Department of Medicine B, Gastroenterology and Hepatology, University Hospital Münster, D-48149 Münster, Germany.
Institute of Palliative Care, University of Münster, D-48149 Münster, Germany.
Cells. 2019 Oct 28;8(11):1328. doi: 10.3390/cells8111328.
The role of neutrophils in the pathogenesis of inflammatory bowel disease (IBD) is still only incompletely understood. Here, we evaluated target-specific fluorescence-mediated tomography (FMT) for visualization of neutrophil infiltration in murine experimental DSS-induced colitis. Colitis was assessed using clinical, endoscopic, and histopathological parameters. Intestinal neutrophil infiltration was determined at day 0, 4, and 10 by targeted FMT after injection of a neutrophil-specific fluorescence-labelled monoclonal antibody (Gr-1). Complementary, immunofluorescence tissue sections with Gr-1 and ELISA-based assessment of tissue myeloperoxidase (MPO) served as the gold standard for the quantification of neutrophil infiltration. Colitic animals showed decreasing body weight, presence of fecal occult blood, and endoscopic signs of inflammation. FMT revealed a significantly increased level of fluorescence only four days after colitis induction as compared to pre-experimental conditions (pmol tracer 73.2 ± 18.1 versus 738.6 ± 80.7; < 0.05), while neither body weight nor endoscopic assessment showed significant changes at this early time. Confirmatory, post-mortem immunofluorescence studies and measurements of tissue MPO confirmed the presence of increased neutrophil infiltration in colitic mice compared to controls. Concluding, Gr-1 targeted FMT can detect early colonic infiltration of neutrophils in experimental colitis even before clinical symptoms or endoscopic alterations occur. Therefore, FMT might be an important tool for repetitive and non-invasive monitoring of inflammatory cell infiltrate in intestinal inflammation.
中性粒细胞在炎症性肠病（IBD）发病机制中的作用仍不完全清楚。在这里，我们评估了针对中性粒细胞浸润的靶向荧光介导断层扫描（FMT）在实验性 DSS 诱导的结肠炎小鼠模型中的应用。通过临床、内镜和组织病理学参数评估结肠炎。在第 0、4 和 10 天通过注射靶向中性粒细胞特异性荧光标记的单克隆抗体（Gr-1）后，用靶向 FMT 来确定肠道中性粒细胞浸润。作为中性粒细胞浸润定量的金标准，补充了 Gr-1 的免疫荧光组织切片和基于 ELISA 的组织髓过氧化物酶（MPO）评估。结肠炎动物的体重下降、粪便潜血阳性和内镜炎症表现。与实验前条件相比（pmol 示踪剂 73.2 ± 18.1 与 738.6 ± 80.7；<0.05），FMT 仅在结肠炎诱导后四天就显示出荧光水平显著增加，而体重或内镜评估在这个早期时间点没有明显变化。尸检免疫荧光研究和组织 MPO 测量进一步证实，与对照组相比，结肠炎小鼠中存在增加的中性粒细胞浸润。总之，Gr-1 靶向 FMT 可在实验性结肠炎中检测到早期结肠中性粒细胞浸润，甚至在出现临床症状或内镜改变之前。因此，FMT 可能是重复、非侵入性监测肠道炎症中炎症细胞浸润的重要工具。
