N-乙酰半胱氨酸对脂多糖诱导的小鼠肝MAPK磷酸化的影响

目的： 探讨N-乙酰半胱氨酸（NAC）对脂多糖（LPS）诱导的肝MAPK磷酸化的影响。方法: 雄性昆明种小鼠54只随机分为对照组(n=6)：0.9 % NaCl 0.2 mL ip；LPS组（n=24）：LPS 5 mg ip；NAC+LPS组（n=24）：NAC 150 mg·kg-1·d-1ip，连续3 d；第3 d NAC灌胃后1 h时，LPS 5 mg ip。将小鼠分别在注射LPS或生理盐水后0.5 h、1 h、2 h和6 h时，在戊巴比妥钠麻醉下开腹取肝，测定肝MDA和还原型谷胱甘肽（GSH）含量；Western blotting方法测定肝脏MEK1/2、ERK1/2、p38MAPK磷酸化水平，放免法测定肝TNF-α含量。结果: NAC预处理使肝MDA含量明显下降，使肝GSH含量升高。NAC预处理显著抑制了LPS所致的肝MEK1/2、ERK1/2、p38MAPK磷酸化，同时使肝TNF-α水平显著降低。结论: 在LPS诱导的急性肝损伤过程中，活性氧（ROS）在激活MAPK信号转导中起重要作用。NAC通过其抗氧化作用部分抑制了LPS诱导的MAPK磷酸化，使TNF-α生成减少，从而发挥抗损伤作用。     

阿魏酸钠抑制Aβ25-35诱导的小鼠腹腔巨噬细胞p38MAPK活化

目的：探讨阿魏酸钠对β淀粉样肽（Aβ_25-35）介导的p38信号转导的影响。方法：培养小鼠腹腔巨噬细胞，采用Western 印迹分析p38 MAPK蛋白激酶水平。用ELISA法、免疫组化法、Griess反应，分别检测TNF-α生成量、iNOS表达和NO含量。结果： Aβ_25-35能诱导p38 MAPK的活化，显著增加腹腔巨噬细胞TNF-α、iNOS和NO水平，阿魏酸钠能显著降低Aβ_25-35诱导的腹腔巨噬细胞核蛋白p38 MAPK的含量及细胞的TNF-α、iNOS、NO水平。结论： 阿魏酸钠可抑制Aβ_25-35介导的p38 MAPK活性，使TNF-α、iNOS、NO水平降低。     

MAPK和NF-κB上调脂多糖诱导的小鼠肺微血管内皮细胞Toll-like受体4的表达

目的 观察MAPK和NF-κB在经脂多糖（LPS）诱导的小鼠肺微血管内皮细胞（PMVECs）Toll-1ike受体4（TLR4）表达增强中的作用。方法 分离培养PMVECs。不同浓度的LPS与PMVECs共培养2h，或与LPS（100μg/L）作用不同时间。用ELISA法检测培养上清液中TNF-α含量。分别用ERK抑制剂PD98059和P38MAPK抑制剂SB203580或NF-κB抑制剂PDTC进行干预。用反转录聚合酶链反应（RT-PCR）检测TLR4和TNF-α mRNA。用Western-blot检测ERK／P38MAPK和核蛋白NF-κB的表达。结果 在LPS浓度为50～500μg／L时，作用于PMVECs 2h，或LPS100μg/L作用不同时间时，培养上清液中TNF-α含量呈剂量和时间依赖性显著增加（P〈0．01）。PMVECs表达TNF-α及TLR4mRNA增加，6h时达高峰。分别用上述抑制剂均可缓解上述变化，而同时联合使用PD98059和SB203580则进一步增强该抑制作用。上述抑制剂分别缓解LPS诱导的PMVECs表达ERK／P38MAPK和NF-κB蛋白增强。结论 MAPK和NF-κB上调给脂多糖诱导的小鼠PMVECs TLR4的表达。     

