This research was supported by NIH/NCI R21CA195002-01A1, The President&#39;s Council of Cornell Women and the SUNY Graduate Diversity Fellowship. Dr. Cummings&#39; laboratory also received funding during the project period from the Cornell Comparative Cancer Biology Training Program and Eli Lilly and Company.

All experimental protocols have been approved by the Cornell University Institutional Animal Care and Use Committee.
1. Pre-surgical Preparation
NOTE: Study mice are typically on a C57BL diet-induced obese background to make studies translationally relevant to human obesity and insulin resistance. Male and female mice may be studied as described in the subsequent steps.
<ol>
	<li>At an age of 2 months, place mice on a 45% or 60% high fat diet for 2 months (see <st...

<ol>
	<li>Buchwald, 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=Bariatric+surgery:+a+systematic+review+and+meta-analysis.">Bariatric surgery: a systematic review and meta-analysis.</a> JAMA. 292 (14), 1724-1737 (2004).</li><li>Wadden, T. A., Butryn, M. L., Byrne, K. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Efficacy+of+lifestyle+modification+for+long-term+weight+control.">Efficacy of lifestyle modification for long-term weight control.</a> Obes Res. 12, 151s-162s (2004).</li><li>Yanovski, S. Z., Yanovski, 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=Obesity.">Obesity.</a> N Engl J Med. 346 (8), 591-602 (2002).</li><li>Abbatini, F., 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=Long-term+effects+of+laparoscopic+sleeve+gastrectomy,+gastric+bypass,+and+adjustable+gastric+banding+on+type+2+diabetes.">Long-term effects of laparoscopic sleeve gastrectomy, gastric bypass, and adjustable gastric banding on type 2 diabetes.</a> Surg Endosc. 24 (5), 1005-1010 (2010).</li><li>Sjostrom, L., 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+bariatric+surgery+on+mortality+in+Swedish+obese+subjects.">Effects of bariatric surgery on mortality in Swedish obese subjects.</a> N Engl J Med. 357 (8), 741-752 (2007).</li><li>Adams, T. D., 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=Cancer+incidence+and+mortality+after+gastric+bypass+surgery.">Cancer incidence and mortality after gastric bypass surgery.</a> Obesity (Silver Spring). 17 (4), 796-802 (2009).</li><li>Vest, A. R., Heneghan, H. M., Schauer, P. R., Young, J. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Surgical+management+of+obesity+and+the+relationship+to+cardiovascular+disease.">Surgical management of obesity and the relationship to cardiovascular disease.</a> Circulation. 127 (8), 945-959 (2013).</li><li>Ahmed, A. R., 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=Laparoscopic+Roux-en-Y+gastric+bypass+and+its+early+effect+on+blood+pressure.">Laparoscopic Roux-en-Y gastric bypass and its early effect on blood pressure.</a> Obes Surg. 19 (7), 845-849 (2009).</li><li>Pories, W. 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=Who+would+have+thought+it?+An+operation+proves+to+be+the+most+effective+therapy+for+adult-onset+diabetes+mellitus.">Who would have thought it? An operation proves to be the most effective therapy for adult-onset diabetes mellitus.</a> Ann Surg. 222 (3), 339-350 (1995).</li><li>Garibay, D., 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=beta-Cell+Glucagon-Like+Peptide-1+Receptor+Contributes+to+Improved+Glucose+Tolerance+After+Vertical+Sleeve+Gastrectomy.">beta-Cell Glucagon-Like Peptide-1 Receptor Contributes to Improved Glucose Tolerance After Vertical Sleeve Gastrectomy.