The authors would like to thank Benjamin J Weigler, D.V.M., Ph.D. and Walt Mandeville, D.V.M. (Animal Resources &#38; Campus Attending Veterinarian, University of Nevada, Reno) for their excellent animal services provided to the mice as well as their counsel on surgical procedures.

The following protocol has been approved by the Institutional Animal Care and Use Committee (IACUC) at the University of Nevada-Reno (UNR) Animal Resources and complies with all institutional ethical guidelines regarding the use of research animals.
1. Animals.
<ol>
	<li>Obtain mature (4-6 weeks old) C57BL/6 mice weighing between 20-30 g. House the colony of laboratory mice in a centralized animal facility at UNR Animal Resources.</li>
</ol>
2. Partial Obstruction Surgery
NOTE: Surgeries are performed in a room dedicated to surgical procedures. All surgical instruments are autoclaved prior to surgery. Sterile surgical gowns and gloves should be worn by all personnel in the surgical room at all times.
<ol>
	<li>Preparation for the surgical mouse
	<ol>
		<li>Check the anesthetic delivery system to ensure the supply of oxygen and isoflurane is adequate for procedure. Turn on the supply oxygen. Turn on the gas flowmeter and adjust it to 500-1000 mL/min. Place the animal in the induction chamber and seal the top.</li>
		<li>Turn on the isoflurane vaporizer to 5%, and monitor the animal until it becomes recumbent. Switch the anesthetic delivery system to the nose cone.</li>
		<li>Flush the induction chamber of any residual gas with oxygen, then turn off the induction chamber line while keeping the nose cone line open.</li>
		<li>Remove the animal from the chamber and carefully place ophthalmic ointment on the eyes of the animal.</li>
		<li>Place the nose cone on a preheated warm pad when gas continues to flow.</li>
		<li>Change the oxygen flow to 100-200 mL/min, with 2-3 % isoflurane. If the animal begins to move, gentlyrestrain the animal with the nose cone on until fully anesthetized again.</li>
		<li>Monitor the respiration and response to stimulation during the procedure and adjust the percentage of isoflurane (2-5 %) as needed. Animal anesthetization level is monitored by the lack of toe pinch reflex before surgery is performed.</li>
		<li>Inject pain medicine (buprenorphine, 1 &#181;g/g of body weight) intraperitoneally away from the incision site.</li>
		<li>Apply hair removal lotion on the abdomen using a clean cotton swab. Let the lotion sit for 3-5 min on mouse, then remove the hair using gauze and cotton swabs. Repeat this step until all hair has been removed from the abdomen of the mouse.</li>
		<li>Clean the skin with 70 % ethanol using gauze and cotton swabs. Apply swabsticks or povidone-iodine solution to clean the abdomen.</li>
	</ol>
	</li>
	<li>Partial obstruction surgery
	<ol>
		<li>Drape the surgical site using 25 x 50 cm sterile paper with a 2.5 x 2.5 cm opening in the middle for the surgery area. Secure the drape to the animal by placing sterile strips at the boundaries of the opening and skin.</li>
		<li>Make a ~3.0 cm abdominal incision longitudinally using a No. 15 blade scalpel, ensuring that only the skin is incised and avoiding cutting into the musculoperitoneal layer at this time.</li>
		<li>Using forceps and surgical scissors, carefully separate the skin from the musculoperitoneal layer without causing any incision to the musculoperitoneal layer. After the layers have been sufficiently separated (approximately 1 cm x 4 cm), identify the linea alba on the musculoperitoneal layer and cut ~2 cm along the linea alba to expose the intraperitoneal cavity using micro-forceps and scissors.</li>
		<li>Carefully locate and identify the cecum. Slowly and gently remove the cecum from the intraperitoneal cavity with micro-forceps, bringing the proximal colon and ileum with the cecum outside onto the sterile drape. Immediately moisten the intestinal tissue with 0.9 % sterile saline soaked gauze and keep exposed tissue moistened at all times while they are outside of the abdominal cavity.</li>
		<li>Locate and identify the mesentery between the ileum and proximal colon. Make an incision (~1 cm) parallel to, and just below, the ileum, in the mesentery and avoid cutting any vasculature.</li>
		<li>Take an autoclaved silicone ring (6 mm in length, 4 mm exterior diameter, 3.5 mm interior diameter). Cut longitudinally to open the tubing and open the ring with micro-forceps.</li>
		<li>Insert one end of the opened ring through the incision in the mesentery tissue. Return the ring to a completed ring shape by bringing one end into contact with another, with the ileum surrounded by the ring.</li>
		<li>Ensure that the silicone ring completely surrounds the ileum, close the ring with suture and carefully place the intestines back in the intraperitoneal cavity.</li>
	</ol>
	</li>
	<li>Surgery closure
	<ol>
		<li>Perform a simple continuous suture on the musculoperitoneal layer along the linea alba to close the musculoperitoneal wound with an absorbable suture. After the suture is complete, clean any bleeding with 0.9 % sterile saline soaked gauze.</li>
		<li>To completely close the wound, with a separate nylon suture, perform a simple continuous suture on the skin.</li>
		<li>After both sutures have been completed, clean the wound with new swabstick or povidone-iodine.</li>
		<li>Intraperitoneally inject antibiotics (gentamicin, 150 &#956;L per mouse based on 20-30 g body weight).</li>
		<li>After the completion of procedure, turn off the isoflurane vaporizer and allow the animal to breathe only flowing oxygen until it start gaining consciousness.</li>
		<li>Once the animal is awake, place the animal into a separate recovery area with thermal support until fully recovered.</li>
	</ol>
	</li>
</ol>
3. Post-operation observation.
<ol>
	<li>After the completion of surgery, move the animals to an incubator in a recovery room where temperature and humidity is regulated. Monitor the animals postoperatively every 15 min for the first hour then every 30 min for the second hour while the animals are in the incubator.</li>
	<li>As soon as the prescribed observation is complete, move the animals to their own individual cage and monitor them daily for clinical indications of pain18, and to ensure that the surgical wound is healing properly without any signs of complications (dehiscence) present.</li>
</ol>

