The authors wish to acknowledge support from NIH funding DK055679, DK089763, DK079392, DK061739, DK072564 and the University of Michigan Pathology Slide Scanning Services.

All animal experiments described were approved by the University of Michigan&#39;s Committee on the Use and Care of Animals.
1. Tissue harvest
<ol>
	<li>Euthanize mice humanely using isoflurane anesthesia followed by cervical dislocation, in accordance with approved protocols. For all animal experiments, approval was obtained by a certified review board in accordance with the National and Institutional guidelines for animal handling.</li>
	<li>Place the mouse on a dissecting pad in a supine position. Immobilize mouse extremities using 20 G x 1 1/2-inch G needles.</li>
	<li>Using forceps and scissors, make a small incision on the abdominal skin and pull it to the side to expose the peritoneum.</li>
	<li>Open the abdominal cavity with a midline incision in the peritoneum from the pubic bone to the sides of the abdomen.</li>
	<li>Carefully remove tissues and organs until large intestine is visualized. Cut the pelvic bone on both sides of the colon to fully visualize the organ, extending from the anus towards the cecum.</li>
	<li>Gently remove fat, small veins and arteries attached to the colon, while carefully dissecting the organ, cutting just proximal to the anus and just distal to the cecum. 
	NOTE: The dissected colon should remain at room temperature while completing the Swiss roll procedure.</li>
	<li>Carefully flush the colon with 1x PBS, using a flexible plastic gavage needle inserted through the anus to remove fecal contents.</li>
	<li>Position the colon in a straight line, and open longitudinally along the mesenteric artery. Bisect the colon longitudinally from the distal to the proximal end (Figure 1A). One half of the tissue can be used for histological analysis while the other can be processed for western blot, PCR or rolled into a second Swiss roll for fresh frozen immunofluorescence microscopy12.</li>
</ol>
2. Preparation of swiss rolls
<ol>
	<li>Trim extra tissue from the proximal colon using a razor blade until approximately the same width along the length of the whole colon is obtained.</li>
	<li>Align the colon to expose the lumen facing-up, and flatten the tissue completely using a flexible gavage needle. Add more PBS, if needed, to keep the tissue moist throughout the procedure.</li>
	<li>Remove the excess of PBS using a paper wipe. With a syringe and gavage needle, add 10% neutral buffered formalin solution over the tissue for 2-3 min to fix and flatten the tissue.</li>
	<li>Use straight forceps to grab the end of the distal colon and twist the colon into concentric circles from the distal to proximal end (Figure 1B). 
	NOTE: It is possible to push back the inside of the Swiss roll while rolling using the forefinger to ensure the tissue is inside the roll.</li>
	<li>Insert a 27 G needle to pin the colon in the middle to hold its Swiss roll shape (Figure 1C).</li>
	<li>Place the Swiss roll with the needle into an embedding cassette inside a histologic specimen container. 
	NOTE: Tissue must be oriented in parallel with respect to the cassette before fixation (Figure 1D).</li>
	<li>Fix the tissue in 10% neutral buffered formalin solution overnight at 4 &#176;C13.</li>
	<li>After overnight fixation, wash the tissue 3x with PBS.</li>
	<li>Add 70% ethanol to the tissue prior to the paraffin embedding process. Remove the needle from the Swiss roll before proceeding. Tissue can be stored in ethanol at room temperature until paraffin embedment13.</li>
	<li>Place samples into the tissue processor, embed in paraffin, and prepare 4 &#181;m sections, mounted on positively charged microscopy slides (Figure 1E). This can be an optional stop point. 
	NOTE: Proper tissue orientation is critical to achieve sections suitable for image analysis. Parallel Swiss roll embedding in the paraffin cassette will result in full sections appropriated for image analysis (Figure 1F-1H). Oblique sections must be avoided to prevent incomplete sections (Figure 1I-1K). For more details, see the Discussion section.</li>
	<li>Stain sections with hematoxylin and eosin (H&#38;E)13.</li>