</a> Endocrinology. 157 (9), 3405-3409 (2016).</li><li>McGavigan, A. 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=TGR5+contributes+to+glucoregulatory+improvements+after+vertical+sleeve+gastrectomy+in+mice.">TGR5 contributes to glucoregulatory improvements after vertical sleeve gastrectomy in mice.</a> Gut. 66 (2), 226-234 (2017).</li><li>McGavigan, A. 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=Vertical+sleeve+gastrectomy+reduces+blood+pressure+and+hypothalamic+endoplasmic+reticulum+stress+in+mice.">Vertical sleeve gastrectomy reduces blood pressure and hypothalamic endoplasmic reticulum stress in mice.</a> Dis Model Mech. 10 (3), 235-243 (2017).</li><li>Esteban Varela, J., Nguyen, N. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Laparoscopic+sleeve+gastrectomy+leads+the+U.S.+utilization+of+bariatric+surgery+at+academic+medical+centers.">Laparoscopic sleeve gastrectomy leads the U.S. utilization of bariatric surgery at academic medical centers.</a> Surg Obes Relat Dis. 11 (5), 987-990 (2015).</li><li>Laferrere, B., 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=Effect+of+weight+loss+by+gastric+bypass+surgery+versus+hypocaloric+diet+on+glucose+and+incretin+levels+in+patients+with+type+2+diabetes.">Effect of weight loss by gastric bypass surgery versus hypocaloric diet on glucose and incretin levels in patients with type 2 diabetes.</a> J Clin Endocrinol Metab. 93 (7), 2479-2485 (2008).</li><li>Adams, T. D., 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=Health+benefits+of+gastric+bypass+surgery+after+6+years.">Health benefits of gastric bypass surgery after 6 years.</a> Jama. 308 (11), 1122-1131 (2012).</li><li>McGavigan, A. 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=TGR5+contributes+to+glucoregulatory+improvements+after+vertical+sleeve+gastrectomy+in+mice.">TGR5 contributes to glucoregulatory improvements after vertical sleeve gastrectomy in mice.</a> Gut. , (2015).</li><li>Peterli, R., 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=Improvement+in+glucose+metabolism+after+bariatric+surgery:+comparison+of+laparoscopic+Roux-en-Y+gastric+bypass+and+laparoscopic+sleeve+gastrectomy:+a+prospective+randomized+trial.">Improvement in glucose metabolism after bariatric surgery: comparison of laparoscopic Roux-en-Y gastric bypass and laparoscopic sleeve gastrectomy: a prospective randomized trial.</a> Ann Surg. 250 (2), 234-241 (2009).</li><li>Ryan, K. 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=FXR+is+a+molecular+target+for+the+effects+of+vertical+sleeve+gastrectomy.">FXR is a molecular target for the effects of vertical sleeve gastrectomy.</a> Nature. 509 (7499), 183-188 (2014).</li><li>Wilson-Perez, H. 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=Vertical+sleeve+gastrectomy+is+effective+in+two+genetic+mouse+models+of+glucagon-like+Peptide+1+receptor+deficiency.">Vertical sleeve gastrectomy is effective in two genetic mouse models of glucagon-like Peptide 1 receptor deficiency.</a> Diabetes. 62 (7), 2380-2385 (2013).</li><li>Pressler, J. 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=Vertical+sleeve+gastrectomy+restores+glucose+homeostasis+in+apolipoprotein+A-IV+KO+mice.">Vertical sleeve gastrectomy restores glucose homeostasis in apolipoprotein A-IV KO mice.</a> Diabetes. 64 (2), 498-507 (2015).</li></ol>

