Department of Surgery, NUTRIM School for Nutrition, Toxicology and Metabolism, Maastricht University Medical Centre, Maastricht, The Netherlands.
Gut. 2013 Feb;62(2):250-8. doi: 10.1136/gutjnl-2011-301956. Epub 2012 May 25.
Colonic ischaemia is frequently observed in clinical practice. This study provides a novel insight into the pathophysiology of colon ischaemia/reperfusion (IR) using a newly developed human and rat experimental model.
In 10 patients a small part of colon that had to be removed for surgical reasons was isolated and exposed to 60 min of ischaemia (60I) with/without different periods of reperfusion (30R and 60R). Tissue not exposed to IR served as control. In rats, colon was exposed to 60I, 60I/30R, 60I/120R or 60I/240R (n=7 per group). The tissue was snap-frozen or fixed in glutaraldehyde, formalin or methacarn fixative. Mucins were stained with Periodic Acid Schiff/Alcian Blue (PAS/AB) and MUC2/Dolichos biflorus agglutinin (DBA). Bacteria were studied using electron microscopy (EM) and fluorescent in situ hybridisation (FISH). Neutrophils were studied using myeloperoxidase staining. qPCR was performed for MUC2, interleukin (IL)-6, IL-1β and tumour necrosis factor α.
In rats, PAS/AB and MUC2/DBA staining revealed mucus layer detachment at ischaemia which was accompanied by bacterial penetration (in EM and FISH). Human and rat studies showed that, simultaneously, goblet cell secretory activity increased. This was associated with expulsion of bacteria from the crypts and restoration of the mucus layer at 240 min of reperfusion. Inflammation was limited to minor influx of neutrophils and increased expression of proinflammatory cytokines during reperfusion.
Colonic ischaemia leads to disruption of the mucus layer facilitating bacterial penetration. This is rapidly counteracted by increased secretory activity of goblet cells, leading to expulsion of bacteria from the crypts as well as restoration of the mucus barrier.
临床实践中经常观察到结肠缺血。本研究通过新开发的人类和大鼠实验模型，为结肠缺血/再灌注（IR）的病理生理学提供了新的见解。
在 10 名患者中，一小部分因手术原因需要切除的结肠被隔离并暴露于缺血 60 分钟（60I），有/无不同时间的再灌注（30R 和 60R）。未暴露于 IR 的组织作为对照。在大鼠中，结肠暴露于 60I、60I/30R、60I/120R 或 60I/240R（每组 7 只）。组织被快速冷冻或固定在戊二醛、福尔马林或甲基卡宾固定剂中。粘蛋白用过碘酸希夫/阿尔辛蓝（PAS/AB）和 MUC2/多花紫藤凝集素（DBA）染色。细菌用电子显微镜（EM）和荧光原位杂交（FISH）研究。用髓过氧化物酶染色研究中性粒细胞。进行 qPCR 以检测 MUC2、白细胞介素（IL）-6、IL-1β 和肿瘤坏死因子 α。
在大鼠中，PAS/AB 和 MUC2/DBA 染色显示缺血时粘液层脱落，同时伴有细菌穿透（在 EM 和 FISH 中）。人和大鼠研究表明，同时，杯状细胞分泌活性增加。这与细菌从隐窝中排出以及在再灌注 240 分钟时粘液层的恢复有关。炎症仅限于再灌注期间少量中性粒细胞的浸润和促炎细胞因子表达的增加。
结肠缺血导致粘液层破裂，促进细菌穿透。这很快被杯状细胞分泌活性的增加所抵消，导致细菌从隐窝中排出，并恢复粘液屏障。