</ol>
3. Digital scanning and analysis
NOTE: For accurate evaluation of mucosal changes, select only sections that include at least 90% of the total colon length.
<ol>
	<li>Scan stained sections using a slide scanner or imager (see Table of Materials). Images produced need a resolution of 0.25 microns per pixel with 40x objective and 40x magnification.</li>
	<li>Install and download an appropriate software for digital analysis of scanned slides (see Table of Materials).</li>
	<li>Open scanned images in the image processing software (Figure 2A). Verify that the entire colon is visible and that there are no missing areas of the sample.</li>
	<li>Activate the label imager and scale bar tools to properly identify scanned slides by clicking Label imager (Figure 2A).</li>
	<li>Open the annotations tool by clicking Annotations, (Figure 2A) and create 3 different layers by clicking New layer (Figure 2B) to quantify the total length the Swiss roll, inflammation/injury, and erosion/ulceration. Choose a different color for each layer by clicking Layer color (Figure 2B).</li>
	<li>Measure the length of each layer/category by clicking the Pen tool (Figure 2A), using the muscularis mucosa as a reference:
	<ol>
		<li>View the image at 400 &#181;m zoom (or more) to facilitate adequate visualization of the muscularis mucosa. 
		NOTE: Magnification is easily controlled using the mouse scroll wheel and will need to be adjusted as necessary while moving across the section to draw all the lines.</li>
		<li>Click on the Pen tool to draw a line following the muscularis mucosa (Figure 2A). Move the pointer as needed to visualize the adjacent area for analysis. 
		NOTE: Each time that the pen is stopped, a small new layer region will be generated. It can be visualized and edited with the Layer regions tab (select desired segment and click Delete Layer in case of mistakes or corrections, Figure 2B).</li>
	</ol>
	</li>
	<li>Once all layers (Figure 2C) are defined, export the data using the Export Grid to Text File button inside the layer regions options (Figure 2B). 
	NOTE: Save files often while creating the layers to ensure data is properly stored.</li>
	<li>Open the text files and copy the data with a spreadsheet software. Total all the segments from each region and calculate percentage of injury and ulceration with respect to total length.</li>
	<li>To calculate the Histological Colitis Score (HCS) and to evaluate the severity of disease, consider three main characteristics as detailed below.
	<ol>
		<li>Check for healthy intestinal mucosa which is characterized by organized epithelial cells in the crypt-luminal axis, lamina propria with few immune cells, and subjacent muscularis mucosa that interfaces the mucosa and submucosa (Figure 3A).</li>
		<li>Check for inflammation/injury which is characterized by epithelial crypts that are attenuated or partially missing epithelial cells and mucosal inflammation with neutrophil infiltration into crypts (Figure 3B).</li>
		<li>Check for the presence of erosion/ulceration which is characterized by areas devoid of surface epithelium or areas completely lacking epithelial crypts with or without associated leukocytes (Figure 3C).</li>
	</ol>
	</li>
	<li>Calculate HCS of injured and ulcerated regions expressed as a percentage of the total length in the following formula: 
	<img alt="Equation 1" src="/files/ftp_upload/62135/62135eq01v2.jpg" /> 
	NOTE: HCS combines the percentage of inflammation/injury and erosion/ulceration adding a factor of two to the latter, based on a reasonable assumption that complete loss of the epithelium results in maximum loss of barrier integrity and hence worse disease. HCS consistently represents the morphological changes caused by DSS induced experimental colitis. Interestingly, we have not seen a clear correlation between the numbers of colonic lymphoid aggregates or follicles and clinical disease severity in DSS colitis and, therefore, we did not include the quantification in this analysis.</li>
	<li>Take a snapshot of the representative images (click Snapshot, Figure 2A), and save. Include scale bars if needed by clicking on Show/Hide Scale Bar (Figure 2A).</li>
</ol>