Bariatric surgery is the most effective long-term treatment for obesity and results in other health benefits such as high rates of type 2 diabetes and hypertension remission1,9,15. Murine models of bariatric surgery provide a powerful tool with which to identify the mechanisms by which bariatric surgery causes rapid and pronounced improvements in obesity comorbidities. Furthermore, murine models of bariatric surgery provide a no...

As the obesity epidemic continues to grow worldwide bariatric surgery has gained popularity as it is the most effective long-term treatment for obesity1. Unfortunately, weight loss by diet and exercise is difficult to achieve and relatively ineffective over the long-term2,3. Bariatric surgery, such as vertical sleeve gastrectomy (VSG), is defined as the manipulation of the gastrointestinal tract for the purpose of weight loss1,4. Although weight loss is a prominent outcome of bariatric surgery, bariatric surgery provides other health benefits such as improving obesity comorbidities and extending lifespan5. For example, bariatric surgery results in high rates of remission of type 2 diabetes and hypertension, and reductions in the lifetime risk of the development of certain types of cancer1,6,7. Of note, the effect of bariatric surgery causing remission of type 2 diabetes and hypertension is often observed soon after surgery and prior to weight loss8,9. This highlights the concept that there are mechanisms independent of body weight contributing to the health benefits observed after surgery. Animal models of bariatric surgery have been developed and are utilized to study the mechanisms by which these health benefits occur10,11,12.
We have validated a mouse model of VSG, which we have applied to various genetically modified mouse models to study the mechanisms by which bariatric surgery improves obesity comorbidities such as type 2 diabetes, hypertension, and colorectal cancer10,11,12. Rodent models allow more experimental control and the ability to perform genetic or pharmaceutical manipulation to define the role of specific genes or signaling pathways of interest. We are focusing primarily on VSG because VSG is the most commonly performed bariatric procedure in the clinic in the United States13. Additionally, VSG is a simple surgical model with fewer anatomic modifications compared to other procedures such as Roux-en-Y gastric bypass or biliopancreatic diversion.
Our mouse model of VSG recapitulates the following effects of bariatric surgery observed in humans: weight loss, reduced food intake, improved glucose regulation, improved islet function, increased post-prandial glucagon-like peptide-1 (GLP-1) secretion, reduced arterial blood pressure, and increased circulating bile acid concentrations10,11,12,13,14,15. Therefore, this is an ideal model to study the body weight dependent and independent mechanisms by which VSG improves or resolves obesity comorbidities. In addition, it is a reliable model that can be combined with other surgical procedures, allowing for the investigation of the impact of VSG under various disease conditions with greater mechanistic insight12.

<table>
	<tbody>
		<tr>
			<td>45% high fat diet</td>
			<td>Research Diets</td>
			<td>D12451</td>
			<td></td>
		</tr>
		<tr>
			<td>60% high fat diet</td>
			<td>Research Diets</td>
			<td>D12492</td>
			<td></td>
		</tr>
		<tr>
			<td>Boost</td>
			<td>Nestle</td>
			<td>160-67538</td>
			<td>rich chocolate flavor</td>
		</tr>
		<tr>
			<td>6-0 Suture</td>
			<td>Ethicon</td>
			<td>Z432</td>
			<td>monofilament absorbable/taper</td>
		</tr>
		<tr>
			<td>7-0 Suture</td>
			<td>Covidien</td>
			<td>8866127-01</td>
			<td>monofilament absorbable/taper</td>
		</tr>
		<tr>
			<td>Cotton Swabs</td>
			<td>Fisherbrand</td>
			<td>23-400-118</td>
			<td>small</td>
		</tr>
		<tr>
			<td>Cotton Swabs</td>
			<td>Fisherbrand</td>
			<td>233-400-101</td>
			<td>large</td>
		</tr>
		<tr>
			<td>Gauze</td>
			<td>Various</td>
			<td></td>
			<td>4x4 4 ply and 2x2 4 ply</td>
		</tr>
		<tr>
			<td>Foil</td>
			<td>Various</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Surgery drape</td>
			<td>Various</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>0.9% saline solution</td>
			<td>Various</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>LRS</td>
			<td>Hospira</td>
			<td>170RX</td>
			<td></td>
		</tr>
		<tr>
			<td>Betadine</td>
			<td>Various</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Alcohol</td>
			<td>Various</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Eye Ointment</td>
			<td>Paralube&#174; Vet Ointment</td>
			<td>17033-211-38</td>
			<td></td>
		</tr>
		<tr>
			<td>Tissue Adhesive</td>
			<td>Vetbond</td>
			<td>1469SB</td>
			<td></td>
		</tr>
		<tr>
			<td>Meloxicam (Metacam)</td>
			<td>Boehringer Ingelheim</td>
			<td>141-213</td>
			<td>5 mg/ml</td>
		</tr>
		<tr>
			<td>Enrofloxacin</td>
			<td>Baytril</td>
			<td>08713254-186599</td>
			<td>22.7 mg/ml</td>
		</tr>
		<tr>
			<td>Thin tipped hemostats</td>
			<td>Fine Science Tools</td>
			<td>13021-12</td>
			<td></td>
		</tr>
		<tr>
			<td>Metzenbaum Scissor</td>
			<td>Fine Science Tools</td>
			<td>14018-18</td>
			<td></td>
		</tr>
		<tr>
			<td>Iris Scissors</td>
			<td>Fine Science Tools</td>
			<td>14058-09</td>
			<td></td>
		</tr>
		<tr>
			<td>Dumont Forcep</td>
			<td>Fine Science Tools</td>
			<td>11251-20</td>
			<td></td>
		</tr>
		<tr>
			<td>Serrated Forcep</td>
			<td>Fine Science Tools</td>
			<td>11020-12</td>
			<td></td>
		</tr>
		<tr>
			<td>Gavage needle</td>
			<td>Fine Science Tools</td>
			<td>18060-20</td>
			<td></td>
		</tr>
		<tr>
			<td>Microneedle driver</td>
			<td>Fine Science Tools</td>
			<td>12075-14</td>
			<td></td>
		</tr>
		<tr>
			<td>Spring Scissor</td>
			<td>Fine Science Tools</td>
			<td>15396-00</td>
			<td></td>
		</tr>
		<tr>
			<td>Insulin syringe</td>
			<td>Various</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>1mL syringe</td>
			<td>Various</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>20mL syringe</td>
			<td>Various</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Glucometer (one touch ultra mini)</td>
			<td>Lifescan</td>
			<td>70021208</td>
			<td></td>
		</tr>
		<tr>
			<td>Multiplex insulin and GLP-1 kit</td>
			<td>Meso Scale Discovery</td>
			<td>K15171C-1</td>
			<td></td>
		</tr>
		<tr>
			<td>GraphPad Prism 6.00</td>
			<td>GraphPad Software</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Nestlets</td>
			<td>Ancare</td>
			<td>NES3600</td>
			<td></td>
		</tr>
	</tbody>
</table>

