Name: creation of abdominal adhesions in mice
Uploaded: 2016-08-27T15:00:00
Description: Watch this Scientific Journal Video about Creation of Abdominal Adhesions in Mice at JoVE.com

C.D.M. was supported by the American College of Surgeons (ACS) Resident Research Scholarship. M.S.H. was supported by the California Institute for Regenerative Medicine (CIRM) Clinical Fellow training grant TG2-01159. M.S.H., H.P.L., and M.T.L. were supported by the American Society of Maxillofacial Surgeons (ASMS)/Maxillofacial Surgeons Foundation (MSF) Research Grant Award. H.P.L. was supported by NIH grant R01 GM087609 and a gift from Ingrid Lai and Bill Shu in honor of Anthony Shu. H.P.L. and M.T.L. were supported by the Hagey Laboratory for Pediatric Regenerative Medicine and The Oak Foundation. M.T.L. was supported by the Gunn/Olivier Fund.

The following protocol has been approved by the Stanford University Institutional Animal Care and Use Committee (IACUC) and complies with all institutional ethical guidelines regarding the use of research animals.
1. Creation of Abdominal Adhesions
<ol>
	<li>Start the mouse on antibiotic chow diet one week prior to the procedure.</li>
	<li>Autoclave the surgical instruments and pre-warm the saline irrigation solution.</li>
	<li>Anesthetize the mouse using 2% inhaled isoflurane.</li>
	<li>Usi...

<ol>
	<li>Ellis, H., 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=Adhesion-related+hospital+readmissions+after+abdominal+and+pelvic+surgery:+a+retrospective+cohort+study.">Adhesion-related hospital readmissions after abdominal and pelvic surgery: a retrospective cohort study.</a> Lancet. 353 (9163), 1476-1480 (1999).</li><li>Brochhausen, 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=Current+strategies+and+future+perspectives+for+intraperitoneal+adhesion+prevention.">Current strategies and future perspectives for intraperitoneal adhesion prevention.</a> J Gastrointest Surg. 16 (6), 1256-1274 (2012).</li><li>diZerega, G. S., Campeau, J. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Peritoneal+repair+and+post-surgical+adhesion+formation.">Peritoneal repair and post-surgical adhesion formation.</a> Hum Reprod Update. 7 (6), 547-555 (2001).</li><li>Hellebrekers, B. W., Kooistra, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pathogenesis+of+postoperative+adhesion+formation.">Pathogenesis of postoperative adhesion formation.</a> Br J Surg. 98 (11), 1503-1516 (2011).</li><li>Herrick, 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=Human+peritoneal+adhesions+are+highly+cellular,+innervated,+and+vascularized.">Human peritoneal adhesions are highly cellular, innervated, and vascularized.</a> J Pathol. 192 (1), 67-72 (2000).</li><li>Beyene, R. T., Kavalukas, S. L., Barbul, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intra-abdominal+adhesions:+Anatomy,+physiology,+pathophysiology,+and+treatment.">Intra-abdominal adhesions: Anatomy, physiology, pathophysiology, and treatment.</a> Curr Probl Surg. 52 (7), 271-319 (2015).</li><li>ten Broek, R. P., 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=Benefits+and+harms+of+adhesion+barriers+for+abdominal+surgery:+a+systematic+review+and+meta-analysis.">Benefits and harms of adhesion barriers for abdominal surgery: a systematic review and meta-analysis.</a> Lancet. 383 (9911), 48-59 (2014).</li><li>Becker, J. M., 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=Prevention+of+postoperative+abdominal+adhesions+by+a+sodium+hyaluronate-based+bioresorbable+membrane:+a+prospective,+randomized,+double-blind+multicenter+study.">Prevention of postoperative abdominal adhesions by a sodium hyaluronate-based bioresorbable membrane: a prospective, randomized, double-blind multicenter study.</a> J Am Coll Surg. 183 (4), 297-306 (1996).</li><li>Cassidy, M. R., Sherburne, A. C., Heydrick, S. J., Stucchi, A. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Combined+intraoperative+administration+of+a+histone+deacetylase+inhibitor+and+a+neurokinin-1+receptor+antagonist+synergistically+reduces+intra-abdominal+adhesion+formation+in+a+rat+model.">Combined intraoperative administration of a histone deacetylase inhibitor and a neurokinin-1 receptor antagonist synergistically reduces intra-abdominal adhesion formation in a rat model.</a> Surgery. 157 (3), 581-589 (2015).</li><li>Thaler, K., 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=Coincidence+of+connective+tissue+growth+factor+expression+with+fibrosis+and+angiogenesis+in+postoperative+peritoneal+adhesion+formation.">Coincidence of connective tissue growth factor expression with fibrosis and angiogenesis in postoperative peritoneal adhesion formation.</a> Eur Surg Res. 37 (4), 235-241 (2005).</li><li>Hong, G. 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=Effects+of+macrophage-dependent+peroxisome+proliferator-activated+receptor+gamma+signalling+on+adhesion+formation+after+abdominal+surgery+in+an+experimental+model.">Effects of macrophage-dependent peroxisome proliferator-activated receptor gamma signalling on adhesion formation after abdominal surgery in an experimental model.</a> Br J Surg. 102 (12), 1506-1516 (2015).</li><li>Whang, S. H., 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=In+search+of+the+best+peritoneal+adhesion+model:+comparison+of+different+techniques+in+a+rat+model.">In search of the best peritoneal adhesion model: comparison of different techniques in a rat model.</a> J Surg Res. 167 (2), 245-250 (2011).</li><li>Buckenmaier, C. C., Pusateri, A. E., Harris, R. A., Hetz, S. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparison+of+antiadhesive+treatments+using+an+objective+rat+model.">Comparison of antiadhesive treatments using an objective rat model.</a> Am Surg. 65 (3), 274-282 (1999).</li><li>Rajab, T. K., 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+improved+model+for+the+induction+of+experimental+adhesions.">An improved model for the induction of experimental adhesions.</a> J Invest Surg. 23 (1), 35-39 (2010).</li></ol>

