We thank Miss Isabelle Lu for the English narration.

All procedures for animal use were approved by the National Yang-Ming University Institutional Animal Care and Use Committee and complied with the &#8220;Guide for the Care and Use of Laboratory Animals. 8th edition, 2011&#8221;. The anesthetic procedure was performed according to the guideline for the pain control, anesthesia, pre-operative, and postoperative care for the experimental animals from National Yang Ming University, ICAUC-016, 2015, 1st edition.
1. Animal preparation
<ol>
	<li>Obtain 20 8-week-old wild type C57BL/6 male mice from the National Laboratory Animal Center (NLAC) that weigh around 16-18 grams. Randomly assign these mice into the SG or the sham operation group with 10 mice each.</li>
	<li>Start the mice on chow or a high-fat diet (see <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/60719/High fat diet.pdf" target="_blank">Supplemental File</a>) prior to the bariatric or sham surgeries9. Produce diet-induced obesity with at least 2 preoperative weeks of the HFD.</li>
	<li>House the mice in the National Yang-Ming University Laboratory Animal Center under a light-dark cycle of 12:12 with light onset at 07:00 A.M. and allow free feeding to standard rodent chow and water.</li>
	<li>Restrict all animals from food but allow free water access on the night before surgery.</li>
</ol>
2. General preoperative preparation
<ol>
	<li>Fast the mice for at least 6 hours before the surgery. Induce anesthesia in an induction chamber with 5% isoflurane and oxygen (both 3-4 L/min).
	<ol>
		<li>Check the depth of anesthesia ensuring that pinch stimulation (blunt curved serrated smooth micro-forceps) of the hind paw, the forepaw, and the ear does not evoke any motor reflex. Administer antibiotics (25 mg/kg cefazolin) via subcutaneous injections before the operation.</li>
	</ol>
	</li>
	<li>Assign a particular work zone for surgical procedures. Clean the surgical area and spray the surgical table with 75% alcohol solution before an operation.</li>
	<li>Place the mouse in the nose cone and maintain anesthesia with 2% isoflurane (2 L/min) and oxygen (4 L/min).</li>
	<li>For sleeve gastrectomy and sham operation, after confirming the appropriate depth of anesthesia by toe stimulation, apply the 0.2% Carbomer eye gel on the mouse&#8217;s eyes to prevent dry eyes.</li>
	<li>Use an electric razor to shave hair from the abdomen to the sternum. Remove and clean the remaining hair with a depilatory cream. Place and fix the mouse on the surgical table in a supine position.</li>
	<li>Disinfect the abdominal wall of the mouse with povidone-iodine solutions alternating with 75% alcohol for 3 applications.</li>
</ol>
3. Sleeve gastrectomy and sham procedures
<ol>
	<li>Median laparotomy
	<ol>
		<li>Use a micro-scissor to make a 1-1.5 cm length midline incision at the upper abdomen.</li>
	</ol>
	</li>
	<li>Stomach and intestine externalization
	<ol>
		<li>Perform the SG procedure with the aid of a magnifying dissecting microscope or magnifier as necessary to prevent the unpredictable bleeding and hypovolemic shock.</li>
		<li>Use two curved smooth serrated micro-forceps to gently move the stomach and complete externalize it.</li>
		<li>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.</li>
	</ol>
	</li>
</ol>
4. Stomach isolation and clip
NOTE: The SG for mice was performed using the new clip applier technique as previously published10.
<ol>
	<li>Stretch the fundus and pylorus of the stomach gently and laterally with forceps, identify the midline (Figure 1 and Figure 2), and carefully apply surgical clips to half of the medial side of the stomach midline from the gastroesophageal junction inferiorly and the lower pole superiorly. Clamp and exclude around 75-80% of stomach, thereby creating the entire lateral sleeve of the stomach (Figure 1 and Figure 2).</li>
	<li>Move the intestine to the bare skin on the side and cover it with a warm-saline moistened gauze and perform intraperitoneal hydration as needed to prevent dehydration and hypothermia.</li>
	<li>Resect the lateral clipped stomach, remove the excluded sleeve of the stomach with microscissors and then sterilize the cut edge of the stomach with povidone-iodine solution.</li>
	<li>Oversew the clip line with a 5-0 monofilament nonabsorbable suture to ensure no leakage. Knot the ends of the suture and anchor to the clips on either end.</li>
	<li>Return the stomach and intestine to the proper position in the abdominal cavity and close the abdomen with a running 5-0 monofilament nonabsorbable continuous and discontinuous suture to the fascia and abdominal wall.</li>
	<li>Administer analgesics with ketoprofen (2-5 mg/kg) and antibiotics with cefazolin (25 mg/kg) intraperitoneally after the whole procedure.</li>
</ol>
5. Sham procedure of SG
<ol>
	<li>Perform a similar procedure as described previously with a midline laparotomy, and externalize the intestine and stomach using 37 &#176;C wet warm saline gauze coverage for 5 min.</li>
	<li>Return the stomach and intestine to the proper sites of these internal organs.</li>
	<li>Close the abdominal wall carefully as previously described with 2 layers of continuous and discontinuous closure to the fascia and skin using slow or non-absorbable monofilament sutures. Administer analgesics with ketoprofen (2-5 mg/kg) and antibiotics with cefazolin (25 mg/kg) intraperitoneally after the whole procedure.</li>
</ol>
6. General postoperative care
<ol>
	<li>Stop isoflurane and continue with a room air flow of 3-5 L/min until the mouse is fully awake.</li>
	<li>Keep watching the mouse while it regains mobility and begins to walk around the cage.</li>
	<li>Place the mouse in a 30 &#176;C independent incubator for 5 days. Make sure there is only one mouse per cage to prevent the mice from injuring each other.</li>
	<li>Return free access to a gel diet food (high-fat gel diet: 10% lard, 10% liquid sugar, 57% water) for 3 days after surgery and reintroduce the previous assigned diet 3 days after surgery.</li>
	<li>Subcutaneously or intraperitoneally inject ketoprofen (2-5 mg/kg), and cefazolin (25 mg/kg) for 1 day after the operation.</li>
	<li>Assess the mouse body weight weekly through the whole study period. Provide ketoprofen (2-5 mg/kg) by intraperitoneal injection for pain control once daily as needed if the animal is in distress after the operation. 
	NOTE: Here, the survival rate of SG was 90% after the learning period.</li>
</ol>
7. Metabolic parameter assessment
<ol>
	<li>Fast mice for 6 h, and take baseline blood samples (0 min). Obtain all blood samples from the tip of the tail vein of freely moving mice11,12.</li>
	<li>Deliver 1 mg/g of 50% dextrose by intraperitoneal injection for the glucose tolerance test.</li>
	<li>Measure the blood glucose from the tips of the tail veins of freely moving mice at 0, 5, 15, 30, 60, and 120 min after glucose administration on duplicate samples using glucometers and test strips.</li>
	<li>Keep the whole blood sample (n = 10 for each group) at room temperature with clotting for 30 minutes.</li>
	<li>Centrifuge the blood sample at 3,000 x g for 10 minutes at 4 &#176;C.</li>
	<li>Transfer the plasma into separate tubes without disturbing blood clots and store at -80 &#176;C.</li>
	<li>Study the plasma samples at the end of the study using commercial mice ELISA kits for hemoglobin A1c (HBA1c), glucose, cholesterol, and insulin levels according to the manufacturer&#8217;s guidelines.</li>
</ol>

