We thank Gilles Mithieux and Aude Barataud (INSERM U1213, Lyon, France) and Marie Liabeuf and Stephanie Lemarchand-Minde (Animal facility, l'Institut du Thorax, Nantes, France) for their help with the animal care protocol. This work was supported by grants from La r&#233;gion des Pays de la Loire, the Fondation d'Avenir, and the Casden Bank. We would like to thank Catherine Postic, Fadila Benhamed and Michelle Ca&#252;zac from l'institut Cochin for their hospitality and their help during the filming process.

Animal and housing: Obtain 8-week-old C57Bl/6 male mice. At 10 weeks old, give the C57Bl/6 mice free access to water and a high-fat diet (DIO diet: 35% kcal from fat, 25.8% caseine, 1.30% mineral AIN, 1.30% vitamins, 1.70% dicalcium phosphate, 0.7% calcium carbonate, 2.10% citrate potassium, 0.026% choline bitartrate, 8.9% sucrose, 0.384% cystine, 6.5% cellulose, 31.7% lard, 3.3% soybean oil, and 16.29% maltodextrine) for 8 (SG) or 14 (RYGB) weeks prior to the bariatric surgeries. To promote weight gain, give the mice dedicated to the RYGB surgery (sham &#38; RYGB) water containing 20% fructose (w/v) in addition to the high-fat diet.
Ethics Statement: All protocol steps described below follow the guidelines of the Ethics Committee for Animal Experimentation of Pays de la Loire under the approval number 01953.01.
1. General Preoperative Preparation
<ol>
	<li>Fast the mice for 6 h before the surgery. Gel diet food was given 3 days before surgery and exclusively one day before surgery. Induce anesthesia in a chamber with 5% isoflurane (0.4 L/min) and O2 (dioxygen; 0.4 L/min). Perform a toe-pinch test to confirm that the anesthetization is effective. Administer analgesics (0.1 mg/kg buprenorphine), antibiotics (10 mg/kg marbofloxacine), and pro-kinetics (1 mg/kg metoclopramide) via subcutaneous injections.</li>
	<li>Allocate a specific work area for surgical procedures (distant from laboratory traffic and ventilation fans). Clean the surgical area with dedicated hard surface disinfectants. Place a heating pad on the working space area to maintain mouse homeothermy during the surgery. Apply a clean, absorbent underpad over the heating pad.</li>
	<li>Shave the abdomen from sternum to pelvis using an electric razor. Wrap the mouse abdomen in sterilized plastic wrap (Figures 1A and 2A) and place the mouse in supine position on the heating pad.</li>
	<li>Apply vet ointment on the eyes to prevent dryness while under anesthesia. Place the mouse in the nose cone and maintain anesthesia with 2% isoflurane (0.4 L/min) and O2 (0.4 L/min).</li>
	<li>Before beginning the surgery, put on a sterile examination gown, a disposable scrubs cap, a facemask, and sterile gloves. Open an autoclaved package containing a sterilized surgical instrument set, which is required for all steps of the surgery. Cut a window in the sterilized plastic wrap and disinfect the skin with 2 successive povidone-iodine solutions.</li>
</ol>
2. Sleeve Gastrectomy: Surgical Procedure
<ol>
	<li>Median laparotomy (Figure 1B)
	<ol>
		<li>Under a binocular microscope and with a scalpel, perform a midline incision from the sternum to the middle of the abdomen to open the abdominal cavity (do not damage the abdominal muscles). Protect the skin with a sterile compress soaked with 37 &#176;C saline solution.</li>
	</ol>
	</li>
	<li>Stomach exposure (Figure 1C)
	<ol>
		<li>Gently mobilize the stomach using moistened-cotton swabs. Free the stomach from its lateral close connective tissue attachments using moistened cotton swabs or micro scissors.</li>
		<li>Gently, externalize the stomach fully and place a hemostatic collagen compress behind the stomach. Suture the pylorus and esophagus vessels along the stomach greater curvature with 8.0 non-absorbable sutures to avoid future bleeding (Figure 1D and E). Note:&#160;Hemostat use can induce tissue damage, make sure to only use it on tissue that aim to be resected.</li>
	</ol>
	</li>
	<li>Resection of the cardiac region of stomach (fundus)
	<ol>
		<li>Perform a gastrotomy on the anatomical line present between the pyloric region (corpus) and the cardiac region of stomach (fundus) (Figure 1F).</li>
		<li>Remove residual food with 2 moistened cotton swabs towards each side of the stomach. Using micro scissors, cut the stomach along the boundary between the fundus and the corpus of the stomach (Figure 1G).</li>
		<li>Press a hemostatic collagen compress for 2 min in case of major bleeding. Close the stomach opening with 8.0 non-absorbable sutures from the gastro-oesophagal junction to the end of the incision (Figure 1H).</li>
	</ol>
	</li>
	<li>Resection of the pyloric region of stomach (corpus)
	<ol>
		<li>Complete the stomach resection along the greater curvature so as to remove approximately 80% of the stomach (Figure 1I). Standardize the width of the SG to 3 mm. Press a hemostatic collagen compress for 2 min in case of major bleeding.</li>
		<li>Close the opening of the pyloric region of the stomach with 8.0 non-absorbable suture (Figure 1J). Gently roll 2 moistened cotton swabs towards each side of the stomach to ensure that the suture is leak-proof.</li>
		<li>Complete with 8.0 non-absorbable sutures in case of leakage. Remove the hemostatic collagen compresses and return the stomach to the abdominal cavity. Leave a hemostatic collagen compress against the suture.</li>
	</ol>
	</li>
	<li>Abdominal closure
	<ol>
