脏组织中MDA的含量低于LPS组（P＜0.05），但小檗碱防治组肝组织中SOD活性与LPS组比较无显著差异。 结论： 小檗碱可以减轻LPS引起的肝脏损伤，其作用机制可能与其抑制LPS诱导的TNF-α释放，减少肝组织脂质过氧化和保护肝细胞线粒体有关。     

Ferroportin-1 is a 'nuclear'-negative acute-phase protein in rat liver: a comparison with other iron-transport proteins

Liver is the central organ of iron metabolism. During acute-phase-response (APR), serum iron concentration rapidly decreases. The current study aimed to compare expression and localization of iron transport protein ferroportin-1 (Fpn-1) and of other iron import proteins after experimental tissue damage induced by injecting turpentine oil in the hind limbs of rats and mice. Serum and spleen iron concentration decreased with an increase in total liver, cytoplasmic and nuclear iron concentration. In liver, mRNA amount of Fpn-1, Fpn-1a, Fpn-1b, HFE, hemojuvelin (HJV) and hephaestin (heph) genes showed a rapid decrease. Hepcidin, divalent metal transporter-1 (DMT-1), transferrin (Tf) and Tf-receptor-1 (TfR1), TfR-2 (TfR2) gene expression was increased. Western blot analysis of liver tissue lysate confirmed the changes observed at mRNA level. In spleen, a rapid decrease in gene expression of Fpn-1, Fpn-1a, Fpn-1b, DMT-1, Tf, TfR1 and TfR2, and an increase in hepcidin was observed. Immunohistochemistry of DMT-1 and TfR2 were mainly detected in the nucleus of rat liver and spleen, whereas TfR1 was clearly localized in the plasma membrane. Fpn-1 was mostly found in the nuclei of liver cells, whereas in spleen, the protein was mainly detected in the cell membrane. Western blot analysis of liver fractions confirmed immunohistochemical results. In livers of wild-type mice, gene expression of Fpn-1, Fpn-1a and Fpn-1b was downregulated, whereas hepcidin gene expression was increased. In contrast, these changes were less pronounced in IL-6ko-mice. Cytokine (IL-6, IL-1b and TNF-a) treatment of rat hepatocytes showed a downregulation of Fpn-1, Fpn-1a and Fpn-1b, and upregulation of hepcidin gene expression. Moreover, western blot analysis of cell lysate of IL-6-treated hepatocytes detected, as expected, an increase of a2-macroglobulin (positive acute-phase protein), whereas albumin (negative acute-phase protein) and Fpn-1 were downregulated. Our results demonstrate that liver behaves as a 'sponge' for iron under acute-phase conditions, and Fpn-1 behaves as a negative acute-phase protein in rat hepatocytes mainly, but not exclusively, because of the effect of IL-6. These changes could explain iron retention in the cytoplasm and in the nucleus of hepatocytes during APR.     

Differences in activation of mouse hepcidin by dietary iron and parenterally administered iron dextran: compartmentalization is critical for iron sensing

The iron regulatory hormone hepcidin responds to both oral and parenteral iron. Here, we hypothesized that the diverse iron trafficking routes may affect the dynamics and kinetics of the hepcidin activation pathway. To address this, C57BL/6 mice were administered an iron-enriched diet or injected i.p. with iron dextran and analyzed over time. After 1 week of dietary loading with carbonyl iron, mice exhibited significant increases in serum iron and transferrin saturation, as well as in hepatic iron, Smad1/5/8 phosphorylation and bone morphogenetic protein 6 (BMP6), and hepcidin mRNAs. Nevertheless, hepcidin expression reached a plateau afterward, possibly due to upregulation of inhibitory Smad7, Id1, and matriptase-2 mRNAs, while hepatic and splenic iron continued to accumulate over 9 weeks. One day following parenteral administration of iron dextran, mice manifested elevated serum and hepatic iron levels and Smad1/5/8 phosphorylation, but no increases in transferrin saturation or BMP6 mRNA. Surprisingly, hepcidin failed to appropriately respond to acute overload with iron dextran, and a delayed (after 5–7 days) hepcidin upregulation correlated with increased transferrin saturation, partial relocation of iron from macrophages to hepatocytes, and induction of BMP6 mRNA. Our data suggest that the physiological hepcidin response is saturable and are consistent with the idea that hepcidin senses exclusively iron compartmentalized within circulating transferrin and/or hepatocytes.     