八肽胆囊收缩素对脂多糖诱导小鼠分泌IL-12的影响及其机制研究

目的：观察八肽胆囊收缩素（CCK-8）对脂多糖诱导小鼠分泌IL-12的影响，探讨核因子-κB（NF-κB）和p38丝裂原活化蛋白激酶（p38 MAPK）的信号转导作用。方法：雌性BALB/c小鼠经LPS诱导后分别给予CCK及CCK-A、B受体拮抗剂。ELISA法检测小鼠血清及肺、脾组织中IL-12p40、p70的表达；Western blotting法检测肺脏、脾脏IκB、p38 MAPK的表达；EMSA法检测肺、脾组织中NF-κB/DNA的结合活性。结果：CCK-8进一步提高了LPS诱导的小鼠血清及肺、脾组织中IL-12p40、p70的表达；抑制IκB磷酸化和NF-κB/DNA结合活性；促进p38 MAPK磷酸化。而CCK-A受体拮抗剂（CR-1409）及CCK-B受体拮抗剂（CR-2945）部分逆转了CCK-8的效应。结论：CCK-8可促进LPS诱导小鼠分泌IL-12，p38 MAPK可能参与了其信号转导机制，而NF-κB途径可能并未参与CCK-8促IL-12分泌这一过程。     

MAPK和NF-κB上调脂多糖诱导的小鼠肺微血管内皮细胞Toll-like受体4的表达

目的观察MAPK和NF-κB在经脂多糖(LPS)诱导的小鼠肺微血管内皮细胞(PMVECs)Toll-like受体4(TLR4)表达增强中的作用。方法分离培养PMVECs。不同浓度的LPS与PMVECs共培养2 h,或与LPS(100μg/L)作用不同时间。用ELISA法检测培养上清液中TNF-α含量。分别用ERK抑制剂PD98059和P38MAPK抑制剂SB203580或NF-κB抑制剂PDTC进行干预。用反转录聚合酶链反应(RT-PCR)检测TLR4和TNF-αmRNA。用W estern-b lot检测ERK/P38 MAPK和核蛋白NF-κB的表达。结果在LPS浓度为50~500μg/L时,作用于PMVECs 2 h,或LPS 100μg/L作用不同时间时,培养上清液中TNF-α含量呈剂量和时间依赖性显著增加(P<0.01)。PMVECs表达TNF-α及TLR4 mRNA增加,6 h时达高峰。分别用上述抑制剂均可缓解上述变化,而同时联合使用PD98059和SB203580则进一步增强该抑制作用。上述抑制剂分别缓解LPS诱导的PMVECs表达ERK/P38 MAPK和NF-κB蛋白增强。结论MAPK和NF-κB上调给脂多糖诱导的小鼠PMVECs TLR4的表达。     

内毒素急性肺损伤中p38MAPK、NF-κB 与HO-1的关系

目的: 探讨内毒素急性肺损伤中丝裂原活化蛋白激酶p38(p38MAPK)、核转录因子κB( NF-κB)与血红素氧合酶-1(HO-1)的相互关系。方法: 健康雄性Wistar大鼠40只,随机分为5组(n=8):对照组或生理盐水组(NS组)、内毒素组(LPS组)、血红素氧合酶-1诱导剂血晶素+内毒素组(Hemin+LPS组)、血红素氧合酶-1抑制剂锌原卟啉IX+内毒素组(ZnPPIX+LPS组)、p38MAPK抑制剂SB203580+内毒素组(SB+LPS组)。气管内滴注LPS或NS 6h后检测动脉血气,右肺肺泡灌洗液(BALF)中性粒细胞比、蛋白含量,右肺上叶肺组织湿/干重比;用Western blotting检测右肺下叶p38MAPK、NF-κB蛋白的表达;用免疫组化检测右肺中叶HO-1蛋白的表达,并进行病理学观察。结果: 与NS组比较,LPS组、Hemin+LPS组、SB+LPS组、ZnPPIX+LPS组肺组织湿/干重比明显增加(P<0.05),BALF中性粒细胞比、蛋白含量显著增加(P<0.05或P<0.01),动脉血PaO₂、PaCO₂和HCO^-₃显著下降(P<0.05),肺组织p38MAPK、NF-κB蛋白表达明显增高(P<0.05),HO-1强阳性表达(P<0.01或P<0.05);与LPS组比较,Hemin+LPS 组、SB+LPS组肺组织湿/干重比,肺泡灌洗液中性粒细胞比、蛋白含量明显减少(P<0.05),p38MAPK、NF-κB蛋白表达显著降低(P<0.05),HO-1的表达明显升高(P<0.05),而ZnPPIX+LPS组恰好相反;Hemin+LPS 组、SB+LPS组之间动脉血PaO₂、PaCO₂和HCO^-₃,BALF中性粒细胞比、蛋白含量,肺组织湿/干重比,肺组织p38MAPK/NF-κB及HO-1蛋白的表达均无显著差异(P>0.05)。ZnPPIX+LPS组肺组织损伤最重,LPS组次之,Hemin+LPS组和SB+LPS组最轻。结论: 在内毒素急性肺损伤中p38MAPK/NF-κB与HO-1相互抑制,各自独立发挥作用。     

