This study was supported by a grant from the Science and Technology Planning Project of Guangdong Province of China (No. 202002020069).

All protocol steps described below follow the guidelines of the Animal Care and Use Committee of the General Hospital of the Southern Theater Command under the approval number 2020112501.
1. General preoperative preparation
NOTE: Thirty 6-week-old male C57BL/6 mice were purchased. Mice were housed in a Specific Pathogen-Free (SPF) laboratory under a 12 h light/dark cycle; temperature, 22 &#177; 2 &#176;C; and humidity, 55-65%. Mice were given free access to water and fed a 60% kcal fat diet for 6 weeks to induce obesity. An intraperitoneal injection of 40 mg/kg streptozotocin was administered for 5 days to induce diabetes17. Among the thirty mice, twenty-two mice were screened for random blood glucose &#62; 300 mg/dL and randomly assigned to the DJB (n=15) and sham surgery (n=7) groups. Eight mice were excluded from the experiment due to substandard blood glucose.
<ol>
	<li>Fast the mice for 8 h prior to the surgery. Withdraw water 2 h before the surgery.</li>
	<li>Administer 1% sodium pentobarbital solution (6 mL/kg) and buprenorphine (1 mg/kg) intraperitoneally. Touch the toes or tails of the mice with forceps and ensure that the mice do not show any obvious twitching or shaking. Under adequate anesthesia, the mice can breathe freely without supplemental oxygen.</li>
	<li>Place the mice in the supine position on a sterileboardand under a stereomicroscope. Apply eye ointment to the eyes. Use an electric blanket to keep the mice warm throughout the procedure. Use sterile procedures, including surgical gowns, sterile gloves, and autoclaved instruments.</li>
	<li>In sham control mice, make the&#160;two incisions respectively in the duodenum 1 cm below the pylorus and in the jejunum 5 cm below the Treitz and then suture the incisions.</li>
</ol>
2. Duodenal jejunal bypass: Surgical Procedure
<ol>
	<li>Apply the depilatory paste from the xiphoid to the abdomen to remove hair from this region. Wipe off the cream and ensure that the skin is clean. Scrub the area three times with alternating scrub of iodine and alcohol solutions.</li>
	<li>Cover the mouse with a sterile drape, leaving the operational area exposed, and make a 2 cm incision from the xiphoid to the abdomen.</li>
	<li>Use an abdominal retractor to expose the abdominal cavity. Push away the abdominal fat using a wet cotton swab, and move the liver to the cephalic side to fully expose the stomach and bowels.</li>
	<li>The stomach and pylorus are below the liver, and the ligament of Treitz is at the distal duodenum. Double ligate the jejunum, 5 cm distal to the ligament of Treitz with a 6-0 silk suture (Figure 1A). Cut the jejunum at the midpoint of the two ligations and suture the jejunal stump with a 10-0 silk suture (Figure 1B). 
	NOTE: Avoid twisting the mesenteric blood vessels.</li>
	<li>Pull the proximal jejunal incision 5 cm along the bowel to the jejunum to create a jejunal-jejunal anastomosis. Align the two bowels horizontally, and then use a 10-0 silk suture to create the lateral anastomosis (Figure 1C). 
	NOTE: During surgery, keep the bowel moist with saline to reduce water loss. This will prevent the bowel from curling up and will make suturing easier.</li>
	<li>Secure both ends of the bowel and cut the incision to equal length (Figure 1D). Suture the second layer of the posterior intestinal wall with a full-thickness continuous suture. 
	NOTE: The incision length is approximately 0.5-0.6 cm, and the needle distance is ~0.5 mm.</li>
	<li>Secure both ends of the bowel and suture the anterior wall of the bowel. Suture the first layer of the anterior wall with a simple continuous suture and the second layer with a horizontal varus suture (Figure 1E-F). 
	NOTE: Swab the intestinal contents with cotton swabs to prevent infection of the abdominal cavity.</li>
	<li>Pull the distal jejunal incision into the duodenum 1 cm below the pylorus to create a duodenal-jejunal anastomosis (Figure 1G). Suture it using the same method as in steps 2.6-2.7&#160;(Figure 1H-K). 
	NOTE: Check the suture at the anastomotic corner to reduce anastomotic leakage.</li>
	<li>Ligate the bowel with the micro forceps and cut the bowel with the micro scissors. Double ligate the duodenum with a 6-0 silk suture, 2 mm from the distal end of the duodenal-jejunal anastomosis. Cut at the midpoint with micro scissors and suture the stump with a 10-0 silk suture (Figure 1L). 
