Traserra Sara, Casabella-Ramón Sergi, Vergara Patri, Jimenez Marcel
Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, Barcelona, Spain.
Centro de Investigación Biomédica en Red de Enfermedades Hepaticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, Madrid, Spain.
Front Physiol. 2023 Jun 2;14:1170822. doi: 10.3389/fphys.2023.1170822. eCollection 2023.
This study aims to assess the barrier integrity and possible activation of enteric neural pathways associated with secretion and motility in the pig colon induced by an enterotoxigenic (ETEC) challenge. 50 Danbred male piglets were used for this study. 16 were challenged with an oral dose of the ETEC strain F4+ 1.5 × 10 colony-forming unit. Colonic samples were studied 4- and 9-days post-challenge using both a muscle bath and Ussing chamber. Colonic mast cells were stained with methylene blue. In control animals, electrical field stimulation induced neurosecretory responses that were abolished by tetrodotoxin (10M) and reduced by the combination of atropine (10M) and α-chymotrypsin (10U/mL). Exogenous addition of carbachol, vasoactive intestinal peptide, forskolin, 5-HT, nicotine, and histamine produced epithelial Cl secretion. At day 4 post-challenge, ETEC increased the colonic permeability. The basal electrogenic ion transport remained increased until day 9 post-challenge and was decreased by tetrodotoxin (10M), atropine (10M), hexamethonium (10M), and ondansetron (10M). In the muscle, electrical field stimulation produced frequency-dependent contractile responses that were abolished with tetrodotoxin (10M) and atropine (10M). Electrical field stimulation and carbachol responses were not altered in ETEC animals in comparison with control animals at day 9 post-challenge. An increase in mast cells, stained with methylene blue, was observed in the mucosa and submucosa but not in the muscle layer of ETEC-infected animals on day 9 post-challenge. ETEC increased the response of intrinsic secretory reflexes and produced an impairment of the colonic barrier that was restored on day 9 post-challenge but did not modify neuromuscular function.
本研究旨在评估产肠毒素大肠杆菌（ETEC）攻击诱导的猪结肠中与分泌和运动相关的肠神经通路的屏障完整性及可能的激活情况。本研究使用了50只丹麦长白雄性仔猪。16只仔猪口服剂量为1.5×10菌落形成单位的ETEC菌株F4进行攻击。在攻击后4天和9天，使用肌肉浴和尤斯灌流室对结肠样本进行研究。结肠肥大细胞用亚甲蓝染色。在对照动物中，电场刺激诱导的神经分泌反应被河豚毒素（10μM）消除，并被阿托品（10μM）和α-糜蛋白酶（10U/mL）的组合所减弱。外源性添加卡巴胆碱、血管活性肠肽、福斯高林、5-羟色胺、尼古丁和组胺可产生上皮氯离子分泌。在攻击后第4天，ETEC增加了结肠通透性。基础生电离子转运在攻击后第9天之前一直增加，并被河豚毒素（10μM）、阿托品（10μM）、六甲铵（10μM）和昂丹司琼（10μM）降低。在肌肉中，电场刺激产生频率依赖性收缩反应，该反应被河豚毒素（10μM）和阿托品（10μM）消除。在攻击后第9天，与对照动物相比，ETEC动物的电场刺激和卡巴胆碱反应未改变。在攻击后第9天，在ETEC感染动物的黏膜和黏膜下层观察到亚甲蓝染色的肥大细胞增加，但在肌肉层未观察到。ETEC增加了内在分泌反射的反应，并导致结肠屏障受损，该损伤在攻击后第9天恢复，但未改变神经肌肉功能。