p38MAPK在重症急性胰腺炎大鼠枯否细胞分泌促炎细胞因子中的作用

目的:探讨p38MAPK信号转导通路在重症急性胰腺炎(SAP)大鼠枯否细胞(KCs)分泌促炎细胞因子TNF-α和IL-1β中的作用。方法:30只SD大鼠随机分为:①假手术对照(SO)组;②SAP组;③SAP+CNI-1493(p38MAPK抑制剂)组。SAP模型通过胰胆管逆行注射5%牛磺胆酸钠诱导。假手术或造模后12h处死动物分离出KCs,采用实时定量PCR方法检测KCs内TNF-α和IL-1βmRNA的表达,采用Westernblot法检测p38MAPK活化情况,并用ELISA法检测血浆的TNF-α和IL-1β含量。结果:SAP大鼠KCs内TNF-α和IL-1βmRNA的表达明显强于假手术组,p38MAPK活性显著高于SO组,同时血浆TNF-α和IL-1β含量明显高于SO组,使用CNI-1493的SAP大鼠上述指标均显著低于SAP组。结论:p38MAPK信号转导通路介导了SAP大鼠的KCs促炎细胞因子TNF-α和IL-1β的分泌,阻断p38MAPK信号转导通路对于SAP防治可能具有重要意义。     

损害性因素对乳鼠心肌细胞甘氨酸受体α1亚基表达的影响

目的：研究脂多糖（LPS）、缺氧/复氧（H/R）、异丙肾上腺素(ISO)以及高糖（HG）对乳鼠心肌细胞甘氨酸受体α₁亚基（GlyRα₁）表达的影响。方法：体外培养乳鼠心肌细胞，分别用LPS、H/R、ISO以及HG处理，采用CCK-8试剂检测细胞活力，RT-PCR方法检测心肌细胞上GlyRα₁亚基mRNA的表达。结果：LPS（5 mg/L、10 mg/L、20 mg/L、40 mg/L、80mg/L）、ISO（20 μmol/L、100 μmol/L、500 μmol/L）以及HG（25 mmol/L、50 mmol/L）处理心肌细胞24 h与心肌细胞缺氧3 h/复氧3 h、单纯缺氧3 h对心肌细胞存活率无明显影响（P＞0.05）；LPS（5 mg/L、10 mg/L、20 mg/L、40 mg/L、80 mg/L）、缺氧（3 h）/复氧（3 h）、单纯缺氧（3 h）以及ISO（20 μmol/L、100 μmol/L、500 μmol/L）组心肌细胞上GlyRα1亚基mRNA表达均高于对照组（P<0.01），而HG（25 mmol/L、50 mmol/L）组心肌细胞上GlyRα₁亚基mRNA表达均低于对照组（P<0.01）。结论：一定浓度的LPS、ISO与一定时间的H/R、单纯缺氧均可上调乳鼠心肌细胞GlyRα₁亚基mRNA的表达，而HG可下调乳鼠心肌细胞GlyRα₁亚基mRNA的表达。     

