Sleeve Gastrectomy in Mice using Surgical Clips
November 14th, 2020
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 chief target of the surgical intervention is to measure the metabolic effects and the insulin resistance of sleeve gastrectomy in a more assessable mouse model. This protocol aims to produce an animal model for the research of the mechanisms that underline the results seen after a bariatric surgery in humans, which may provide insights into the pathogenesis of obesity and type 2 diabetes treatment. For sleeve gastrectomy and sham operation, after confirming the appropriate depth of anesthesia by toe stimulation, apply the Carbomer 0.2%eye gel on the mouse's eyes to prevent dry eyes.
The mouse is placed and fixed on the surgical table. Remove and clean the remaining hair with a depilatory cream. Disinfect the abdomen of the mouse with povidone-iodine solutions alternating with alcohol for three applications.
Perform the SG procedure with the aid of a magnifying dissecting microscope or magnifier as necessary to prevent any unpredictable bleeding and hypovolemic shock. Make a one to 1.5 centimeters in length midline incision at the upper abdomen. Use two curved smooth serrated micro-forceps to gently move the stomach and complete externalize it.
Move the intestine to the bare skin on the side and cover it with warm saline moistened gauze to prevent dehydration. Carefully divide the gastrosplenic ligament connecting the left stomach to the spleen using a cotton-tipped probe and electrocautery as needed, thereby dissecting the gastric fundus from the surrounding spleen and other internal organs. Stretch the fundus and pylorus of the stomach gently and laterally with forceps, identify the midline of the stomach and carefully apply two surgical clips using the LIGACLIP applier to the 15%medial segment of the stomach from the gastroesophageal junction inferiorly and pylorus superiorly.
Clamp and isolate around 75-80%of stomach, thereby creating the entire lateral sleeve of the stomach. Resect the lateral isolated stomach with a microscissors. Use cotton swabs to remove any residual food from the stomach and then clean the cut edge of the stomach with povidone-iodine aqueous solution.
Oversew the clip line with a 5-0 monofilament nonabsorbable suture to make sure of no leakage. Knot the ends of the suture and anchor to the clips on either end. Return the stomach and intestine to the proper position in the abdominal cavity and close the abdomen with a running 5-0 monofilament nonabsorbable suture to the abdominal wall.
For sham procedure of SG, perform a similar procedure as described previously with a midline laparotomy, externalize the intestine and stomach using 37 degree Celsius wet warm saline gauze coverage for five minutes. Return the stomach and intestine to the proper sites of these internal organs. Administer ketoprofen two to five milligrams per kilogram and cefazolin 25 milligrams per kilogram subcutaneously or intraperitoneally after surgery for the pain control and infection prevention.
Stop the isoflurane and continuing with a room air flow of three to five liters per minute until the mouse is fully awake. Keep watching the mouse while it regains mobility and begins to walk around the cage. Place the mouse in the independent incubator around 30 degrees Celsius in temperature condition for five days, making sure there is only one mouse per cage.
In our experienced hands, the successful rate of SG was around 90%after the learning period. The body weight of sham operated and high-fat diet fed mice gained steadily. But the sleeve gastrectomy and high-fat diet fed mice decreased continuously.
The difference of the cholesterol level was significant between the high-fat diet fed mice with sham and sleeve gastrectomy. This might indicate that oxidative stress improvement after the sleeve gastrectomy. The difference of the levels of hemoglobin A1C and IPGTT were significant as well.
Between the high-fat diet fed mice with sham and sleeve gastrectomy and by indicating insulin-resistance and sugar control improvement after the sleeve gastrectomy. This animal model can help us to investigate the clinical relevance of diabetes and obesity in using a brief surgical procedure with sleeve gastrectomy. This procedure can shorten the operation time and improve the surgical survival rate.
The main advantage of this study is to imitate the clinical outcomes of bariatric surgery in human patients using a simple surgical mouse model.
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Overview
This article presents a protocol for sleeve gastrectomy (SG) in animals, serving as a preclinical model for bariatric surgery. The study aims to investigate the metabolic effects and insulin resistance associated with SG, contributing to the understanding of obesity and diabetes.