	NOTE: The gastroduodenal vessels branch perpendicular to the head of the pancreas and are adjacent to the pylorus, requiring careful exploration of the vessels in the transverse section. The confluence of the common bile duct and duodenum was located, taking care not to damage the pancreas or the common bile duct.</li>
	<li>Rinse the abdominal cavity with 30 &#176;C saline. Return the bowel to the abdominal cavity. Suture the muscle and the skin separately with a 6-0 silk. Then, disinfect the skin with iodophor.</li>
	<li>After surgery, inject 30 &#176;C saline (30 mL/kg) subcutaneously in the back to prevent dehydration. Inject penicillin (10 mg/kg) intramuscularly to prevent infection.</li>
</ol>
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/66049/66049fig01.jpg" /> 
Figure 1: Duodenal-jejunal bypass procedure. (A)&#160;Location of the jejunum 5 cm distal to the ligament of Treitz. (B)&#160;Double ligate the jejunum with 6-0 silk, cut through the middle of the ligature. (C) Jejunal-jejunal anastomosis. (D)&#160;Make a 0.5-0.6 cm incision, and suture the posterior wall. (E-F)&#160;Complete Jejunal-jejunal anastomosis. (G) Pull the distal jejunal to the duodenum 1 cm below the pylorus. (H) Duodenal-jejunal anastomosis. (I)&#160;Cut the duodenal-jejunal anastomosis with a 0.5-0.6 cm incision and suture the posterior wall with a simple continuous suture. (J-K)&#160;Complete duodenal-jejunal anastomosis. (L)&#160;At 2 mm from the distal to the duodenal-jejunal anastomosis, double ligate the duodenum with 6-0 silk and cut through the middle of the ligature. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/66049/66049fig01large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
3. General postoperative care
<ol>
	<li>After surgery, place the mice on an electric blanket to prevent hypothermia. Allow the mice to crawl freely until fully awake before returning to their cages.</li>
	<li>On the postoperative day, restrict the food and water and inject 2 mL of saline subcutaneously into the back of the mice. On the first postoperative day, give 10 mL of 10% glucose and a functional drink (1:1 ratio) without food, and inject 1 mL of saline subcutaneously.</li>
	<li>On the second and third postoperative days, feed the mice with a mixture of 20 mL of 10% glucose and a functional drink. After the fourth day, give the mice pure water and a high-fat diet. Transitional feeding should be performed according to the postoperative recovery status in the following order: solution, semi-liquid, or solid food.</li>
	<li>Postoperative analgesia: inject buprenorphine (0.1 mg/kg) every 12 h from Days 1 to 3, and then once daily until Day 5.</li>
	<li>After surgery, observe the feeding conditions, activity, feces, and wound healing of the mice.</li>
</ol>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/66049/66049fig02.jpg" /> 
Figure 2: The&#160;diagram of DJB surgery. (A)&#160;Duodenal-jejunal anastomosis. (B)&#160;Jejunal-jejunal anastomosis. (C)&#160;Biliopancreatic limb. (D) Digestive limb. (E)&#160;Common limb. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/66049/66049fig02large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/66049/66049fig03.jpg" /> 
Figure 3:&#160;Anatomy of DJB surgery. (A)&#160;Duodenal-jejunal anastomosis. (B)&#160;Jejunal-jejunal anastomosis. (C)&#160;Biliopancreatic limb. (D) Digestive limb. (E)&#160;Common limb. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/66049/66049fig03large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
4. Postoperative evaluation of metabolic parameters
<ol>
	<li>Body weight measurement
	<ol>
		<li>Fast the mice for 8 h prior to the measurement. Weigh the mice weekly on Monday before and after surgery for 8 weeks.</li>
	</ol>
	</li>
	<li>Food intake measurement
	<ol>
		<li>House one mouse in each cage. Measure the amount of solid food in each cage before and after 24 h. The difference between the two values represents daily food intake.</li>
	</ol>
	</li>
	<li>Random blood glucose measurement
	<ol>
		<li>At 8:00 a.m. on the weekly Monday of measurement, collect a drop of blood from the tip of the mouse tail and apply it to a glucose strip inserted into the glucometer.</li>
	</ol>
	</li>
	<li>Oral glucose tolerance test
	<ol>
		<li>Eight weeks after the DJB surgery, fast the mice for 8 h before the oral glucose tolerance test. Collect a drop of blood from the tip of the mouse tail and place it on a glucose strip inserted into the glucometer. Administer an oral dose of 20% D-glucose (2 g/kg). Measure the blood glucose levels at 0, 15, 30, 60, 90, 120, 150, and 180 mins after gavage.</li>
	</ol>
	</li>
</ol>

