All methods described here have been approved by the veterinary government authority (Landesamt f&#252;r Landwirtschaft, Lebensmittelsicherheit und Fischerei Mecklenburg-Vorpommern, (LALLF M-V)).
1. Preoperative Care and Preparation of the Animal
<ol>
	<li>Upon arrival in the animal facility, divide animals (C57Bl/6) into groups of similar size, cage each group together, and keep groups constant throughout the experiments. 
	NOTE: Use animals of the same sex. The results described were obtained with male mice. 
	NOTE: If male animals are used, cage groups together starting when they are 7 weeks of age so that a hierarchy can be established, thus minimizing the risk of aggressive behavior during experiments.</li>
	<li>At least one week before surgery, switch to a high energy (&#62;14 MJ/kg) and high protein (&#62;20%) feed containing all the essential trace elements and vitamins (for details, see list of materials). 
	NOTE: Assure all mice weigh at least 25 g when surgery is performed.</li>
	<li>Induce anaesthesia and analgesia by intraperitoneal injection of ketamine (87 mg/kg i.p.) and xylazine hydrochloride (13 mg/kg i.p.).&#160;Wait until the mouse tolerates mechanical stimulation, e.g. toe pitch, without motor response.</li>
	<li>Secure the narcotized mouse with tapes in a supine position on a heat underlay positioned at the operation desk, guaranteeing stable positioning during operation and avoiding an overwhelming loss of body heat. 
	NOTE: The heat underlay should have a surface temperature of 36 &#176;C to 40 &#176;C; the operating room temperature should be 21 &#176;C.</li>
</ol>
2. Distal Colostomy Operation
<ol>
	<li>Shave the abdominal hair. Before starting surgery, disinfect the operation field three times using alcohol 70% and an iodophor. Drape the operation field to guarantee for aseptic conditions.</li>
	<li>Perform a 15-mm median laparotomy by incising the abdominal muscles and the peritoneum along the linea alba, thus minimizing blood loss.</li>
	<li>Use two DeBakey atraumatic forceps, carefully pull the cecum, terminal ileum, and ascending and transverse colon from the peritoneal cavity. 
	NOTE: Be careful to strictly limit mechanical manipulation of the intestine to prevent injury to mesenteric structures.</li>
	<li>Identify the cecal pole, the ascending colon, and small intestine (Figures 1a and 1b). 
	NOTE: Correct identification of the ascending colon is fundamental for correct placement of the colostomy. In cases where the anatomy of the ileocecal region is ambiguous, the presence of Peyer&#39;s patches identifies the small intestine, and the presence of formed stool characterizes the colon.</li>
	<li>Use a ruler to determine the position of the future colostomy. It should be placed 20 mm distal to the ileocecal valve for a distal colostomy.</li>
	<li>Make a second 3-mm incision in the abdominal wall in the upper right quadrant. Pull the previously identified colon segment through this incision to form a loop, being careful not to distort the loop.</li>
	<li>Carefully pass a 22-gauge flexible i.v. cannula through the mesocolon. Take care not to damage mesenteric vascular structures.</li>
	<li>Return the intestine to the peritoneal cavity.</li>
	<li>Fix both ends of the flexible tube to the skin using simple stitches and a resorbable suture (e.g., polyglactin 910 or polyfil 4-0 1/2c).</li>
	<li>Before closing the laparotomy, perform fluid resuscitation using an intraperitoneal injection of 0.5 mL 0.9% saline.</li>
	<li>Close the peritoneum and the muscle layer with a continuous suture using a resorbable suture (e.g., polyglactin 910 or polyfil 4-0 1/2c). Close the skin with a continuous suture using a resorbable suture (e.g., polyglactin 910 or polyfil 4-0 1/2c).</li>
	<li>Open the exteriorized colon loop by performing a subtotal transection using a fine scissor. Avoid all injury to the mesentery. Do not transect the colon completely.</li>
	<li>Fix each colostomy opening using three single full-thickness stitches to the peritoneum and skin using a monofil, absorbable suture (e.g., polydioxanone or monofil 6-0 3/8s). The afferent loop, which is a functional end-colostomy, and the efferent loop, which is a mucous fistula, are clearly separated at this point (Figure 1c). 
	NOTE: Operation time should be less than 20 minutes to limit fluid and thermal losses.</li>
	<li>After finishing surgery, disinfect instruments using an aldehyde-free disinfection solution in an ultrasonic bath according to the instructions of the manufacturer.</li>
</ol>
3. Sham Operation (Colotomy)
<ol>
	<li>Perform steps 1.1. through 2.4.</li>
	<li>Use a ruler to determine the future colotomy position. The colotomy should be positioned the same distance from the ileocecal valve as the colostomy in the experimental group.</li>
	<li>Open the colon at least two-thirds its circumference using fine scissors.</li>
	<li>Close the colotomy with a single layer, full-thickness interrupted suture using a monofil, absorbable suture (e.g., polydioxanone, monofil 6-0 3/8s). 
	NOTE: Operation time should be less than 20 minutes for an experimented surgeon, limiting fluid and thermal losses.</li>
	<li>Perform steps 2.10. , 2.11. and 2.14.</li>
</ol>
4. Postoperative Care
<ol>
	<li>Return animals to their cages. Provide a well-tempered atmosphere of 37 &#176;C (e.g., with an infrared lamp) until mice are fully awake. Then, keep mice in a temperature- and humidity-regulated environment (21 &#176;C; 30% &#177; 10% relative humidity). Allow free access to food and drinking water. To facilitate fluid uptake, provide additional water-soaked animal feed.</li>
	<li>Start postoperative analgesia by injecting 0.1 mg/kg body weight buprenorphine s.c. when animals show response to mechanical stimulation. Be careful to avoid respiratory depression.</li>
	<li>Supplement drinking water with 1 mg/mL tramadol for continued analgesia during the first postoperative week.</li>
	<li>To compensate for decreased fluid intake due to reduced mobility, supply a Solid Drink Pad in the cage during the first postoperative week.</li>
	<li>Weigh the animals and score animal behavior daily during the first week, every second day during remainder of the first month, and every third day during the second month using the disease severity score described in Kleinwort et al.6.</li>
</ol>