<ol>
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The process is not a form of enteritis but lymphedema contaminated by intestinal contents.</a> Chir Ital. 52, 109-121 (2000).</li><li>Limsrivilai, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Meta-analytic+Bayesian+model+for+differentiating+intestinal+tuberculosis+from+Crohn's+disease.">Meta-analytic Bayesian model for differentiating intestinal tuberculosis from Crohn's disease.</a> Am J Gastroenterol. 112, 415-427 (2017).</li><li>Dvorak, D., Adamova, Z., Bar, T., Slovacek, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Internal+hernia+as+a+cause+of+small+bowel+obstruction.">Internal hernia as a cause of small bowel obstruction.</a> Rozhl Chir. 96, 34-36 (2017).</li><li>Massani, M., Capovilla, G., Ruffolo, C., Bassi, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gastrointestinal+stromal+tumour+(GIST)+presenting+as+a+strangulated+inguinal+hernia+with+small+bowel+obstruction.">Gastrointestinal stromal tumour (GIST) presenting as a strangulated inguinal hernia with small bowel obstruction.</a> BMJ Case Rep. , (2007).</li><li>Chen, J., Chen, H., Sanders, M., Perrino, B. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regulation+of+SRF/CArG-dependent+gene+transcription+during+chronic+partial+obstruction+of+murine+small+intestine.">Regulation of SRF/CArG-dependent gene transcription during chronic partial obstruction of murine small intestine.</a> Neurogastroenterol Motil. 20, 829-842 (2008).</li><li>Chang, I. Y., 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=Loss+of+interstitial+cells+of+Cajal+and+development+of+electrical+dysfunction+in+murine+small+bowel+obstruction.">Loss of interstitial cells of Cajal and development of electrical dysfunction in murine small bowel obstruction.</a> J Physiol. 536 (Pt 2), 555-568 (2001).</li><li>Liu, D. 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J., 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=Duodenal+Brunner's+glade+adenoma+causing+chronic+small+intestinal+obstruction+in+a+dog.">Duodenal Brunner's glade adenoma causing chronic small intestinal obstruction in a dog.</a> J Small Anim Pract. 53, 136-139 (2012).</li><li>Bettini, G., 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=Hypertrophy+of+intestinal+smooth+muscle+in+cats.">Hypertrophy of intestinal smooth muscle in cats.</a> Res Vet Sci. 75, 43-53 (2003).</li><li>Macdonald, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Smooth+muscle+phenotypic+plasticity+in+mechanical+obstruction+of+the+small+intestine.">Smooth muscle phenotypic plasticity in mechanical obstruction of the small intestine.</a> J Neurogastroenterol Motil. 20, 737-740 (2008).</li><li>Ha, S. E., 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=Transcriptome+analysis+of+PDGFR&#945;++Cells+identifies+T-types+Ca2++channel+CACNA1G+as+a+new+pathological+marker+for+PDGFR&#945;++cell+hyperplasia.">Transcriptome analysis of PDGFR&#945;+ Cells identifies T-types Ca2+ channel CACNA1G as a new pathological marker for PDGFR&#945;+ cell hyperplasia.</a> PLoS One. 12, e0182265 (2017).</li><li>Park, 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=Serum+response+factor+is+essential+for+prenatal+gastrointestinal+smooth+muscle+development+and+maintenance+of+differentiated+phenotype.">Serum response factor is essential for prenatal gastrointestinal smooth muscle development and maintenance of differentiated phenotype.</a> J Neurogastroenterol Motil. 21, 589-602 (2015).</li><li>Spencer, N. 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D., Notari, L., Sun, R., Zhao, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanisms+of+smooth+muscle+responses+to+inflammation.">Mechanisms of smooth muscle responses to inflammation.</a> Neurogastroenterol Motil. 24, 802-811 (2012).</li><li>Chen, W., 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=Smooth+muscle+hyperplasia/hypertrophy+is+the+most+prominent+histological+change+in+Crohn's+fibrostenosing+bowel+strictures:+A+semiquantitative+analysis+by+using+a+novel+histological+grading+scheme.">Smooth muscle hyperplasia/hypertrophy is the most prominent histological change in Crohn's fibrostenosing bowel strictures: A semiquantitative analysis by using a novel histological grading scheme.</a> J Crohns Colitis. 11, 92-104 (2017).</li><li>Huizinga, J. D., Chen, J. 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The authors have nothing to disclose.