		<li>Close the muscle layer of the abdominal wall with 5.0 non-absorbable sutures (Figure 1K). Reduce anesthesia by reducing the isoflurane concentration to 1%. Close the skin using 5.0 non-absorbable sutures (Figure 1L).</li>
	</ol>
	</li>
</ol>
3. Roux-en-Y Gastric Bypass: Surgical Procedure
<ol>
	<li>Median laparotomy
	<ol>
		<li>Under a binocular microscope and with a scalpel, perform a midline incision from the sternum to the middle of the abdomen to open the abdominal cavity (do not damage the abdominal muscles). Protect the skin with a sterile compress soaked with 37 &#176;C saline solution (Figure 2B).</li>
	</ol>
	</li>
	<li>Biliopancreatic limb and alimentary limb
	<ol>
		<li>Externalize the intestine (Figure 2C). Measure 8 cm from the pylorus and perform two ligatures of the intestine with 5.0 non-absorbable sutures (Figure 2D).</li>
		<li>Cut the intestine between the two ligatures (Figure 2E). Place the proximal limb of the two ends in the upper-left quadrant of the abdomen. Note: This will be used as the alimentary limb (Figure 2F).</li>
		<li>Place the distal limb of the two ends facing the alimentary limb 6 cm below the proximal limb (Figure 2F). 
		NOTE: This will be used as the biliary limb.</li>
	</ol>
	</li>
	<li>Jejuno-jejunostomy
	<ol>
		<li>Cut both the proximal limb and the intestine loop using micro scissors and perform two antimesenteric incisions of the same length (Figure 2G and 2H).</li>
		<li>Perform side-to-side anastomosis with two 8.0 non-absorbable sutures. Perform the dorsal side anastomosis first (Figure 2I), followed by the ventral side anastomosis (Figure 2J).</li>
		<li>Gently roll 2 moistened cotton swabs towards each side of the anastomosis to ensure that the suture is leak-proof. Complete with 8.0 non-absorbable sutures in case of leakage.</li>
	</ol>
	</li>
	<li>Gastro-jejunostomy
	<ol>
		<li>Gently mobilize the stomach using moistened cotton swabs. Free the stomach from its lateral close connective tissue attachments using moistened cotton swabs or micro scissors.</li>
		<li>Gently, externalize the stomach fully, placing a re-absorbable hemostatic collagen compress behind the stomach. Perform a ligature of the pylorus using a 5.0 non-absorbable suture passed through the omentum using curved micro forceps (Figure 2K and 2L).</li>
		<li>Cut both the ventral side of the stomach, 1.5 cm from the pylorus, and the distal limb using micro scissors, creating two incisions of the same length (Figure 2M).</li>
		<li>Perform side-to-side anastomosis with two 8.0 non-absorbable sutures. Start with the dorsal side anastomosis (Figure 2N), and then perform the ventral side anastomosis (Figure 2O). Gently roll 2 moistened-cotton swabs towards each side of the anastomosis to ensure that the suture is leak-proof. Complete with 8.0 non-absorbable sutures in case of leakage.</li>
	</ol>
	</li>
	<li>Abdominal closure
	<ol>
		<li>Close the muscle layer of the abdominal wall using 5.0 non-absorbable sutures (Figure 2P). Reduce the anesthesia by reducing the isoflurane concentration to 1%. Close the skin using 5.0 non-absorbable sutures (Figure 2Q).Administer 25 mL/kg of warm saline solution via subcutaneous injection.</li>
	</ol>
	</li>
</ol>
4. General Postoperative Care
<ol>
	<li>Stop isoflurane and continue with an O2 flow of 0.8 L/min until the mouse is fully awake. Do not leave the mouse unattended until it regains motor control, indicated by the animal starting to move around the cage and being able to stand and walk without falling.</li>
	<li>Place the mouse (only one mouse per cage) in an incubator under 30 &#176;C temperature condition for 5 days.</li>
	<li>Maintain iron (0.5 mg/kg/day; subcutaneous injection) and vitamin (800 mg/180 mL in water) supplementations in the RYGB mice until the end of the protocol.</li>
	<li>Return free access to gel diet food (high-fat gel diet: 10% lard, 10% liquid sugar, 57% water) for 5 days after surgery. Reintroduce a solid diet 3 days after surgery.</li>
	<li>Subcutaneously inject buprenorphine (0.1 mg/kg, twice daily, from day 0 to day 3 after surgery), meloxicam (1 mg/kg, from day 0 to day 3 after surgery), metoclopramide (1 mg/kg, from day 0 to day 5 after surgery), and marbofloxacine (10 mg/kg, from day 0 to day 3 after surgery).</li>
</ol>
5. Postoperative Metabolic Parameters Assessment
<ol>
	<li>Food intake measurement
	<ol>
		<li>Allow the mice to recover for 1 week after surgery. House the mice one per cage. Measure the amount of solid diet placed in the cage. Weight the remaining food 24 h later. Repeat this step as long as required.</li>
	</ol>
	</li>
	<li>Oral glucose tolerance test
	<ol>
		<li>Fast the mice for 6 h before the oral bolus. Harvest a blood drop from the tail tip and apply it on a glucose strip inserted in a glucometer to determine the time 0 blood glucose value.</li>
		<li>Administer an oral bolus of 20% D-glucose solution (2 g/kg). Measure the blood glucose levels at 15, 30, 60, and 120 min post gavage.</li>
	</ol>
	</li>
	<li>Hemoglobin level analysis
	<ol>
		<li>Using a hematology system, measure 20 &#181;L of fresh blood to sample the hemoglobin level.</li>
	</ol>
	</li>
</ol>
6. Euthanasia
<ol>
	<li>Anesthetize the mice by intraperitoneally injecting a xylazine/ketamine solution (10/80 mg/kg). Perform a cervical dislocation. Verify complete euthanasia by ensuring that the heart is not beating and the eyeball blink reflex is lost.</li>
</ol>