The critical steps in this procedure are: thoroughly abrading the cecum without causing perforation, placing sutures in the abdominal sidewall, and applying the right amount of starch. Only apply sandpaper to the cecum, or to a small specific portion of the bowel. Wide use of sandpaper on large amounts of small bowel tends to cause significant ileus. Take care to abrade the cecum with enough force that the surface becomes rough, but not so much that the wall tears. Finding this balance can take some time. Always handle t...

Abdominal adhesions are a form of scar tissue that form in the abdomen in response to inflammation, typically following surgery or intraabdominal infection. Adhesions are a major cause of chronic abdominal pain and infertility, and are the most common cause of small bowel obstruction1. The presence of adhesions makes performing a second abdominal operation more difficult and increases the likelihood of complications2.
Despite years of research, the mechanisms underlying the formation of adhesions remain poorly understood. It is known that an initial injury to the peritoneal surface causes an exudation of fibrin-rich fluid, which then forms a clot that binds the surfaces of bowel and the abdominal wall together3. Later, fibroblasts and other cells migrate into the adhesive space and secrete connective tissue4. Over months to years the adhesion matures by developing blood vessels and nerves5.
Several commercial products exist that are designed to reduce the formation of adhesions after abdominal surgery (e.g., Seprafilm). All of these products act as mechanical barriers and stop adhesion formation by preventing physical contact between loops of bowel and the abdominal wall6,7. Despite evidence from a controlled trial that a surgical adhesion barrier reduces the formation of adhesions8, many surgeons anecdotally have been disappointed with the effectiveness of mechanical barrier products.
Currently there are no drug-based anti-adhesion therapies, which reflects the fact that the precise processes involved in adhesion formation are poorly understood. Developing a therapy that specifically targets cellular or molecular agents involved in the formation of adhesions will require an improved understanding of the events that are involved in the formation of the adhesion. Several groups have identified molecular pathways that may be important for adhesion formation9-11. Animal models provide a superb environment for studying the formation of adhesions. Many studies have been published describing the surgical creation of adhesion in several animals, particular the rat and mouse6,12-14. Given our experience with studying fibrosis in the mouse and the wide availability of transgenic mice and mouse-based antibodies, we chose the mouse as our model for the study of adhesions. Herein, we report the technique that we have developed to reproducibly and reliably create abdominal adhesions in the mouse.