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The authors declare no conflicts of interest.

In 1953, Varco et al.18 performed the first jejuno-ileal bypass as the beginning of bariatric surgery. Since then, numerous bariatric surgeries have been performed by surgeons. These surgeries have resulted in weight loss and improved metabolic complications4,19,20. Furthermore, in 1967, Mason and Ito21 performed the first Roux-en-Y gastric bypass (RYGB), which can effectively reduce weight and improve metabolic syndrome. Similar to RYGB, DJB is a stomach-preserving deformation of RYGB that divides the small intestine into the biliopancreatic, digestive, and common limbs. DJB surgery provides significantly durable glycemic control without relying on reduced food intake or weight loss22,23. Therefore, DJB has been recommended as a suitable bariatric surgery for type 2 diabetics with low body mass index24.
The development of bariatric surgery is inseparable from the study of animal models, and most researchers have performed DJB in rats25,26. To date, few studies have used a mouse model to study DJB despite its suitability for studying changes in metabolic indicators after intestinal reconstruction27. The paucity of such studies is due to the fact that surgical models of DJB cannot fully replicate human procedures, making it difficult to compare results between different research groups28. Liang et al.29 initially demonstrated the significant therapeutic effect of DJB surgery on obesity and T2DM in db/db mice. The duodenum was double ligated with 5-0 suture, transected 2 mm distal to the pylorus, cut 4-5 cm below the ligament of Treitz, and the distal jejunum was sutured to the pylorus with a single interrupted end-to-end suture of 9-0 silk thread. The opening of the biliopancreatic limb was sutured with 9-0 silk ~4 cm distal to the jejunal anastomosis. Barataud et al. have also successfully established a mouse model of DJB using db/db mice30. Therefore, in our study, the small bowel was transected 5 cm below the ligament of Treitz. A jejunojejunostomy was performed on the distal 5 cm of the small bowel. The distal jejunum and duodenum were then sutured.
As shown in Table 1, the mice were divided into DJB (n=15) and sham surgery (n=7), nine mice survived in the DJB group, with a survival rate of 60.0%. We have also shown the dead cases and percentage of postoperative deaths in each group. As shown in Table 2, to increase the success rate of this technique, we have continuously improved each step. Intestinal anastomotic bleeding is the most common type of postoperative bleeding, and this complication is the leading cause of death. Therefore, the operation must be performed carefully. An intestinal incision was made at the anti-intestinal mesenteric border to keep away from the blood vessels. In our study, the anastomotic leakage was duodenojejunal anastomosis, which may be due to excessive tension in the anastomosis. Anastomotic leakage has been observed in the duodenal intestinal stump. Therefore, the corners of the anastomosis should be carefully checked during surgery, and if the suture is inadequate, the suture can be used for reinforcement. The suture distance should not be excessively long to reduce anastomotic leakage. Anastomotic obstruction was observed in the jejunal-jejunal anastomosis. Due to the unique physiological structure of the intestine in mice, the small bowel was easily twisted. The anastomotic stoma was shorter than expected when the sutures were pulled tight. During the operation, the mesentery should be adequately dissected, and the bowel should be smoothed out as much as possible to provide enough space for the placement. We should also take care of the suture tightness and the size of the anastomosis.
The main limitation of this DJB technique is that it is performed in mice. The use of microscopic equipment is becoming increasingly important in the establishment of DJB mouse models, as it provides a clear surgical field of view31,32,33. After extensive preliminary experiments, we were familiar with the anatomical structures involved in the surgical procedure and were able to skillfully perform microsurgical manipulations with improved suture precision, reduced surgical injury, and significantly shortened surgical time, thereby enabling DJB surgery in mice. However, the skilled operation of microscopic instruments is a gradual process. We analyzed the causes of death in mice in order to improve the surgical procedure, including shortening the surgical and postoperative recovery times, strengthening the postoperative feeding management, and improving the overall survival rate of the mice.
In conclusion, the application of this surgery in mice allows for a better understanding of the mechanisms underlying the powerful metabolic effects of this procedure. We believe that our study provides a solid foundation for further improving the application of DJB in the treatment of diabetes.