<ol><li>Kagnoff, M. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((The+intestinal+epithelium+is+an+integral+component+of+a+communications+network%5BTitle%5D)+AND+%22Journal+of+Clinical+Investigation%22%5BJournal%5D)">The intestinal epithelium is an integral component of a communications network.</a> Journal of Clinical Investigation. 124 (7), 2841-2843 (2014).</li>
<li>Laukoetter, M. G., Nava, P., Nusrat, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Role+of+the+intestinal+barrier+in+inflammatory+bowel+disease%5BTitle%5D)+AND+%22World+Journal+of+Gastroenterology%22%5BJournal%5D)">Role of the intestinal barrier in inflammatory bowel disease.</a> World Journal of Gastroenterology. 14 (3), 401-407 (2008).</li>
<li>Baumgart, D. C., Sandborn, W. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Crohn%27s+disease%5BTitle%5D)+AND+%22Lancet%22%5BJournal%5D)">Crohn's disease.</a> Lancet. 380 (9853), 1590-1605 (2012).</li>
<li>Ordas, I., Eckmann, L., Talamini, M., Baumgart, D. C., Sandborn, W. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Ulcerative+colitis%5BTitle%5D)+AND+%22Lancet%22%5BJournal%5D)">Ulcerative colitis.</a> Lancet. 380 (9853), 1606-1619 (2012).</li>
<li>Vowinkel, T., Kalogeris, T. J., Mori, M., Krieglstein, C. F., Granger, D. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Impact+of+dextran+sulfate+sodium+load+on+the+severity+of+inflammation+in+experimental+colitis%5BTitle%5D)+AND+%22Digestive+Diseases+and+Sciences%22%5BJournal%5D)">Impact of dextran sulfate sodium load on the severity of inflammation in experimental colitis.</a> Digestive Diseases and Sciences. 49 (4), 556-564 (2004).</li>
<li>Kitajima, S., Takuma, S., Morimoto, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Histological+analysis+of+murine+colitis+induced+by+dextran+sulfate+sodium+of+different+molecular+weights%5BTitle%5D)+AND+%22Experimental+Animals%22%5BJournal%5D)">Histological analysis of murine colitis induced by dextran sulfate sodium of different molecular weights.</a> Experimental Animals. 49 (1), 9-15 (2000).</li>
<li>Mahler, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Differential+susceptibility+of+inbred+mouse+strains+to+dextran+sulfate+sodium-induced+colitis%5BTitle%5D)+AND+%22American+Journal+of+Physiology%22%5BJournal%5D)">Differential susceptibility of inbred mouse strains to dextran sulfate sodium-induced colitis.</a> American Journal of Physiology. 274 (3), 544-551 (1998).</li>
<li>Wirtz, S., Neufert, C., Weigmann, B., Neurath, M. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Chemically+induced+mouse+models+of+intestinal+inflammation%5BTitle%5D)+AND+%22Nature+Protocols%22%5BJournal%5D)">Chemically induced mouse models of intestinal inflammation.</a> Nature Protocols. 2 (3), 541-546 (2007).</li>
<li>Kozlowski, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((An+entirely+automated+method+to+score+DSS-induced+colitis+in+mice+by+digital+image+analysis+of+pathology+slides%5BTitle%5D)+AND+%22Disease+Models+%26+Mechanisms%22%5BJournal%5D)">An entirely automated method to score DSS-induced colitis in mice by digital image analysis of pathology slides.</a> Disease Models & Mechanisms. 6 (3), 855-865 (2013).</li>
<li>Perse, M., Cerar, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Dextran+sodium+sulphate+colitis+mouse+model%3A+traps+and+tricks%5BTitle%5D)+AND+%22Journal+of+Biomedicine+and+Biotechnology%22%5BJournal%5D)">Dextran sodium sulphate colitis mouse model: traps and tricks.</a> Journal of Biomedicine and Biotechnology. 2012, 718617(2012).</li>
<li>Mizoguchi, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Animal+models+of+inflammatory+bowel+disease%5BTitle%5D)+AND+%22Progress+in+Molecular+Biology+and+Translational+Science%22%5BJournal%5D)">Animal models of inflammatory bowel disease.</a> Progress in Molecular Biology and Translational Science. 105, 263-320 (2012).</li>
<li>Flemming, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Desmocollin-2+promotes+intestinal+mucosal+repair+by+controlling+integrin-dependent+cell+adhesion+and+migration%5BTitle%5D)+AND+%22Molecular+Biology+of+the+Cell%22%5BJournal%5D)">Desmocollin-2 promotes intestinal mucosal repair by controlling integrin-dependent cell adhesion and migration.</a> Molecular Biology of the Cell. 31 (6), 407-418 (2020).</li>
<li>Luna, L. G. <a target="_blank" href="http://scholar.google.com/scholar?hl=en&safe=off&q=author%3aLuna%2C+LG+%22Armed+Forces+Institute+of+Pathology+%28U.S%29+%26+Armed+Forces+Institute+of+Pathology+%28U.S.%29.+Manual+of+Histologic+Staining+Methods+of+the+Armed+Forces+Institute+of+Pathology.+3d+edn%22">Armed Forces Institute of Pathology (U.S) & Armed Forces Institute of Pathology (U.S.). Manual of Histologic Staining Methods of the Armed Forces Institute of Pathology. 3d edn</a>. , Blakiston Division. (1968).</li>
<li>Kelm, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Targeting+epithelium-expressed+sialyl+Lewis+glycans+improves+colonic+mucosal+wound+healing+and+protects+against+colitis%5BTitle%5D)+AND+%22The+Journal+of+Clinical+Investigation+Insight%22%5BJournal%5D)">Targeting epithelium-expressed sialyl Lewis glycans improves colonic mucosal wound healing and protects against colitis.</a> The Journal of Clinical Investigation Insight. 5 (12), (2020).</li>
<li>Reed, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Epithelial+CD47+is+critical+for+mucosal+repair+in+the+murine+intestine+in+vivo%5BTitle%5D)+AND+%22Nature+Communications%22%5BJournal%5D)">Epithelial CD47 is critical for mucosal repair in the murine intestine in vivo.</a> Nature Communications. 10 (1), 5004(2019).</li>
<li>Laukoetter, M. G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((JAM-A+regulates+permeability+and+inflammation+in+the+intestine+in+vivo%5BTitle%5D)+AND+%22Journal+of+Experimental+Medicine%22%5BJournal%5D)">JAM-A regulates permeability and inflammation in the intestine in vivo.</a> Journal of Experimental Medicine. 204 (13), 3067-3076 (2007).</li>
<li>Khounlotham, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Compromised+intestinal+epithelial+barrier+induces+adaptive+immune+compensation+that+protects+from+colitis%5BTitle%5D)+AND+%22Immunity%22%5BJournal%5D)">Compromised intestinal epithelial barrier induces adaptive immune compensation that protects from colitis.</a> Immunity. 37 (3), 563-573 (2012).</li>
</ol>