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creation of abdominal adhesions in mice

Abdominal adhesions consist of fibrotic tissue that forms in the peritoneal space in response to an inflammatory insult, typically surgery or intraabdominal infection. The precise mechanisms underlying adhesion formation are poorly understood. Many compounds and physical barriers have been tested for their ability to prevent adhesions after surgery with varying levels of success. The mouse and rat are important models for the study of abdominal adhesions. Several different techniques for the creation of adhesions in the mouse and rat exist in the literature. Here we describe a protocol utilizing abrasion of the cecum with sandpaper and sutures placed in the right abdominal sidewall. The mouse is anesthetized and the abdomen is prepped. A midline laparotomy is created and the cecum is identified. Sandpaper is used to gently abrade the surface of the cecum. Next, several figure-of-eight sutures are placed into the peritoneum of the right abdominal sidewall. The abdominal cavity is irrigated, a small amount of starch is applied, and the incision is closed. We have found that this technique produces the most consistent adhesions with the lowest mortality rate.

At seven days after surgery, the cecum and possibly ascending colon, liver, and loops of small bowel should be adherent to the right-sided abdominal wall. (Figure 8) Excised tissue can be embedded and sectioned and will yield excellent histological slides. (Figure 11, 12)
When the procedure is performed properly, 100% of mice should have substantial adhesions at seven days. Mortality should be l...

Watch this Scientific Journal Video about Creation of Abdominal Adhesions in Mice at JoVE.com

Creation of Abdominal Adhesions in Mice

Abdominal adhesions that form after surgery are a major cause of pain, infertility, and hospitalization and reoperation for small bowel obstruction. Our surgical procedure for creating abdominal adhesions in mice is a reliable tool to study the mechanisms underlying the formation of adhesions.

Abdominal adhesions consist of fibrotic tissue that forms in the peritoneal space in response to an inflammatory insult, typically surgery or ...

The overall goal of this procedure is to consistently produce abdominal adhesions in the mouse while minimizing mortality. This method can help answer key questions in the field of abdominal adhesions, such as what cells, macromolecules, signaling pathways and cytokines are involved in adhesion formation. The main advantages of this technique are that the mice produce adhesions 100%of the time and the mortality rate is very low when the procedure is performed correctly.Generally individuals new to this procedure will struggle with applying the appropriate amount of force when using the sandpaper and also when applying the correct amount of starch. Visual demonstration of this technique is critical because too much force will perforate the cecum, but too little force may not result in the formation of adhesions. On the day of the surgery, use hair clippers to trim the abdominal fur of the anesthetized animal.Then transfer the animal to a warming device and secure the limbs with tape. Next, disinfect the abdomen with betadine, followed by 70%ethanol, taking care to include the hair on the edges of the shaved area. Place a sterile drape over the mouse.Then grasp the lower abdominal skin with a forceps and make a shallow vertical cut. Continue the incision up to the xiphoid process. Then grasp the abdominal musculature at the midline and use sharp scissors to carefully make a small incision, taking care to avoid the internal organs.When the abdominal organs are visible, insert the scissors into the incision and carefully cut in both directions to extend the cut from the xiphoid process to above the bladder. Once the intestines have been exposed, locate the cecum and use an atraumatic forceps to gently exteriorize the tissue. Orient the cecum with the tip facing toward the dominant hand and drape the cecum over the non-dominant index finger.Using 100 grit sandpaper, gently abrade the entire surface of both sides of the externalized intestine for 30 to 60 seconds. A small amount of grittiness should be felt as the sandpaper's moved along the cecal surface. If a cecal blood vessel is sheared during the abrasion, gently press gauze onto the site of bleeding for up to two minutes.If the bleeding continues after two minutes, place a figure of 870 monofilament suture around the vessel. When the cecal surface becomes less shiny and petechia appear, use a new strip of sandpaper to abrade the peritoneal surface of the right abdominal side wall muscle until the entire surface of the side wall appears rough. Then use a castroviejo needle driver to place two to four figure of 840 silk stitches into the muscular layer of the right abdominal side wall, leaving fine millimeter long tails.Use a 10 milliliter syringe of warmed saline to irrigate the intestines and the abdominal cavity several times. If the area underneath the mouse becomes soaked, move the mouse to a dry surface to avoid hypothermia. When the intestines have been well-irrigated, place sterile gauze over the incision to soak up the excess saline.Then position the cecum next to the sutures in the right abdominal side wall. Use a gauze sponge to apply pressure onto any points of active bleeding. Then sprinkle a pinch of rice starch onto the surface of the right abdominal side wall and the cecum.To close the abdomen, use a 60 absorbable braided suture to place a running stitch into the muscular layer at the top of the incision. Run the suture down toward the bottom of the incision, bringing together three by three millimeter sections of the musculature with each new stitch. At the bottom of the incision, leave a loop of suture from the previous stitch to instrument tie the suture and cut the suture, leaving five millimeter tails.Use a 60 nylon monofilament suture to close the skin in the same manner. Then administer a 20 milliliter per kilogram subcutaneous saline bolus and thoroughly dry the entire animal with fresh gauze. Finally, loosely wrap an adhesive dressing around the incision, taking care not to constrain the animal's legs or breathing mechanics and monitor the mouse until it is fully recovered.At seven days after the surgery, the cecum and possibly the ascending colon, liver and loops of small bowel should be adherent to the right-sided abdominal wall. Embedding and sectioning of the excised abdominal tissue yields excellent slides for histological and immunohistochemical analyses. Once this procedure is mastered, it can be performed in under 30 minutes.Following this procedure, other methods such as quantitative PCR and fiberglass culture can be used to answer questions about gene expression within the adhesion tissue.