a murine model of vertical sleeve gastrectomy

Bariatric surgery, such as vertical sleeve gastrectomy (VSG), is a surgery of the gastrointestinal tract that is performed for the purpose of weight loss. Bariatric surgery is currently the most effective long-term treatment for obesity. In addition to weight loss, bariatric surgery produces additional health benefits such as remission of type 2 diabetes, remission of hypertension, and decreased risk of developing certain types of cancer. The mechanisms beyond weight loss for these benefits remain incompletely defined. Therefore, animal models of bariatric surgery are being developed and validated to identify the mechanisms leading to these benefits, with the goal of improving understanding of gastrointestinal physiology and identifying new therapeutic targets. VSG has become the most commonly performed bariatric procedure in the clinic in the United States because it is highly effective at producing weight loss and metabolic improvement, and is simpler to perform than other bariatric procedures. Therefore, we have developed and validated a murine model of VSG. This murine VSG model recapitulates many of the effects of VSG seen in humans, including improved glucose and blood pressure regulation. The method is based on isolation of the stomach, ligation of gastric vessels, and removal of 70% of the stomach by transecting along the greater curvature of the stomach. We have successfully applied this surgical protocol to various genetically modified mouse lines to define the mechanistic contributors to the benefits of VSG. Furthermore, this murine VSG model has been combined with other surgical techniques, to achieve deeper mechanistic insight. Therefore, this is a simple and versatile model for studying gastrointestinal physiology and the health benefits of bariatric surgery.

The sham and VSG procedures are depicted in Figure 1. Figure 1A shows where the suture line is placed along the gastric walls during the sham procedure. This same area is where the stomach is cut during VSG surgery. Figure 1B shows the tubular remnant of stomach left after performance of VSG.
Statistics and Data Analysis<br...

Watch this Scientific Journal Video about A Murine Model of Vertical Sleeve Gastrectomy at JoVE.com

A Murine Model of Vertical Sleeve Gastrectomy

The following describes the performance of vertical sleeve gastrectomy in mice. This is a type of weight-loss surgery that involves removal of approximately 70% of the stomach.

Bariatric surgery, such as vertical sleeve gastrectomy (VSG), is a surgery of the gastrointestinal tract that is performed for the purpose of weight loss. ...