与IGFBP-3相关的RXRα、STAT-1信号通路在β-淀粉样肽1～42诱导大鼠海马神经元凋亡中的可能作用

目的 探讨胰岛素样生长因子结合蛋白-3(IGFBP-3）、视网膜X受体α（RXRα）及信号转导子和转录激动子（STAT-1）在β-淀粉样肽_1～42(Aβ_1～42)诱导大鼠海马神经元凋亡中的可能作用。方法 以原代培养的大鼠海马神经元为模型，分为对照组和Aβ_1～42组，加入不同浓度的凝聚态Aβ_1～42，原位缺口末端标记法（TUNEL）观察凋亡细胞的形态；免疫细胞荧光方法检测凋亡细胞及IGFBP3、RXRα阳性细胞；免疫印迹法检测RXRα蛋白和STAT-1蛋白的表达水平。结果 20μmol/L Aβ_1～42作用大鼠海马神经元24h能明显诱导神经元凋亡，表现为TUNEL/DAPI染色出现阳性细胞；20μmol/L Aβ_1～42作用大鼠海马神经元3～6h后IGFBP3阳性细胞、RXRα阳性细胞、RXRα蛋白的表达水平均较对照组有明显增高（P<0.01），在较高水平保持一段时间后逐渐下降；而STAT-1蛋白的表达水平则显著降低（P<0.01）。 结论 IGFBP3/RXRα或STAT-1信号转导通路可能在Aβ_1～42诱导大鼠海马神经元凋亡中起一定作用。     

雌激素对内皮素诱导心肌细胞肥大反应的影响及其机制

目的： 探讨雌激素（E₂）对内皮素-1（ET-1）诱导心肌细胞肥大反应的影响及其机制。方法： 以ET-1刺激体外培养的新生大鼠心肌细胞，建立心肌肥大细胞模型；观察E₂对ET-1诱导心肌细胞肥大反应的影响，并检测心肌细胞中ERK1/2活性的变化。结果： ET-1可使心肌细胞蛋白质含量、表面积和［³H］^-亮氨酸掺入显著增加，这些作用可被E₂明显抑制。E₂预处理抑制ET-1诱导的心肌细胞ERK1/2活性的增加。雌激素受体拮抗剂他莫昔芬（Ta）可抑制E₂对ET-1诱导的心肌细胞［³H］^-亮氨酸（［³H］^-Leu）掺入和ERK1/2活性的作用。MEK1/2抑制剂PD98059预处理使ET-1诱导的心肌细胞［³H］^-Leu掺入减少，使E2对ET-1诱导的心肌细胞肥大反应的抑制作用加强。结论： E₂通过雌激素受体抑制ET-1诱导的心肌细胞肥大反应，这一过程与ERK1/2信号转导途径有关。     

Mercury alters endotoxin-induced inflammatory cytokine expression in liver: differential roles of p38 and extracellular signal-regulated mitogen-activated protein kinases

Mercury is a widespread metal in the environment and consequently large populations are currently exposed to low levels of mercury. Endotoxin, a component of the Gram-negative bacteria, promotes inflammatory responses. We recently reported that mercury modulates the production of nitric oxide and various inflammatory cytokines induced by endotoxin in a macrophage cell line (Nitric Oxide 2002, 7:67). The present study was designed to determine the impact of mercury on endotoxin-induced inflammatory cytokine expression and corresponding signal transduction in mouse liver. Male BALB/c mice were exposed continuously to 0, 0.3, 1.5, 7.5, or 37.5 ppm of mercury in drinking water for 14 days and at the end of the treatment period lipopolysaccharide (LPS, 0.5 mg/kg) was injected intraperitoneally 2 hr prior to euthanasia. The doses of mercury and LPS did not cause hepatotoxicity as indicated by unaltered circulating alanine aminotransferase and aspartate aminotransferase levels. Mercury decreased liver glutathione (GSH) and with LPS additively decreased GSH. Mercury activated p38 mitogen-activated protein kinase (MAPK) and additively increased LPS-induced p38 MAPK phosphorylation. In contrast, mercury alone had no effect on activation of extracellular signal-regulated kinase (ERK) but inhibited LPS-induced ERK activation. Mercury increased the expression of tumor necrosis factor alpha (TNFalpha) and further potentiated LPS-induced TNFalpha expression. Mercury did not affect LPS-induced interleukin (IL)-1beta expression but decreased LPS-induced IL-6 expression. Results indicated that low levels of mercury augment LPS-induced TNFalpha expression by altering GSH and p38 MAPK. Mercury modulates LPS-induced p38 and ERK activation and downstream TNFalpha and IL-6 expression in mouse liver.     