Obesity and type 2 diabetes are the most common chronic diseases in the world, and their prevalence is increasing among young individuals1. Bariatric surgery is the most effective treatment for obesity and diabetes, facilitating long-term blood glucose stabilitywhile also improving the complications associated with obesity2,3. There are several types of bariatric surgery, classified by whether they reduce gastric volume or intestinal absorption; these include restrictive, malabsorptive, and combination4,5.
Duodenal-jejunal bypass (DJB) was first developed by Rubino and Marescaux, who demonstrated that type 2 diabetes could be alleviated by connecting the duodenum and jejunum rather than by reducing the gastric volume6,7. DJB preserves the entire stomach and bypasses the entire duodenum and proximal jejunum. The bowel is divided into biliopancreatic, digestive, and common limbs6,8. DJB shares some similarities with bariatric surgeries, including Roux-en-Y gastric bypass (RYGB), mini-gastric bypass, biliopancreatic bypass, duodenal diversion, and DJB plus sleeve gastrectomy9. Compared to RYGB, DJB does not require a gastrointestinal anastomosis, which reduces the operative time and improves the success rate of the procedure. DJB is similar to RYGB in improving glucose metabolism but does not affect body weight10. After DJB surgery, rapid food delivery to the distal small intestine stimulates the secretion of glucagon-like peptide-1 (GLP-1), resulting in improved glucose metabolism11,12.
The use of animal models is essential for understanding the metabolic, cellular, and molecular pathways. Animal models of bariatric surgery have contributed to our understanding of potential mechanisms underlying obesity and diabetes13,14. However, due to the physiological differences between species, it is impossible to perfectly replicate human diseases in animal models15. Among various animal models available for research purposes, the diet-induced obesity (DIO) mouse model most closely resembles human obesity and metabolic syndrome16. Mice were selected for DJB surgery to determine the feasibility of the surgery and to provide techniques for further research. This manuscript provides a comprehensive summary of both technical aspects and experimental details of DJB surgery.

