Name: Assessment of Gastric Emptying in Non-obese Diabetic Mice Using a 13C -octanoic Acid Breath Test (Video) | JoVE Journal
Uploaded: 2013-03-23T14:00:00.000+00:00
Duration: 12 min 24 s
Description: Learn a non-invasive breath test method to measure gastric emptying in mice using [13C]-octanoic acid. This technique enables repeated measurements for studying gastroparesis progression.

ai_agent_IP

ai_agent

maintenance

instantTrialDurationMinutes

isBiopharma

enableNewMyJoveSectionDesign

educationFeatures

seoMetaApi

ai_copilot_institution_blacklist

ai_chat_institution_blacklist

freeAccessWindow

ssoRoleCapture

scheduledMaintenanceBanner

joveLabsFeatures

disable_autoplay_for_bots

extended_trial_duration

5 minutes

This video publication was made possible by funding from the National Institute of Diabetes and Digestive and Kidney diseases (NIDDK) for the Program Project Grant "Pathobiology of the Enteric System" DK 68055. Christopher T. Creedon was supported by the Rochester Public Schools Mentorship Program.
We thank Mr. Gary Stoltz for technical assistance, Ms. Kristy Zodrow for secretarial assistance and Dr. Douglas Baer from Los Gatos Research, Inc (Mountain View, CA).

1. Training and Habituation of the Mice
<ol>
 <li>Prior to analysis, put all mice in the testing chambers for 2-4 hr with constant airflow in order to habituate them to the testing conditions. This markedly reduces stress levels that might otherwise cause aberrant detection of delayed gastric emptying. Treat the mice the same way as if the gastric emptying experiment was running. Prepare egg yolk (see further) without adding octanoic acid and feed 0.2 g to each mouse. </li>
 <li>Repeat this process till the mice are sufficiently trained (typically 2-3 times). The mice typically are easily habituated as long as the environmental conditions are kept the same. </li>
</ol>
Note: Non-habituated mice continue to move around for about 1 hr after transfer to the chamber, and defecate and urinate frequently, while habituated mice quickly settle in their new environment and rest quietly.
Note: During the experiment: Monitor animals for signs of loss of habituation such as excess urination, defecation, lack of interest in eating the egg. If this is the case consider re habituating in an empty chamber 1-2 times prior to obtaining gastric emptying data. Consistency is extremely important while doing this experiment. Doing things exactly the same way every time is the only way to get reliable and reproducible results. This includes giving treatment (e.g. insulin) every day at the same time, not separating the mice from their cage-mates unless absolutely necessary, fasting the mice and starting the gastric emptying test at the same time, and handling the mice the same way.
2. Preparation of the Isotope Containing Test Meal 
<ol>
 <li>Start with weighing out 5 g of egg yolk in a 50 ml falcon tube. Repeat these steps each experimental day to prepare a fresh test meal. </li>
 <li>Add 10 &mu;l of octanoic acid with a concentration of 2 &mu;l/g to the 50 ml falcon tube containing the egg and mix vigorously for 1 min with a spatula in the falcon tube. </li>
 <li>The egg is then transferred to a glass beaker and heated over a Bunsen burner until it coagulates and its consistency is suitable to make small balls. This typically takes about 30 sec. </li>
</ol>
Note: The balls of egg yolk should weigh 0.2 g per mouse. This is important to keep the cumulative dose constant in all the mice. 
3. Starting the Experiment
<ol>
 <li>Once trained and ready for gastric emptying, fast the mice overnight (12 hr) on a metal "mesh-bottom" fasting rack to prevent coprophagia. Make sure they have free access to drinking water. Since diabetic mice are used in the current experiment, they should not be fasted for more than 16 hr.</li>
 <li>Start by setting up the gastric emptying chambers. Use clean chambers and covers that have been air-dried. Also, any tubes connecting the chambers to the analyzer or the CO2 air supply should be moisture free; water can interfere with the signal read by the analyzer </li>
 <li>Connect the chambers to the inlet tubes that provide a constant air flow. Then connect the outlet tubes from the chambers to the machine. Close the tubes and turn on the airflow. </li>
</ol>
Note: Apply a very small amount of Vaseline at the end of the cover lids so they close easily and are securely sealed. This tight seal is necessary to collect all the carbon dioxide produced by the mice.
4. Experimental Procedures
<ol>
 <li>Start out by weighing each mouse. Body weight is a measure of their continuing good health. Then place each mouse in the appropriate chamber. It is of course important to have the air flowing into the chambers at this time. </li>
 <li>To start the measurement, allow the mice to acclimate to the chambers before adjusting the air levels. </li>
 <li>Once the mice appear calm, which may take a few minutes, adjust the air flow rate for each mouse chamber. This may be different for each mouse. Typically, the air flow is adjusted at the beginning of the experiment to make sure that exhaled CO2 reaches levels detectable by whatever equipment is being used, and to make sure that the level stays low enough to ensure healthy air turnover. We use initial CO2 levels between 1,000 and 1,500 parts per million. </li>
 <li>If having difficulty with adjustments, check for air leaks. Then repeat the process for each of the chambers and watch for another round of measurements to see if adjustments made to airflow have corrected the CO2 level. It is important to obtain a steady baseline reading prior to feeding the mice. We use a machine with a self calibration feature. If this is not the case calibration should be checked. </li>
 <li>When this is achieved, administer the egg meal to the first mouse and record the time each mouse receives the food. </li>
 <li>We run the procedure for 4 hr to obtain enough values for fitting the 13CO2 enrichment curve for each mouse. Check on the mice every 30-60 min to make sure that the CO2 levels are still safe for the mice.</li>
 <li>Prepare new boxes containing food before the end of the test so the mice can start eating immediately after the test is over. </li>
</ol>