The overall goal of this procedure is to model the health benefits of vertical sleeve gastrectomy in mice. This method can help answer key questions in obesity research about the mechanisms by which bariatric surgery improves obesity and obesity comorbidities. The advantage of this technique is that it provides a model for studying these mechanisms which will facilitate identification of novel targets for the treatment of obesity and its comorbidities.Before beginning the procedure, apply veterinary ointment to the eyes of an anesthetized mouse and place the mouse on a heating pad. Remove the hair from the umbilicus to the axilla gently holding the skin taught to avoid skin lesions and use cotton-tip applicators to sequentially disinfect the exposed skin with povidone-iodine and ethanol. Wearing sterile gloves and using sterile technique, place sterile surgical drapes on either side of the animal.Cut a small hole in the foil to allow access to the mouse's abdomen and use a piece of autoclaved aluminum foil as a surgical drape. Make a skin incision from the mid abdomen to the xiphoid cartilage. Under a dissecting microscope, use iris scissors to cut through the body wall along the linea alba.And use new cotton-tip applicators to gently elevate the stomach out of the abdomen. Bluntly dissect the greater omentum from the greater curvature of the stomach. Then use 7-0 monofilament absorbable sutures to place two ligatures around the short gastric artery that runs between the fundus of the stomach and the spleen.When both ligatures have been placed, use spring scissors to cut between the two sutures and fully exteriorize the stomach from the abdominal cavity. Place gauze under the stomach and hydrate the organ with saline. For a sham procedure, use a 6-0 monofilament absorbable suture with a taper needle to place a loose simple continuous pattern starting two millimeters to the right of the esophagus along the ventral gastric wall and continuing along the dorsal gastric wall.Make sure the suture lies flat without restricting the stomach and use three to four throws to gently tie off the suture. For a vertical sleeve gastrectomy procedure, use a 7-0 monofilament absorbable suture with a taper needle to ligate the prominent branches of the gastric artery and vein just below the intended line of transection. Place a simple continuous line of 6-0 monofilament absorbable suture through both gastric walls just below the intended line of transection to prevent spillage of the gastric contents.Place thin-tipped hemostats above the suture line and use spring scissors to cut between the suture line and the hemostats. Remove the transected gastric tissue from the sterile surgical field and use fresh cotton-tip applicators to clean the blood and digesta from the stomach. Use a 6-0 monofilament absorbable suture with a taper needle to reinforce the apposition of the gastric walls in a simple discontinuous pattern.Using a 20-gauge gavage needle attached to a 20-milliliter syringe, perform gastric lavage with fresh saline and securely close the stomach with a minimum of 20 knots. Then gently press the stomach with a cotton applicator to test for leaks. If no leaks are detected, lavage the stomach with at least 60 more milliliters of fresh saline to remove any infectious particulates.After either procedure, use a cotton-tip applicator to return the stomach under the liver within the abdominal cavity and place an applicator along the dorsal aspect of the abdominal cavity to absorb any excess fluid. Use a blunt 18-gauge needle to inject lactated Ringer's solution with our without antibiotics directly into the abdominal cavity and use 6-0 monofilament absorbable sutures to close the abdominal muscle layer in a simple discontinuous pattern and the skin layer in a simple continuous pattern. Then place tissue adhesive on the skin and fold the skin over the suture line to protect the suture from disruption by the animal.Vertical sleeve gastrectomy operated, high-fat-diet fed mice exhibit a reduced energy intake and body weight compared to ad libitum fed, sham operated mice. Vertical sleeve gastrectomy improves glucose tolerance, increases glucose stimulated insulin secretion and increases postprandial glucagon-like peptide one secretion compared to sham operated, ad libitum fed control mice consistent with outcomes observed in humans and other rodent models of bariatric surgery. Once mastered, this procedure should be performed in 90 minutes.While learning this procedure it is important to remember to be gentle when manipulating the gastrointestinal tract. The GI tract is a very sensitive organ in mice and accidental manipulation of the small intestine can lead to GI stasis. After successfully learning this procedure, researchers can apply genetic or pharmaceutical manipulations to various disease models to investigate the mechanisms by which bariatric surgery improves health.

a-murine-model-of-vertical-sleeve-gastrectomy

Research

JoVE Journal

Biology

10.9K vues.  Cornell University. The overall goal of this procedure is to model the health benefits of vertical sleeve gastrectomy in mice. This method can help answer key questions in obesity research about the mechanisms by which bariatric surgery improves obesity and obesity comorbidities. The advantage of this technique is that it provides a model for studying these mechanisms which will facilitate identification of novel targets for the treatment of obesity and its comorbidities.Before beginning the procedure, ap...