We demonstrated that mice receiving the intestinal PO surgery consistently and reproducibly develop intestinal smooth muscle hypertrophy, which mimics human intestinal obstruction. Intestinal obstruction surgeries have been developed for different animals including mice7, rats10, guinea pigs11, dog12 and cats13. The mouse model of intestinal obstruction has time, cost, size, and phenotypic advantages ov...

Intestinal obstructions are a partial or complete blockage in the small or large intestine which prevents digested food, fluids, and gas from moving through the intestines1. Due to the obstruction, the blockage induces the intestinal walls to become thickened, narrowing the lumen2. Intestinal obstruction can occur as a result of abdominal or pelvic surgeries that cause abdominal adhesion tissue formation or from GI disorders such as inflammatory bowel diseases (Crohn&#39;s disease), diverticulitis, hernias, volvulus, stricture, intussusception, constipation, fecal impaction, pseudo-obstruction, cancers and tumors3,4,5. Intestinal obstructions in these cases often lead to the hypertrophy of the tunica muscularis of the intestine6.
PO of the lumen induces intestinal distention, and increases smooth muscle layer thickness around the obstruction in response to the need to continue functional peristalsis7,8,9,10,11,12,13. Animal models of intestinal PO have been developed to study smooth muscle hypertrophy in mice7, rats10, guinea pigs11, dogs12, and cats13 that consistently develop similar hypertrophy within the intestinal muscle layers.
A mouse model of intestinal PO is the most cost effective way to generate and study intestinal obstructions in vivo. Small intestine obstructions are carried out in mice by using a silicone ring surgically placed surrounding the ileum. The PO mice showed an early increase in the number of cells (hyperplasia), and an increase in muscle layer thickness (hypertrophy) after PO surgery8,15. SMC are the primary plastic cells that are growing within smooth muscle layers in response to the hypertrophic conditions14, but other cells such as ICC and PDGFR&#945;+ cells that are closely associated with SMC, are also repopulated. We have previously reported that the PO mice develop hypertrophy in the small intestine, in which SMC are dedifferentiated into PDGFR&#945;+ cells that are highly proliferative7,15,16. Conversely, ICC are degenerated and lost within the hypertrophied smooth muscle layers during the development of intestinal obsruction7. Another major benefit of the PO model is its capacity to induce changes in the enteric nervous system and propagating neurogenic motor patterns. The major propagating neurogenic motor pattern in the mouse small bowel is the migrating motor complex (MMC), which is neurogenic and does not require ICC or electrical slow waves17. The PO model can provide clear insights into how MMCs and enteric nerves are remodeled by partial obstruction.
Here, we propose a murine protocol for intestinal PO surgery using a silicone ring. Mice receiving PO surgery reliably produce hypertrophy in the tunica muscularis of the small intestine. Within hypertrophic muscle, SMC, ICC, PDGFR&#945;+, and neuronal cells are dramatically remodeled.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Surgical drape</td>