<ol><li>Glotzer, D. J., Glick, M. E., Goldman, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Proctitis+and+colitis+following+diversion+of+the+fecal+stream%5BTitle%5D)+AND+%22Gastroenterology%22%5BJournal%5D)">Proctitis and colitis following diversion of the fecal stream.</a> Gastroenterology. 80, 438-441 (1981).</li>
<li>Morson, B., Dawson, I. <a target="_blank" href="http://scholar.google.com/scholar?hl=en&safe=off&q=author%3aMorson%2C+B+%22Gastrointestinal+Pathology%22">Gastrointestinal Pathology</a>. , Blackwell Scientific Publications. London. (1972).</li>
<li>Whelan, R. L., Abramson, D., Kim, D. S., Hashmi, H. F. <a target="_blank" href="https://www.ncbi.nlm.nih.gov/pubmed/8153859">Diversion colitis. A prospective study.</a> Surg Endosc. 8, 19-24 (1994).</li>
<li>Haas, P. A., Fox, T. A., Szilagy, E. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Endoscopic+examination+of+the+colon+and+rectum+distal+to+a+colostomy%5BTitle%5D)+AND+%22Am+J+Gastroenterol%22%5BJournal%5D)">Endoscopic examination of the colon and rectum distal to a colostomy.</a> Am J Gastroenterol. 85, 850-854 (1990).</li>
<li>Valatas, V., Bamias, G., Kolios, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Experimental+colitis+models%3A+Insights+into+the+pathogenesis+of+inflammatory+bowel+disease+and+translational+issues%5BTitle%5D)+AND+%22Eur+J+Pharmacol%22%5BJournal%5D)">Experimental colitis models: Insights into the pathogenesis of inflammatory bowel disease and translational issues.</a> Eur J Pharmacol. 759, 253-264 (2015).</li>
<li>Kleinwort, A., Döring, P., Hackbarth, C., Heidecke, C. D., Schulze, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Deviation+of+the+Fecal+Stream+in+Colonic+Bowel+Segments+Results+in+Increased+Numbers+of+Isolated+Lymphoid+Follicles+in+the+Submucosal+Compartment+in+a+Novel+Murine+Model+of+Diversion+Colitis%5BTitle%5D)+AND+%22Biomed+Res+Int%22%5BJournal%5D)">Deviation of the Fecal Stream in Colonic Bowel Segments Results in Increased Numbers of Isolated Lymphoid Follicles in the Submucosal Compartment in a Novel Murine Model of Diversion Colitis.</a> Biomed Res Int. 2017, 13(2017).</li>
<li>Tangjarukij, C., Navasumrit, P., Zelikoff, J. T., Ruchirawat, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((The+effects+of+pyridoxine+deficiency+and+supplementation+on+hematological+profiles%2C+lymphocyte+function%2C+and+hepatic+cytochrome+P450+in+B6C3F1+mice%5BTitle%5D)+AND+%22J+Immunotoxicol%22%5BJournal%5D)">The effects of pyridoxine deficiency and supplementation on hematological profiles, lymphocyte function, and hepatic cytochrome P450 in B6C3F1 mice.</a> J Immunotoxicol. 6, 147-160 (2009).</li>
<li>Soave, O., Brand, C. D. <a target="_blank" href="https://www.ncbi.nlm.nih.gov/pubmed/1954740">Coprophagy in animals: a review.</a> Cornell Vet. 81, 357-364 (1991).</li>
<li>Ebino, K. Y., Yoshinaga, K., Suwa, T., Kuwabara, Y., Takahashi, K. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Effects+of+prevention+of+coprophagy+on+pregnant+mice--is+coprophagy+beneficial+on+a+balanced+diet%5BTitle%5D)+AND+%22Jikken+Dobutsu%22%5BJournal%5D)">Effects of prevention of coprophagy on pregnant mice--is coprophagy beneficial on a balanced diet.</a> Jikken Dobutsu. 38, 245-252 (1989).</li>
<li>Babickova, J., Tothova, L., Lengyelova, E., Bartonova, A., Hodosy, J., Gardlik, R., Celec, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Sex+Differences+in+Experimentally+Induced+Colitis+in+Mice%3A+a+Role+for+Estrogens%5BTitle%5D)+AND+%22Inflammation%22%5BJournal%5D)">Sex Differences in Experimentally Induced Colitis in Mice: a Role for Estrogens.</a> Inflammation. 38, 1996-2006 (2015).</li>
<li>Lee, S. M., Kim, N., Son, H. J., Park, J. H., Nam, R. H., Ham, M. H., Choi, D., Sohn, S. H., Shin, E., Hwang, Y. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((The+Effect+of+Sex+on+the+Azoxymethane%2FDextran+Sulfate+Sodium-treated+Mice+Model+of+Colon+Cancer%5BTitle%5D)+AND+%22J+Cancer+Prev%22%5BJournal%5D)">The Effect of Sex on the Azoxymethane/Dextran Sulfate Sodium-treated Mice Model of Colon Cancer.</a> J Cancer Prev. 21, 271-278 (2016).</li>