内皮素在诱导人气管上皮下成纤维细胞转分化中的作用

目的： 探讨ET-1在诱导气道上皮下成纤维细胞转分化为肌成纤维细胞过程中的作用及其信号与离子机制。方法: 将人气道上皮下成纤维细胞或种植在胶原凝胶中的成纤维细胞与经机械划伤加细菌脂多糖（LPS）刺激(L+M)的人气道上皮细胞株（16HBE）共培养，并加入ET受体A（ETRA）阻断剂BQ123或p38 MAPK、ERK1/2丝裂原活化蛋白激酶（MAPKs）特异性抑制剂，观察成纤维细胞α-平滑肌肌动蛋白（α-SMA）的表达情况与收缩反应性，以及p38 MAPK、ERK1/2信号通路的活化及其对α-SMA表达的影响；经钙离子荧光探针（Fluo-3/AM）负载，应用激光共聚焦显微镜观察成纤维细胞胞内钙的动态变化。结果: 损伤的气道上皮细胞诱导了上皮下成纤维细胞转分化为表达α-SMA、具有显著收缩反应能力的肌成纤维细胞，BQ123对其有一定的抑制效应；p38 MAPK、ERK1/2的特异性阻断剂（SB203580、PD98059）可钝化损伤上皮对成纤维细胞α-SMA表达的诱导作用。添加外源性ET-1增加成纤维细胞α-SMA表达并诱导p38 MAPK、ERK1/2信号通路的活化；同时，引起胞内钙水平的迅速上升。结论: 损伤的气道上皮细胞通过释放ET-1能够诱导上皮下成纤维细胞转分化为具有收缩反应性的肌成纤维细胞， p38 MAPK、 ERK1/2信号通路介导了这一过程，ET-1增强成纤维细胞Ca2+内流可能是启动其转分化的早期事件。     

Poly-<Emphasis Type="SmallCaps">l</Emphasis>-Arginine Acts Synergistically with LPS to Promote the Release of IL-6 and IL-8 via p38/ERK Signaling Pathways in NCI-H292 Cells

Major basic protein (MBP) derived from activated eosinophil can exacerbate atopic asthma induced by lipopolysaccharide (LPS). The pharmacological function of MBP can be mimicked by poly-l-arginine (PLA), however, the potential signaling mechanisms of LPS-PLA-induced release of the inflammatory cytokines interleukin (IL)-6 and IL-8 remain unclear. In the present study, airway epithelia NCI-H292 cell lines were treated with LPS and/or PLA. We found that the expression levels of IL-6 and IL-8 induced by LPS-PLA were increased significantly compared with that in untreated cells. Meanwhile, the phosphorylation of p38 MAPK and ERK1/2 was also up-regulated dramatically by LPS-PLA, but this increase could be blocked by specific inhibitor. Importantly, blocking the phosphorylation of p38 MAPK and ERK1/2 reduced the expression levels of IL-6 and IL-8 as well. Collectively, LPS-PLA-induced release of IL-6 and IL-8 from NCI-H292 cells may be due to the synergistic activation of p38 MAPK and ERK1/2 signaling transduction pathways.     

Porphyromonas gingivalis Lipopolysaccharide Activates Canonical Wnt/β-Catenin and p38 MAPK Signalling in Stem Cells from the Apical Papilla