			<td>Medical and veterinary supplies</td>
			<td>SMS40</td>
			<td>40&#8221;X100 yards</td>
		</tr>
		<tr>
			<td>Underpad, econ, pro plus</td>
			<td>Medical and veterinary supplies</td>
			<td>MSC281224</td>
			<td>17x24&#8221;</td>
		</tr>
		<tr>
			<td>Iris scissors</td>
			<td>Braintree scientific, Inc</td>
			<td>SC-i-130</td>
			<td></td>
		</tr>
		<tr>
			<td>Iris scissors</td>
			<td>Vantage</td>
			<td>V95-304</td>
			<td></td>
		</tr>
		<tr>
			<td>Dumont electronic &#38; jeweler tweezers</td>
			<td>Dumont</td>
			<td>98-180-3</td>
			<td></td>
		</tr>
		<tr>
			<td>Braided absorbable suture</td>
			<td>Covidien polysorb</td>
			<td>SL-5687G</td>
			<td>5-0, polyglactin</td>
		</tr>
		<tr>
			<td>Nylon non-absorbable mono filament</td>
			<td>AD surgical</td>
			<td>S-N618R13</td>
			<td>6-0, nylon</td>
		</tr>
		<tr>
			<td>Surgical blade</td>
			<td>Dynarex</td>
			<td></td>
			<td>No.15</td>
		</tr>
		<tr>
			<td>Needle holder</td>
			<td>Jacobson microvascular</td>
			<td>36-1342TC</td>
			<td>8.5 inch</td>
		</tr>
		<tr>
			<td>Scalpel handle</td>
			<td>Flinn scientific</td>
			<td>AB1049</td>
			<td></td>
		</tr>
		<tr>
			<td>Microsurgical scissor</td>
			<td>WPI</td>
			<td>503305</td>
			<td></td>
		</tr>
		<tr>
			<td>Petrolatum ophthalmic ointment</td>
			<td>Puralube VET</td>
			<td></td>
			<td>3.5 g</td>
		</tr>
		<tr>
			<td>Fluriso (isoflurane)</td>
			<td>Vetone</td>
			<td>V1 502017</td>
			<td>250 ml</td>
		</tr>
		<tr>
			<td>Steri-strip reinforced skin closure</td>
			<td>3M</td>
			<td>R1547</td>
			<td></td>
		</tr>
		<tr>
			<td>Surgical gloves</td>
			<td>Medline</td>
			<td>MSG2270</td>
			<td></td>
		</tr>
		<tr>
			<td>Ear loop face mask</td>
			<td>The safety zone</td>
			<td>RS700</td>
			<td></td>
		</tr>
		<tr>
			<td>Avant gauze non-woven sponges</td>
			<td>Caring</td>
			<td>PRM25444</td>
			<td></td>
		</tr>
		<tr>
			<td>Surgical cup</td>
			<td>Admiral&#160; craft OYC-2</td>
			<td>725-A42</td>
			<td>2.5 oz</td>
		</tr>
		<tr>
			<td>Swabstick</td>
			<td>ChloraPrep</td>
			<td>260103</td>
			<td>2% w/v Chlorhexidine&#160; Gluconate (CHG) and 70% v/v Isopropyl Alcohol (IPA)</td>
		</tr>
		<tr>
			<td>Cotton tipped applicator</td>
			<td>Puritan</td>
			<td>806-WC</td>
			<td></td>
		</tr>
		<tr>
			<td>Buprenorphine</td>
			<td>Zoo pharm</td>
			<td>BZ8069317</td>
			<td>1 mg/ml</td>
		</tr>
		<tr>
			<td>Gentamycin sulfate</td>
			<td>Vetone</td>
			<td>G-6336-04</td>
			<td>100 mg/ml</td>
		</tr>
		<tr>
			<td>Fast acting gel cream remover</td>
			<td>Veet</td>
			<td>8111002</td>
			<td></td>
		</tr>
		<tr>
			<td>Syringe</td>
			<td>AHS</td>
			<td>AH01T2516</td>
			<td>1 ml with needle</td>
		</tr>
		<tr>
			<td>Silicon ring</td>
			<td>VWR</td>
			<td>60985-720</td>
			<td>6 mm in length, 4 mm exterior diameter, 3.5 mm interior diameter</td>
		</tr>
		<tr>
			<td>C57BL/6 mice</td>
			<td>The Jackson Laboratory</td>
			<td></td>
			<td>4-6 weeks old</td>
		</tr>
	</tbody>
</table>