The authors have nothing to disclose.

Our Histological Colitis Score system constitutes a reliable tool to quantify tissue inflammation and damage in the intestine. This approach provides an improved understanding of the histopathological state of the whole organ without the bias of selecting small areas or incomplete sections. Among the critical steps to successfully execute this protocol are proper preparation of Swiss rolls that allow for analysis of at least 90% of the length of the colon; parallel orientation during paraffin embedding and sectioning to ...

The gastrointestinal epithelial barrier plays a pivotal role in separating luminal antigens and pathogens from underlying tissue compartments1. Epithelial injury and mucosal wounds seen in pathologic conditions such as inflammatory bowel disease (IBD), ischemia, or surgical injury are associated with clinical symptoms that include diarrhea, weight loss, blood in stool, and abdominal pain. In response to injury, epithelial cells migrate and proliferate to re-epithelialize and repair mucosal barrier defects. Resolution of inflammation and restitution of mucosal integrity are crucial to re-establishing intestinal mucosal homeostasis and function2,3,4.
Various animal models have been employed to study the underlying molecular mechanisms that are associated with the damage to the intestinal epithelial barrier. Well-established and easily applicable models of chemically induced colitis are widely used, particularly in studies related to inflammatory injury such as IBD. A common, reproducible, and reliable murine colitis model employs dextran sodium sulfate (DSS) mediated colonic injury and inflammation. The severity of disease varies depending upon mouse strain, dose of DSS, length of DSS administration, and molecular weight of DSS5,6,7.
Intestinal mucosal damage during DSS colitis is usually evaluated using the Disease Activity Index (DAI), a composite score determined by weight loss, fecal blood content, and stool consistency. The fecal blood content can be microscopic (detected using a stool guaiac acid test) or macroscopic; fecal consistency is classified as hard, soft, or liquid (i.e., diarrhea)5,8. Scoring of these clinical parameters can be subjective and may vary depending on the user&#39;s experience and bias, although overall, the data provides reliable information and is thus widely used by IBD researchers. In contrast, there is no generally accepted method for histological evaluation of mucosal damage. Most commonly, selected areas of the colon are inspected by a trained pathologist and scored based on several parameters that usually include crypt injury and leukocyte infiltration9,10,11. However, because the number of investigated parameters and the amount of tissue analyzed varies considerably between individual reports, comparability of many published studies is limited. To reduce observer bias and enhance inter-study concordance, an ideal histological scoring protocol should: 1) include the entire length of the colon, as intestinal mucosal inflammation is most often variable and skip lesions are common, 2) limit analysis to specific key and easily interpretable parameters to reduce subjectivity, 3) facilitate fast, consistent processing of large numbers of samples, and 4) use widely available and affordable tools for data acquisition, analysis and presentation.
Here we describe a technique to process the entire colon or long segments of the small intestine in a &#34;Swiss roll&#34; configuration along with the use of a free computer-assisted scoring system to analyze intestinal mucosal inflammation and damage because of DSS-induced colitis.

<table><tbody><tr><td>Aperio AT2 &amp;ndash; High Volume, Digital Whole Slide Scanning</td><td>Leica Biosystems</td><td>Aperio AT2</td><td></td></tr><tr><td>Absorbent Underpads with waterproof moisture barrier</td><td>VWR International</td><td>56616-032</td><td></td></tr><tr><td>American Line 66-0089 Single Edge Blade, 100 per pkg</td><td>GT Midwest</td><td>TL5837</td><td></td></tr><tr><td>BD Luer-Lok Disposable Syringes without Needles</td><td>Fisher scientific</td><td>14-823-2A</td><td></td></tr><tr><td>Bonn Strabismus Scissors - ToughCut</td><td>Fine Science tools</td><td>11103-09</td><td></td></tr><tr><td>Bonn Strabismus Scissors - ToughCut</td><td>Fine Science tools</td><td>14084-09</td><td></td></tr><tr><td>Dumont #5 Forceps</td><td>Fine Science tools</td><td>11251-20</td><td></td></tr><tr><td>Formalin solution, neutral buffered, 10%</td><td>Sigma</td><td>HT501640-19L</td><td></td></tr><tr><td>HistoPrep 70% Ea</td><td>Fisherbran</td><td>70% denatured ethyl alcohol</td><td></td></tr><tr><td>ImageScope</td><td>Aperio</td><td>Version 12.3.3.5039</td><td>http://www.leicabiosystems.com/pathology-imaging/aperio-epathology/integrate/imagescope/</td></tr><tr><td>LeakBuster Specimen Containers: Sterile</td><td>Starplex Scientific</td><td>B120210</td><td></td></tr><tr><td>Phosphate-Buffere Saline, without calcium &amp;amp; magnesium</td><td>Corning</td><td>21-040-CV</td><td></td></tr><tr><td>Plastic Feeding tubes, 20 GA x 30 mm</td><td>Instech</td><td>FTP2030</td><td></td></tr><tr><td>PrecisionGlide Needle, Size: 20 G x 1 1/2 in</td><td>BD (Becton, Dickinson and Company)</td><td>305176</td><td></td></tr><tr><td>PrecisionGlide Needle, Size: 27 G x 1/2 in</td><td>BD (Becton, Dickinson and Company)</td><td>305109</td><td></td></tr><tr><td>Syringe, 10 ml</td><td>BD (Becton, Dickinson and Company)</td><td>302995</td><td></td></tr><tr><td>Unisette Tissue Cassettes</td><td>Simport</td><td>M505-2</td><td></td></tr></tbody></table>

systematic scoring analysis for intestinal inflammation in a murine dextran sodium sulfate-induced colitis model