Research

JoVE Journal

Medicine

The C-seal: A Biofragmentable Drain Protecting the Stapled Colorectal Anastomosis from Leakage

Colorectal anastomotic leakage (AL) is a serious complication in colorectal surgery leading to high morbidity and mortality rates1. The incidence of AL varies between 2.5 and 20% 2-5. Over the years, many strategies aimed at lowering the incidence of anastomotic leakage have been examined6, 7. 
The cause of AL is probably multifactorial. Etiological factors include insufficient arterial blood supply, tension on the anastomosis, hematoma and/or infection at the anastomotic site, and co-morbid factors of the patient as diabetes and atherosclerosis8. Furthermore, some anastomoses may be insufficient from the start due to technical failure.
Currently a new device is developed in our institute aimed at protecting the colorectal anastomosis and lowering the incidence of AL. This so called C-seal is a biofragmentable drain, which is stapled to the anastomosis with the circular stapler. It covers the luminal side of the colorectal anastomosis thereby preventing leakage.
The C-seal is a thin-walled tube-like drain, with an approximate diameter of 4 cm and an approximate length of 25 cm (figure 1). It is a tubular device composed of biodegradable polyurethane. Two flaps with adhesive tape are found at one end of the tube. These flaps are used to attach the C-seal to the anvil of the circular stapler, so that after the anastomosis is made the C-seal can be pulled through the anus. The C-seal remains in situ for at least 10 days. Thereafter it will lose strength and will degrade to be secreted from the body together with the gastrointestinal natural contents.
The C-seal does not prevent the formation of dehiscences. However, it prevents extravasation of faeces into the peritoneal cavity. This means that a gap at the anastomotic site does not lead to leakage.
Currently, a phase II study testing the C-seal in 35 patients undergoing (colo-)rectal resection with stapled anastomosis is recruiting. The C-seal can be used in both open procedures as well as laparoscopic procedures. The C-seal is only applied in stapled anastomoses within 15cm from the anal verge. In the video, application of the C-seal is shown in an open extended sigmoid resection in a patient suffering from diverticular disease with a stenotic colon.

The C-seal is a biofragmentable drain protecting the stapled colorectal anastomosis. In this video, details of the manufacturing, deployment and use are shown.

Colorectal anastomotic leakage (AL) is a serious complication in colorectal surgery leading to high morbidity and mortality rates1. The incidence of AL ...