Vidéo: A Murine Model of Vertical Sleeve Gastrectomy

Murine Pancreatic Islet Isolation

Murine Model of Hindlimb Ischemia 

In the United States, peripheral arterial disease (PAD) affects about 10 million individuals, and is also prevalent worldwide. Medical therapies for symptomatic relief are limited. Surgical or endovascular interventions are useful for some individuals, but long-term results are often disappointing. As a result, there is a need for developing new therapies to treat PAD. The murine hindlimb ischemia preparation is a model of PAD, and is useful for testing new therapies. When compared to other models of tissue ischemia such as coronary or cerebral artery ligation, femoral artery ligation provides for a simpler model of ischemic tissue. Other advantages of this model are the ease of access to the femoral artery and low mortality rate. 
In this video, we demonstrate the methodology for the murine model of unilateral hindimb ischemia. The specific materials and procedures for creating and evaluating the model will be described, including the assessment of limb perfusion by laser Doppler imaging. This protocol can also be utilized for the transplantation and non-invasive tracking of cells, which is demonstrated by Huang et al.1.

Murine Model of Hindlimb Ischemia

The surgical procedure for induction of unilateral hindlimb ischemia is demonstrated, with confirmation of ischemia by laser Doppler perfusion imaging.

In the United States, peripheral arterial disease (PAD) affects about 10 million individuals, and is also prevalent worldwide.  Medical therapies for ...

Murine Renal Transplantation Procedure

Renal orthotopic transplantation in mice is a technically challenging procedure. Although the first kidney transplants in mice were performed by Russell et al over 30 years ago (1) and refined by Zhang et al years later (2), few people in the world have mastered this procedure. In our laboratory we have successfully performed 1200 orthotopic kidney transplantations with &gt; 90% survival rate. The key points for success include stringent control of reperfusion injury, bleeding and thrombosis, both during the procedure and post-transplantation, and use of 10-0 instead of 11-0 suture for anastomoses.
Post-operative care and treatment of the recipient is extremely important to transplant success and evaluation. All renal graft recipients receive antibiotics in the form of an injection of penicillin immediately post-transplant and sulfatrim in the drinking water continually. Overall animal health is evaluated daily and whole blood creatinine analyses are performed routinely with a portable I-STAT machine to assess graft function.

Renal transplantation in mice is a technically challenging procedure that requires careful post-operative care and treatment for success.

Renal orthotopic transplantation in mice is a technically challenging procedure. Although the first kidney transplants in mice were performed by Russell ...

LAD-Ligation: A Murine Model of Myocardial Infarction

Research models of infarction and myocardial ischemia are essential to investigate the acute and chronic pathobiological and pathophysiological processes in myocardial ischemia and to develop and optimize future treatment.
Two different methods of creating myocardial ischemia are performed in laboratory rodents. The first method is to create cryo infarction, a fast but inaccurate technique, where a cryo-pen is applied on the surface of the heart (1-3). Using this method the scientist can not guarantee that the cryo-scar leads to ischemia, also a vast myocardial injury is created that shows pathophysiological side effects that are not related to myocardial infarction. The second method is the permanent ligation of the left anterior descending artery (LAD). Here the LAD is ligated with one single stitch, forming an ischemia that can be seen almost immediately. By closing the LAD, no further blood flow is permitted in that area, while the surrounding myocardial tissue is nearly not affected. This surgical procedure imitates the pathobiological and pathophysiological aspects occurring in infarction-related myocardial ischemia.
The method introduced in this video demonstrates the surgical procedure of a mouse infarction model by ligating the LAD. This model is convenient for pathobiological and pathophysiological as well as immunobiological studies on cardiac infarction. The shown technique provides high accuracy and correlates well with histological sections.

This video demonstrates how to use a fast and reliable model to study pathobiological and pathophysiological processes of myocardial ischemia.

Research models of infarction and myocardial ischemia are essential to investigate the acute and chronic pathobiological and pathophysiological processes ...