Murine colitis models are tools that are extensively employed in studies focused on understanding the pathobiology of inflammatory intestinal disorders. However, robust standards for objective and reproducible quantification of disease severity remain to be defined. Most colitis analysis methods rely on limited histological scoring of small segments of intestine, leading to partial or biased analyses. Here, we combine high-resolution image acquisition and longitudinal analysis of the entire colon to quantify intestinal injury and ulceration in the dextran sodium sulfate (DSS) induced model of murine colitis. This protocol allows for the generation of objective and reproducible results without extensive user training. Here, we provide comprehensive details on sample preparation and image analysis using examples of data from DSS induced colitis. This method can be easily adapted to other models of murine colitis that have significant inflammation associated with mucosal injury. We demonstrate that the fraction of inflamed/injured and eroded/ulcerated mucosa relative to the complete length of the colon closely parallels clinical findings such as weight loss amid DSS-induced disease progression. This histological protocol provides a reliable time and cost-effective aid to standardize analyses of disease activity in an unbiased way in DSS colitis experiments.

To illustrate the reliability of this Histological Colitis Score Analysis in the context of mucosal damage after DSS challenge and subsequent recovery from colitis, we administered 2.5% DSS in the drinking water of eight 10 weeks old male C57BL6 wild type mice for 5 days followed by a recovery period with regular water for 5 days. There was no change in body weight during the acute administration of DSS, from day 0 to 5 (Figure 4A). Body weight dramatically d...

Watch this Scientific Journal Video about Systematic Scoring Analysis for Intestinal Inflammation in a Murine Dextran Sodium Sulfate-Induced Colitis Model at JoVE.com

Systematic Scoring Analysis for Intestinal Inflammation in a Murine Dextran Sodium Sulfate-Induced Colitis Model

Systematic scoring of intestinal inflammation using a free computer-assisted system is a powerful tool to quantitatively compare histopathological changes in colitis models characterized by the presence of ulcers and inflammatory changes. Histological colitis score evaluation strengthens clinical observations and facilitates data interpretation.

Murine colitis models are tools that are extensively employed in studies focused on understanding the pathobiology of inflammatory intestinal disorders. ...

systematic-scoring-analysis-for-intestinal-inflammation-murine

Research

JoVE Journal

Immunology and Infection

9.2K Views.  University of Michigan. De systematische scoringsanalyse is een techniek voor het evalueren van mucosale letsels, waardoor histologische interpretatie wordt vergemakkelijkt die kan worden uitgevoerd door getrainde onderzoekers. De belangrijkste voordelen van deze methode is dat het gratis en gemakkelijk te gebruiken is. Het maakt kwantitatieve analyse mogelijk van histologische gegevens verkregen uit de darmen van muizen met colitis.Dit protocol biedt een snelle en reproduceerbare manier om de ernst van de zi...

Video: Systematic Scoring Analysis for Intestinal Inflammation in a Murine Dextran Sodium Sulfate-Induced Colitis Model

Flexible Colonoscopy in Mice to Evaluate the Severity of Colitis and Colorectal Tumors Using a Validated Endoscopic Scoring System

The use of modern endoscopy for research purposes has greatly facilitated our understanding of gastrointestinal pathologies. In particular, experimental endoscopy has been highly useful for studies that require repeated assessments in a single laboratory animal, such as those evaluating mechanisms of chronic inflammatory bowel disease and the progression of colorectal cancer. However, the methods used across studies are highly variable. At least three endoscopic scoring systems have been published for murine colitis and published protocols for the assessment of colorectal tumors fail to address the presence of concomitant colonic inflammation. This study develops and validates a reproducible endoscopic scoring system that integrates evaluation of both inflammation and tumors simultaneously. This novel scoring system has three major components: 1) assessment of the extent and severity of colorectal inflammation (based on perianal findings, transparency of the wall, mucosal bleeding, and focal lesions), 2) quantitative recording of tumor lesions (grid map and bar graph), and 3) numerical sorting of clinical cases by their pathological and research relevance based on decimal units with assigned categories of observed lesions and endoscopic complications (decimal identifiers). The video and manuscript presented herein were prepared, following IACUC-approved protocols, to allow investigators to score their own experimental mice using a well-validated and highly reproducible endoscopic methodology, with the system option to differentiate distal from proximal endoscopic colitis (D-PECS).

Over the past few years, new generation endoscopes have emerged as important diagnostic research aids for evaluating murine colitis and colorectal tumors. We present herein a detailed protocol for endoscopic assessment of inflammation and colorectal tumors in mice, as well as a novel scoring system that uses decimal identifiers to document the endoscopic severity of colitis and colorectal tumors.