<li>Angele, M. K., Pratschke, S., Hubbard, W. J., Chaudry, I. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Gender+differences+in+sepsis%3A+cardiovascular+and+immunological+aspects%5BTitle%5D)+AND+%22Virulence%22%5BJournal%5D)">Gender differences in sepsis: cardiovascular and immunological aspects.</a> Virulence. 5, 12-19 (2013).</li>
<li>Brown, R. Z. <a target="_blank" href="http://onlinelibrary.wiley.com/doi/10.2307/1943592/abstract">Social Behaviour, reproduction, and population changes in the house mouse (Mus musculus L).</a> Eccological Monographs. 23, 788-795 (1953).</li>
<li>Poole, T. B., Morgan, H. D. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Differences+in+aggressive+behaviour+betweeen+male+mice+%28Mus+musculus+L.%29+in+colonies+of+different+sizes%5BTitle%5D)+AND+%22Animal+Behaviour%22%5BJournal%5D)">Differences in aggressive behaviour betweeen male mice (Mus musculus L.) in colonies of different sizes.</a> Animal Behaviour. 21, 788-795 (1973).</li>
<li>Pasquarelli, N., Voehringer, P., Henke, J., Ferger, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Effect+of+a+change+in+housing+conditions+on+body+weight%2C+behavior+and+brain+neurotransmitters+in+male+C57BL%2F6J+mice%5BTitle%5D)+AND+%22Behav+Brain+Res%22%5BJournal%5D)">Effect of a change in housing conditions on body weight, behavior and brain neurotransmitters in male C57BL/6J mice.</a> Behav Brain Res. 333, 35-42 (2017).</li>
<li>Langgartner, D., Foertsch, S., Fuchsl, A. M., Reber, S. O. <a target="_blank" href="https://www.ncbi.nlm.nih.gov/pubmed/27788633">Light and water are not simple conditions: fine tuning of animal housing in male C57BL/6 mice.</a> Stress. 20, 10-18 (2017).</li>
<li>Nicholson, A., Malcolm, R. D., Russ, P. L., Cough, K., Touma, C., Palme, R., Wiles, M. V. <a target="_blank" href="https://www.ncbi.nlm.nih.gov/pubmed/19930822">The response of C57BL/6J and BALB/cJ mice to increased housing density.</a> J Am Assoc Lab Anim Sci. 48, 740-753 (2009).</li>
<li>Buchler, G., Wos-Oxley, M. L., Smoczek, A., Zschemisch, N. H., Neumann, D., Pieper, D. H., Hedrich, H. J., Bleich, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Strain-specific+colitis+susceptibility+in+IL10-deficient+mice+depends+on+complex+gut+microbiota-host+interactions%5BTitle%5D)+AND+%22Inflamm+Bowel+Dis%22%5BJournal%5D)">Strain-specific colitis susceptibility in IL10-deficient mice depends on complex gut microbiota-host interactions.</a> Inflamm Bowel Dis. 18, 943-954 (2012).</li>
<li>Nakanishi, M., Tazawa, H., Tsuchiya, N., Sugimura, T., Tanaka, T., Nakagama, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Mouse+strain+differences+in+inflammatory+responses+of+colonic+mucosa+induced+by+dextran+sulfate+sodium+cause+differential+susceptibility+to+PhIP-induced+large+bowel+carcinogenesis%5BTitle%5D)+AND+%22Cancer+Sci%22%5BJournal%5D)">Mouse strain differences in inflammatory responses of colonic mucosa induced by dextran sulfate sodium cause differential susceptibility to PhIP-induced large bowel carcinogenesis.</a> Cancer Sci. 98, 1157-1163 (2007).</li>
<li>Mahler, M., Bristol, I. J., Leiter, E. H., Workman, A. E., Birkenmeier, E. H., Elson, C. O., Sundberg, J. P. <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+%22Am+J+Physiol%22%5BJournal%5D)">Differential susceptibility of inbred mouse strains to dextran sulfate sodium-induced colitis.</a> Am J Physiol. 274, 544-551 (1998).</li>
<li>Mekada, K., Abe, K., Murakami, A., Nakamura, S., Nakata, H., Moriwaki, K., Obata, Y., Yoshiki, A. <a target="_blank" href="https://www.ncbi.nlm.nih.gov/pubmed/19448337">Genetic differences among C57BL/6 substrains.</a> Exp Anim. 58, 141-149 (2009).</li>
<li>Sellers, R. S., Clifford, C. B., Treuting, P. M., Brayton, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Immunological+variation+between+inbred+laboratory+mouse+strains%3A+points+to+consider+in+phenotyping+genetically+immunomodified+mice%5BTitle%5D)+AND+%22Vet+Pathol%22%5BJournal%5D)">Immunological variation between inbred laboratory mouse strains: points to consider in phenotyping genetically immunomodified mice.</a> Vet Pathol. 49, 32-43 (2012).</li>
<li>Mills, C. D., Kincaid, K., Alt, J. M., Heilman, M. J., Hill, A. M. <a target="_blank" href="https://www.ncbi.nlm.nih.gov/pubmed/10843666">M-1/M-2 macrophages and the Th1/Th2 paradigm.</a> J Immunol. 164, 6166-6173 (2000).</li>
</ol>