<ol>
	<li>Ng, M., Fleming, T., 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=Global,+regional,+and+national+prevalence+of+overweight+and+obesity+in+children+and+adults+during+1980-2013:+a+systematic+analysis+for+the+Global+Burden+of+Disease+Study+2013.">Global, regional, and national prevalence of overweight and obesity in children and adults during 1980-2013: a systematic analysis for the Global Burden of Disease Study 2013.</a> The Lancet. 384 (9945), 766-781 (2014).</li><li>Calle, E. E., Thun, M. J., Petrelli, J. M., Rodriguez, C., Heath, C. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Body-mass+index+and+mortality+in+a+prospective+cohort+of+U.S.+adults.">Body-mass index and mortality in a prospective cohort of U.S. adults.</a> The New England Journal of Medicine. 341 (15), 1097-1105 (1999).</li><li>Sj&#246;str&#246;m, L., Lindroos, 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=Lifestyle,+diabetes,+and+cardiovascular+risk+factors+10+years+after+bariatric+surgery.">Lifestyle, diabetes, and cardiovascular risk factors 10 years after bariatric surgery.</a> The New England Journal of Medicine. 351 (26), 2683-2693 (2004).</li><li>Buchwald, H., Avidor, 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=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>Yin, D. P., Gao, Q., 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=Assessment+of+different+bariatric+surgeries+in+the+treatment+of+obesity+and+insulin+resistance+in+mice.">Assessment of different bariatric surgeries in the treatment of obesity and insulin resistance in mice.</a> Annals of surgery. 254 (1), 73-82 (2011).</li><li>Buchwald, H., Oien, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Metabolic/Bariatric+Surgery+Worldwide+2008.">Metabolic/Bariatric Surgery Worldwide 2008.</a> Obesity Surgery. 19 (12), 1605-1611 (2009).</li><li>Liu, W., Zassoko, 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=Establishment+of+duodenojejunal+bypass+surgery+in+mice:+A+model+designed+for+diabetic+research.">Establishment of duodenojejunal bypass surgery in mice: A model designed for diabetic research.</a> Microsurgery. 28 (3), 197-202 (2008).</li><li>Lan, Z., Zassoko, 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=Development+of+techniques+for+gastrojejunal+bypass+surgery+in+obese+mice.">Development of techniques for gastrojejunal bypass surgery in obese mice.</a> Microsurgery. , (2010).</li><li>Schlager, A., Khalaileh, A., 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=A+mouse+model+for+sleeve+gastrectomy:+Applications+for+diabetes+research.">A mouse model for sleeve gastrectomy: Applications for diabetes research.</a> Microsurgery. 31 (1), 66-71 (2011).</li><li>Troy, S., Soty, 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=Intestinal+Gluconeogenesis+Is+a+Key+Factor+for+Early+Metabolic+Changes+after+Gastric+Bypass+but+Not+after+Gastric+Lap-Band+in+Mice.">Intestinal Gluconeogenesis Is a Key Factor for Early Metabolic Changes after Gastric Bypass but Not after Gastric Lap-Band in Mice.</a> Cell Metabolism. 8 (3), 201-211 (2008).</li><li>Seyfried, F., Lannoo, 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=Roux-en-Y+gastric+bypass+in+mice--surgical+technique+and+characterisation.">Roux-en-Y gastric bypass in mice--surgical technique and characterisation.</a> Obesity surgery. 22 (7), 1117-1125 (2012).</li></ol>

The authors declare no conflicts of interest.