<ol><li>Yeung, C. K., McCurrie, J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((A+simple+method+to+investigate+the+inhibitory+effects+of+drugs+on+gastric+emptying+in+the+mouse+in+vivo%5BTitle%5D)+AND+%22J.+Pharmacol.+Toxicol.+Methods%22%5BJournal%5D)">A simple method to investigate the inhibitory effects of drugs on gastric emptying in the mouse in vivo.</a> J. Pharmacol. Toxicol. Methods. 45, 235-240 (2001).</li>
<li>Osinski, M. A., Seifert, T. R., Cox, B. F., Gintant, G. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((An+improved+method+of+evaluation+of+drug-evoked+changes+in+gastric+emptying+in+mice%5BTitle%5D)+AND+%22J.+Pharmacol.+Toxicol.+Methods%22%5BJournal%5D)">An improved method of evaluation of drug-evoked changes in gastric emptying in mice.</a> J. Pharmacol. Toxicol. Methods. 47, 115-120 (2002).</li>
<li>Ghoos, Y. F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Measurement+of+gastric+emptying+rate+of+solids+by+means+of+a+carbon-labeled+octanoic+acid+breath+test%5BTitle%5D)+AND+%22Gastroenterology%22%5BJournal%5D)">Measurement of gastric emptying rate of solids by means of a carbon-labeled octanoic acid breath test.</a> Gastroenterology. 104, 1640-1647 (1993).</li>
<li>Symonds, E., Butler, R., Omari, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Noninvasive+breath+tests+can+detect+alterations+in+gastric+emptying+in+the+mouse%5BTitle%5D)+AND+%22Eur.+J.+Clin.+Invest%22%5BJournal%5D)">Noninvasive breath tests can detect alterations in gastric emptying in the mouse.</a> Eur. J. Clin. Invest. 32, 341-344 (2002).</li>
<li>Symonds, E. L., Butler, R. N., Omari, T. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Assessment+of+gastric+emptying+in+the+mouse+using+the+%5B13C%5D-octanoic+acid+breath+test%5BTitle%5D)+AND+%22Clin.+Exp.+Pharmacol.+Physiol%22%5BJournal%5D)">Assessment of gastric emptying in the mouse using the [13C]-octanoic acid breath test.</a> Clin. Exp. Pharmacol. Physiol. 27, 671-675 (2000).</li>
<li>Verhulst, P. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Role+of+ghrelin+in+the+relationship+between+hyperphagia+and+accelerated+gastric+emptying+in+diabetic+mice%5BTitle%5D)+AND+%22Gastroenterology%22%5BJournal%5D)">Role of ghrelin in the relationship between hyperphagia and accelerated gastric emptying in diabetic mice.</a> Gastroenterology. 135, 1267-1276 (2008).</li>
<li>Schoonjans, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((The+13C-octanoic+acid+breath+test%3A+validation+of+a+new+noninvasive+method+of+measuring+gastric+emptying+in+rats%5BTitle%5D)+AND+%22Neurogastroenterol.+Motil%22%5BJournal%5D)">The 13C-octanoic acid breath test: validation of a new noninvasive method of measuring gastric emptying in rats.</a> Neurogastroenterol. Motil. 14, 287-293 (2002).</li>
<li>Choi, K. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Determination+of+gastric+emptying+in+nonobese+diabetic+mice%5BTitle%5D)+AND+%22Am.+J.+Physiol.+Gastrointest.+Liver+Physiol%22%5BJournal%5D)">Determination of gastric emptying in nonobese diabetic mice.</a> Am. J. Physiol. Gastrointest. Liver Physiol. 293, 1039-1045 (2007).</li>
<li>Atkinson, M. A., Leiter, E. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((The+NOD+mouse+model+of+type+1+diabetes%3A+as+good+as+it+gets%3F%5BTitle%5D)+AND+%22Nat.+Med%22%5BJournal%5D)">The NOD mouse model of type 1 diabetes: as good as it gets?</a> Nat. Med. 5, 601-604 (1999).</li>
<li>Camilleri, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Clinical+practice.+Diabetic+gastroparesis%5BTitle%5D)+AND+%22N.+Engl.+J.+Med%22%5BJournal%5D)">Clinical practice. Diabetic gastroparesis.</a> N. Engl. J. Med. 356, 820-829 (2007).</li>
<li>Choi, K. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Heme+oxygenase-1+protects+interstitial+cells+of+Cajal+from+oxidative+stress+and+reverses+diabetic+gastroparesis%5BTitle%5D)+AND+%22Gastroenterology%22%5BJournal%5D)">Heme oxygenase-1 protects interstitial cells of Cajal from oxidative stress and reverses diabetic gastroparesis.</a> Gastroenterology. 135, 2055-2064 (2008).</li>
<li>Kashyap, P. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Carbon+monoxide+reverses+diabetic+gastroparesis+in+NOD+mice%5BTitle%5D)+AND+%22Am.+J.+Physiol.+GI%22%5BJournal%5D)">Carbon monoxide reverses diabetic gastroparesis in NOD mice.</a> Am. J. Physiol. GI. G298, G1013-G1019 (2010).</li>
</ol>