The Murine Choline-Deficient, Ethionine-Supplemented (CDE) Diet Model of Chronic Liver Injury

Chronic liver diseases, such as viral hepatitis, alcoholic liver disease, or non-alcoholic fatty liver disease, are characterized by continual inflammation, progressive destruction and regeneration of the hepatic parenchyma, liver progenitor cell proliferation, and fibrosis. The end-stage of every chronic liver disease is cirrhosis, a major risk factor for the development of hepatocellular carcinoma. To study processes regulating disease initiation, establishment, and progression, several animal models are used in laboratories. Here we describe a six-week time course of the choline-deficient and ethionine-supplemented (CDE) mouse model, which involves feeding six-week old male C57BL/6J mice with choline-deficient chow and 0.15% DL-ethionine-supplemented drinking water. Monitoring of animal health and a typical body weight loss curve are explained. The protocol demonstrates the gross examination of a CDE-treated liver and blood collection by cardiac puncture for subsequent serum analyses. Next, the liver perfusion technique and collection of different hepatic lobes for standard evaluations are shown, including liver histology assessments by hematoxylin and eosin or Sirius Red stainings, immunofluorescent detection of hepatic cell populations as well as transcriptome profiling of the liver microenvironment. This mouse model is suitable for studying inflammatory, fibrogenic, and liver progenitor cell dynamics induced through chronic liver disease and can be used to test potential therapeutic agents that may modulate these processes.

The Murine Choline-Deficient, Ethionine-Supplemented CDE Diet Model of Chronic Liver Injury

Here we describe a common method to induce chronic liver injury in mice by feeding of a choline-deficient and ethionine-supplemented (CDE) diet. We demonstrate health monitoring, liver perfusion, isolation, and preservation. A time course of six weeks can inform about liver injury, pathohistology, fibrosis, inflammatory, and liver progenitor cell responses.

Chronic liver diseases, such as viral hepatitis, alcoholic liver disease, or non-alcoholic fatty liver disease, are characterized by continual ...

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 Murine Model of a Burn Wound Reconstructed with an Allogeneic Skin Graft

Trivial superficial wounds heal without complications by primary intention. Deep wounds, such as full thickness burns, heal by secondary intention and require surgical debridement and skin grafting. Successful integration of the donor graft into a recipient wound bed depends on timely recruitment of immune cells, robust angiogenic response and new extracellular matrix formation. The development of novel therapeutic agents, which target some key processes involved in wound healing, are hindered by the lack of reliable preclinical models with optimized objective assessment of wound closure. Here, we describe an inexpensive and reproducible model of experimental full thickness burn wound reconstructed with an allogeneic skin graft. The wound is induced on the dorsum surface of anaesthetized inbred wild type mice from the BALB/C and SKH1-Hrhr backgrounds. The burn is produced using a brass template measuring 10 mm in diameter, which is preheated to 80 &#176;C and delivered at a constant pressure for 20 s. Burn eschar is excised 24 hours after the injury and replaced with a full thickness graft harvested from the tail of a genetically similar donor mouse. No specialized equipment is required for the procedure and surgical techniques are straightforward to follow. The method may be effortlessly implemented and reproduced in most research settings. Certain limitations are associated with the model. Due to technical difficulties, the harvest of thinner split thickness skin grafts is not possible. The surgical method we describe here allows for the reconstruction of burn wounds using full thickness skin grafts. It may be used to carry out preclinical therapeutic testing.

The aim of this study was to develop a murine model of burn wound healing. A thermal burn was induced on the dorsal skin of mice using a preheated brass template. Burned tissue was debrided and overlaid with a skin graft harvested from the tail of a genetically similar donor mouse.

Trivial superficial wounds heal without complications by primary intention. Deep wounds, such as full thickness burns, heal by secondary intention and ...

The Establishment of a Murine Mandibular Molar Extraction Socket Healing Model

This study introduces the development of a molar extraction model in the murine mandible to provide a practicable model for studying alveolar bone regeneration and intramembranous ossification. C57/J6 mice were used to extract the mandibular first molar to establish this model. They were euthanized, and the bilateral mandibles harvested, at 1 week and 4 weeks post-surgery, respectively. Subsequent serial stereoscopic harvest, histological assessment, and immunofluorescence staining were performed to demonstrate successful surgery. Immediately after surgery, the stereoscopic images displayed an empty extraction socket. The hematoxylin and eosin (H&#38;E) at 1 week and Masson staining at 4 weeks post-surgery showed that the area of the original root was partially and fully filled with bone trabeculae, respectively. The immunofluorescence staining showed that, compared with the homeostasis side, the Sp7 expression increased at 1 week post-surgery, suggesting vigorous osteogenesis in the alveolar fossa. All these results demonstrated a practicable murine tooth extraction socket healing model. Upcoming studies revealing the mechanisms of jawbone defect healing or socket healing could adopt this method.