To overcome the growing epidemic of obesity, the first bariatric surgery procedures emerged in the 1960s in the United States. Since then, the number of procedures performed worldwide each year still increase, and today, these techniques represent the best therapeutic option for the management of morbid obesity6. Among the procedures developed, SG and RYGB are the two most popular methods used in clinical practice4. Animal models, notably rodents, have been used to decipher...

The worldwide pandemic of obesity and diabetes is devastating in severity. Over two billion adults worldwide (30% of the population) are either overweight (BMI &#62;25 kg/m2) or obese (BMI &#62;30 kg/m2)1. This can come along with metabolic complications, such as type 2 diabetes, hypertension, and dyslipidemia, leading to increased morbidity and mortality. Obesity increases the overall mortality and the prevalence of cancer2. Due to the lack of any effective noninvasive treatments, bariatric surgery represents the only option that can lead to long-term, sustained weight loss3,4. A number of different surgical methods have been developed, but the sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB) are the two procedures most commonly used in clinical practice. During the SG procedure, 80% of the initial volume of the stomach is removed; thus, this technique is one of the restrictive surgeries that improves satiety. The RYGB is one of the restrictive-malabsorptive techniques. During RYGB, a small gastric pouch (1-2% of the total gastric volume) is created and the intestine is rearranged into a Y-shape, which delays digestion and the absorption of nutrients. These two techniques lead to significant body weight reductions and general improvements in frequently-associated comorbidities (e.g., hypertension, type 2 diabetes, and dyslipidemia)3, with a higher efficiency seen in RYGB. However, the molecular mechanisms behind the pleiotropic beneficial effects of the bariatric surgeries are often not fully elucidated. Due to the numerous genetically-modified strains available, a mouse model is the most convenient animal model to explore these molecular mechanisms.
However, bariatric procedures are difficult to directly adapt to small animal models and require high surgical dexterity. While SG can be easily performed in rodents with a very good survival rate, RYGB is lethal in mice due to severe bowel obstructions5. Different modified RYGB techniques have been proposed to counteract this problem, notably the oesojejunostomy5. Here, we present another alternative: the gastrojejunostomy without a stomach excision. This modified RYGB reproduces most of the beneficial effects observed in humans (i.e., a significant body weight reduction and an improvement in glucose and lipid homeostasis).
This manuscript aims to summarize and discuss the technical and experimental details of SG and RYGB in mice and to facilitate these procedures with the help of videos. A specific highlight will be made regarding the optimization of the preoperative and postoperative healthcare protocols that allow the reduction of vitamin and iron deficiencies.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Drugs</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>High Fat diet</td>
			<td>DIO diet</td>
			<td>Safe</td>
			<td></td>
		</tr>
		<tr>
			<td>Isoflurane</td>
			<td>Forane</td>
			<td>Baxter</td>
			<td></td>
		</tr>
		<tr>
			<td>Buprenorphin</td>
			<td>Buprecare</td>
			<td>Animalcare</td>
			<td></td>
		</tr>
		<tr>
			<td>Marbofloxacine</td>
			<td>Marbocyl</td>
			<td>Vetoquinol</td>
			<td></td>
		</tr>
		<tr>
			<td>Ammonium iron citrate, vitamins PP-B12</td>
			<td>Fercobsang</td>
			<td>Vetoquinol</td>
			<td></td>
		</tr>
		<tr>
			<td>Vitamins A-D3-E-K-B</td>
			<td>Vita Rongeur</td>
			<td>Virbac</td>
			<td></td>
		</tr>
		<tr>
			<td>NaCl 0,9%</td>
			<td>NaCl 0,9%</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Povidone solution</td>
			<td>Betadine Scrub</td>
			<td>Betadine</td>
			<td></td>
		</tr>
		<tr>
			<td>Povidone solution</td>
			<td>Betadine Solution</td>
			<td>Betadine</td>
			<td></td>
		</tr>
		<tr>
			<td>Carboptol 980 NF</td>
			<td>Ocrygel</td>
			<td>TVM</td>
			<td></td>
		</tr>
		<tr>
			<td>Name</td>
			<td>References</td>
			<td>Company</td>
			<td>Comments</td>
		</tr>
		<tr>
			<td>Sutures</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Prolene&#174;</td>
			<td>8.0, 6,5 mm</td>
			<td>Ethicon</td>
			<td></td>
		</tr>
		<tr>
			<td>Prolene&#174;</td>
			<td>5.0, 13 mm</td>
			<td>Ethicon</td>
			<td></td>
		</tr>
		<tr>
			<td>Name</td>
			<td>References</td>
			<td>Company</td>
			<td>Comments</td>
		</tr>
		<tr>
			<td>Surgical equipments</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Scissors</td>
			<td></td>
			<td>FST</td>
			<td></td>
		</tr>
		<tr>
			<td>Needle holder</td>
			<td>Olsen-Hegar</td>
			<td>FST</td>
			<td></td>
		</tr>
		<tr>
			<td>Micro scissors</td>
			<td>Vannas</td>
			<td>FST</td>
			<td></td>
		</tr>
		<tr>
			<td>Micro forceps&#160;</td>
			<td>Graefe</td>
			<td>FST</td>
			<td></td>
		</tr>
		<tr>
			<td>Micro forceps curved</td>
			<td>Graefe</td>
			<td>FST</td>
			<td></td>
		</tr>
		<tr>
			<td>Curved micro needle holder</td>
			<td>Castroviejo</td>
			<td>FST</td>
			<td></td>
		</tr>
		<tr>
			<td>Hemostatic collagen compress</td>
			<td>Pangen</td>
			<td>Urgo</td>
			<td></td>
		</tr>
		<tr>
			<td>Absorbent underpads</td>
			<td></td>
			<td>VWR</td>
			<td></td>
		</tr>
		<tr>
			<td>Name</td>
			<td>References</td>
			<td>Company</td>
			<td>Comments</td>
		</tr>
		<tr>
			<td>Specific equipments</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Hematology system&#160;</td>
			<td>Hemavet 950FS</td>
			<td>Hemavet</td>
			<td></td>
		</tr>
		<tr>
			<td>Glucose strips and glucometer</td>
			<td>One touch Verio</td>
			<td>Life scan</td>
			<td></td>
		</tr>
		<tr>
			<td>Stereo microscope</td>
			<td>MZ6</td>
			<td>Leica&#160;</td>
			<td></td>
		</tr>
	</tbody>
</table>