As dental precursor cells, stem cells from the apical papilla (SCAP) are capable of forming roots and undergoing apexogenesis, which are impaired upon exposure to bacterial infection. Porphyromonas gingivalis is a common Gram-negative bacterium that is involved in pulpal and periapical infection. The purpose of this study was to investigate the effects of P. gingivalis lipopolysaccharide (LPS) on the Wnt/β-catenin and p38 mitogen-activated protein kinase (MAPK) signalling pathways in SCAP. As indicated by the IL-1β and TNF-α mRNA levels, P. gingivalis LPS induced the expression of pro-inflammatory cytokines in a dose-dependent manner. In addition, activation of the p38 MAPK and Wnt/β-catenin pathways was confirmed by the augmentation of phospho-p38 and β-catenin protein expression and increased expression of c-myc and cyclin D1 mRNA. Despite no significant increase in β-catenin mRNA expression, increased phosphorylation of glycogen synthase kinase (GSK)-3β suggested that GSK-3β was responsible for the accumulation of β-catenin in the cytoplasm and translocation to the nucleus. Previous studies have shown that GSK-3β plays a critical role in crosstalk between the Wnt/β-catenin and p38 MAPK pathways. In the present study, we showed that the level of p38 phosphorylation decreased upon pretreatment with a p38 MAPK inhibitor for 1 h before stimulating SCAP with 10 μg/ml P. gingivalis LPS. However, the levels of GSK-3β and β-catenin phosphorylation in the cytoplasm and nucleus were not significantly altered. Our results suggest that the p38 MAPK and canonical Wnt/β-catenin signalling pathways are activated by P. gingivalis LPS in SCAP, but we have no evidence that p38 MAPK is upstream of GSK-3β in the Wnt/β-catenin signalling pathway.     

MAPKs ERK and p38, but not JNK phosphorylation, modulate IL-6 and TNF-α secretion following OK-432 in vitro stimulation of purified human monocytes

Interaction between the immune system and cancer allows for the use of biological response modifiers, e.g. OK-432, in cancer therapy. OK-432, penicillin-killed Streptococcus pyogenes, is used in treating carcinomas, but also lymphangiomas. We have studied the role of monocytes (MOs) in the immune response to OK-432 by examining IL-6 and tumour necrosis factor (TNF)-α secretion after in vitro MO stimulation with OK-432, to some extent in comparison with lipoteichoic acid (LTA) and lipopolysaccharide (LPS). LTA stimulation of whole blood gave IL-6 but not TNF-α secretion, as previously shown with OK-432 stimulation, whereas both cytokines were secreted following LPS stimulation. Addition of the MAPK kinase (MAPKK) MEK inhibitor U0126 inhibited IL-6/TNF-α secretion in a dose-dependent manner. Flow cytometry and to some extent Western blot (Wb) analyses showed that MAPK ERK, located downstream of MEK1/2, is predominantly phosphorylated at isolation from peripheral blood. Addition of the p38 MAP kinase inhibitor SB202190 decreased MO IL-6/TNF-α production upon OK-432 stimulation in a dose-dependent manner. Addition of the MAPK JNK inhibitor SP600125 did not systematically change the MO IL-6/TNF-α OK-432 response. Flow cytometry showed that when stimulating the MOs before isolation from blood, LPS yielded ERK phosphorylation and LPS/LTA p38 phosphorylation, whereas OK-432 had no effects on phosphorylation levels. In conclusion, we have shown that OK-432 resembles TLR2 more than TLR4 stimulation of MOs and depends on MAPKK MEK and MAPK p38, but not on JNK phosphorylation. The MEK and p38 MO OK-432 stimulation dependence is possibly related to the differentiation of cells of the MO lineage.     

The phosphatidylinositol 3-kinase/protein kinase B signaling pathway is activated by lipoteichoic acid and plays a role in Kupffer cell production of interleukin-6 (IL-6) and IL-10

Sepsis caused by gram-positive bacteria lacking lipopolysaccharide (LPS) has become a major and increasing cause of mortality in intensive-care units. We have recently demonstrated that the gram-positive-specific bacterial cell wall component lipoteichoic acid (LTA) stimulates the release of the proinflammatory cytokines in Kupffer cells in culture. In the present study, we have started to assess the signal transduction events by which LTA induces the production of tumor necrosis factor alpha (TNF-alpha), interleukin-6 (IL-6), and the anti-inflammatory cytokine IL-10 in rat Kupffer cells. LTA was found to trigger phosphorylation of mitogen-activated protein kinases (MAPK) (p38 MAPK and ERK 1/2) and protein kinase B (PKB). Compared to LPS, LTA was more potent in inducing PKB phosphorylation after 40 min, although we found that the cytokine responses were similar. For both bacterial molecules, blocking phosphatidylinositol 3-kinase (PI3-K; Ly294002) or Janus kinase 2 (JAK-2; AG490) particularly affected the induction of IL-6 and IL-10 release, whereas TNF-alpha levels were strongly reduced by inhibition of Src family tyrosine kinases (PP2). All three cytokines were reduced by inhibition of p38 MAPK (SB202190) or the broad-range tyrosine kinase inhibitor genistein, whereas IL-6 release was particularly blocked by inhibition of ERK 1/2 (PD98059). Divergences in the regulatory pathways controlling TNF-alpha, IL-10, and IL-6 production in Kupffer cells following LPS or LTA stimulation may create a basis for understanding how the balance between pro- and anti-inflammatory cytokines is regulated in the liver following infections by gram-positive or gram-negative bacteria.     