Key Study Components
Area of Science
- Neuroscience
- Metabolic research
- Bariatric surgery
Background
- The prevalence of diabetes and obesity is increasing globally.
- Understanding the mechanisms linking these conditions is crucial.
- Animal models are essential for studying surgical interventions.
- Sleeve gastrectomy is a common bariatric procedure in humans.
Purpose of Study
- To develop an animal model for studying sleeve gastrectomy.
- To assess metabolic effects and insulin resistance post-surgery.
- To provide insights into obesity and type 2 diabetes treatment mechanisms.
Methods Used
- Confirming anesthesia depth through toe stimulation.
- Applying eye gel to prevent dry eyes during surgery.
- Preparing the surgical site by shaving and disinfecting the abdomen.
- Conducting sleeve gastrectomy and sham operations on mice.
Main Results
- Establishment of a reliable animal model for SG.
- Measurement of metabolic changes post-surgery.
- Insights into insulin resistance mechanisms.
- Potential implications for human obesity and diabetes research.
Conclusions
- The protocol provides a framework for future studies on SG.
- Understanding metabolic effects can guide treatment strategies.
- Animal models are vital for advancing bariatric surgery research.
Frequently Asked Questions
Executive Industry Relevance
Preclinical sleeve gastrectomy models in mice enable mechanistic investigation of metabolic outcomes relevant to obesity and type 2 diabetes. This approach supports target validation and predictive confidence for metabolic disease research, bridging discovery biology with translational relevance. The model's reproducibility and operational simplicity facilitate robust evaluation of surgical interventions in metabolic pathways.
Strategic Applications in Biopharma R&D
Early Discovery & Target Validation
- Enables interrogation of metabolic pathways implicated in obesity and diabetes.
- Supports functional validation of targets modulating insulin resistance and glucose homeostasis.
- Facilitates mechanistic de-risking by modeling human bariatric surgery outcomes in mice.
- Provides a platform for hypothesis-driven exploration of metabolic intervention effects.
Screening & Assay Development
- Establishes a validated in vivo system for quantitative metabolic readouts post-surgery.
- Supports assay standardization for measuring glucose, cholesterol, and insulin resistance.
- Enables reproducible comparison between surgical and sham-operated controls.
- Prepares a scalable model for downstream compound or genetic intervention studies.
Translational & Preclinical Research
- Aligns preclinical findings with clinical bariatric surgery outcomes for translational continuity.
- Enables risk-adjusted advancement of metabolic disease targets based on in vivo efficacy.
- Supports biomarker development for metabolic improvement post-intervention.
- Facilitates decision-making for advancing candidates into late-stage preclinical studies.
Pipeline & Workflow Integration
This mouse sleeve gastrectomy model integrates into the discovery-to-preclinical continuum for metabolic disease research, supporting both early mechanistic studies and translational validation.
- Discovery Biology: Provides a platform for null hypothesis testing of metabolic intervention effects.
- Screening: Delivers quantitative outputs for glucose, cholesterol, and insulin resistance metrics.
- Analytics: Enables statistical comparison of metabolic parameters between experimental groups.
- Translational Research: Bridges preclinical findings with human bariatric surgery outcomes.
- Enterprise Reuse: Offers a standardized, reproducible model for ongoing metabolic research programs.
Operational & Enterprise Impact
- Scientific Value: Increases predictive confidence in metabolic target validation and mechanistic understanding.
- Operational Value: Streamlines model establishment with high reproducibility and low complication rates.
- Strategic Value: Supports informed go/no-go decisions for metabolic disease portfolios.
- Portfolio Impact: Enables risk-adjusted prioritization of metabolic intervention strategies.
Implementation Considerations
- Requires surgical expertise and access to microsurgical instrumentation.
- Necessitates infrastructure for metabolic phenotyping and statistical analysis.
- Demands cross-team standardization for reproducibility and data comparability.
- Adaptable to various mouse strains and dietary models for broader applicability.
- Limitations include the need for post-operative monitoring and single-housing for recovery.