All authors declare that they have no competing interests.

The murine model of DC presented in this protocol reliably reproduces the histopathological features of human DC (e.g., de novo development of lymphoid follicles in the submucosa of inflamed bowel segments, crypt shortening, and reductions in goblet cell numbers). Aside from this advantage, this model is induced by a very similar triggering factor and presents with a clinical course of moderate to mild severity as is the case in most affected humans.
To obtain reproducible re...

In recent years, a substantial number of non-infectious colitis entities different from classical inflammatory bowel diseases (IBDs; i.e., Crohn&#39;s disease or colitis ulcerosa) have been clinically and histopathologically characterized in humans. The pathophysiological mechanisms leading to the development of these colitis forms are not completely understood partially because appropriate animal models are scarce. Diversion colitis is one of these recently described entities. Although the term was coined in 1980 by Glotzer1, the initial description of a similar phenotype was given in 1972 by Morson2. The disease develops in 50% to 91% of patients with diverting enterostomy, and its clinical intensity varies3,4. Given the annual incidence of around 120,000 colostomy patients in the United States of America, this disease entity constitutes an important health problem.
The overall goal of developing this protocol was to provide a murine DC model that relies on a colitis trigger similar to that seen in human DC and that reproduces the primary histopathological features of the human disease. In contrast to other murine colitis models, colitis induction in our model does not require genetically modified animals (e.g., IL-7 transgenic mice, N-cadherin dominant negative mice, or TGF&#946;-/- mice), the application of chemically irritating substances (e.g., dextran sulfate sodium (DSS)-induced colitis, or trinitrobenzene sulfonic acid (TNBS)-induced colitis), or the transfer of specific cell populations in immune deficient mice (as in the CD45RBhigh transfer model of colitis) (for a review, see5). In contrast to other models, the intact immune system of our DC model allows assessment of the immunological mechanism involved in DC development. The limitation of mucosal inflammation to the excluded bowel segment allows assessment of its repercussion on mucosal immunity in other parts of the gastrointestinal tract, on the immune homeostasis in other immune compartments of the intestinal tract (e.g., Peyer&#39;s patches and mesenteriale lymph nodes), and on the immune homeostasis of the entire organism. Finally, our model constitutes an appropriate tool for investigating the mechanisms controlling local inflammatory stimuli originating from changes in the normal local environment for both the local microbiome as well as alimentary antigens.