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S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+sleeve+gastrectomy+in+high+fat+diet-induced+obese+mice:+respective+role+of+reduced+caloric+intake,+white+adipose+tissue+inflammation+and+changes+in+adipose+tissue+and+ectopic+fat+depots.">Effects of sleeve gastrectomy in high fat diet-induced obese mice: respective role of reduced caloric intake, white adipose tissue inflammation and changes in adipose tissue and ectopic fat depots.</a> Surgical Endoscopy. 28 (2), 592-602 (2014).</li><li>Rubino, F., R'Bibo, S. L., del Genio, F., Mazumdar, M., McGraw, T. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Metabolic+surgery:+the+role+of+the+gastrointestinal+tract+in+diabetes+mellitus.">Metabolic surgery: the role of the gastrointestinal tract in diabetes mellitus.</a> Nature Reviews Endocrinology. 6 (2), 102-109 (2010).</li><li>Wilson-Perez, H. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vertical+sleeve+gastrectomy+is+effective+in+two+genetic+mouse+models+of+glucagon-like+Peptide+1+receptor+deficiency.">Vertical sleeve gastrectomy is effective in two genetic mouse models of glucagon-like Peptide 1 receptor deficiency.</a> Diabetes. 62 (7), 2380-2385 (2013).</li><li>Lopez, P. P., Nicholson, S. E., Burkhardt, G. E., Johnson, R. A., Johnson, F. 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The authors declare no conflict of interest.