The use of modern endoscopy for research purposes has greatly facilitated our understanding of gastrointestinal pathologies. In particular, experimental ...

Medicine

Murine Colitis Modeling using Dextran Sulfate Sodium (DSS)

Colitis can occur from viral or bacterial infections, ischemic insult, or autoimmune disorders; most notably Ulcerative Colitis and the colonic variant of Crohn&rsquo;s Disease - Crohn&rsquo;s Colitis. Acute colitis may present with abdominal pain and distention, malabsorption, diarrhea, hematochezia and mucus in the stool. We are beginning to understand the complex interactions between the environment, genetics, and epithelial barrier dysfunction in Inflammatory Bowel Disease and animal models of colitis have been essential in advancing our understanding of this disease. One popular model involves supplementing the drinking water of mice with low-molecular weight Dextran Sodium Sulfate (DSS), resulting in epithelial damage and a robust inflammatory response in the colon lasting several days 1.Variations of this approach can be used to model acute injury, acute injury followed by repair, and repeated cycles of DSS interspersed with recovery modeling chronic inflammatory diseases 2. After a single four-day treatment of 3% DSS in drinking water, mice show signs of acute colitis including weight loss, bloody stools, and diarrhea. Mice are euthanized at the conclusion of the treatment course and at necropsy dissected colons are processed and can be 'Swiss rolled" 3 to allow microscopic analysis of the entire colon or infused with formalin as "sausages" to allow macroscopic analysis. Tissue is then embedded in paraffin, sectioned, and stained for histologic review.

Murine Colitis Modeling using Dextran Sulfate Sodium DSS

Dextran sulfate sodium (DSS) administered in the drinking water is an established murine inflammatory injury model of acute colitis. This protocol outlines the method for DSS treatment and the preparation of tissues.

Colitis can occur from viral or bacterial infections, ischemic insult, or autoimmune disorders; most notably Ulcerative Colitis and the colonic variant of ...

Biology

Murine Endoscopy for In Vivo Multimodal Imaging of Carcinogenesis and Assessment of Intestinal Wound Healing and Inflammation

Mouse models are widely used to study pathogenesis of human diseases and to evaluate diagnostic procedures as well as therapeutic interventions preclinically. However, valid assessment of pathological alterations often requires histological analysis, and when performed ex vivo, necessitates death of the animal. Therefore in conventional experimental settings, intra-individual follow-up examinations are rarely possible. Thus, development of murine endoscopy in live mice enables investigators for the first time to both directly visualize the gastrointestinal mucosa and also repeat the procedure to monitor for alterations. Numerous applications for in vivo murine endoscopy exist, including studying intestinal inflammation or wound healing, obtaining mucosal biopsies repeatedly, and to locally administer diagnostic or therapeutic agents using miniature injection catheters. Most recently, molecular imaging has extended diagnostic imaging modalities allowing specific detection of distinct target molecules using specific photoprobes. In conclusion, murine endoscopy has emerged as a novel cutting-edge technology for diagnostic experimental in vivo imaging and may significantly impact on preclinical research in various fields.

Murine Endoscopy for In Vivo Multimodal Imaging of Carcinogenesis and Assessment of Intestinal Wound Healing and Inflammation

Small animal imaging techniques allow serial diagnostic examinations and therapeutic interventions in vivo. Recently, the scope of applications has significantly widened and currently includes assessment of colonic tumor development, wound healing and monitoring of inflammation. This protocol illustrates these diverse potential applications of murine endoscopy.

Mouse models are widely used to study pathogenesis of human diseases and to evaluate diagnostic procedures as well as therapeutic interventions ...

Investigating Intestinal Inflammation in DSS-induced Model of IBD

Inflammatory bowel disease (IBD) encompasses a range of intestinal pathologies, the most common of which are ulcerative colitis (UC) and Crohn's Disease (CD). Both UC and CD, when present in the colon, generate a similar symptom profile which can include diarrhea, rectal bleeding, abdominal pain, and weight loss.1 Although the pathogenesis of IBD remains unknown, it is described as a multifactorial disease that involves both genetic and environmental components.2
There are numerous and variable animal models of colonic inflammation that resemble several features of IBD. Animal models of colitis range from those arising spontaneously in susceptible strains of certain species to those requiring administration of specific concentrations of colitis-inducing chemicals, such as dextran sulphate sodium (DSS). Chemical-induced models of gut inflammation are the most commonly used and best described models of IBD. Administration of DSS in drinking water produces acute or chronic colitis depending on the administration protocol.3 Animals given DSS exhibit weight loss and signs of loose stool or diarrhea, sometimes with evidence of rectal bleeding.4,5 Here, we describe the methods by which colitis development and the resulting inflammatory response can be characterized following administration of DSS. These methods include histological analysis of hematoxylin/eosin stained colon sections, measurement of pro-inflammatory cytokines, and determination of myeloperoxidase (MPO) activity, which can be used as a surrogate marker of inflammation.6
The extent of the inflammatory response in disease state can be assessed by the presence of clinical symptoms or by alteration in histology in mucosal tissue. Colonic histological damage is assessed by using a scoring system that considers loss of crypt architecture, inflammatory cell infiltration, muscle thickening, goblet cell depletion, and crypt abscess.7 Quantitatively, levels of pro-inflammatory cytokines with acute inflammatory properties, such as interleukin (IL)-1&beta;, IL-6 and tumour necrosis factor (TNF)-&alpha;,can be determined using conventional ELISA methods. In addition, MPO activity can be measured using a colorimetric assay and used as an index of inflammation.8
In experimental colitis, disease severity is often correlated with an increase in MPO activity and higher levels of pro-inflammatory cytokines. Colitis severity and inflammation-associated damage can be assessed by examining stool consistency and bleeding, in addition to assessing the histopathological state of the intestine using hematoxylin/eosin stained colonic tissue sections. Colonic tissue fragments can be used to determine MPO activity and cytokine production. Taken together, these measures can be used to evaluate the intestinal inflammatory response in animal models of experimental colitis.

