Department of Surgery, Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany.
Am J Physiol Gastrointest Liver Physiol. 2013 Feb 15;304(4):G401-12. doi: 10.1152/ajpgi.00161.2012. Epub 2012 Dec 13.
Standardized intestinal manipulation (IM) leads to local bowel wall inflammation subsequently spreading over the entire gastrointestinal tract. Previously, we demonstrated that this so-called gastrointestinal field effect (FE) is immune-mediated. The aim of this study was to investigate the role of secondary lymphoid organs [mesenteric lymph nodes (MLN), gut-associated lymphoid tissue (GALT)] in IM-mediated FE by employing mice with deficient secondary lymphoid organs (aly/aly, MLN ex) or by administration of 2-amino-2-[2-(4-octylphenyl)ethyl]-1,3-propanediol (FTY720), an immunomodulating agent that inhibits emigration of lymphocytes out of lymphoid organs. Small bowel muscularis, and colonic muscularis from wild-type mice as control, from aly/aly mice, FTY720-treated mice (daily dose of 1.0 mg/kg mouse ip starting 3 days before surgical procedure), and wild-type mice that had undergone removal of mesenteric lymph nodes before IM (MLN ex mice) were obtained after selective IM of the jejunum or sham operation. FE was analyzed by measuring transit time of orally administered fluorescent dextran in the gastrointestinal tract [geometric center (GC) of fluorescent dextran], colonic transit time, infiltration of myeloperoxidase-positive cells, and circular smooth muscle contractility. Furthermore, mRNA levels of inflammatory cytokines [interleukin (IL)-6, tumor necrosis factor (TNF)-α, macrophage inflammatory protein (MIP)-1α] were determined by Taqman-PCR. We observed a significantly reduced upregulation of proinflammatory cytokines (IL-6, TNF-α, MIP-1α) in colonic muscularis of MLN ex mice, aly/aly mice, and FTY720-treated mice compared with wild-type mice. Contractility of circular muscularis strips of the colon but not the jejunum was significantly improved in aly/aly mice and FTY720-treated wild-type mice. Additionally, inflammation of the colon determined by the number of myeloperoxidase-positive cells and colonic transit time were significantly improved in aly/aly mice, FTY720-treated wild-type mice, and in MLN ex mice. In summary, lack of secondary lymphoid organs (MLN + GALT) in aly/aly mice or administration of FTY720 abrogated FE after IM as opposed to wild-type mice. These data demonstrate that secondary lymphoid organs are involved in the propagation of FE and postoperative ileus. FTY720 indirectly affects FE by inhibiting migration of activated T cells from the jejunum and adjacent secondary lymphoid organs to the colon. These findings support the crucial role of the adaptive immune system in FE, most likely by a sphyngosine 1-phosphate-dependent mechanism.
标准化肠道操作（IM）导致局部肠壁炎症随后扩散到整个胃肠道。此前，我们证明这种所谓的胃肠道场效应（FE）是免疫介导的。本研究的目的是通过使用缺乏次级淋巴器官的小鼠（aly/aly，MLN ex）或给予 2-氨基-2-[2-（4-辛基苯基）乙基]-1,3-丙二醇（FTY720），一种抑制淋巴细胞从淋巴器官迁出的免疫调节药物，来研究次级淋巴器官[肠系膜淋巴结（MLN）、肠道相关淋巴组织（GALT）]在 IM 介导的 FE 中的作用。从小肠肌层和结肠肌层中获得野生型小鼠（作为对照）、aly/aly 小鼠、FTY720 治疗的小鼠（在手术前 3 天开始每天给予 1.0 mg/kg 体重的腹腔注射）和在 IM 前切除肠系膜淋巴结的野生型小鼠（MLN ex 小鼠），进行空肠选择性 IM 或假手术。通过测量口服荧光葡聚糖在胃肠道中的迁移时间（荧光葡聚糖的几何中心（GC））、结肠通过时间、髓过氧化物酶阳性细胞浸润和环形平滑肌收缩性来分析 FE。此外，通过 Taqman-PCR 测定炎性细胞因子[白细胞介素（IL）-6、肿瘤坏死因子（TNF）-α、巨噬细胞炎症蛋白（MIP）-1α]的 mRNA 水平。我们观察到 MLN ex 小鼠、aly/aly 小鼠和 FTY720 治疗的野生型小鼠结肠肌层中促炎细胞因子（IL-6、TNF-α、MIP-1α）的上调明显减少。与野生型小鼠相比，结肠环形肌条的收缩性在 aly/aly 小鼠和 FTY720 治疗的野生型小鼠中显著改善。此外，通过髓过氧化物酶阳性细胞数量和结肠通过时间确定的结肠炎症在 aly/aly 小鼠、FTY720 治疗的野生型小鼠和 MLN ex 小鼠中均得到显著改善。总之，与野生型小鼠相比，aly/aly 小鼠缺乏次级淋巴器官（MLN+GALT）或给予 FTY720 可消除 IM 后的 FE。这些数据表明，次级淋巴器官参与 FE 和术后肠梗阻的传播。FTY720 通过抑制激活的 T 细胞从空肠和相邻的次级淋巴器官向结肠迁移，间接影响 FE。这些发现支持适应性免疫系统在 FE 中的关键作用，可能是通过鞘氨醇 1-磷酸依赖性机制。