Most of the prospective cohort studies have confirmed that increasing the body mass index is related to increasing the mortality. Obesity is associated with a higher risk of diabetes, cardiovascular diseases (CVD), and death in both sexes. The specific pathologic processes have established a link between diabetes, obesity, and mortality14. The systematic reviews indicate the benefits of bariatric surgery in reducing risk factors for CVD with evidence for ventricular hypertrophy regression and improved diastolic function as well15. Bariatric/metabolic surgery can improve traditional CVD risk factors in obese diabetic patients, and the 10-year CHD and fatal CHD risk have shown to be reduced by up to 50% after various bariatric/metabolic surgical procedures in obese patients with T2D4.
Bariatric surgery is the most effective long-term therapeutic strategy for obesity. The significant improvements of metabolic parameters from bariatric surgery such as lipid profile, inflammatory biomarkers, blood pressure, and heart failure are also noted especially in the unexpected type 2 diabetic control. SG has reduced and modified adipose tissue inflammation and development and has possibly reduced the atherosclerosis risk.
Changes of gastro-intestinal hormones might play a role in long-term weight control16,17. The SG has also reduced caloric intake and normalized the glycemic control18. The gastric bypass surgery related glycemic tolerance effects are related to the foregut hormonal effects evoked by bypassing the proximal bowel from the current theories19. However, the SG has demonstrated the comparable antidiabetic effect, suggesting further non-bypassing related unknown mechanisms even beyond the effect of glucagon-like peptide 1 receptor16,20. Lopez et al. have shown that SG promotes weight loss, improves the cholesterol and glucose profile, leptin insensitivity, and decreases insulin resistance, which is independent of the ghrelin level changes in obese Zucker rats21. All these above issues need further animal studies to clarify the connection with diabetes, obesity and diseases. SG is a bariatric procedure that does not involve intestinal bypass, which has become increasingly popular in recent decades in the US and globally due to low long term complications22.
The bariatric surgical procedure is technically difficult and time consuming with high surgical mortality and long-term complication and is the main critical step for small animal experiments. The SG is currently the most used surgery for weight reduction in the US because it is a simple procedure with high effectiveness, low co-morbidity, and low mortality. This protocol has similar advantages mimicking the weight reduction and metabolic surgeries practiced routinely in humans. In general, surgical techniques are quite difficult in mice because of the small body size, and a dissecting microscope is frequently needed with high surgical mortality.
Schlager et al. have developed a mouse model of SG with a surgical clip application instead of a hand sewn closure for the stomach. This animal model has demonstrated similar effects of body weight reduction and glucose control, but has failed to reveal significant pancreatic islet cell proliferation10. This effect on the metabolism from this mice model is similar to the human bariatric/metabolic surgery with a very low operative mortality.
This current study demonstrates constant weight reduction after the SG in the HFD fed mice with improved glycated hemoglobin, IPGTT, HOMA-IR (homeostatic model assessment for insulin resistance), and cholesterol level. This surgical procedure is safe and easy to perform in mice.
The surgical survival rate of this protocol in our laboratory is around 90% after a learning period, and the procedure takes less than 15 minutes. This protocol may provide significant value in future small rodent studies with surgical feasibility, safety, reproducibility, and clinical relevance. This method may also be used to highlight physiological changes observed after bariatric surgery in humans. The difficulty of SG surgery plays an important factor in the success of animal studies. This protocol is easy to perform, and imitates the SG as commonly practiced in other animal and human studies.
This animal model can investigate the clinical relevance of diabetes and obesity using a brief surgical procedure with sleeve gastrectomy. These procedures can shorten the operation time and improve the surgical survival rate. The main advantage of this study is to mimic the clinical outcomes of bariatric surgery in human patients using a simple surgical model.

