Ding Shengli, Blue Randal E, Morgan Douglas R, Lund Pauline K
*Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina; and †Division of Gastroenterology, Hepatology and Nutrition, School of Medicine, Vanderbilt University, Nashville, Tennessee.
Inflamm Bowel Dis. 2014 Feb;20(2):363-77. doi: 10.1097/01.MIB.0000440612.98950.79.
Activatable near-infrared fluorescent (NIRF) probes have been used for ex vivo and in vivo detection of intestinal tumors in animal models. We hypothesized that NIRF probes activatable by cathepsins or metalloproteinases will detect and quantify dextran sulphate sodium (DSS)-induced acute colonic inflammation in wild type mice or chronic colitis in interleukin-10 (IL-10)-null mice ex vivo or in vivo.
Wild type mice given DSS, water controls, and IL-10-null mice with chronic colitis were administered probes by retro-orbital injection. FMT2500 LX system imaged fresh and fixed intestine ex vivo and mice in vivo. Inflammation detected by probes was verified by histology and colitis scoring. NIRF signal intensity was quantified using 2-dimensional region of interest ex vivo or 3-dimensional region of interest analysis in vivo.
Ex vivo, 7 probes tested yielded significant higher NIRF signals in colon of DSS-treated mice versus controls. A subset of probes was tested in IL-10-null mice and yielded strong ex vivo signals. Ex vivo fluorescence signal with 680 series probes was preserved after formalin fixation. In DSS and IL-10-null models, ex vivo NIRF signal strongly and significantly correlated with colitis scores. In vivo, ProSense680, CatK680FAST, and MMPsense680 yielded significantly higher NIRF signals in DSS-treated mice than controls, but background was high in controls.
Both cathepsin or metalloproteinase-activated NIRF probes can detect and quantify colonic inflammation ex vivo. ProSense680 yielded the strongest signals in DSS colitis ex vivo and in vivo, but background remains a problem for in vivo quantification of colitis.
可激活的近红外荧光（NIRF）探针已用于动物模型中肠道肿瘤的体外和体内检测。我们假设，组织蛋白酶或金属蛋白酶可激活的NIRF探针将在体外或体内检测并量化硫酸葡聚糖钠（DSS）诱导的野生型小鼠急性结肠炎症或白细胞介素-10（IL-10）基因敲除小鼠的慢性结肠炎。
通过眶后注射向给予DSS的野生型小鼠、水对照以及患有慢性结肠炎的IL-10基因敲除小鼠施用探针。FMT2500 LX系统对新鲜和固定的肠道进行体外成像，并对小鼠进行体内成像。通过组织学和结肠炎评分验证探针检测到的炎症。使用二维感兴趣区域进行体外NIRF信号强度量化，或使用三维感兴趣区域进行体内分析。
在体外，与对照组相比，测试的7种探针在DSS处理小鼠的结肠中产生了显著更高的NIRF信号。在IL-10基因敲除小鼠中测试了一部分探针，并产生了强烈的体外信号。福尔马林固定后，680系列探针的体外荧光信号得以保留。在DSS和IL-10基因敲除模型中，体外NIRF信号与结肠炎评分密切且显著相关。在体内，ProSense680、CatK680FAST和MMPsense680在DSS处理小鼠中产生的NIRF信号明显高于对照组，但对照组的背景较高。
组织蛋白酶或金属蛋白酶激活的NIRF探针均可在体外检测并量化结肠炎症。ProSense680在DSS结肠炎的体外和体内均产生最强信号，但背景仍然是体内结肠炎量化的一个问题。