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.

Partial obstruction (PO) was surgically induced in one month old mice by placing a silicone ring around the ileum close to the ileocecal sphincter. This ring created a partial blockage in the ileum. Sham operations (SO) were also performed without a ring on age/sex matched mice and these mice did not show any symptoms similar to those found in PO mice. Mice quickly recovered from PO surgery within a few hours. They showed no obvious behavioral changes or weakness within the first week, bu...

Watch this Scientific Journal Video about A Mouse Model of Intestinal Partial Obstruction at JoVE.com

A Mouse Model of Intestinal Partial 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 ...

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JoVE Journal

Biology

20.8K Views.  University of Nevada, Reno School of Medicine. 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.

Video: A Mouse Model of Intestinal Partial Obstruction

In vivo Imaging and Therapeutic Treatments in an Orthotopic Mouse Model of Ovarian Cancer

Human cancer and response to therapy is better represented in orthotopic animal models. This paper describes the development of an orthotopic mouse model of ovarian cancer, treatment of cancer via oral delivery of drugs, and monitoring of tumor cell behavior in response to drug treatment in real time using in vivo imaging system. In this orthotopic model, ovarian tumor cells expressing luciferase are applied topically by injecting them directly into the mouse bursa where each ovary is enclosed. Upon injection of D-luciferin, a substrate of firefly luciferase, luciferase-expressing cells generate bioluminescence signals. This signal is detected by the in vivo imaging system and allows for a non-invasive means of monitoring tumor growth, distribution, and regression in individual animals. Drug administration via oral gavage allows for a maximum dosing volume of 10 mL/kg body weight to be delivered directly to the stomach and closely resembles delivery of drugs in clinical treatments. Therefore, techniques described here, development of an orthotopic mouse model of ovarian cancer, oral delivery of drugs, and in vivo imaging, are useful for better understanding of human ovarian cancer and treatment and will improve targeting this disease.

In vivo Imaging and Therapeutic Treatments in an Orthotopic Mouse Model of Ovarian Cancer

Orthotopic animal models of ovarian cancer replicate better human disease and therefore enhance our understanding of cancer progression and tumor response to therapy. A mouse model receives an intrabursal injection of luciferase-expressing ovarian tumor cells. Treatment is administered via oral gavage. Tumor growth is monitored by in vivo imaging system.