The prevalence of obesity has increased nearly threefold worldwide since 1975. In 2016, more than 1.9 billion adults older than 18 years were overweight and over 650 million adults were obese. The prevalence of T2D in the adult population has also doubled from 4.7% to 8.5% with the number rising from 108 million to 422 million adults between 1980 and 2014 globally1. Most bariatric surgeries result in significant weight loss, a reduction of body fat, and improvement in glucose tolerance, insulin resistance and diabetes control2. In addition to weight loss and remission of T2D, bariatric surgery further produces additional health advantages such as hypertension control and a lower incidence of certain types of obesity related cancer development and progression3. Bariatric surgery also induces durable complete, partial remission of T2D, and decreases the risk of ten-year major coronary heart disease (CHD) and some degree of cerebrovascular risk. However, the underlying mechanisms are not completely understood4.
There are several procedures for bariatric/metabolic surgery. Both restrictive and gastrointestinal bypass surgeries provide positive effects on metabolism5. Of the bariatric surgical models, SG and modified Roux-en-Y gastric bypass have higher success and lower mortality rates and demonstrate reliable restrictive and gastrointestinal bypass surgery models in mice6. Although the gastrointestinal bypass surgery provides more weight loss and a significant improvement of glucose tolerance and liver steatosis than the restrictive procedure in the long term, the SG still produces good control of body weight and glucose levels and is easy to perform with a low incidence of complications6. The proportion of SG increased from 30% to 54% and Roux-en-Y gastric bypass surgery decreased from 52% to 32% from 2008 to 20147. Currently, laparoscopic SG is the most commonly performed bariatric procedure at the national level within academic centers in the United States8. Although there have been many published reports regarding the pathophysiological processes between bariatric surgery, diabetes and obesity, we need more animal experiments to further explore unknown mechanisms.
This protocol aims to produce an animal method to investigate the mechanisms underlying the outcomes seen after bariatric surgery in humans. The current translational study may provide insights on the mechanism of obesity and T2D treatment from the SG.

