Cartwright Ian M, Colgan Sean P
Mucosal Inflammation Program, University of Colorado Anschutz Medical Campus; Department of Medicine, University of Colorado Anschutz Medical Campus; Rocky Mountain Regional Veterans Affairs Medical Center.
Mucosal Inflammation Program, University of Colorado Anschutz Medical Campus; Department of Medicine, University of Colorado Anschutz Medical Campus; Rocky Mountain Regional Veterans Affairs Medical Center;
J Vis Exp. 2021 Jun 3(172). doi: 10.3791/62169.
Early accumulation of neutrophils (PMN) is a hallmark of acute intestinal inflammation. This acute inflammation is either resolved or progresses to chronic inflammation. Without efficient PMN clearance at sites of infiltration, PMN can accumulate and contribute to chronic inflammatory conditions, including the intestinal diseases ulcerative colitis (UC) and Crohn's Disease (CD). The pH in the distal colon in individuals with active UC can range between a pH of 5 and 6, whereas healthy individuals maintain colonic pH in the range of 6.8-7.4. Extracellular pH has been shown to influence both intestinal epithelial cells and the infiltrating immune cells. More specifically, extracellular acidosis significantly impacts PMN. At pH below 6.5, there are increases in the production of H2O2, inhibition of apoptosis, and increases in the functional lifespan of PMN. Given the significant presence of PMN and extracellular acidification at sites of inflammation, we developed a novel model that allows for the monitoring of extracellular pH during PMN transepithelial migration in real time. Here, we describe this model and how it can be utilized to measure both the apical and basal pH during PMN trafficking. This model can be utilized to monitor extracellular pH under a wide range of conditions; including, hypoxia, PMN transepithelial migration, and for extended periods of time.
中性粒细胞（PMN）的早期积聚是急性肠道炎症的一个标志。这种急性炎症要么得到缓解，要么发展为慢性炎症。如果在浸润部位没有有效地清除PMN，PMN就会积聚并导致慢性炎症状态，包括肠道疾病溃疡性结肠炎（UC）和克罗恩病（CD）。活动性UC患者远端结肠的pH值范围在5至6之间，而健康个体的结肠pH值维持在6.8 - 7.4范围内。细胞外pH已被证明会影响肠道上皮细胞和浸润的免疫细胞。更具体地说，细胞外酸中毒对PMN有显著影响。在pH低于6.5时，过氧化氢的产生增加，细胞凋亡受到抑制，PMN的功能寿命延长。鉴于炎症部位PMN的大量存在和细胞外酸化，我们开发了一种新型模型，可实时监测PMN跨上皮迁移过程中的细胞外pH。在此，我们描述该模型以及如何利用它来测量PMN运输过程中的顶端和基底pH。该模型可用于在广泛的条件下监测细胞外pH，包括缺氧、PMN跨上皮迁移以及长时间监测。