techniques of sleeve gastrectomy and modified roux-en-y gastric bypass in mice

Obesity is a major public health issue, with a prevalence of 4 to 28% for men and 6.2 to 36.5% for women in Europe (from 2003 to 2008). Morbid obesity is frequently associated with metabolic complications, such as type 2 diabetes, hypertension, and dyslipidemia, reducing life expectancy and quality. In the absence of any effective noninvasive treatments, bariatric surgery is a valuable therapeutic option for patients with morbid obesity (body mass index (BMI) &#62;40 kg/m2), leading to long-term, sustained weight loss and improvements in metabolic complications. However, the underlying cellular and molecular mechanisms sustaining the beneficial effects of bariatric surgery are not yet fully understood. Due to the numerous genetically-modified strains available, the mouse model is the most convenient animal model to explore the molecular mechanisms behind the pleiotropic beneficial effects of bariatric surgeries. Here, we detailed the optimized healthcare methods and surgical protocols in mice for the two most widely-used bariatric surgeries: the sleeve gastrectomy and the modified Roux-en-Y gastric bypass. Deciphering the molecular mechanisms underlying the therapeutic effects of bariatric surgeries offers the promise of identifying new therapeutics targets.

General conditions
The mean operative time for the SG procedure was 49.3 &#177; 1.5 min. We removed 62.8 &#177; 5.0 mg of stomach, which represents about 80% percent of the stomach. No mice died during the surgery or during the following seven days. One mouse (7.1%) died on the 11th postoperative day because of a gastric obstruction caused by a bezoar.
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Watch this Scientific Journal Video about Techniques of Sleeve Gastrectomy and Modified Roux-en-Y Gastric Bypass in Mice at JoVE.com

Techniques of Sleeve Gastrectomy and Modified Roux-en-Y Gastric Bypass in Mice

Bariatric surgery is the most efficient way to reduce body weight and the deadly metabolic complications (diabetes, obesity, and dyslipidemia) frequently associated with morbid obesity. Mouse models of bariatric surgery represent a unique asset for deciphering molecular mechanisms behind the beneficial effects of these surgeries on diabetes, hypertension, and dyslipidemia.

Obesity is a major public health issue, with a prevalence of 4 to 28% for men and 6.2 to 36.5% for women in Europe (from 2003 to 2008). Morbid obesity is ...

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11.9K Views.  INSERM, CNRS, UNIV Nantes. Bariatric surgery is the most efficient way to reduce body weight and the deadly metabolic complications (diabetes, obesity, and dyslipidemia) frequently associated with morbid obesity. Mouse models of bariatric surgery represent a unique asset for deciphering molecular mechanisms behind the beneficial effects of these surgeries on diabetes, hypertension, and dyslipidemia.

Video: Techniques of Sleeve Gastrectomy and Modified Roux-en-Y Gastric Bypass in Mice

Modified Technique for Coronary Artery Ligation in Mice

Myocardial infarction (MI) is one of the most important causes of mortality in humans1-3. In order to improve morbidity and mortality in patients with MI we need better knowledge about pathophysiology of myocardial ischemia. This knowledge may be valuable to define new therapeutic targets for innovative cardiovascular therapies4. Experimental MI model in mice is an increasingly popular small-animal model in preclinical research in which MI is induced by means of permanent or temporary ligation of left coronary artery (LCA)5. In this video, we describe the step-by-step method of how to induce experimental MI in mice.
The animal is first anesthetized with 2% isoflurane. The unconscious mouse is then intubated and connected to a ventilator for artificial ventilation. The left chest is shaved and 1.5 cm incision along mid-axillary line is made in the skin. The left pectoralis major muscle is bluntly dissociated until the ribs are exposed. The muscle layers are pulled aside and fixed with an eyelid-retractor. After these preparations, left thoracotomy is performed between the third and fourth ribs in order to visualize the anterior surface of the heart and left lung. The proximal segment of LCA artery is then ligated with a 7-0 ethilon suture which typically induces an infarct size ~40% of left ventricle. At the end, the chest is closed and the animals receive postoperative analgesia (Temgesic, 0.3 mg/50 ml, ip). The animals are kept in a warm cage until spontaneous recovery.