<table><tbody><tr><td>0.9% normal saline</td><td>China Chemical &amp;amp; Pharmaceutical Co., Ltd.</td><td></td><td></td></tr><tr><td>5-0 monofilament suture</td><td>Shineteh Inc. Taiwan</td><td></td><td>Ethicon</td></tr><tr><td>Alm</td><td>Shineteh Inc. Taiwan</td><td>ST-A072PK</td><td>UNIK</td></tr><tr><td>Animal Anesthesia</td><td>Step Technology</td><td>0712VAP11076</td><td>Matrx</td></tr><tr><td>Barraqer-Troutman forceps</td><td>Shineteh Inc. Taiwan</td><td>ST-N309(H-4410)</td><td>UNIK</td></tr><tr><td>cefazolin</td><td>Taiwan veteran pharmacy company</td><td></td><td></td></tr><tr><td>Chow diet</td><td>Research Diets</td><td></td><td></td></tr><tr><td>Glucose strips and glucometer</td><td>BeneCheck</td><td>BKM13-1</td><td>BeneCheck</td></tr><tr><td>HbA1c kit</td><td>Level</td><td>OKEH00661</td><td></td></tr><tr><td>Hematology system</td><td>Fuji</td><td>FUJI DRI-CHEM 4000i</td><td>Europe</td></tr><tr><td>High Fat diet</td><td>Research Diets</td><td>1810724</td><td>LabDiet</td></tr><tr><td>Iris Forceps</td><td>Shineteh Inc. Taiwan</td><td>ST-1210</td><td>UNIK</td></tr><tr><td>Iris Scissors</td><td>Shineteh Inc. Taiwan</td><td>ST-S011</td><td>UNIK</td></tr><tr><td>Isoflurane</td><td>Panion &amp;amp; BF biotech INC</td><td>8547</td><td>Panion &amp;amp; BF</td></tr><tr><td>Ketoprofen</td><td>Sigma</td><td>22071154</td><td>Sigma-Aldrich</td></tr><tr><td>Stereo microscope</td><td>MicroTech</td><td>SZ-5T</td><td>MicroTech</td></tr><tr><td>Surgical clip (M)</td><td>Echicon Inc., Somerville, NJ</td><td></td><td>Size M, 5mm</td></tr><tr><td>Vidisic gel</td><td>Dr. Gerhard Mann Chem.-pharm. Fabrik GmbH</td><td></td><td></td></tr></tbody></table>

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.

Results of the operation are shown in Figure 3 and Figure 4. The survival rate of the study was 90%. One mouse died in the sham group because of weakness and another mouse died in the SG group on the third day after operation for unknown reasons. Results obtained on weight loss (Figure 3A) after operation (at week 3) on HFD fed mice were quite similar to those observed in humans, with a final body weight loss of about 15-20%13. The study also demonstrated that the cholesterol level (Figure 3B) decreased significantly after SG surgery in the HFD fed mice.
Better insulin sensitivity and glucose tolerance were observed soon after the surgery by an intraperitoneal glucose tolerance test (IPGTT). In the current study, we demonstrated that the HFD-induced obesity evoked insulin resistance and glucose intolerance in wild type C57BL/6 mice and can be corrected by SG. After SG, the insulin resistance, glucose, and lipid levels all improved in this study.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/60719/60719fig01.jpg" /> 
Figure 1: Surgical procedures of SG. 
(A) The 5 mm surgical clip used in this experimental model. (B) Check the depth of anesthesia with pinch stimulation. (C,D) Apply the clip to the half of medial side of the stomach midline from gastroesophageal junction inferiorly and lower pole superiorly. (E) Sterilize and suture the cut edge of the stomach to ensure no leakage. (F-H) Hydrate the mice with warm saline, return the stomach and intestine back to the proper site in the abdominal cavity. Close the abdominal cavity carefully. Recover from the anesthetizing status in the induction chamber and return to the cage when the condition was fully recovered and stabilized. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/60719/60719fig01large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/60719/60719fig02.jpg" /> 
Figure 2: Sites of surgical clip usage to the stomach. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/60719/60719fig02large.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/60719/60719fig03.jpg" /> 
Figure 3: The effect of SG on (A) weekly body weight changes and (B) cholesterol level. 
Data are represented as mean &#177; SD. *P &#60; 0.05; **P &#60; 0.001. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/60719/60719fig03large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/60719/60719fig4v2.jpg" /> 
Figure 4: Effect of SG on (A) IPGTT (B) Hba1c and (C) HOMA-IR at the end of the study. 
(n = 5 VSG; n = 7 sham); Data are represented as mean &#177; SD. *P &#60; 0.05; **P &#60; 0.001. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/60719/60719fig4v2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

Watch this Scientific Journal Video about Sleeve Gastrectomy in Mice using Surgical Clips at JoVE.com

Sleeve Gastrectomy in Mice using Surgical Clips

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 ...