Human cancer and response to therapy is better represented in orthotopic animal models.  This paper describes the development of an orthotopic mouse model ...

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 ...

Real Time Analysis of Metabolic Profile in Ex Vivo Mouse Intestinal Crypt Organoid Cultures

The small intestinal mucosa exhibits a repetitive architecture organized into two fundamental structures: villi, projecting into the intestinal lumen and composed of mature enterocytes, goblet cells and enteroendocrine cells; and crypts, residing proximal to the submucosa and the muscularis, harboring adult stem and progenitor cells and mature Paneth cells, as well as stromal and immune cells of the crypt microenvironment. Until the last few years, in vitro studies of small intestine was limited to cell lines derived from either benign or malignant tumors, and did not represent the physiology of normal intestinal epithelia and the influence of the microenvironment in which they reside. Here, we demonstrate a method adapted from Sato et al. (2009) for culturing primary mouse intestinal crypt organoids derived from C57BL/6 mice. In addition, we present the use of crypt organoid cultures to assay the crypt metabolic profile in real time by measurement of basal oxygen consumption, glycolytic rate, ATP production and respiratory capacity. Organoids maintain properties defined by their source and retain aspects of their metabolic adaptation reflected by oxygen consumption and extracellular acidification rates. Real time metabolic studies in this crypt organoid culture system are a powerful tool to study crypt organoid energy metabolism, and how it can be modulated by nutritional and pharmacological factors.

Real Time Analysis of Metabolic Profile in Ex Vivo Mouse Intestinal Crypt Organoid Cultures

Small intestinal crypt organoids cultured ex vivo provide a tissue culture system that recapitulates growth of crypts dependent on stem cells and their niche. We established a method to assay the metabolic profile in real time in primary mouse crypt organoids. We found organoids maintain physiological properties defined by their source.

The small intestinal mucosa exhibits a repetitive architecture organized into two fundamental structures: villi, projecting into the intestinal lumen and ...

A Protocol for Lentiviral Transduction and Downstream Analysis of Intestinal Organoids

Intestinal crypt-villus structures termed organoids, can be kept in sustained culture three dimensionally when supplemented with the appropriate growth factors. Since organoids are highly similar to the original tissue in terms of homeostatic stem cell differentiation, cell polarity and presence of all terminally differentiated cell types known to the adult intestinal epithelium, they serve as an essential resource in experimental research on the epithelium. The possibility to express transgenes or interfering RNA using lentiviral or retroviral vectors in organoids has increased opportunities for functional analysis of the intestinal epithelium and intestinal stem cells, surpassing traditional mouse transgenics in speed and cost. In the current video protocol we show how to utilize transduction of small intestinal organoids with lentiviral vectors illustrated by use of doxycylin inducible transgenes, or IPTG inducible short hairpin RNA for overexpression or gene knockdown. Furthermore, considering organoid culture yields minute cell counts that may even be reduced by experimental treatment, we explain how to process organoids for downstream analysis aimed at quantitative RT-PCR, RNA-microarray and immunohistochemistry. Techniques that enable transgene expression and gene knock down in intestinal organoids contribute to the research potential that these intestinal epithelial structures hold, establishing organoid culture as a new standard in cell culture.

In this video protocol we give a step by step explanation of lentiviral transduction in organoids of primary intestinal epithelium and of processing and downstream analysis of these cultures by quantitative RT-PCR, RNA-microarray and immunohistochemistry.

Intestinal crypt-villus structures termed organoids, can be kept in sustained culture three dimensionally when supplemented with the appropriate growth ...

Partial Bile Duct Ligation in the Mouse: A Controlled Model of Localized Obstructive Cholestasis

In rodents, complete bile duct ligation (cBDL) of the common bile duct is an established surgical technique for studying obstructive cholestasis and bile duct proliferation. However, long-term experiments can lead to increased morbidity and mortality. In select mouse strains with underlying liver disease, meaningful comparisons can be made even with ligation of a single lobe of the liver, which can reduce animal losses and expenses. Here, we describe partial bile duct ligation (pBDL) in the mouse, in which only the left hepatic bile duct is ligated, causing biliary obstruction in the left lobe but not the remaining lobes. With careful microsurgical technique, pBDL experiments can be cost-effective, since the unligated lobe serves as an internal control to the ligated lobes, when subjected to the same conditions in the same animal. Unlike cBDL, a separate sham-operated control group is not necessary. pBDL is highly useful to directly compare localized versus systemic effects of cholestasis and other retained bile components. pBDL can also be repurposed as a novel method to investigate mechanisms related to medications and cell migration.