<table><tbody><tr><td>&lt;em&gt;Operation material&lt;/em&gt;</td><td></td><td></td><td></td></tr><tr><td>heat underlay, 6 watt</td><td>ThermoLux, Witte + Sutor GmbH</td><td>461265</td><td></td></tr><tr><td>Ethanol 70% (with methylethylketon)</td><td>Pharmacie of the University Hospital Greifswald</td><td></td><td></td></tr><tr><td>Wooden applicators, small cotton head onesided, wooden stick, 150 mm length</td><td>Centramed GmbH, Germany</td><td>8308370</td><td>for disinfection of operation field</td></tr><tr><td>Scissor</td><td>Aesculap (BRAUN)</td><td>BC064R</td><td></td></tr><tr><td>Atraumatic DeBakey forceps</td><td>Aesculap (BRAUN)</td><td>OC021R</td><td></td></tr><tr><td>Needle holder</td><td>Aesculap (BRAUN)</td><td>BM012R</td><td></td></tr><tr><td>Vasofix Safety &lt;em&gt;i.v.&lt;/em&gt; cannula 22G</td><td>Braun Melsungen AG, Germany</td><td>4268091S-01</td><td></td></tr><tr><td>VICRYL Plus 4-0 violet braided; V-5 17 m 1/2c; 70 cm</td><td>ETHICON, Inc.</td><td>VCP994H</td><td></td></tr><tr><td>PDS II 6-0 monofil; V-18 13 mm 3/8c; 70 cm</td><td>ETHICON, Inc.</td><td>Z991H</td><td></td></tr><tr><td>BD Plastipak 1 mL (Syringes with needle with sterile interior)</td><td>BD Medical</td><td>305501</td><td></td></tr><tr><td>Triacid-N (N-Dodecylpropan-1,3-diamin)</td><td>ANTISEPTICA, Germany</td><td>18824-01</td><td>disinfection of surgical instruments in ultrasonic bath</td></tr><tr><td>&lt;em&gt;Medications&lt;/em&gt;</td><td></td><td></td><td></td></tr><tr><td>ketamine 10%, 100 mg/mL (ketamine hydrochloride)</td><td>selectavet, Dr. Otto Fischer GmbH</td><td>9089.01.00</td><td>87 mg/kg &lt;em&gt;i.p.&lt;/em&gt;</td></tr><tr><td>Xylasel, 20 mg/mL (xylazine hydrochloride)</td><td>selectavet, Dr. Otto Fischer GmbH</td><td>400300.00.00</td><td>13 mg/kg &lt;em&gt;i.p.&lt;/em&gt;</td></tr><tr><td>NaCl 0.9%</td><td>Braun Melsungen AG, Germany</td><td>6697366.00.00</td><td></td></tr><tr><td>Buprenovet 0.3 mg/mL (buprenorphine)</td><td>Bayer, Germany</td><td>PZN: 01498870</td><td>0.1 mg/kg &lt;em&gt;s.c.&lt;/em&gt;</td></tr><tr><td>Tramal Drops, 100 mg/mL (tramadol hydrochloride)</td><td>Gr&amp;uuml;nenthal GmbH, Germany</td><td>10116838</td><td>1 mg/mL drinking water</td></tr><tr><td>Ceftriaxon-saar 2 g (ceftriaxone)&amp;nbsp;</td><td>Cephasaar GmbH, Germany</td><td>PZN: 08844252</td><td>25 mg/kg body weight &lt;em&gt;i.p.&lt;/em&gt;</td></tr><tr><td>metronidazole 5 mg/mL</td><td>Braun Melsungen AG, Germany</td><td>PZN: 05543515</td><td>12.5 mg/kg body weight &lt;em&gt;i.p.&lt;/em&gt;</td></tr><tr><td>&lt;em&gt;Food&lt;/em&gt;</td><td></td><td></td><td></td></tr><tr><td>ssniff M-Z Ereich</td><td>ssniff, Germany</td><td>&amp;nbsp;V1184-3</td><td></td></tr><tr><td>Solid Drink Dehyprev Vit BIO, pouches</td><td>TripleATrading, the Netherlands</td><td>SDSHPV-75</td><td></td></tr><tr><td>Equipment</td><td></td><td></td><td></td></tr><tr><td>Nikon Eclipse Ci-L</td><td>Nikon Instruments Europe BV, Germany</td><td></td><td>light microscopy</td></tr><tr><td>VetScan HM 5&amp;nbsp;</td><td>Abaxis, USA</td><td>770-9000</td><td>Veterinary hematology analyzer of 50 &amp;micro;l venous EDTA-blood</td></tr><tr><td>Bandelin SONOREX (Ultrasonic bath)</td><td>Bandelin electronics, Germany</td><td>RK 100 H</td><td>disinfection of surgical instruments</td></tr><tr><td>&lt;em&gt;Software&lt;/em&gt;</td><td></td><td></td><td></td></tr><tr><td>NIS-Element BR4 software</td><td>Nikon Instruments Europe BV, Germany</td><td></td><td></td></tr><tr><td>GraphPad Prism Version 6</td><td>GraphPad Software, Inc.</td><td></td><td></td></tr></tbody></table>

murine distal colostomy, a novel model of diversion colitis in c57bl/6 mice

Diversion colitis (DC) is a frequent clinical condition occurring in patients with bowel segments excluded from the fecal stream as a result of a diverting enterostomy. The etiology of this disease remains ill-defined but appears to differ from that of classical inflammatory bowel diseases such as Crohn's disease and ulcerative colitis. Research aimed to decipher the pathophysiological mechanisms leading to the development of this disease has been severely hampered by the lack of an appropriate murine model. This protocol generates a murine model of DC that facilitates the study of the immune system's role and its interaction with the microbiome in the development of DC. In this model using C57BL/6 animals, distal parts of the colon are excluded from the fecal stream by creating a distal colostomy, triggering the development of mild to moderate inflammation in the excluded bowel segments and reproducing the hallmark lesions of human DC with a moderate systemic inflammatory response. In contrast to the rat model, a large number of genetically-modified murine models on the C57BL/6 background are available. The combination of these animals with our model allows the potential roles of individual cytokines, chemokines, or receptors of bioactive molecules (e.g., interleukin (IL)-17; IL-10, chemokine CXCL13, chemokine receptors CXCR5 and CCR7, and the sphingosine-1-phosphate receptor 4) to be assessed in the pathogenesis of DC. The availability of congenic mouse strains on the C57BL/6 background largely facilitates transfer experiments to establish the roles of distinct cell types involved in the etiology of DC. Finally, the model offers the opportunity to assess the influences of local interventions (e.g., modification of the local microbiome or local anti-inflammatory therapy) on mucosal immunity in affected and non-affected bowel segments and the on systemic immune homeostasis.

Surgery is well tolerated both in the experimental (colostomy) and sham (colotomy) groups. Perioperative mortality should not exceed 10% when surgery and perioperative management is correctly performed. In the first postoperative week, significant weight loss is seen in both the experimental and sham groups. Animals of the sham group attain their weight nadir usually toward the fourth postoperative day, but it occurs one day later in the experimental group. Weight loss is more pronounced ...