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duodenal-jejunal bypass surgery in diet-induced obese diabetic mice

The prevalence of obesity and type 2 diabetes is a serious global health concern. Obesity is a major pathogenic factor in type 2 diabetes, cardiovascular disease, and some cancers. Bariatric surgery offers a long-term and effective treatment option for both obesity and diabetes. Sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB) are widely recognized as the most popular bariatric surgeries. Additionally, several exploratory bariatric surgeries have demonstrated promising therapeutic effects. Duodenal-jejunal bypass (DJB), specifically tailored for diabetics with low body mass index, has shown beneficial metabolic outcomes. However, its weight-independent metabolic benefits are not fully understood due to limited animal models. In this article, we describe the optimized care protocols and surgical techniques for performing DJB surgery in diet-induced obese (DIO) diabetic mice. Using a mouse model contributes to a better understanding of the nature of changes induced by DJB surgery while facilitating related clinical practice.

General conditions 
The mean operative time for the DJB procedure was 84.5 &#177; 2.6 min. Fifteen mice underwent DJB surgery, nine mice survived. As shown in Table 1, the majority of deaths occurred during surgery or in the following 7 days. The causes of postoperative death were bleeding (n=2) on postoperative day 1, anastomotic leakage (n=1) on postoperative day 4, anastomotic obstruction (n=2) on postoperative day 7, and unknown cause (n=1) three weeks after surgery.
For 8 weeks prior to this experiment, we performed DJB surgery on 10 mice weekly as a pre-experiment to simplify the operation. As shown in Figure 4, we obtained a trend of the weekly survival rate of the mice during the pre-experiment. We observed a progressive improvement in the survival rate, indicating that intensive surgical training is required to master the DJB technique.
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/66049/66049fig04.jpg" /> 
Figure 4: The survival rate of mice seven days after the DJB Surgery. The data show the benefit of the pre-experiment on the survival rate of DJB mice. The data are shown as the survival rate 7 days post-surgery (%). <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/66049/66049fig04large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
Body weight, food intake, and glucose homeostasis 
The mice had similar body weights and food intakes before surgery and 8 weeks after surgery. DJB mice showed no significant weight loss compared to the sham control mice at 8 weeks after surgery (P &#62; 0.05; Figure 5A). Daily food intake was reduced after the 7 days following DJB and sham control surgery and returned to preoperative levels 3 weeks later (P &#62; 0.05; Figure 5B). We have observed improvements in fasting blood glucose levels and glucose tolerance after DJB surgery (P &#60; 0.01; Figure 5C, 5D).
<img alt="Figure 5" class="xfigimg" src="/files/ftp_upload/66049/66049fig05.jpg" /> 
Figure 5: Effect of DJB on body weight, daily food intake, random blood glucose, and oral glucose tolerance test. The data are shown as the mean &#177; SD, n=6. ns: not significant; ** p &#60;0.01 (Mann-Whitney and ANOVA tests). <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/66049/66049fig05large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

Duodenal-jejunal bypass (DJB) surgery can improve glucose metabolism and reduce insulin resistance. Here, we present a protocol to establish a stable and reliable mouse model of DJB.

Duodenal-Jejunal Bypass Surgery in Diet-Induced Obese Diabetic Mice

The prevalence of obesity and type 2 diabetes is a serious global health concern. Obesity is a major pathogenic factor in type 2 diabetes, cardiovascular ...

duodenal-jejunal-bypass-surgery-in-diet-induced-obese-diabetic-mice

Nanyang Technological University

Research

JoVE Journal

Medicine

419 Views.  Jinshazhou Hospital of Guangzhou University of Chinese Medicine. Duodenal-jejunal bypass (DJB) surgery can improve glucose metabolism and reduce insulin resistance. Here, we present a protocol to establish a stable and reliable mouse model of DJB.

Video: Duodenal-Jejunal Bypass Surgery in Diet-Induced Obese Diabetic Mice

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 ...