The authors declare that they have no competing financial interests.

The described technique herein allows for repeated and non-invasive in vivo measurement of solid gastric emptying in mice. This system has the advantage that the animals are not restrained in the measurement chamber, allowing them to move and turn freely. Since this is an unfamiliar environment, the mice still need to be trained and habituated to the testing chambers to prevent effects of stress on gastric emptying. In general, we assume the gastric emptying data are reliable if the intra-mouse variability betwe...

This manuscript describes the technical and methodological considerations involved in non-invasive measurement of gastric emptying in mice. By following the protocol described here, investigators can reliably and reproducibly follow changes in gastric emptying due to development of disease, study the impact of pharmacological agents on gastric emptying and follow the response of gastric emptying to treatment of underlying diseases or defects6,8,11,12. In previous publications, the application of 13C octanoic acid breath tests was shown to be a useful way of measuring gastric emptying in humans and animals3,8.This paper describes in detail, the procedures necessary to obtain reliable data over the 6 to 8 months necessary for a longitudinal study of gastric emptying in mice with diabetes. The advantages of following this protocol when compared to previously published methods are that the investigator can be assured the data obtained will be reliable and reproducible. In addition, the automated system for collecting and analyzing the gas samples described here increases the number of animals that can be followed simultaneously in a study. Overall, the goal of this paper is to identify the key factors that maintain habituation of the mice to the test and that reduce variability in obtained results.
For the in vivo measurement of gastric emptying, mice are fasted overnight and put into the transparent plastic testing chambers with constant airflow. After the mice get habituated to the tubes, baseline exhaled 13CO2 levels are determined and airflow adjusted accordingly. Next, we administer a test meal consisting of egg yolk mixed with 13C-labeled octanoic acid. Because the mice are fasted and trained, they generally eat the test meal within 2 min. The administered octanoic acid is not absorbed in the stomach but will be taken up in the duodenum and will get metabolized in the liver into 13CO2, which is released and exhaled, resulting in an enrichment of 13CO2 in the surrounding air. Air samples are collected at determined time intervals and are analyzed by the carbon isotope analyzer. The rate-limiting step in this whole process is gastric emptying and the pulmonary excretion of 13CO2 directly corresponds with gastric emptying of the labeled meal. 
<img src="/files/ftp_upload/50301/50301fig1.jpg" alt="Isotope analysis diagram, mouse setup, measuring [13C]/[12C] ratio, breath test experiment." fo:content-width="6in" fo:src="/files/ftp_upload/50301/50301fig1highres.jpg" data-altupdatedat="1787630408000" data-alt="Figure 1"> 
Figure 1. Schematic of gastric emptying apparatus. After overnight fasting, mice are placed in transparent chambers allowing them to move and turn freely. An inlet tube allows fresh and constant air influx and an outlet leads to the isotope analyzer to measure the 13C-to-12C ratio in the exhaled breath. The chamber also has a central port for delivery of food containing [13C]-octanoic acid.