Creation of Reversible Cholestatic Rat Model

Cholestasis is a clinical condition commonly encountered by both surgeons and gastroenterologists. Cholestasis can cause various physiological changes and affect the nutritional status and surgical outcomes. Study of the pathophysiological changes occurring in the liver and other organs is of importance. Various studies have been done in cholestatic rat models.
We used a reversible cholestatic rat model in our recent study looking at the role of methylprednisolone in the ischemia reperfusion injury. Various techniques for creation of a reversible cholestatic model have been described. Creation of a reversible cholestatic rat model can be challenging in view of the smaller size and unique hepatopancreatobiliary anatomy in rats. This video article demonstrates the creation of a reversible cholestatic model.
This model can be used in various studies, such as looking at the changes in nutritional, physiological, pathological, histological and immunological changes in the gastrointestinal tract. This model can also be used to see the effects of cholestasis and various therapeutic interventions on major hepatic surgeries.

Cholestasis is a clinical condition commonly encountered by both surgeons and gastroenterologists. Creation of a reversible cholestatic rat model can be challenging in view of the smaller size and unique hepatopancreatobiliary anatomy in rats. This video article demonstrates the creation of a reversible cholestatic model.

Cholestasis is a clinical condition commonly encountered by both surgeons and gastroenterologists. Cholestasis can cause various physiological changes and ...

Orthotopic Liver Transplantation in Rats

Clinical progress in the field of liver transplantation has been largely supported by animal models1,2. Since the publication of the first orthotopic rat liver transplantation in 1979 by Kamada et al.3, this model has remained the gold standard despite various proposed alternative techniques4. Nevertheless, its broader use is limited by its steep learning curve5.
In this video paper, we show a simple and easy-to-establish revision of Kamada's two-cuff technique. The suprahepatic vena cava anastomosis is performed manually with a running suture, and the vena porta and infrahepatic vena cava anastomoses are performed utilizing a quick-linker cuff system6. Manufacturing the quick-linker kit is shown in a separate video paper.

We present an easy-to-establish revision of the classical two-cuff technique for orthotopic liver transplantation in rat.

Clinical progress in the field of liver transplantation has been largely supported by animal models1,2. Since the publication of the first orthotopic rat ...

Ascending Aortic Constriction in Rats for Creation of Pressure Overload Cardiac Hypertrophy Model

Ascending aortic constriction is the most common and successful surgical model for creating pressure overload induced cardiac hypertrophy and heart failure. Here, we describe a detailed surgical procedure for creating pressure overload and cardiac hypertrophy in rats by constriction of the ascending aorta using a small metallic clip. After anesthesia, the trachea is intubated by inserting a cannula through a half way incision made between two cartilage rings of trachea. Then a skin incision is made at the level of the second intercostal space on the left chest wall and muscle layers are cleared to locate the ascending portion of aorta. The ascending aorta is constricted to 50&#8211;60% of its original diameter by application of a small sized titanium clip. Following aortic constriction, the second and third ribs are approximated with prolene sutures. The tracheal cannula is removed once spontaneous breathing was re-established. The animal is allowed to recover on the heating pad by gradually lowering anesthesia. The intensity of pressure overload created by constriction of the ascending aorta is determined by recording the pressure gradient using trans-thoracic two dimensional Doppler-echocardiography. Overall this protocol is useful to study the remodeling events and contractile properties of the heart during the gradual onset and progression from compensated cardiac hypertrophy to heart failure stage.

We describe a stepwise procedure for creating pressure overload and left ventricular hypertrophy in Wistar rats by constriction of the ascending aorta using a small metallic clip. This model is extensively used for studying remodeling changes during cardiac hypertrophy and for identifying and evaluating strategies for regression of such changes.

Ascending aortic constriction is the most common and successful surgical model for creating pressure overload induced cardiac hypertrophy and heart ...