对脂多糖攻击小鼠血及肝IL-6和TNF-α含量的影响

目的：研究重组人白细胞介素-10（rhIL-10）对脂多糖（LPS）诱导的血、肝IL-6和TNF-α炎症介质含量变化的影响。 方法： 小鼠腹腔注射LPS建立炎症模型，并同时静脉注射不同剂量的rhIL-10，ELISA法测定12 h、24 h、48 h和72 h肝组织和血清IL-6和TNF-α的含量。 结果： 注射rhIL-10后12 h，肝组织和血清IL-6、TNF-α水平开始下调，24-48 h抑制作用最明显（P＜0.05），72 h后抑制作用减弱，且呈剂量效应关系。 结论： 利用基因工程技术制备的重组人白细胞介素10（rhIL-10）显著下调肝组织和血清IL-6和TNF-α的水平。     

Transferrin Receptor Expression in Normal, Iron-deficient and Iron-overloaded Rats

The distribution of transferrin receptor (TfR) positive cells and their staining intensity were examined in the liver, duodenum, pancreas, spleen, kidney and brain of iron deficient, iron-overloaded and normal Wistar rats to elucidate the regulatory effects of iron on TfR expression in vivo. Iron deficiency was produced by an iron deficient food and water regimen, and iron overload by repeated intraperitoneal injections of ferric nitrilotriacetate (Fe³-NTA) for 12 weeks. In iron deficient rats, levels of hemoglobin (Hb= 5.9 ± 0.7) and serum iron (Sl = 29.9 ± 4.4) were lower, and total iron binding capacity (TIBC = 624.4 ± 72.7) was higher than in normal rats (Hb = 15.6 ± 0.9, Sl = 206.5 # 20.5, TIBC = 416.0 ± 56.0), and Wee versa for SI (217.7 ± 15.5) and TIBC (307.1 ± M45.4) in iron-overloaded rats. In normal rats, TfR positive granules were observed in hepatocytes and Kupffer cells of the liver, absorptive epithelium of the duodenum, acinar and Langerhans islet cells of the pancreas, macrophages and red pulp erythro-blasts of the spleen, and distal convoluted tubular epithelium of the kidney. Although the tissue distribution pattern of TfR positive cells was similar in normal, iron deficient and iron overloaded rats, the staining intensity and number of TfR positive cells were obviously higher in iron deficient, and lower in iron overloaded rats. We conclude that TfR expression is negatively regulated by the tissue concentration of iron. Acta Pathol Jpn 39: 759-764, 1989.     

Discriminating between iron deficiency anemia and anemia of chronic disease using traditional indices of iron status vs transferrin receptor concentration

We compared the ability of soluble serum transferrin receptor (TfR) concentration, quantified using the R&D Systems (Minneapolis, MN) enzyme-linked immunosorbent TfR assay, with other, more traditional indicators of iron status (total iron binding capacity [TIBC], mean corpuscular volume [MCV], percent transferrin saturation [%TS], RBC distribution width [RDW], and serum iron concentration [SIC]) for discriminating between patients with iron deficiency anemia (IDA) or anemia of chronic disease (ACD). The TfR concentration was determined in 72 serum samples selected from men and nonpregnant women classified biochemically on the basis of ferritin concentration as having IDA (n = 41) or ACD (n = 31). By using receiver operating characteristic curve analysis, the diagnostic accuracy of the various indicators of iron status that we evaluated for discriminating between IDA and ACD decreased in the following order: TIBC > TfR > MCV > (%TS = RDW) > SIC. There was no significant difference between the diagnostic accuracy of TIBC and TfR. Thus, the routine measurement of TfR offers no advantage over TIBC for discriminating between people with biochemically defined IDA or ACD.     

Duodenal HFE expression and hepcidin levels determine body iron homeostasis: modulation by genetic diversity and dietary iron availability

HFE affects the interaction of transferrin bound iron with transferrin receptors (TfR) thereby modulating iron uptake. To study genetically determined differences in HFE expression we examined individual HFE levels in C57BL/Sv129 mice and assessed their relationship to the regulation of iron homeostasis in the duodenum and the liver, and their regulation by diet. We found an up to 14-fold variation in inter-individual expression of HFE mRNA in the duodenum. Mice with high duodenal HFE mRNA expression presented with significantly higher levels of TfR and DMT-1 mRNAs and an increased IRP-1 binding affinity as compared to mice with low HFE levels. Duodenal HFE expression was positively associated with serum iron and liver HFE levels. Dietary iron supplementation decreased HFE in the duodenum but not in the liver. This was paralleled by reduced amounts of DMT-1 and FP-1 in the duodenum while the expression of DMT-1, FP-1, and hepcidin in the liver were increased with dietary iron overload. Duodenal and liver HFE levels are regulated by divergent penetration of as yet unelucidated modifier genes and to a much lesser extent by dietary iron. These measures control duodenal iron transport and liver iron homeostasis by modulating HFE expression either directly or via stimulation of iron sensitive regulatory molecules, such as hepcidin, which then exert their effects on body iron homeostasis.Susanne Ludwiczek and Igor Theurl contributed equally to the work     

Transferrin receptor expression in normal, iron-deficient and iron-overloaded rats

