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

Published: August 21st, 2021



1Department of Surgery, University of Alberta, 2Faculty of Medicine and Dentistry, University of Alberta, 3Department of Medicine, University of Alberta

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 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.

Obesity and type 2 diabetes have become worldwide epidemics1. Although medical weight loss can improve diabetes in patients, those with severe diabetes benefit most from bariatric surgery. Bariatric surgery has proven to be safe and effective at weight loss and improving or curing type 2 diabetes2,3, even in those with long-standing disease4. Metabolic bariatric procedures, such as the current gold-standard Roux-en-Y gastric bypass (RYGB) surgery, induce rapid and sustained improvements in glucose homeostasis while also reducing the need for diabetic medications<....

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Animal use protocols were approved by the Health Science Animal Care and Use Committee at the University of Alberta (AUP00003000). See Figure 1 for a diagram demonstrating the RYGB anatomy.

1. Roux-en-Y gastric bypass

  1. Preparation of animals and operative setup
    1. One week prior to the surgery, provide the rats with oral rehydration therapy and liquid diet in addition to their solid diet and water to acclimatize them to this new diet.
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Animals and housing
36 male Wistar rats were housed in pairs and were fed 60% sterile rodent high-fat diet starting from six weeks of age (Figure 2). At 16 weeks of age, they underwent RYGB or sham surgery. After the first postoperative week, rats were resumed on a high fat diet. Half of the rats were euthanized at 2 weeks post-operative and the other half were euthanized at 14 weeks postoperative.

Overall, 3.......

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RYGB involves the creation of a small gastric pouch (less than 30 mL), and the creation of a biliopancreatic limb and a Roux limb (Figure 1). In humans, the biliopancreatic limb is typically 30 to 50 cm and transports secretions from the gastric remnant, liver, and pancreas. The Roux limb is typically 75 to 150 cm in length and is the primary channel for ingested food. The common channel is the remaining small bowel distal to where the two limbs join and is where the majority of digestion an.......

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This study was funded by the American Society for Metabolic and Bariatric Surgery Research Award. Ethicon graciously supplied sutures, staplers, and clips. The lead author's doctoral research was funded in by the University of Alberta Clinician Investigator Program and the Alberta Innovates Clinician Fellowship. We would also like to thank Michelle Tran for her medical illustration of the RYGB anatomy.


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Name Company Catalog Number Comments
2-0 Silk Sutures Ethicon K533
3-0 Vicryl Sutures Ethicon J219H
4% Isoflurane N/A N/A
5% Dextrose and 0.9% Sodium Chloride Solution - 1000 mL Baxter 2B1064
50 mL Conical Centrifuge Tubes Fisher Scientific 14-432-22
6-0 Prolene Sutures Ethicon 8805H
Anesthetic Machine N/A N/A
Animal Hair Shaver N/A N/A
Betadine Solution N/A N/A
Castrojievo Needle Holder with lock 14 cm (smooth curved) World Precision Instruments 503258
ECHELON FLEX Articulating Endoscopic Linear Cutter Ethicon EC45A
Economy Tweezers #4 World Precision Instruments 501978
ENDOPATH ETS Articulating Linear Cutter 45mm Reloads Ethicon 6R45B
Far Infrared Warming Pad Controller with warming pad (15.2 cm W x 20.3 cm L), pad temperature probe, and 10 disposable, non-sterile sleeve protectors Kent Scientific RT-0515
Large Rat Elizabethan Collar Kent Scientific EC404VL-10
Liquid Diet Feeding Tube (150 mL) Bio-Serv 9007
Liquid Diet Feeding Tube Holder (short adjustable) Bio-Serv 9015
Micro Mosquito Forceps World Precision Instruments 500452
Micro Scissors World Precision Instruments 503365
Mouse Diet, High Fat Fat Calories (60%), Soft Pellets Bio-Serv S3282
No. 11 Blade and Scalpel Handle N/A N/A
OPMI Vario Surgical Microscope ZEISS S88
Raised Floor Grid Tecniplast GM500150 Raised Floor Grid
Rodent Liquid Diet, Lieber-DeCarli '82, Control, 4 Liters/Bag Bio-Serv F1259
Sodium Chloride Irrigation 0.9% Solution - 500 mL Baxter JF7633
Sterile Cotton Swabs N/A N/A
Sterile Drape N/A N/A
Sterile Towel N/A N/A
Thermal Cautery Unit World Precision Instruments 501293

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