Moriez Raphaël, Leveque Mathilde, Salvador-Cartier Christel, Barreau Frederic, Theodorou Vassilia, Fioramonti Jean, Bueno Lionel, Eutamene Helene
4MR 1054, INRA, Neuro-Gastroenterology and Nutrition Unit, ESA-Purpan, Toulouse, France.
Shock. 2007 Jul;28(1):118-24. doi: 10.1097/SHK.0b013e3180315ba9.
LPS-induced endotoxemia is associated with gut immune stimulation, mucosal inflammation, colonic paracellular permeability (CPP) alteration, and it promotes bacterial translocation (BT). Gut permeability increase linked to LPS promotes mucosal barrier dysfunction resulting to BT. However, the mechanisms involved in these alterations remain unknown. We aimed to evaluate the role of colonic mucosal mast cells and luminal serine protease activity (PA) in the alterations of CPP and BT induced by LPS. Rats receiving doxantrazole, a mast cell stabilizer, combined or not with LPS from Escherichia coli and CPP as well as BT were evaluated after each treatment. Mucosal mast cell activation was assessed by histological methods and by rat mast cell protease 2 level measurement in colonic content. Colonic luminal PA and mucosal inflammation (myeloperoxidase activity) were biochemically determined. In addition, the ability of luminal contents to act on CPP was evaluated in vitro in Ussing chambers. Peripheral administration of LPS promoted mast cell degranulation and increased CPP, BT, mucosal myeloperoxidase activity as well as rat mast cell protease 2 levels, and PA in colonic content. LPS-induced CPP increase and BT were prevented by doxantrazole. In vitro, exposure of the apical side of colonic tissues with supernatants from colonic contents of LPS-treated rats increased CPP. This effect was blocked by the serine protease inhibitor soybean trypsin inhibitor. Our data bring evidence of a key role of mucosal mast cells in LPS-induced increase of CPP and BT through the release of serine proteases into the colonic lumen.
脂多糖（LPS）诱导的内毒素血症与肠道免疫刺激、黏膜炎症、结肠细胞旁通透性（CPP）改变相关，并且促进细菌移位（BT）。与LPS相关的肠道通透性增加会导致黏膜屏障功能障碍，进而引起细菌移位。然而，这些改变所涉及的机制仍不清楚。我们旨在评估结肠黏膜肥大细胞和肠腔丝氨酸蛋白酶活性（PA）在LPS诱导的CPP改变和BT中的作用。每次处理后，对接受肥大细胞稳定剂多氮唑（doxantrazole）联合或不联合大肠杆菌LPS处理的大鼠的CPP以及BT进行评估。通过组织学方法以及测量结肠内容物中大鼠肥大细胞蛋白酶2水平来评估黏膜肥大细胞的激活情况。通过生化方法测定结肠肠腔PA和黏膜炎症（髓过氧化物酶活性）。此外，在尤斯灌流小室（Ussing chambers）中体外评估肠腔内容物作用于CPP的能力。外周给予LPS会促进肥大细胞脱颗粒，并增加CPP、BT、黏膜髓过氧化物酶活性以及结肠内容物中大鼠肥大细胞蛋白酶2水平和PA。多氮唑可预防LPS诱导的CPP增加和BT。在体外，用LPS处理大鼠的结肠内容物上清液处理结肠组织的顶端会增加CPP。这种作用被丝氨酸蛋白酶抑制剂大豆胰蛋白酶抑制剂阻断。我们的数据证明了黏膜肥大细胞通过向结肠腔释放丝氨酸蛋白酶在LPS诱导的CPP增加和BT中起关键作用。