Watch this Scientific Journal Video about Murine Distal Colostomy, A Novel Model of Diversion Colitis in C57BL/6 Mice at JoVE.com

Murine Distal Colostomy, A Novel Model of Diversion Colitis in C57BL/6 Mice

Murine distal colostomy provides a murine model for human diversion colitis, a predominantly lymphocytic colitis in colon segment excluded from the fecal stream.

Diversion colitis (DC) is a frequent clinical condition occurring in patients with bowel segments excluded from the fecal stream as a result of a ...

murine-distal-colostomy-novel-model-diversion-colitis-c57bl6

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JoVE Journal

Medicine

12.9K Views.  Universitätsmedizin Greifswald. Murine distal colostomy provides a murine model for human diversion colitis, a predominantly lymphocytic colitis in colon segment excluded from the fecal stream.

Video: Murine Distal Colostomy, A Novel Model of Diversion Colitis in C57BL/6 Mice

A Genetically Engineered Mouse Model of Sporadic Colorectal Cancer

Despite the advantages of easy applicability and cost-effectiveness, colorectal cancer mouse models based on tumor cell injection have severe limitations and do not accurately simulate tumor biology and tumor cell dissemination. Genetically engineered mouse models have been introduced to overcome these limitations; however, such models are technically demanding, especially in large organs such as the colon in which only a single tumor is desired.
As a result, an immunocompetent, genetically engineered mouse model of colorectal cancer was developed which develops highly uniform tumors and can be used for tumor biology studies as well as therapeutic trials. Tumor development is initiated by surgical, segmental infection of the distal colon with adeno-cre virus in compound conditionally mutant mice. The tumors can be easily detected and monitored via colonoscopy. We here describe the surgical technique of segmental adeno-cre infection of the colon, the surveillance of the tumor via high-resolution colonoscopy and present the resulting colorectal tumors.

A protocol for the establishment of a genetically engineered mouse model of colorectal cancer by segmental adeno-cre infection and its surveillance via high-resolution colonoscopy is presented.

Despite the advantages of easy applicability and cost-effectiveness, colorectal cancer mouse models based on tumor cell injection have severe limitations ...

Cancer Research

Modeling Colitis-Associated Cancer with Azoxymethane (AOM) and Dextran Sulfate Sodium (DSS)

Individuals with inflammatory bowel disease (IBD), such as Crohn's disease (CD) or ulcerative colitis (UC) are at increased risk of developing colorectal cancer (CRC) over healthy individuals. This risk is proportional to the duration and extent of disease, with a cumulative incidence as high as 30% in individuals with longstanding UC with widespread colonic involvement.1 Colonic dysplasia in IBD and colitis associated cancer (CAC) are believed to develop as a result of repeated cycles of epithelial cell injury and repair while these cells are bathed in a chronic inflammatory cytokine milieu.2 While spontaneous and colitis-associated cancers share the quality of being adenocarcinomas, the sequence of underlying molecular events is believed to be different.3 This distinction argues the need for specific animal models of CAC.
Several mouse models currently exist for the study of CAC. Dextran sulfate sodium (DSS), an agent with direct toxic effects on the colonic epithelium, can be administered in drinking water to mice in multiple cycles to create a chronic inflammatory state. With sufficient duration, some of these mice will develop tumors.4 Tumor development is hastened in this model if administered in a pro-carcinogenic setting. These include mice with genetic mutations in tumorigenesis pathways (APC, p53, Msh2), as well as mice pre-treated with genotoxic agents (azoxymethane [AOM], 1,2-dimethylhydrazine [DMH]).5 
The combination of DSS with AOM as a model for colitis associated cancer has gained popularity for its reproducibility, potency, low price, and ease of use. Though they have a shared mechanism, AOM has been found to be more potent and stable in solution than DMH. While tumor development in other models generally requires several months, mice injected with AOM and subsequently treated with DSS develop adequate tumors in as little as 7-10 weeks.6, 7 Finally, AOM and DSS can be administered to mice of any genetic background (knock out, transgenic, etc.) without cross-breeding to a specific tumorigenic strain. Here, we demonstrate a protocol for inflammation-driven colonic tumorigenesis in mice utilizing a single injection of AOM followed by three seven-day cycles of DSS over a 10 week period. This model induces tumors with histological and molecular changes closely resembling those occurring in human CAC and provides a highly valuable model for the study of oncogenesis and chemoprevention in this disease.8

Modeling Colitis-Associated Cancer with Azoxymethane AOM and Dextran Sulfate Sodium DSS

We demonstrate a protocol in which administration of the genotoxic agent azoxymethane (AOM) followed by three cycles of the pro-inflammatory agent dextran sulfate sodium (DSS) rapidly and consistently generates colon tumors in mice with morphologic and molecular similarities to those seen in human colitis-associated cancer.

Individuals with inflammatory bowel disease (IBD), such as Crohn's disease (CD) or ulcerative colitis (UC) are at increased risk of developing colorectal ...