Here, we present partial bile duct ligation as a surgical model of liver injury and regeneration in rodents.

In rodents, complete bile duct ligation (cBDL) of the common bile duct is an established surgical technique for studying obstructive cholestasis and bile ...

Trans-inner Cell Mass Injection of Embryonic Stem Cells Leads to Higher Chimerism Rates

In an effort to increase efficiency in the creation of genetically modified mice via ES Cell methodologies, we present an adaptation to the current blastocyst injection protocol. Here we report that a simple rotation of the embryo, and injection through Trans-Inner cell mass (TICM) increased the percentage of chimeric mice from 31% to 50%, with no additional equipment or further specialized training. 26 different inbred clones, and 35 total clones were injected over a period of 9 months. There was no significant difference in either pregnancy rate or recovery rate of embryos between traditional injection techniques and TICM. Therefore, without any major alteration in the injection process and a simple positioning of the blastocyst and injecting through the ICM, releasing the ES cells into the blastocoel cavity can potentially improve the quantity of chimeric production and subsequent germline transmission.

Here we present a protocol to increase chimera production without the use of new equipment. A simple orientation change of the embryo for injection can increase the number of embryos produced, and potentially reduce the timeline to germline transmission.

In an effort to increase efficiency in the creation of genetically modified mice via ES Cell methodologies, we present an adaptation to the current ...

Mass Spectrometry Analysis to Identify Ubiquitylation of EYFP-tagged CENP-A (EYFP-CENP-A)

Studying the structure and the dynamics of kinetochores and centromeres is important in understanding chromosomal instability (CIN) and cancer progression. How the chromosomal location and function of a centromere (i.e., centromere identity) are determined and participate in accurate chromosome segregation is a fundamental question. CENP-A is proposed to be the non-DNA indicator (epigenetic mark) of centromere identity, and CENP-A ubiquitylation is required for CENP-A deposition at the centromere, inherited through dimerization between cell division, and indispensable to cell viability.
Here we describe mass spectrometry analysis to identify ubiquitylation of EYFP-CENP-A K124R mutant suggesting that ubiquitylation at a different lysine is induced because of the EYFP tagging in the CENP-A K124R mutant protein. Lysine 306 (K306) ubiquitylation in EYFP-CENP-A K124R was successfully identified, which corresponds to lysine 56 (K56) in CENP-A through mass spectrometry analysis. A caveat is discussed in the use of GFP/EYFP or the tagging of high molecular weight protein as a tool to analyze the function of a protein. Current technical limit is also discussed for the detection of ubiquitylated bands, identification of site-specific ubiquitylation(s), and visualization of ubiquitylation in living cells or a specific single cell during the whole cell cycle.
The method of mass spectrometry analysis presented here can be applied to human CENP-A protein with different tags and other centromere-kinetochore proteins. These combinatory methods consisting of several assays/analyses could be recommended for researchers who are interested in identifying functional roles of ubiquitylation.

Mass Spectrometry Analysis to Identify Ubiquitylation of EYFP-tagged CENP-A EYFP-CENP-A

CENP-A ubiquitylation is an important requirement for CENP-A deposition at the centromere, inherited through dimerization between cell division, and indispensable to cell viability. Here we describe mass spectrometry analysis to identify ubiquitylation of EYFP-tagged CENP-A (EYFP-CENP-A) protein.

Studying the structure and the dynamics of kinetochores and centromeres is important in understanding chromosomal instability (CIN) and cancer ...