Heterotopic Cervical Heart Transplantation in Mice

The heterotopic cervical heart transplantation in mice is a valuable tool in transplant and cardiovascular research. The cuff technique greatly simplifies this model by avoiding challenging suture anastomoses of small vessels thereby reducing warm ischemia time. In comparison to abdominal graft implantation the cervical model is less invasive and the implanted graft is easily accessible for further follow-up examinations. Anastomoses are performed by pulling the ascending aorta of the graft over the cuff with the recipient&#8217;s common carotid artery and by pulling the main pulmonary artery over the cuff with the external jugular vein. Selection of appropriate cuff size and complete mobilization of the vessels are important for successful revascularization. Ischemia-reperfusion (I/R) injury can be minimized by perfusing the graft with a cardioplegic solution and by hypothermia. In this article, we provide technical details for a simplified and improved cuff technique, which should allow surgeons with basic microsurgical skills to perform the procedure with a high success rate.

The cuff technique shortens and facilitates the model of heterotopic cervical heart transplantation in mice by avoiding technically challenging suture anastomoses of small vessels. The technical details shown in this video paper should allow researches to establish this model in their laboratories.

The heterotopic cervical heart transplantation in mice is a valuable tool in transplant and cardiovascular research. The cuff technique greatly simplifies ...

Vein Interposition Model: A Suitable Model to Study Bypass Graft Patency

Bypass grafting is an established treatment method for coronary artery disease. Graft patency continues to be the Achilles heel of saphenous vein grafts. Research models for bypass graft failure are essential for a better understanding of pathobiological and pathophysiological processes during graft patency loss. Large animal models, such as pigs or sheep, resemble human anatomical structures but require special facilities and equipment. This video describes a rat vein interposition model to investigate vein graft patency loss. Rats are inexpensive and easy to handle. Compared to mouse models, the convenient size of rats permits better operability and enables a sufficient amount of material to be obtained for further diverse analysis. In brief, the inferior epigastric vein of a donor rat is harvested and used to replace a segment of the femoral artery. Anastomosis is conducted via single stitches and sealed with fibrin glue. Graft patency can be monitored non-invasively using duplex sonography. Myointimal hyperplasia, which is the main cause for graft patency loss, develops progressively over time and can be calculated from histological cross sections.

This video demonstrates a model to study the development of myointimal hyperplasia after venous interposition surgery in rats.

Bypass grafting is an established treatment method for coronary artery disease. Graft patency continues to be the Achilles heel of saphenous vein grafts. ...

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.

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 ...

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 ...

An Experimental Model of Diet-Induced Metabolic Syndrome in Rabbit: Methodological Considerations, Development, and Assessment

In recent years, obesity and metabolic syndrome (MetS) have become a growing problem for public health and clinical practice, given their increased prevalence due to the rise of sedentary lifestyles and unhealthy eating habits. Thanks to animal models, basic research can investigate the mechanisms underlying pathological processes such as MetS. Here, we describe the methods used to develop an experimental rabbit model of diet-induced MetS and its assessment. After a period of acclimation, animals are fed a high-fat (10% hydrogenated coconut oil and 5% lard), high-sucrose (15% sucrose dissolved in water) diet for 28 weeks. During this period, several experimental procedures were performed to evaluate the different components of MetS: morphological and blood pressure measurements, glucose tolerance determination, and the analysis of several plasma markers. At the end of the experimental period, animals developed central obesity, mild hypertension, pre-diabetes, and dyslipidemia with low HDL, high LDL, and an increase of triglyceride (TG) levels, thus reproducing the main components of human MetS. This chronic model allows new perspectives for understanding the underlying mechanisms in the progression of the disease, the detection of preclinical and clinical markers that allow the identification of patients at risk, or even the testing of new therapeutic approaches for the treatment of this complex pathology.

We describe methods to develop an experimental model of diet-induced metabolic syndrome (MetS) in rabbits using a high-fat, high-sucrose diet. Animals developed central obesity, mild hypertension, pre-diabetes, and dyslipidemia, thus reproducing the main components of human MetS. This chronic model will allow acquisition of knowledge underlying mechanisms of disease progression.