sleeve-gastrectomy-in-mice-using-surgical-clips

Nanyang Technological University

Research

JoVE Journal

Medicine

6.5K Views.  Min-Sheng General Hospital. Het belangrijkste doel van de chirurgische ingreep is het meten van de metabolische effecten en de insulineresistentie van mouwgastrectomie in een meer beoordelingsmodel. Dit protocol is bedoeld om een diermodel te produceren voor het onderzoek van de mechanismen die de resultaten van een bariatrische operatie bij de mens onderstrepen, die inzicht kunnen geven in de pathogenese van obesitas en diabetesbehandeling type 2. Voor mouwgastrectomie en schijnoperatie, na het bevestigen van de juiste...

Video: Sleeve Gastrectomy in Mice using Surgical Clips

Implantation of Radiotelemetry Transmitters Yielding Data on ECG, Heart Rate, Core Body Temperature and Activity in Free-moving Laboratory Mice

The laboratory mouse is the animal species of choice for most biomedical research, in both the academic sphere and the pharmaceutical industry. Mice are a manageable size and relatively easy to house. These factors, together with the availability of a wealth of spontaneous and experimentally induced mutants, make laboratory mice ideally suited to a wide variety of research areas.
In cardiovascular, pharmacological and toxicological research, accurate measurement of parameters relating to the circulatory system of laboratory animals is often required. Determination of heart rate, heart rate variability, and duration of PQ and QT intervals are based on electrocardiogram (ECG) recordings. However, obtaining reliable ECG curves as well as physiological data such as core body temperature in mice can be difficult using conventional measurement techniques, which require connecting sensors and lead wires to a restrained, tethered, or even anaesthetized animal. Data obtained in this fashion must be interpreted with caution, as it is well known that restraining and anesthesia can have a major artifactual influence on physiological parameters1, 2.
Radiotelemetry enables data to be collected from conscious and untethered animals. Measurements can be conducted even in freely moving animals, and without requiring the investigator to be in the proximity of the animal. Thus, known sources of artifacts are avoided, and accurate and reliable measurements are assured. This methodology also reduces interanimal variability, thus reducing the number of animals used, rendering this technology the most humane method of monitoring physiological parameters in laboratory animals3, 4. Constant advancements in data acquisition technology and implant miniaturization mean that it is now possible to record physiological parameters and locomotor activity continuously and in realtime over longer periods such as hours, days or even weeks3, 5.
Here, we describe a surgical technique for implantation of a commercially available telemetry transmitter used for continuous measurements of core body temperature, locomotor activity and biopotential (i.e. onelead ECG), from which heart rate, heart rate variability, and PQ and QT intervals can be established in freeroaming, untethered mice. We also present pre-operative procedures and protocols for post-operative intensive care and pain treatment that improve recovery, well-being and survival rates in implanted mice5, 6.

A surgical technique for implantation of commercially available telemetry transmitters used for continuous measurement of biopotential (one-lead ECG), heart rate, core body temperature and locomotor activity in freely moving mice is shown. Recommendations and protocols for post-operative care and pain relief, improving recovery, well being and survival rate are also presented.

The laboratory mouse is the animal species of choice for most biomedical research, in both the academic sphere and the pharmaceutical industry. Mice are a ...

Minimal Invasive Surgical Procedure of Inducing Myocardial Infarction in Mice

Myocardial infarction still remains the main cause of death in western countries, despite considerable progress in the stent development area in the last decades. For clarification of the underlying mechanisms and the development of new therapeutic strategies, the availability of valid animal models are mandatory. Since we need new insights into pathomechanisms of cardiovascular diseases under in vivo conditions to combat myocardial infarction, the validity of the animal model is a crucial aspect. However, protection of animals are highly relevant in this context. Therefore, we establish a minimally invasive and simple model of myocardial infarction in mice, which assures a high reproducibility and survival rate of animals. Thus, this models fulfils the requirements of the 3R principle (Replacement, Refinement and Reduction) for animal experiments and assure the scientific information needed for further developing of therapeutical strategies for cardiovascular diseases.