Experimental models of inflammatory bowel disease have allowed us to examine the complex innate and adaptive immune responses associated with pathogenesis. Using histological scoring, quantification of pro-inflammatory cytokines and myeloperoxidase activity, one can begin to assess these responses seen in inflammatory bowel disease.

Inflammatory bowel disease (IBD) encompasses a range of intestinal pathologies, the most common of which are ulcerative colitis (UC) and Crohn's Disease ...

Using Robotic Systems to Process and Embed Colonic Murine Samples for Histological Analyses

The understanding of human diseases has been greatly expanded thanks to the study of animal models. Nonetheless, histopathological evaluation of experimental models needs to be as rigorous as that applied for human samples. Indeed, drawing reliable and accurate conclusions is critically influenced by the quality of tissue section preparation. Here, we describe a protocol for histopathological analysis of murine tissues that implements several automated steps during the procedure, from the initial preparation to the paraffin embedding of the murine samples. The reduction of methodological variables through rigorous protocol standardization from automated procedures contributes to increased overall reliability of murine pathological analysis. Specifically, this protocol describes the utilization of automated processing and embedding robotic systems, routinely used for the tissue processing and paraffin embedding of human samples, to process murine specimens of intestinal inflammation. We conclude that the reliability of histopathological examination of murine tissues is significantly increased upon introduction of standardized and automated techniques.

Lack of standardization for murine tissue processing reduces the quality of murine histopathological analysis as compared to human specimens. Here, we present a protocol to perform histopathological examination of murine inflamed and uninflamed colonic tissues to show the feasibility of robotic systems routinely used for processing and embedding&#160;human samples.

The understanding of human diseases has been greatly expanded thanks to the study of animal models. Nonetheless, histopathological evaluation of ...

Effects of Taste Signaling Protein Abolishment on Gut Inflammation in an Inflammatory Bowel Disease Mouse Model

Inflammatory bowel disease (IBD) is one of the immune-related gastrointestinal disorders, including ulcerative colitis and Crohn's disease, that affects the life quality of millions of people worldwide. IBD symptoms include abdominal pain, diarrhea, and rectal bleeding, which may result from the interactions among gut microbiota, food components, intestinal epithelial cells, and immune cells. It is of particular importance to assess how each key gene expressed in intestinal epithelial and immune cells affects inflammation in the colon. G protein-coupled taste receptors, including G protein subunit &#945;-gustducin and other signaling proteins, have been found in the intestines. Here, we use &#945;-gustducin as a representative and describe a dextran sulfate sodium (DSS)-induced IBD model to evaluate the effect of gustatory gene mutations on gut mucosal immunity and inflammation. This method combines gene knockout technology with the chemically induced IBD model, and thus can be applied to assess the outcome of gustatory gene nullification as well as other genes that may exuberate or dampen the DSS-induced immune response in the colon. Mutant mice are administered with DSS for a certain period during which their body weight, stool, and rectal bleeding are monitored and recorded. At different timepoints during administration, some mice are euthanized, then the sizes and weights of their spleens and colons are measured and gut tissues are collected and processed for histological and gene expression analyses. The data show that the &#945;-gustducin knockout results in excessive weight loss, diarrhea, intestinal bleeding, tissue damage, and inflammation vs. wild-type mice. Since the severity of induced inflammation is affected by mouse strains, housing environment, and diet, optimization of DSS concentration and administration duration in a pilot experiment is particularly important. By adjusting these factors, this method can be applied to assess both anti- and pro-inflammatory effects.

Here we present a protocol to investigate the effect of the nullification of gustation-related genes on immune responses in a dextran sulfate sodium (DSS)-induced inflammatory bowel disease (IBD) mouse model.

Inflammatory bowel disease (IBD) is one of the immune-related gastrointestinal disorders, including ulcerative colitis and Crohn's disease, that affects ...