This protocol demonstrates step-by-step details of how to extract the mandibular first molar in the mouse. It provides an alternative method for researchers focusing on jawbone healing and regeneration.

This study introduces the development of a molar extraction model in the murine mandible to provide a practicable model for studying alveolar bone ...

Exploring HR-Dependent Cardiac Performance Using an Atrial-Pacing Protocol

A Pacing-Controlled Procedure for the Assessment of Heart Rate-Dependent Diastolic Functions in Murine Heart Failure Models

Heart failure with preserved ejection fraction (HFpEF) is a condition characterized by diastolic dysfunction and exercise intolerance. While exercise-stressed hemodynamic tests or MRI can be used to detect diastolic dysfunction and diagnose HFpEF in humans, such modalities are limited in basic research using mouse models. A treadmill exercise test is commonly used for this purpose in mice, but its results can be influenced by body weight, skeletal muscle strength, and mental state. Here, we describe an atrial-pacing protocol to detect heart rate (HR)-dependent changes in diastolic performance and validate its usefulness in a mouse model of HFpEF. The method involves anesthetizing, intubating, and performing pressure-volume (PV) loop analysis concomitant with atrial pacing. In this work, a conductance catheter was inserted via a left ventricular apical approach, and an atrial pacing catheter was placed in the esophagus. Baseline PV loops were collected before the HR was slowed with ivabradine. PV loops were collected and analyzed at HR increments ranging from 400 bpm to 700 bpm via atrial pacing. Using this protocol, we clearly demonstrated HR-dependent diastolic impairment in a metabolically induced HFpEF model. Both the relaxation time constant (Tau) and the end-diastolic pressure-volume relationship (EDPVR) worsened as the HR increased compared to control mice. In conclusion, this atrial pacing-controlled protocol is useful for detecting HR-dependent cardiac dysfunctions. It provides a new way to study the underlying mechanisms of diastolic dysfunction in HFpEF mouse models and may help develop new treatments for this condition.

Author Spotlight: Investigating HR-Dependent Cardiac Function in Mouse Models Through a Novel Atrial-Pacing Approach 

The present protocol describes obtaining the pressure-volume relationship through transesophageal pacing, which serves as a valuable tool in evaluating diastolic function&#160;in mouse models of heart failure.

Heart failure with preserved ejection fraction (HFpEF) is a condition characterized by diastolic dysfunction and exercise intolerance. While ...

Vertical Immobilization Method for Time-Lapse Microscopy Analysis in Filamentous Cyanobacteria

A main event in bacterial cell division is the septation process, where the protein FtsZ is the key element. FtsZ polymerizes forming a ring-like structure (Z-ring) in the middle of the cell that serves as a scaffold for other division proteins. Super-resolution microscopy in bacterial models Escherichia coli and Bacillus subtilis showed that the Z-ring is discontinuous, while live cell imaging studies demonstrated that FtsZ moves along the ring by a mechanism known as treadmilling. To study the dynamics of FtsZ in vivo, a special cell placement in a vertical position is necessary for imaging the complete structure of the ring in the XY plane. In the case of FtsZ imaging in multicellular cyanobacteria, such as Anabaena sp. PCC7120, maintaining the filaments in a vertical position is challenging because of the size of the cells and the filaments' length. In this article, we describe a method that allows the vertical immobilization of Anabaena sp. PCC 7120 filaments using low melting point agarose and syringes, to record the Z-ring in a mutant that expresses a FtsZ-sfGFP fusion protein. This method is a rapid and inexpensive way to register protein dynamics at the division site using confocal microscopy.

We present a simple and accessible method for filamentous cyanobacterial visualization in the XY plane. A low-melting point agarose matrix was used, allowing the acquisition of images of proteins involved in the division, in a vertical orientation. Therefore, this methodology can be applied to any filamentous organism and different kinds of proteins.