The distribution of transferrin receptor (TfR)-positive cells and their staining intensity were examined in the liver, duodenum, pancreas, spleen, kidney and brain of iron-deficient, iron-overloaded and normal Wistar rats to elucidate the regulatory effects of iron on TfR expression in vivo. Iron deficiency was produced by an iron-deficient food and water regimen, and iron overload by repeated intraperitoneal injections of ferric nitrilotriacetate (Fe3(+)- NTA) for 12 weeks. In iron-deficient rats, levels of hemoglobin (Hb = 5.9 +/- 0.7) and serum iron (SI = 29.9 +/- 4.4) were lower, and total iron-binding capacity (TIBC = 624.4 +/- 72.7) was higher than in normal rats (Hb = 15.6 +/- 0.9, SI = 206.5 +/- 20.5, TIBC = 416.0 +/- 56.0), and vice versa for SI (217.7 +/- 15.5) and TIBC (307.1 +/- 45.4) in iron-overloaded rats. In normal rats, TfR-positive granules were observed in hepatocytes and Kupffer cells of the liver, absorptive epithelium of the duodenum, acinar and Langerhans islet cells of the pancreas, macrophages and red pulp erythroblast of the spleen, and distal convoluted tubular epithelium of the kidney. Although the tissue distribution pattern of TfR-positive cells was similar in normal, iron-deficient and iron-overloaded rats, the staining intensity and number of TfR-positive cells were obviously higher in iron-deficient, and lower in iron-overloaded rats. We conclude that TfR expression is negatively regulated by the tissue concentration of iron.     

小窝蛋白1脚手架区多肽减轻LPS诱导的小鼠急性肺损伤

目的:探究人工合成的小窝蛋白1(caveolin-1,Cav-1)脚手架区多肽cavtratin对血红素加氧酶1(heme oxygenase-1,HO-1)活性及脂多糖(lipopolysaccharide,LPS)诱导的小鼠急性肺损伤的作用。方法:成年雄性BALB/c小鼠随机分为6组,每组8~10只,实验分为对照(control)组、触足肽内化序列(Antennapedia internalization sequence,AP)组、LPS组、LPS+血晶素(hemin)组、LPS+hemin+cavtratin组和LPS+hemin+cavtratin+锌原卟啉(zinc protoporphyrin IX,Zn PP)组。小鼠气管滴注LPS 24 h后,苏木素-伊红染色观察肺组织病理形态变化;检测肺组织湿/干重比、肺泡灌洗液中细胞数和血清中乳酸脱氢酶活性。免疫荧光观察HO-1和Cav-1的结合情况并检测HO-1活性;实时荧光定量PCR检测炎症因子(IL-1β、IL-6、TNF-α、MCP-1和i NOS)的mRNA水平。结果:组织免疫荧光以及HO-1活性检测发现,与LPS组比较,LPS+hemin+cavtratin组HO-1与细胞膜Cav-1的结合减少,HO-1的活性增高(P0.05);与LPS组比较,LPS+hemin+cavtratin组肺组织受损程度明显减轻,肺湿/干重比、肺泡灌洗液细胞数和血清中乳酸脱氢酶活性显著降低(P0.05);与LPS组比较,LPS+hemin+cavtratin组炎症因子的mRNA表达降低(P0.05);HO-1活性抑制剂Zn PP可以消除cavtratin的保护作用。结论:Cavtratin可以通过减少HO-1与细胞膜Cav-1的结合使得HO-1活性增加,进而减轻LPS诱导的小鼠急性肺损伤。     

Kupffer cells modulate iron homeostasis in mice via regulation of hepcidin expression

Hepcidin, a small cationic liver derived peptide, is a master regulator of body iron homeostasis. Cytokines and iron availability have so far been identified as regulators of hepcidin expression. Herein, we investigated the functional role of Kupffer cells for hepcidin expression because of their vicinity to the hepatocytes and their importance for iron recycling via erythrophagocytosis. We investigated C57Bl6 mice and littermates, in which Kupffer cells were eliminated in vivo upon intravenous injection of liposome-encapsulated clodronate. Primary cultures of hepatocytes and Kupffer cells were used to study direct regulatory effects ex vivo. The in vivo depletion of Kupffer cells resulted in a significant increase in liver hepcidin expression, which was paralleled by a significant reduction in serum iron levels. The same pattern of regulation by Kupffer cell depletion was observed upon injection of bacterial lipopolysaccharide into mice and in primary (Hfe -/-) and in secondary iron-overloaded mice. Accordingly, the messenger ribonucleic acid (mRNA) concentrations of the hepcidin iron-sensing molecule hemojuvelin were not significantly changed upon Kupffer cell depletion. When primary hepatocytes were cocultivated with Kupffer cells or stimulated with a Kupffer cell-conditioned medium ex vivo, a significant reduction in hepatocyte hepcidin mRNA expression was observed. Our data suggest that Kupffer cells control body iron homeostasis by exerting negative regulatory signals toward hepcidin expression, which may be primarily referred to the secretion of yet unidentified hepcidin-suppressing molecules by Kupffer cells.