The surgical procedure used to induce experimental myocardial infarction in mice begins with left thoracotomy between the third and the fourth ribs in order to visualize the anterior surface of the heart and left lung. The left coronary artery is ligated, the chest is closed and the mouse is allowed to recover spontaneously.

Myocardial infarction (MI) is one of the most important causes of mortality in humans1-3. In order to improve morbidity and mortality in patients with MI ...

Roux-en-Y Gastric Bypass Operation in Rats

Currently, the most effective therapy for the treatment of morbid obesity to induce significant and maintained body weight loss with a proven mortality benefit is bariatric surgery1,2. Consequently, there has been a steady rise in the number of bariatric operations done worldwide in recent years with the Roux-en-Y gastric bypass (gastric bypass) being the most commonly performed operation3. Against this background, it is important to understand the physiological mechanisms by which gastric bypass induces and maintains body weight loss. These mechanisms are yet not fully understood, but may include reduced hunger and increased satiation4,5, increased energy expenditure6,7, altered preference for food high in fat and sugar8,9, altered salt and water handling of the kidney10 as well as alterations in gut microbiota11. Such changes seen after gastric bypass may at least partly stem from how the surgery alters the hormonal milieu because gastric bypass increases the postprandial release of peptide-YY (PYY) and glucagon-like-peptide-1 (GLP-1), hormones that are released by the gut in the presence of nutrients and that reduce eating12.
During the last two decades numerous studies using rats have been carried out to further investigate physiological changes after gastric bypass. The gastric bypass rat model has proven to be a valuable experimental tool not least as it closely mimics the time profile and magnitude of human weight loss, but also allows researchers to control and manipulate critical anatomic and physiologic factors including the use of appropriate controls. Consequently, there is a wide array of rat gastric bypass models available in the literature reviewed elsewhere in more detail 13-15. The description of the exact surgical technique of these models varies widely and differs e.g. in terms of pouch size, limb lengths, and the preservation of the vagal nerve. If reported, mortality rates seem to range from 0 to 35%15. Furthermore, surgery has been carried out almost exclusively in male rats of different strains and ages. Pre- and postoperative diets also varied significantly.
Technical and experimental variations in published gastric bypass rat models complicate the comparison and identification of potential physiological mechanisms involved in gastric bypass. There is no clear evidence that any of these models is superior, but there is an emerging need for standardization of the procedure to achieve consistent and comparable data. This article therefore aims to summarize and discuss technical and experimental details of our previously validated and published gastric bypass rat model.

Numerous studies using gastric bypass rat models have been recently conducted to uncover the underlying physiological mechanisms of Roux-en-Y gastric bypass operations. This article aims to demonstrate and discuss the technical and experimental details of our published gastric bypass rat model to understand advantages and limitations of this experimental tool.

Currently, the most effective therapy for the treatment of morbid obesity to induce significant and maintained body weight loss with a proven mortality ...

Assessment of Gastric Emptying in Non-obese Diabetic Mice Using a [13C]-octanoic Acid Breath Test

Gastric emptying studies in mice have been limited by the inability to follow gastric emptying changes in the same animal since the most commonly used techniques require killing of the animals and postmortem recovery of the meal1,2. This approach prevents longitudinal studies to determine changes in gastric emptying with age and progression of disease. The commonly used [13C]-octanoic acid breath test for humans3 has been modified for use in mice4-6 and rats7 and we previously showed that this test is reliable and responsive to changes in gastric emptying in response to drugs and during diabetic disease progression8. In this video presentation the principle and practical implementation of this modified test is explained. As in the previous study, NOD LtJ mice are used, a model of type 1 diabetes9. A proportion of these mice develop the symptoms of gastroparesis, a complication of diabetes characterized by delayed gastric emptying without mechanical obstruction of the stomach10.
This paper demonstrates how to train the mice for testing, how to prepare the test meal and obtain 4 hr gastric emptying data and how to analyze the obtained data. The carbon isotope analyzer used in the present study is suitable for the automatic sampling of the air samples from up to 12 mice at the same time. This technique allows the longitudinal follow-up of gastric emptying from larger groups of mice with diabetes or other long-standing diseases.

Assessment of Gastric Emptying in Non-obese Diabetic Mice Using a [13C]-octanoic Acid Breath Test

Determination of gastric emptying with a non-invasive [13C]-octanoic acid breath test for tracking gastroparesis in female NOD LtJ mice.

Gastric emptying studies in mice have been limited by the inability to follow gastric emptying changes in the same animal since the most commonly used ...