The Citrobacter rodentium Mouse Model: Studying Pathogen and Host Contributions to Infectious Colitis

This protocol outlines the steps required to produce a robust model of infectious disease and colitis, as well as the methods used to characterize Citrobacter rodentium infection in mice. C. rodentium is a gram negative, murine specific bacterial pathogen that is closely related to the clinically important human pathogens enteropathogenic E. coli and enterohemorrhagic E. coli. Upon infection with C. rodentium, immunocompetent mice suffer from modest and transient weight loss and diarrhea. Histologically, intestinal crypt elongation, immune cell infiltration, and goblet cell depletion are observed. Clearance of infection is achieved after 3 to 4 weeks. Measurement of intestinal epithelial barrier integrity, bacterial load, and histological damage at different time points after infection, allow the characterization of mouse strains susceptible to infection.
The virulence mechanisms by which bacterial pathogens colonize the intestinal tract of their hosts, as well as specific host responses that defend against such infections are poorly understood. Therefore the C. rodentium model of enteric bacterial infection serves as a valuable tool to aid in our understanding of these processes. Enteric bacteria have also been linked to Inflammatory Bowel Diseases (IBDs). It has been hypothesized that the maladaptive chronic inflammatory responses seen in IBD patients develop in genetically susceptible individuals following abnormal exposure of the intestinal mucosal immune system to enteric bacteria. Therefore, the study of models of infectious colitis offers significant potential for defining potentially pathogenic host responses to enteric bacteria. C. rodentium induced colitis is one such rare model that allows for the analysis of host responses to enteric bacteria, furthering our understanding of potential mechanisms of IBD pathogenesis; essential in the development of novel preventative and therapeutic treatments.

The Citrobacter rodentium Mouse Model: Studying Pathogen and Host Contributions to Infectious Colitis

Citrobacter rodentium infection provides a valuable model to study enteric bacterial infections as well as host immune responses and colitis in mice. This protocol outlines the measurement of barrier integrity, pathogen load and histological damage allowing for the thorough characterization of pathogen and host contributions to murine infectious colitis.

This protocol  outlines the steps required to produce a robust model of infectious disease and  colitis, as well as the methods used to characterize ...

Immunology and Infection

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

Non-invasive Assessment of the Efficacy of New Therapeutics for Intestinal Pathologies Using Serial Endoscopic Imaging of Live Mice

Animal models of inflammatory bowel disease (IBD) and colorectal cancer (CRC) have provided significant insight into the cell intrinsic and extrinsic mechanisms that contribute to the onset and progression of intestinal diseases. The identification of new molecules that promote these pathologies has led to a flurry of activity focused on the development of potential new therapies to inhibit their function. As a result, various pre-clinical mouse models with an intact immune system and stromal microenvironment are now heavily used. Here we describe three experimental protocols to test the efficacy of new therapeutics in pre-clinical models of (1) acute mucosal damage, (2) chronic colitis and/or colitis-associated colon cancer, and (3) sporadic colorectal cancer. We also outline procedures for serial endoscopic examination that can be used to document the therapeutic response of an individual tumor and to monitor the health of individual mice. These protocols provide complementary experimental platforms to test the effectiveness of therapeutic compounds shown to be well tolerated by mice.

We describe methods for longitudinal monitoring of the efficacy of therapeutics for the treatment of colonic pathologies in mice using a rigid endoscope. This protocol can be readily used for the characterization of the therapeutic response of an individual tumor in live mice and also for monitoring potential disease relapse.

Animal models of inflammatory bowel disease (IBD) and colorectal cancer (CRC) have provided significant insight into the cell intrinsic and extrinsic ...

Creation of Colonic Anastomosis in Mice

Intestinal anastomoses are commonly performed in both elective and emergent operations. Even so, anastomotic leaks are a highly feared complications of colonic surgeries and can occur in up to 26% of surgical anastomoses, with mortality being up to 39% for patients with such a leak. Currently, there remains a paucity of data detailing the cellular mechanisms of anastomotic healing. Devising preventative strategies and treatment modalities for anastomotic leak could be greatly potentiated by a better understanding of appropriate anastomotic healing.
A murine model is ideal as previous studies have shown that the murine anastomosis is the most clinically similar to the human case as compared with other animal models. We offer an easily reproducible murine model of colonic anastomosis in mice that will allow for further illustration of anastomotic healing.

Anastomotic leak or breakdown after surgery is a major cause of postoperative morbidity and mortality. Our surgery for creating a colonic anastomosis is a reliable and reproducible method for studying the healing mechanisms of anastomoses.

Intestinal anastomoses are commonly performed in both elective and emergent operations. Even so, anastomotic leaks are a highly feared complications of ...

Murine Appendectomy Model of Chronic Colitis Associated Colorectal Cancer by Precise Localization of Caecal Patch

The human appendix has been recently implicated to play important biological roles in the pathogenesis of various complex diseases, such as colorectal cancer, inflammatory bowel disease, and Parkinson&#8217;s disease. To study the function of the appendix, a gut disease-associated murine appendectomy model has been established and its step-by-step protocol is described here. This report introduces a facile protocol for caecal patch removal in mice followed by the chemical induction of chronic colitis-associated colorectal cancer using a combination of dextran sulfate sodium (DSS) and azoxymethane (AOM). IgA specific cells and IgA concentration were significantly reduced upon removal of the caecal patch in male C57BL/6 mice&#160;compared to those in the sham group. Simultaneously administering 2% DSS and AOM resulted in nearly 80% mice survival in both sham and appendectomy groups without significant body weight loss. Histological results confirmed colonic inflammation and different degrees of adenocarcinoma. This model can be used for the study of the functional role of the appendix in maintaining gut microbiota homeostasis and pathogenesis of gut colitis and malignancies, as well as for the potential development of drug targeting therapies.