A highly reproducible model for myocardial infarction in mice with minimal invasive manipulations is described. The model can be easily performed, resulting in a high reproducibility and survival rate. Thus, the described model will reduce the number of required animals as requested by the 3R principle (Replacement, Refinement and Reduction).

Myocardial infarction still remains the main cause of death in western countries, despite considerable progress in the stent development area in the last ...

Measuring Ascending Aortic Stiffness In Vivo in Mice Using Ultrasound

We present a protocol for measuring in vivo aortic stiffness in mice using high-resolution ultrasound imaging. Aortic diameter is measured by ultrasound and aortic blood pressure is measured invasively with a solid-state pressure catheter. Blood pressure is raised then lowered incrementally by intravenous infusion of vasoactive drugs phenylephrine and sodium nitroprusside. Aortic diameter is measured for each pressure step to characterize the pressure-diameter relationship of the ascending aorta. Stiffness indices derived from the pressure-diameter relationship can be calculated from the data collected. Calculation of arterial compliance is described in this protocol.
This technique can be used to investigate mechanisms underlying increased aortic stiffness associated with cardiovascular disease and aging. The technique produces a physiologically relevant measure of stiffness compared to ex vivo approaches because physiological influences on aortic stiffness are incorporated in the measurement. The primary limitation of this technique is the measurement error introduced from the movement of the aorta during the cardiac cycle. This motion can be compensated by adjusting the location of the probe with the aortic movement as well as making multiple measurements of the aortic pressure-diameter relationship and expanding the experimental group size.

Measuring Ascending Aortic Stiffness In Vivo in Mice Using Ultrasound

We describe a technique for measuring aortic stiffness from its pressure-diameter relationship in vivo in mice. Aortic diameter is recorded by ultrasound and aortic pressure is measured invasively with a solid-state pressure catheter. Blood pressure is changed incrementally and the resulting diameter is measured.

We present a protocol for measuring in vivo aortic stiffness in mice using high-resolution ultrasound imaging. Aortic diameter is measured by ultrasound ...

Surgical Models of Gastroesophageal Reflux with Mice

Multiple surgical procedures have been reported to induce gastroesophageal reflux in animals. Herein, we report three surgical models with mice aiming to induce reflux of gastric contents, duodenal contents or mixed contents. Surgical procedures and general principles have been described in detail. A researcher with surgical experience should be able to grasp the technique after a short period of practice. After surgery, most mice can survive and develop reflux esophagitis similar to that in humans. However, it should be noted that histological differences between mouse and human esophagus are the inherent limitations of these surgical models. If used for research on Barrett&#8217;s esophagus and adenocarcinoma, these procedures may need to be combined with genetic modifications.

This article demonstrates surgical procedures of gastroesophageal reflux with mice. These models are useful tools for research on mechanisms and treatment of gastroesophageal reflux disease and potentially Barrett&#8217;s esophagus and esophageal adenocarcinoma.

Multiple surgical procedures have been reported to induce gastroesophageal reflux in animals. Herein, we report three surgical models with mice aiming to ...

Using Saccadometry with Deep Brain Stimulation to Study Normal and Pathological Brain Function

The oculomotor system involves a large number of brain areas including parts of the basal ganglia, and various neurodegenerative diseases including Parkinson's and Huntington's can disrupt it. People with Parkinson's disease, for example, tend to have increased saccadic latencies. Consequently, the quantitative measurement of saccadic eye movements has received considerable attention as a potential biomarker for neurodegenerative conditions. A lot more can be learned about the brain in both health and disease by observing what happens to eye movements when the function of specific brain areas is perturbed. Deep brain stimulation is a surgical intervention used for the management of a range of neurological conditions including Parkinson's disease, in which stimulating electrodes are placed in specific brain areas including several sites in the basal ganglia. Eye movement measurements can then be made with the stimulator systems both off and on and the results compared. With suitable experimental design, this approach can be used to study the pathophysiology of the disease being treated, the mechanism by which DBS exerts it beneficial effects, and even aspects of normal neurophysiology.

