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 ...

<ol>
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F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chemically+induced+mouse+models+of+intestinal+inflammation.">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/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+entirely+automated+method+to+score+DSS-induced+colitis+in+mice+by+digital+image+analysis+of+pathology+slides.">An entirely automated method to score DSS-induced colitis in mice by digital image analysis of pathology slides.</a> Disease Models &amp; Mechanisms. 6 (3), 855-865 (2013).</li><li>Perse, M., Cerar, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dextran+sodium+sulphate+colitis+mouse+model:+traps+and+tricks.">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/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Animal+models+of+inflammatory+bowel+disease.">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/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Desmocollin-2+promotes+intestinal+mucosal+repair+by+controlling+integrin-dependent+cell+adhesion+and+migration.">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. 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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 border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Aperio AT2 &#8211; 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 &#38; 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. ...

The systematic scoring analysis is a technique for evaluating mucosal injury, facilitating histological interpretation that can be performed by trained researchers. The main advantages of this method is that it's free and easy to use. It allows for quantitative analysis of histological data obtained from the intestines of mice with colitis.This protocol provides a rapid and reproducible way to interpret disease severity of the entire colon, which is necessary for comparing disease from animals of different genetic backgrounds. For tissue preparation, it's important to organize all reagents and materials. Begin by placing a euthanized mouse on a dissecting pad in a supine position and immobilize the mouse extremities using 20 gauge 1.5 inch needles.Using forceps and scissors, make a small incision on the abdominal skin and pull it to the side to expose the peritoneum, then open the abdominal cavity with a midline incision in the peritoneum from the pubic bone to the sides of the abdomen. Carefully remove tissues and organs until the 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.Gently remove fat, small veins, and arteries attached to the colon while carefully dissecting the organ, cutting just proximal to the anus and distal to the cecum. Carefully flush the colon with PBS to remove fecal contents using a flexible plastic gavage needle inserted through the anus. 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. Use half of the tissue for histological analysis and the other half for Western blot, PCR, or rolled into a second Swiss roll for fresh frozen immunofluorescence microscopy. Trim extra tissue from the proximal colon with a razor blade until approximately the same width along the length of the whole colon is obtained.Align the colon to expose the lumen and flatten the tissue completely using a flexible gavage needle. Add more PBS if needed to keep the tissue moist throughout the procedure. Remove the excess PBS using a paper wipe.With a syringe and gavage needle, add 10%neutral buffered formalin solution for two to three minutes to fix and flatten the tissue, then use straight forceps to grab the end of the distal colon and twist the colon into concentric circles from the distal to proximal end. Insert a 27 gauge needle to pin the colon in the middle and hold its Swiss roll shape, then place the Swiss roll into an embedding cassette inside a histological specimen container orienting the tissue in parallel with respect to the cassette. Fix the tissue in 10%neutral buffered formalin solution overnight at four degrees Celsius.After overnight fixation, wash the tissue three times with PBS. Add 70%ethanol prior to the paraffin embedding process and remove the needle from the Swiss roll before proceeding. The tissue can be stored in ethanol at room temperature until paraffin embedment.After opening the scanned images in the image processing software, verify that the entire colon is visible and that there are no missing areas of the sample. Activate the label imager and scale bar tools to properly identify scanned slides by clicking label imager. Open the annotations tool by clicking annotations and create three different layers by clicking new layer to quantify the total length of the Swiss roll, inflammation or injury, and erosion or ulceration.Choose a different color for each layer by clicking layer color. Measure the length of each layer or category by clicking the pen tool to draw a line following the muscularis mucosa, moving the pointer as needed to visualize the adjacent area for analysis. View the image at 400 micrometer zoom to facilitate adequate visualization of the muscularis mucosa.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. Review the total length, inflammation or injury, and erosion or ulceration measured using the muscularis mucosa as a reference.Once all layers are defined, export the data using the export grid to text file button inside the layer regions options. Open the text files and copy the data to a spreadsheet software. Total all the segments from each region and calculate the percentage of injury and ulceration with respect to total length.Consider three main characteristics to calculate the histological colitis score and to evaluate the severity of disease. 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. Next, check for inflammation or injury, which is characterized by epithelial crypts that are attenuated or partially missing epithelial cells and mucosal inflammation with neutrophil infiltration into crypts.Finally, check for the presence of erosion or ulceration, which is characterized by areas devoid of surface epithelium or areas completely lacking epithelium crypts with or without associated leukocytes. To illustrate the reliability of this histological colitis score analysis in the context of mucosal damage, 2.5%DSS was administered in the drinking water of eight C57BL6 wild-type mice for five days, followed by a recovery period with regular water for five days. Body weight remained constant during the acute administration of DSS, but dramatically decreased when mice started drinking regular tap water.Blood and soft stools appeared after three days of DSS administration and continued until day eight of the experiment. These observations suggested that the most detrimental effects of exposure to DSS were observed during the recovery period between days five and eight. Measurement of colon length on day 10 confirmed a significant shortening at the end of the experiment.Colons were harvested at day zero, two, five, seven, eight, and 10 to make paraffin Swiss rolls. The tissue was stained with H&E and high definition scans were analyzed to calculate the histological colitis score and percentage of injury and ulceration. Normal crypt architecture was observed in untreated mice.After two days of DSS administration, immune cell recruitment was observed. On day five, epithelial cells appear damaged and there was an infiltration of neutrophils across the epithelium associated with epithelial injury. From day five to eight, areas of epithelial loss with inflammation and ulceration were observed.On day 10, epithelial cells began to regenerate and repopulate ulcerated areas, slowly restoring colonic mucosa. When attempting this protocol, it is important to create a properly oriented and well-preserved Swiss roll, as well as to correctly identify mucosal inflammation or injury and ulceration or erosion. This method can be used to quantitatively evaluate injury along the entire length of the colonic mucosa in other models of colitis, such as TMS or T-cell transfer model.

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Research

JoVE Journal

Immunology and Infection

8.7K visualizações.  University of Michigan. A análise sistemática de pontuação é uma técnica para avaliar lesões mucosas, facilitando a interpretação histológica que pode ser realizada por pesquisadores treinados. As principais vantagens deste método é que ele é livre e fácil de usar. Permite a análise quantitativa dos dados histológicos obtidos dos intestinos de camundongos com colite.Este protocolo fornece uma maneira rápida e reprodutível de interpretar a gravidade da doença de todo o cólon, o que é neces...