Fluorescence-mediated Tomography for the Detection and Quantification of Macrophage-related Murine Intestinal Inflammation

Murine models of disease are indispensable to scientific research. However, many diagnostic tools such as endoscopy or tomographic imaging are not routinely employed in animal models. Conventional experimental readouts often rely on post mortem and ex vivo analyses, which prevent intra-individual follow-up examinations and increase the number of study animals needed. Fluorescence-mediated tomography enables the non-invasive, repetitive, quantitative, three-dimensional assessment of fluorescent probes. It is highly sensitive and permits the use of molecular makers, which allows for the specific detection and characterization of distinct molecular targets. In particular, targeted probes represent an innovative tool for analyzing gene activation and protein expression in inflammation, autoimmune disease, infection, vascular disease, cell migration, tumorigenesis, etc. In this article, we provide step-by-step instructions on this sophisticated imaging technology for the in vivo detection and characterization of inflammation (i.e., F4/80-positive macrophage infiltration) in a widely used murine model of intestinal inflammation. This technique might also be used in other research areas, such as immune cell or stem cell tracking.

Target-specific probes represent an innovative tool for analyzing molecular mechanisms, such as protein expression in various types of disease (e.g., inflammation, infection, and tumorigenesis). In this study, we describe a quantitative three-dimensional tomographic assessment of intestinal macrophage infiltration in a murine model of colitis using F4/80-specific fluorescence-mediated tomography.

Murine models of disease are indispensable to scientific research. However, many diagnostic tools such as endoscopy or tomographic imaging are not ...

Evaluation and Quantification of Micro Epithelial Gaps in the Colonic Mucosa using Immunofluorescence Staining

Epithelial cells lining the intestinal mucosa create a physical barrier that separates the luminal content from the interstitium. Epithelial barrier impairment has been associated with the development of various pathologies such as inflammatory bowel diseases (IBD). In the inflamed mucosa, superficial erosions or micro-erosions that corrupt epithelial monolayers correspond to sites of high permeability. Several mechanisms have been implicated in the formation of micro-erosions including cell shedding and apoptosis. These micro-erosions often represent microscopic epithelial gaps randomly distributed in the colon. Visualization and quantification of those epithelial gaps has emerged as an important tool to investigate intestinal epithelial barrier function. Here, we describe a new method to visualize the specific location of where transcellular and paracellular permeability is enhanced in the inflamed colonic mucosa. In this assay, we apply a 10 kDa fluorescent dye conjugated to a lysine fixable dextran to visualize high permeability regions (HPR) in the colonic mucosa. Additional use of cell death markers revealed that HPR encompass apoptotic foci where epithelial extrusion/shedding occurs. The protocol described here provides a simple but effective approach to visualize and quantify micro-erosions in the intestine, which is a very useful tool in disease models, in which the intestinal epithelial barrier is compromised.

Here, we describe a new method to visualize the specific location of where transcellular and paracellular permeability is enhanced in the inflamed colonic mucosa. In this assay, we apply a 10 kDa fluorescent dye conjugated to a lysine fixable dextran to visualize high permeability regions (HPR) in the colonic mucosa.

Epithelial cells lining the intestinal mucosa create a physical barrier that separates the luminal content from the interstitium. Epithelial barrier ...

Hematoxylin and Eosin Staining to Assess Colon Damage in DSS-Induced Colitis

Source: Du, Y., et al. <a href="https://app.jove.com/v/58668">Effects of Taste Signaling Protein Abolishment on Gut Inflammation in an Inflammatory Bowel Disease Mouse Model.</a> J. Vis. Exp. (2018)
This video demonstrates the hematoxylin and eosin (H&#38;E) staining method to evaluate colon damage in a murine model of DSS-induced colitis &#8212; an inflammatory bowel disease. Upon isolating the colon from a DSS-treated mouse and obtaining sections of the tissue, H&#38;E staining of the sections helps identify the inflammation-mediated tissue damage.

Source: Du, Y., et al. Effects of Taste Signaling Protein Abolishment on Gut Inflammation in an Inflammatory Bowel Disease Mouse Model. J. Vis. Exp. ...

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Immunology

Immune Response

Host-Pathogen Interaction

A Technique to Generate a Murine Model of Dextran Sulfate Sodium-Induced Colitis

Source: Du, Y., et al. <a href="https://app.jove.com/v/58668">Effects of Taste Signaling Protein Abolishment on Gut Inflammation in an Inflammatory Bowel Disease Mouse Model.</a> J. Vis. Exp. (2018)
This video demonstrates a technique to generate a chemical-induced murine model of colitis &#8212; an inflammatory bowel disease. The mouse is allowed to consume a dextran sodium sulfate (DSS) solution for an adequate duration. Upon consumption, DSS damages the mucus and epithelial layer barrier in the colon, allowing gut microbes to enter the underlying tissue &#8212; where they are sensed by the resident immune cells to mediate an exaggerated immune response, resulting in inflammation.

Systematic Scoring Analysis for Intestinal Inflammation in a Murine Dextran Sodium Sulfate-Induced Colitis Model

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