Using the Sleeve Technique in a Mouse Model of Aortic Transplantation - An Instructional Video

Orthotopic aortic transplantation using the sleeve technique reduces injury to the aorta with failure rate of only 10-20%. The time to anastomose the aorta in mice using the sleeve method was short and easy averaging 20 min, permitting studies of iso/allo grafts. The following article describes the aortic transplantation procedure used in our laboratory. The mice were anesthetized with a mixture of 1.5% volume isoflurane and 100% oxygen through a face mask. At this point, the segment of the aorta between the renal arteries and its bifurcation was separated from the vena cava, freely prepared and clampedat the proximal and distal segments with a single silk suture. Prior to the removal of the aorta, a saline solution containing heparin was injected into the inferior vena cava. Then the aorta was cut between the clamps and a saline heparin solution was used to flush the lumen. The sleeve technique with monofilament sutures was used in order to transplant the abdominal aorta in the orthotopic position.

We present an orthotopic aortic transplantation model using the sleeve technique in mice. It is a very rapid anastomosis method, which can be employed in studies of vascular disease.

Orthotopic aortic transplantation using the sleeve technique reduces injury to the aorta with failure rate of only 10-20%. The time to anastomose the ...

Cardiopulmonary Bypass in a Mouse Model: A Novel Approach

As prolonged cardiopulmonary bypass becomes more essential during cardiac interventions, an increasing clinical demand arises for procedure optimization and for minimizing organ damage resulting from prolonged extracorporal circulation. The goal of this paper was to demonstrate a fully functional and clinically relevant model of cardiopulmonary bypass in a mouse. We report on the device design, perfusion circuit optimization, and microsurgical techniques. This model is an acute model, which is not compatible with survival due to the need for multiple blood drawings. Because of the range of tools available for mice (e.g., markers, knockouts, etc.), this model will facilitate investigation into the molecular mechanisms of organ damage and the effect of cardiopulmonary bypass in relation to other comorbidities.

This paper describes how to perform cardiopulmonary bypass in mice. This novel model will facilitate the investigation of the molecular mechanisms involved in organ damage.

As prolonged cardiopulmonary bypass becomes more essential during cardiac interventions, an increasing clinical demand arises for procedure optimization ...

One-anastomosis Gastric Bypass (OAGB) in Rats

The goal of this protocol is to set up a preclinical model of bariatric surgery and, more specifically, OAGB in obese rats. Based on this preclinical model, longitudinal studies can be carried out to provide an improved understanding of the mechanisms underlying the outcomes seen after bariatric surgery in humans. For this purpose, rats are operated on through a laparotomy under general anesthesia with isoflurane. First, the surgeon creates a long and tubular gastric pouch: after greater curve and hiatal dissection, the nonglandular stomach is stapled and removed. Then, the remaining stomach is also stapled in order to create a gastric tube and exclude the antrum of the stomach. After that, the surgeon performs a single end-to-side gastrojejunostomy 35 cm from the duodenojejunal angle. This limb length has been chosen in order to reproduce the same ratio between the biliopancreatic limb (BPL) and common limb (CL) length as in human bariatric surgery. The operation ends by aponeurotic and cutaneous closure. The early postoperative management consists of subcutaneous hydration, an intramuscular prophylactic antibiotic injection, a parietal injection of xylocaine, the administration of painkillers, and a progressive reintroduction of diet.

One-anastomosis Gastric Bypass OAGB in Rats

This protocol is for the performance of one-anastomosis gastric bypass (OAGB) on rat. The operator performs a long and tubular-stapled gastric pouch followed by hand-sewn anastomosis. For this model, the operator reproduces the same ratio between biliopancreatic and common limb in humans; therefore, the biliopancreatic limb measures 35 cm.

The goal of this protocol is to set up a preclinical model of bariatric surgery and, more specifically, OAGB in obese rats. Based on this preclinical ...

Sleeve Gastrectomy in Mice using Surgical Clips

The number of people who are overweight and obese is continually increasing both in the adult and adolescent populations. This coincides with the increased universal phenomenon of type 2 diabetes (T2D) and other metabolic problems. Bariatric surgery, such as SG, is currently one of the most effective and commonly used long-term treatment for obesity and T2D, but the association between them is not completely explored yet. The mechanisms underlying the outcomes seen after bariatric surgery in humans can be investigated based on preclinical animal studies. The SG reduces body weight, glucose levels and many metabolic parameters, and is easy to perform with a low incidence of complications. The goal of this work is to provide a simple method and an uncomplicated preclinical model of bariatric surgery in animals for researchers.

The prevalence of diabetes and obesity is continuously increasing worldwide. The mechanisms between diabetes, obesity and their associated mortality and co-morbidities need to be further investigated. Here, we present a protocol for sleeve gastrectomy (SG) in animals as an uncomplicated preclinical model of bariatric surgery.

The number of people who are overweight and obese is continually increasing both in the adult and adolescent populations. This coincides with the ...