This paper describes the use of quantitative measurement of eye movements in conjunction with stimulation of focal areas of the deep brain in order to study physiology, pathophysiology, and the mechanisms of deep brain stimulation.

The oculomotor system involves a large number of brain areas including parts of the basal ganglia, and various neurodegenerative diseases including ...

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 ...

Single-Anastomosis Duodeno-Ileal Bypass with Sleeve Gastrectomy Model in Mice

Obesity is a major health issue worldwide. As a response, bariatric surgeries have emerged to treat obesity and its related comorbidities (e.g., diabetes mellitus, dyslipidemia, non-alcoholic steatohepatitis, cardiovascular events, and cancers) through restrictive and malabsorptive mechanisms. Understanding the mechanisms by which these procedures allow such improvements often require their transposition into animals, especially in mice, because of the ease of generating genetically modified animals. Recently, the single-anastomosis duodeno-ileal bypass with sleeve gastrectomy (SADI-S) has emerged as a procedure that uses both restrictive and malabsorptive effects, which is being used as an alternative to gastric bypass in case of major obesity. Thus far, this procedure has been associated with strong metabolic improvements, which has led to a marked increase in its use in daily clinical practice. However, the mechanisms underlying these metabolic effects have been poorly studied as a result of a lack of animal models. In this article, we present a reliable and reproducible model of SADI-S in mice, with a special focus on perioperative management. The description and use of this new rodent model will be helpful for the scientific community to better understand the molecular, metabolic, and structural changes induced by the SADI-S and to better define the surgical indications for clinical practice.

Single-anastomosis duodeno-ileal bypass (SADI-S) is an emerging bariatric procedure with important metabolic effects. In this article, we present a reliable and reproducible model of SADI-S in mice.

Obesity is a major health issue worldwide. As a response, bariatric surgeries have emerged to treat obesity and its related comorbidities (e.g., diabetes ...

A Murine Model of Vertical Sleeve Gastrectomy

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

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

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

Biology

Murine Vertical Sleeve Gastrectomy: A Surgical Procedure to Downsize Stomach in Experimental Mouse Models

Source: Garibay, D., Cummings, B. P. <a href="https://www-jove-com.remotexs.ntu.edu.sg/video/56534" target="_blank">A Murine Model of Vertical Sleeve Gastrectomy.</a> J. Vis. Exp. (2017)
In this video, a vertical sleeve gastrectomy procedure is performed on an experimental mouse model. This procedure helps remove a significant portion of the stomach along its greater curvature.

Source: Garibay, D., Cummings, B. P. A Murine Model of Vertical Sleeve Gastrectomy. J. Vis. Exp. (2017)
In this video, a vertical sleeve gastrectomy ...

JoVE Encyclopedia of Experiments

Cancer Research

Gastrointestinal Cancer

Animal model studies

Roux-en-Y Gastric Bypass Procedure: A Bariatric Surgical Procedure for Gastric Resectioning in Murine Model

Source: Ayer, A., et al., <a href="https://www-jove-com.remotexs.ntu.edu.sg/v/54905">Techniques of Sleeve Gastrectomy and Modified Roux-en-Y Gastric Bypass in Mice.</a> J. Vis. Exp. (2017).
This video describes a bariatric surgery-Roux-en-Y procedure. This involves the cutting of the jejunum- the middle portion of the intestine- to generate two intestinal limbs. The biliary limb is attached to the existing intestinal loop and the alimentary limb is attached to the stomach, creating a gastric bypass. The gastric bypass created here helps to decrease the nutrient uptake and efficiently reduces body weight.

Source: Ayer, A., et al., Techniques of Sleeve Gastrectomy and Modified Roux-en-Y Gastric Bypass in Mice. J. Vis. Exp. (2017).
This video describes a ...

Sleeve Gastrectomy in Mice using Surgical Clips

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