A Mouse Model of Lumbar Spine Instability

Intervertebral disc degeneration (IDD) is a common pathological change leading to low back pain. Appropriate animal models are desired for understanding the pathological processes and evaluating new drugs. Here, we introduced a surgically induced lumbar spine instability (LSI) mouse model that develops IDD starting from 1 week post operation. In detail, the mouse under anesthesia was operated by low back skin incision, L3&#8211;L5 spinous processes exposure, detachment of paraspinous muscles, resection of processes and ligaments, and skin closure. L4&#8211;L5 IVDs were chosen for the observation. The LSI model develops lumbar IDD by porosity and hypertrophy in endplates at an early stage, decrease in intervertebral disc volume, shrinkage in nucleus pulposus at an intermediate stage, and bone loss in lumbar vertebrae (L5) at a later stage. The LSI mouse model has the advantages of strong operability, no requirement of special equipment, reproducibility, inexpensive, and relatively short period of IDD development. However, LSI operation is still a trauma that causes inflammation within the first week post operation. Thus, this animal model is suitable for study of lumbar IDD.

We developed a lumbar intervertebral disc degeneration mouse model by resection of L3&#8211;L5 spinous processes along with supra- and inter-spinous ligaments and detachment of paraspinous muscles.

Intervertebral disc degeneration (IDD) is a common pathological change leading to low back pain. Appropriate animal models are desired for understanding ...

Organoid-Derived Epithelial Monolayer: A Clinically Relevant In Vitro Model for Intestinal Barrier Function

In the past, intestinal epithelial model systems were limited to transformed cell lines and primary tissue. These model systems have inherent limitations as the former do not faithfully represent original tissue physiology, and the availability of the latter is limited. Hence, their application hampers fundamental and drug development research. Adult stem-cell-based organoids (henceforth referred to as organoids) are miniatures of normal or diseased epithelial tissue from which they are derived. They can be established very efficiently from different gastrointestinal (GI) tract regions, have long-term expandability, and simulate tissue- and patient-specific responses to treatments in vitro. Here, the establishment of intestinal organoid-derived epithelial monolayers has been demonstrated along with methods to measure epithelial barrier integrity, permeability and transport,&#160;antimicrobial protein secretion, as well as histology. Moreover, intestinal organoid-derived monolayers can be enriched with proliferating stem and transit-amplifying cells as well as with key differentiated epithelial cells. Therefore, they represent a model system that can be tailored to study the effects of compounds on target cells and their mode of action. Although organoid cultures are technically more demanding than cell lines, once established, they can reduce failures in the later stages of drug development as they truly represent in vivo epithelium complexity and interpatient heterogeneity.

Here, we describe the preparation of human organoid-derived intestinal epithelial monolayers for studying intestinal barrier function, permeability, and transport. As organoids represent original epithelial tissue response to external stimuli, these models combine the advantages of expandability of cell lines and the relevance and complexity of primary tissue.

In the past, intestinal epithelial model systems were limited to transformed cell lines and primary tissue. These model systems have inherent limitations ...

Partial Hepatectomy in Adult Zebrafish

Liver failure is one of the leading causes of death worldwide, and mortality from chronic liver disease is rising sharply in the United States. Healthy livers are capable of regenerating from toxic damage, but in advanced liver disease, the natural ability of the liver to regenerate is impaired. Zebrafish have emerged as a powerful experimental system for studying regeneration. They are an ideal model for studying liver regeneration from partial hepatectomy, a procedure with direct clinical relevance in which part of the liver is surgically removed, leaving the rest intact. There is no standard protocol for partial hepatectomy; previous studies using this model have used slightly different protocols and reported disparate results. Described here is an efficient, reproducible protocol for performing a partial hepatectomy in adult zebrafish. We use this technique to demonstrate that zebrafish are capable of epimorphic regeneration of the resected lobe. This protocol can be used to further interrogate the mechanisms required for liver regeneration in zebrafish.

This protocol describes the procedure for removing the ventral lobe of the liver in adult zebrafish to enable the study of liver regeneration.

Liver failure is one of the leading causes of death worldwide, and mortality from chronic liver disease is rising sharply in the United States. Healthy ...