A Protocol for Roux-en-Y Gastric Bypass in Rats using Linear Staplers

Roux-en-Y gastric bypass (RYGB) is commonly performed for the treatment of severe obesity and type 2 diabetes. However, the mechanism of weight loss and metabolic changes are not well understood. Multiple factors are thought to play a role, including reduced caloric intake, decreased nutrient absorption, increased satiety, the release of satiety-promoting hormones, shifts in bile acid metabolism, and alterations in the gut microbiota.
The rat RYGB model presents an ideal framework to study these mechanisms. Prior work on mouse models have had high mortality rates, ranging from 17 to 52%, limiting their adoption. Rat models demonstrate more physiologic reserve to surgical stimulus and are technically easier to adopt as they allow for the use of surgical staplers. One challenge with surgical staplers, however, is that they often leave a large gastric pouch which is not representative of RYGB in humans. 
In this protocol, we present a RYGB protocol in rats that result in a small gastric pouch using surgical staplers. Utilizing two stapler fires which remove the forestomach of the rat, we obtain a smaller gastric pouch similar to that following a typical human RYGB. Surgical stapling also results in better hemostasis than sharp division. Additionally, the forestomach of the rat does not contain any glands and its removal should not alter the physiology of RYGB.
Weight loss and metabolic changes in the RYGB cohort were significant compared to the sham cohort, with significantly lower glucose tolerance at 14 weeks. Furthermore, this protocol has an excellent survival of 88.9% after RYGB. The skills described in this protocol can be acquired without previous microsurgical experience. Once mastered, this procedure will provide a reproducible tool for studying the mechanisms and effects of RYGB.

Roux-en-Y gastric bypass (RYGB) is performed to treat obesity and diabetes. However, the mechanisms underlying RYGB's efficacy are not fully understood, and studies are limited by technical difficulty leading to high mortality in animal models. This article provides instructions on how to perform RYGB in rats with high success rates.

Roux-en-Y gastric bypass (RYGB) is commonly performed for the treatment of severe obesity and type 2 diabetes. However, the mechanism of weight loss and ...

Robotic Central Pancreatectomy with Roux-en-Y Pancreaticojejunostomy

Central pancreatectomy is a parenchyma-sparing alternative to distal pancreatectomy in patients with a benign or low-grade malignant tumor in the body of the pancreas. The aim of central pancreatectomy is to prevent postoperative life-long endocrine and exocrine insufficiency. The downside of central pancreatectomy is the high rate of postoperative pancreatic fistula, which is the main reason that many surgeons do not routinely use central pancreatectomy in eligible patients. Most studies report open or laparoscopic central pancreatectomy with a pancreatico-gastrostomy anastomosis in adults. This is the first description of a standardized approach to robotic central pancreatectomy with Roux-en-Y pancreaticojejunostomy reconstruction in an adolescent (16-year-old boy) with a pseudopapillary tumor in the body of the pancreas. The operation time was 248 min with 20 mL of blood loss. The postoperative course was uneventful except for the short-term medical treatment for a grade B pancreatic fistula. Robotic central pancreatectomy can be safely applied in selected patients in experienced centers.

Robotic central pancreatectomy may be used in selected patients in experienced centers. This protocol presents all steps and the feasibility of a robotic central pancreatectomy with Roux-en-Y pancreaticojejunostomy in a 16-year-old adolescent patient.

Central pancreatectomy is a parenchyma-sparing alternative to distal pancreatectomy in patients with a benign or low-grade malignant tumor in the body of ...

A Modified Simple Method for Induction of Myocardial Infarction in Mice

Myocardial infarction (MI) represents one of the leading causes of death. MI models are widely used for investigating the pathomechanisms of post-MI remodeling and evaluation of novel therapeutics. Different methods (e.g., isoproterenol treatment, cryoinjury, coronary artery ligation, etc.) have been used to induce MI. Compared with isoproterenol treatment and cryoinjury, coronary artery ligation may better reflect the ischemic response and chronic remodeling after MI. However, traditional methods for coronary ligation in mice are technically challenging. The current study describes a simple and efficient process for induction of MI in mice with readily available materials. The mouse chest skin was cut open under stable anesthesia. The heart was immediately externalized through the intercostal space after blunt separation of the pectoralis major and pectoralis minor. The left anterior descending branch (LAD) was ligated with a 6-0 suture 3 mm from its origin. Following LAD ligation, staining with 2,3,5-Triphenyltetrazolium chloride (TTC) indicated successful induction of MI and temporal changes of post-MI scar size. Meanwhile, survival analysis results showed overt mortality within 7 days after MI, mainly due to cardiac rupture. Moreover, post-MI echocardiographic assessment demonstrated successful induction of contractile dysfunction and ventricular remodeling. Once mastered, an MI model can be established in mice within 2-3 min with readily available materials.

Under adequate anesthesia, the mouse heart was externalized through the intercostal space, and myocardial infarction was successfully induced by ligating the left anterior descending artery (LAD) using materials readily available in most laboratories.

Myocardial infarction (MI) represents one of the leading causes of death. MI models are widely used for investigating the pathomechanisms of post-MI ...