Carotid Artery Infusions for Pharmacokinetic and Pharmacodynamic Analysis of Taxanes in Mice

When proposing the use of a drug, drug combination, or drug delivery into a novel system, one must assess the pharmacokinetics of the drug in the study model. As the use of mouse models are often a vital step in preclinical drug discovery and drug development1-8, it is necessary to design a system to introduce drugs into mice in a uniform, reproducible manner. Ideally, the system should permit the collection of blood samples at regular intervals over a set time course. The ability to measure drug concentrations by mass-spectrometry, has allowed investigators to follow the changes in plasma drug levels over time in individual mice1, 9, 10. In this study, paclitaxel was introduced into transgenic mice as a continuous arterial infusion over three hours, while blood samples were simultaneously taken by retro-orbital bleeds at set time points. Carotid artery infusions are a potential alternative to jugular vein infusions, when factors such as mammary tumors or other obstructions make jugular infusions impractical. Using this technique, paclitaxel concentrations in plasma and tissue achieved similar levels as compared to jugular infusion. In this tutorial, we will demonstrate how to successfully catheterize the carotid artery by preparing an optimized catheter for the individual mouse model, then show how to insert and secure the catheter into the mouse carotid artery, thread the end of the catheter out through the back of the mouse&#8217;s neck, and hook the mouse to a pump to deliver a controlled rate of drug influx. Multiple low volume retro-orbital bleeds allow for analysis of plasma drug concentrations over time.

This method was developed with the goal of delivering a steady drug solution via the carotid artery, to assess the pharmacokinetics of novel drugs in mouse models.

When proposing the use of a drug, drug combination, or drug delivery into a novel system, one must assess the pharmacokinetics of the drug in the study ...

Creation of a Rodent Model of Abdominal Aortic Aneurysm by Blocking Adventitial Vasa Vasorum Perfusion

The adventitial vasa vasorum (VV) provides oxygen and nourishment to the aortic wall. Hypoxia in the aortic wall can cause enlarged abdominal aortic aneurysms (AAAs). This article introduces and describes a standard protocol used to induce AAAs through adventitial VV hypoperfusion created with a combination of polyurethane catheter insertion into the aortic lumen and suture ligation of the infrarenal abdominal aorta.
The protocol involves the use of male rats weighing 300-400 g, which are provided food and water ad libitum. After laparotomy with a ventral midline abdominal incision, exfoliation of the aorta is performed, which blocks blood flow from the perivascular tissue. Aortotomy involving a small incision adjacent to the renal artery branches is performed, and a polyurethane catheter is inserted using an 18-gauge indwelling needle. After repairing the incision, tight ligation of the aorta over the catheter blocks VV blood flow from the proximal direction through the aortic wall without disturbing the aortic blood flow. This technique can induce an AAA with progressive aortic dilatation.
The greatest benefit of this model is that VV hypoperfusion causes tissue hypoxia and the development of an infrarenal AAA, which has morphological and pathological characteristics similar to those of a human AAA.

Polyurethane catheter insertion into the aortic lumen and suture ligation of the aorta induce chronic hypoxia due to hypoperfusion of the adventitial vasa vasorum. This article describes a novel animal model of abdominal aortic aneurysm (AAA) with characteristics similar to those of AAA in humans.

The adventitial vasa vasorum (VV) provides oxygen and nourishment to the aortic wall. Hypoxia in the aortic wall can cause enlarged abdominal aortic ...

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 ...

Ultrasound Imaging of the Thoracic and Abdominal Aorta in Mice to Determine Aneurysm Dimensions

Contemporary high-resolution ultrasound instruments have sufficient resolution to facilitate the measurement of mouse aortas. These instruments have been widely used to measure aortic dimensions in mouse models of aortic aneurysms. Aortic aneurysms are defined as permanent dilations of the aorta, which occur most frequently in the ascending and abdominal regions. Sequential measurements of aortic dimensions by ultrasound are the principal approach for assessing the development and progression of aortic aneurysms in vivo. Although many reported studies used ultrasound imaging to measure aortic diameters as a primary endpoint, there are confounding factors, such as probe position and cardiac cycle, that may impact the accuracy of data acquisition, analysis, and interpretation. The purpose of this protocol is to provide a practical guide on the use of ultrasound to measure the aortic diameter in a reliable and reproducible manner. This protocol introduces the preparation of mice and instruments, the acquisition of appropriate ultrasound images, and data analysis.