Urinary trypsin inhibitor attenuates lipopolysaccharide-induced acute lung injury by blocking the activation of p38 mitogen-activated protein kinase

Objective

To investigate the protective effect of urinary trypsin inhibitor (UTI) in a rat model of lipopolysaccharide (LPS)-induced acute lung injury (ALI) and the underlying molecular mechanism.

Methods

Rats were randomly assigned into three groups: control group, LPS treatment group and LPS/UTI treatment group. The serum concentrations of tumor necrosis factor (TNF)-?? and interleukin (IL)-10 were measured by ELISA. The expression of p38 mitogen-activated protein kinase (MAPK) in lung tissues was determined by Western blot analysis.

Results

Administration of UTI reduced the lung wet/dry weight ratio and ameliorated the tissue damage. In the LPS/UTI treatment group, levels of TNF-?? were significantly lower than those in the LPS treatment group, while the levels of IL-10 were significantly higher than those in the LPS treatment group. Western blot analysis revealed that UTI inhibited the phosphorylation of p38 MAPK in lung tissues.

Conclusions

UTI attenuates LPS-induced ALI, probably by adjusting the balance between proinflammatory and anti-inflammatory cytokines. The mechanism responsible for the decreased TNF-?? expression may be related to the inhibitory effect of UTI on p38 MAPK activation.     

正正常肠淋巴液对内毒素休克小鼠多器官损伤的作用*

 目的： 观察正常肠淋巴液对内毒素休克小鼠肺、心、肝等器官损伤以及MAPK信号通路主要信号分子p38 MAPK、ERK1/2和JNK磷酸化水平的影响。方法: 引流18只BALB/c雄性小鼠正常肠淋巴液,去除细胞成分后用于内毒素休克的干预。18只小鼠均分为假休克组、内毒素休克组与肠淋巴液干预组（n=6）;腹腔注射脂多糖（LPS,35 mg/kg）,复制小鼠内毒素休克模型;在LPS注射60 min后,淋巴液干预组小鼠经股动脉注射正常淋巴液（全血量的1/15）;整个实验过程监测平均动脉血压（MAP）;在腹腔注射LPS后6 h或相应时点,心尖穿刺取血,检测反映心肌和肝细胞损伤的生化指标;同时,留取固定位置的肺、心肌和肝组织,部分观察组织形态,部分检测p38 MAPK、ERK1/2和JNK的磷酸化水平。结果: 内毒素休克组与肠淋巴液干预组小鼠在腹腔注射LPS后90 min多个时点的MAP显著低于假休克组,肠淋巴液干预组小鼠MAP在腹腔注射LPS后80 min、90 min、190 min、210 min、240 min、250 min、340 min、350 min和360 min显著高于内毒素休克组。假休克组小鼠肺、肝和心肌组织结构基本正常,内毒素休克组小鼠出现了一定的结构损伤,肠淋巴液干预组小鼠组织损伤较轻;内毒素休克组小鼠血浆AST、ALT和CK-MB活性高于假休克组,肠淋巴液干预组小鼠血浆CK-MB活性亦高于假休克组,AST和LDH-1活性低于内毒素休克组。注射LPS后6 h,小鼠肺组织p38 MAPK、ERK 1/2和JNK的磷酸化水平显著升高,心肌和肝组织的这些指标未见显著变化;输入正常肠淋巴液降低了内毒素休克小鼠肺组织p38 MAPK以及心肌组织p38 MAPK、ERK 1/2和JNK磷酸化水平。结论: 输入正常肠淋巴液可减轻内毒素休克小鼠的器官损伤,降低肺组织p38 MAPK磷酸化水平。