In recent years, obesity and metabolic syndrome (MetS) have become a growing problem for public health and clinical practice, given their increased ...

Surgical Swine Model of Chronic Cardiac Ischemia Treated by Off-Pump Coronary Artery Bypass Graft Surgery

Chronic cardiac ischemia that impairs cardiac function, but does not result in infarct, is termed hibernating myocardium (HM). A large clinical subset of coronary artery disease (CAD) patients have HM, which in addition to causing impaired function, puts them at higher risk for arrhythmia and future cardiac events. The standard treatment for this condition is revascularization, but this has been shown to be an imperfect therapy. The majority of pre-clinical cardiac research focuses on infarct models of cardiac ischemia, leaving this subset of chronic ischemia patients largely underserved. To address this gap in research, we have developed a well-characterized and highly reproducible model of hibernating myocardium in swine, as swine are ideal translational models for human heart disease. In addition to creating this unique disease model, we have optimized a clinically relevant treatment model of coronary artery bypass surgery in swine. This allows us to accurately study the effects of bypass surgery on heart disease, as well as investigate additional or alternate therapies. This model surgically induces single vessel stenosis by implanting a constrictor on the left anterior descending (LAD) artery in a young pig. As the pig grows, the constrictor creates a gradual stenosis, resulting in chronic ischemia with impaired regional function, but preserving tissue viability. Following the establishment of the hibernating myocardium phenotype, we perform off-pump coronary artery bypass graft surgery to revascularize the ischemic region, mimicking the gold-standard treatment for patients in the clinic.

This protocol presents a surgical large animal model of chronic, single vessel ischemia that results in regional abnormalities but does not create infarct, known as hibernating myocardium. Following establishment of chronic ischemia, animals are treated with off-pump LIMA-LAD coronary artery bypass graft surgery to revascularize the ischemic tissue.

Chronic cardiac ischemia that impairs cardiac function, but does not result in infarct, is termed hibernating myocardium (HM). A large clinical subset of ...

Protocol to Create Chronic Wounds in Diabetic Mice

Chronic wounds develop as a result of defective regulation in one or more complex cellular and molecular processes involved in proper healing. They impact ~6.5M people and cost ~$40B/year in the US alone. Although a significant effort has been invested in understanding how chronic wounds develop in humans, fundamental questions remain unanswered. Recently, we developed a novel mouse model for diabetic chronic wounds that have many characteristics of human chronic wounds. Using db/db-/- mice, we can generate chronic wounds by inducing high levels of oxidative stress (OS) in the wound tissue immediately after wounding, using a one-time treatment with inhibitors specific to the antioxidant enzymes catalase and glutathione peroxidase. These wounds have high levels of OS, develop biofilm naturally, become fully chronic within 20 days after treatment and can remain open more for more than 60 days. This novel model has many features of diabetic chronic wounds in humans and therefore can contribute significantly to advancing fundamental understanding of how wounds become chronic. This is a major breakthrough because chronic wounds in humans cause significant pain and distress to patients and result in amputation if unresolved. Moreover, these wounds are very expensive and time-consuming to treat, and lead to significant loss of personal income to patients. Advancements in this field of study through the use of our chronic wound model can significantly improve health care for millions who suffer under this debilitating condition. In this protocol, we describe in great detail the procedure to cause acute wounds to become chronic, which has not been done before.

Chronic wounds are developed from acute wounds on a diabetic mouse model by inducing high levels of oxidative stress after a full-thickness cutaneous wound. The wound is treated with inhibitors for catalase and glutathione peroxidase, resulting in impaired healing and biofilm development by bacteria present in the skin microbiome.

Chronic wounds develop as a result of defective regulation in one or more complex cellular and molecular processes involved in proper healing. They impact ...

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 ...