Ultrasound imaging has become a common modality to determine the luminal dimensions of thoracic and abdominal aortic aneurysms in mice. This protocol describes the procedure to acquire reliable and reproducible two-dimensional ultrasound images of the ascending and abdominal aorta in mice.

Contemporary high-resolution ultrasound instruments have sufficient resolution to facilitate the measurement of mouse aortas. These instruments have been ...

Porcine Model of Infrarenal Abdominal Aortic Aneurysm

Large animal models to study abdominal aortic aneurysms are sparse. The purpose of this model is to create reproducible, clinically significant infrarenal abdominal aortic aneurysms (AAA) in swine. To achieve this, we use a combination of balloon angioplasty, elastase and collagenase, and a lysyl oxidase inhibitor, called &#946;-aminopropionitrile (BAPN), to create clinically significant infrarenal aortic aneurysms, analogous to human disease.
Noncastrated male swine are fed BAPN for 7 days prior to surgery to achieve a steady state in the blood. A midline laparotomy is performed and the infrarenal aorta is circumferentially dissected. An initial measurement is recorded prior to aneurysm induction with a combination of balloon angioplasty, elastase (500 units)/collagenase (8000 units) perfusion, and topical elastase application. Swine are fed BAPN daily until terminal procedure on either postoperative day 7, 14, or 28, at which time the aneurysm is measured, and tissue procured. BAPN + surgery pigs are compared to pigs that underwent surgery alone.
Swine treated with BAPN and surgery had a mean aortic dilation of 89.9% &#177; 47.4% at day 7, 105.4% &#177; 58.1% at day 14, and 113.5% &#177; 30.2% at day 28. Pigs treated with surgery alone had significantly smaller aneurysms compared to BAPN + surgery animals at day 28 (p &#60; 0.0003). The BAPN + surgery group had macroscopic and immunohistochemical evidence of end stage aneurysmal disease.
Clinically significant infrarenal AAA can be induced using balloon angioplasty, elastase/collagenase perfusion and topical application, supplemented with oral BAPN. This model creates large, clinically significant AAA with hallmarks of human disease. This has important implications for the elucidation of AAA pathogenesis and testing of novel therapies and devices for the treatment of AAA. Limitations of the model include variation in BAPN ingested by swine, quality of elastase perfusion, and cost of BAPN.&#160;

This novel model creates robust infrarenal abdominal aortic aneurysms in swine using a combination of balloon angioplasty, elastase/collagenase perfusion, topical elastase application, and oral compound &#946;-aminopropionitrile administration, which interferes with collagen cross-linking.

Large animal models to study abdominal aortic aneurysms are sparse. The purpose of this model is to create reproducible, clinically significant infrarenal ...

Establishing In Situ Closed Circuit Perfusion of Lower Abdominal Organs and Hind Limbs in Mice

Ex vivo perfusion is an important physiological tool to study the function of isolated organs (e.g. liver, kidneys). At the same time, due to the small size of mouse organs, ex vivo perfusion of bone, bladder, skin, prostate, and reproductive organs is challenging or not feasible. Here, we report for the first time an in situ lower body perfusion circuit in mice that includes the above tissues, but bypasses the main clearance organs (kidney, liver, and spleen). The circuit is established by cannulating the abdominal aorta and inferior vena cava above the iliac artery and vein and cauterizing peripheral blood vessels. Perfusion is performed via a peristaltic pump with perfusate flow maintained for up to 2 h. In situ staining with fluorescent lectin and Hoechst solution confirmed that the microvasculature was successfully perfused. This mouse model can be a very useful tool for studying pathological processes as well as mechanisms of drug delivery, migration/metastasis of circulating tumor cells into/from the tumor, and interactions of immune system with perfused organs and tissues.

A protocol is described for in situ perfusion of the mouse lower body, including the bladder, the prostate, sex organs, bone, muscle and foot skin.

Ex vivo perfusion is an important physiological tool to study the function of isolated organs (e.g. liver, kidneys). At the same time, due to the small ...