The presented protocol describes a facile surgical removal of the appendix (caecal patch) in a mouse followed by the induction of inflammatory bowel disease-associated colorectal cancer. This murine appendectomy model enables investigation of the biological role of the appendix in the pathogenesis of human gastrointestinal disease.

The human appendix has been recently implicated to play important biological roles in the pathogenesis of various complex diseases, such as colorectal ...

A Mouse Model of Intestinal Partial Obstruction

Intestinal obstructions, that impede or block peristaltic movement, can be caused by abdominal adhesions and most gastrointestinal (GI) diseases including tumorous growths. However, the cellular remodeling mechanisms involved in, and caused by, intestinal obstructions are poorly understood. Several animal models of intestinal obstructions have been developed, but the mouse model is the most cost/time effective. The mouse model uses the surgical implantation of an intestinal partial obstruction (PO) that has a high mortality rate if it is not performed correctly. In addition, mice receiving PO surgery fail to develop hypertrophy if an appropriate blockade is not used or not properly placed. Here, we describe a detailed protocol for PO surgery which produces reliable and reproducible intestinal obstructions with a very low mortality rate. This protocol utilizes a surgically placed silicone ring that surrounds the ileum which partially blocks digestive movement in the small intestine. The partial blockage makes the intestine become dilated due to the halt of digestive movement. The dilation of the intestine induces smooth muscle hypertrophy on the oral side of the ring that progressively develops over 2 weeks until it causes death. The surgical PO mouse model offers an in vivo model of hypertrophic intestinal tissue useful for studying pathological changes of intestinal cells including smooth muscle cells (SMC), interstitial cells of Cajal (ICC), PDGFR&#945;+, and neuronal cells during the development of intestinal obstruction.

Intestinal obstructions are a partial or complete blockage of the intestine that can cause severe abdominal pain, nausea, vomiting, and preventing the passage of stool. This procedure for creating intestinal partial obsructions in mice is reliable in studying the mechanisms underlying pathological cell growth and death in the intestine.

Intestinal obstructions, that impede or block peristaltic movement, can be caused by abdominal adhesions and most gastrointestinal (GI) diseases including ...

Experimental Rat Model of Pouchitis for Studying Ulcerative Colitis Pathogenesis and Treatment

A Rat Model of Pouchitis Following Proctocolectomy and Ileal Pouch-Anal Anastomosis Using Dextran Sulfate Sodium

Ulcerative colitis (UC) is a chronic immune-mediated disease that affects the entire colon and rectum with a relapsing and remitting course, causing lifelong morbidity. When medical treatment is ineffective, especially in cases of massive gastrointestinal bleeding, perforation, toxic megacolon, or carcinogenesis, surgery becomes the last line of defense to cure UC. Total colorectal resection and ileal pouch-anal anastomosis (IPAA) offer the best chance for long-term treatment. Pouchitis is the most common and troublesome postoperative complication. In this investigation, microsurgery is employed to create an ileal pouch model in experimental rats via IPAA surgery. Subsequently, a sustained rat model of pouchitis is established by inducing inflammation of the ileal pouch with dextran sulfate sodium (DSS). The successful establishment of rat pouchitis is validated through analysis of postoperative general status, weight, food and water intake, fecal data, as well as pouch tissue pathology, immunohistochemistry, and inflammatory factor analysis. This experimental animal model of pouchitis provides a foundation for studying the pathogenesis and treatment of the condition.

Author Spotlight: Developing a Rat Model for Pouchitis Research and Treatment

This protocol describes the method for establishing a rat model of pouchitis. The ileal pouch model was created by performing ileal pouch-anal anastomosis (IPAA) surgery using microsurgical techniques. After the surgery, the rat was treated with 4% dextran sulfate sodium (DSS) for 4 days.

Ulcerative colitis (UC) is a chronic immune-mediated disease that affects the entire colon and rectum with a relapsing and remitting course, causing ...

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.

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

Murine Distal Colostomy, A Novel Model of Diversion Colitis in C57BL/6 Mice

Summary

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A Genetically Engineered Mouse Model of Sporadic Colorectal Cancer

Modeling Colitis-Associated Cancer with Azoxymethane (AOM) and Dextran Sulfate Sodium (DSS)

The Citrobacter rodentium Mouse Model: Studying Pathogen and Host Contributions to Infectious Colitis

Murine Colitis Modeling using Dextran Sulfate Sodium (DSS)

Non-invasive Assessment of the Efficacy of New Therapeutics for Intestinal Pathologies Using Serial Endoscopic Imaging of Live Mice

Creation of Colonic Anastomosis in Mice

Murine Appendectomy Model of Chronic Colitis Associated Colorectal Cancer by Precise Localization of Caecal Patch

A Mouse Model of Intestinal Partial Obstruction

A Rat Model of Pouchitis Following Proctocolectomy and Ileal Pouch-Anal Anastomosis Using Dextran Sulfate Sodium

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