<table><tbody><tr><td>A source of constant air-supply, flow as well as composition</td><td>central air supply in the research facility</td><td></td><td></td></tr><tr><td>130 ml sampling chamber that has air inlet, air outlet, and food administration opening&lt;br/&gt; Plastic tubes for air supply</td><td>In-house built</td><td></td><td></td></tr><tr><td>Octanoic acid</td><td>Cambridge isotope laboratories (Andover, MA)</td><td>CLM-293-1</td><td></td></tr><tr><td>To prepare the egg meal: &lt;br/&gt; &lt;ul&gt; &lt;li&gt;small beaker&lt;/li&gt; &lt;li&gt;50 ml plastic tube&lt;/li&gt; &lt;li&gt;Bunsen burner&lt;/li&gt; &lt;li&gt;egg&lt;/li&gt; &lt;li&gt;spatula&lt;/li&gt; &lt;/ul&gt;</td><td>Any supplier</td><td></td><td>Try to be consistent with the egg supplier since the nutritional content and palatability of the eggs can affect ingestion and gastric emptying of the meal</td></tr><tr><td>Carbon dioxide isotope analyzer</td><td>Los Gatos Research Inc. (Mountain View, CA)</td><td></td><td></td></tr></tbody></table>

assessment of gastric emptying in non-obese diabetic mice using a [13c]-octanoic acid breath test

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.

A representative data set from three different mice is shown in Figure 2. The black graph represents the data points from a mouse with normal gastric emptying. It shows the fraction of 13C that is recovered in the exhaled air expressed as a percentage of the administered dose per hour expressed as a function of time. The blue curve is from a mouse with an accelerated gastric emptying with a T half value of 40 min and the red curve is from a mouse with a delayed gastric emptying with a T half v...

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 ...

The overall goal of this procedure is to establish a method for the inbivo measuring of gastric emptying in mice using a 13 carbon Octa NOIC acid breath Test. Mice and Other small animals have of course been really useful to help us understand the pathophysiology of disease our laboratory studies gastroparesis, and one of the issues with gastroparesis is that, you know, to study disease we need to follow gastric empty over time. This has been a problem with current techniques because current techniques require you to put a substance in the, in either liquid or solid in the mouse stomach, and then sometime later kill the mouse and estimate what has left the stomach.What we wanted to do was establish a non-invasive technique of measuring gastric emptying, and what we did is we adapted the known 13 carbon ano acid breath test to enable us to use it on mice. This allows us to do repeated measurements over time and then correlate what we see with both histology as well as physiology. The equipment we use here allows us to automate the procedure, although of course it can also be done manually.The advantage of automation is not only the fact that we can do many more gastric emptys over time, but that we can actually do it in multiple mice at the same time. What we'll be showing is a method where we can do up to 12 mice at one time. The following animation shows the setup of our gastric emptying experiment for the in vivo measurement of gastric emptying.The mice are put in transparent plastic tubes with constant airflow. After the mice get habituated to the tubes and after adjustment of the airflow, we administer a test meal consisting of egg yolk mixed with 13 carbon labeled Octo NOIC acid. Because the mice are fastened and trained, they generally eat the test meal.Within two minutes, the administered OCT NOIC acid will be taken up in the duodenum and will get metabolized in the liver released and exhaled, resulting in an enrichment of 13 carbon dioxide in the surrounding air, which is then measured by our isotope analyzer. Let's have a more detailed look into what happens in the mouse body. After eating the test meal containing 13 carbon labeled OCT NOIC acid, the meal enters the stomach.The OCT NOIC acid remains intact in the stomach. After passage through the pylorus, it is rapidly absorbed in the duodenum. The labeled compound reaches the liver through the portal vein and is metabolized to 13 carbon labeled carbon dioxide.The labeled carbon dioxide is released in the venous blood and is exhaled. The rate limiting step in this whole process is gastric emptying. This means that the pulmonary excretion of 13 carbon dioxide directly corresponds with gastric emptying of the labeled meal.Air samples are collected at certain time intervals and are analyzed by the carbon isotope analyzer. Various isotope analyzers can be used. In this study, we chose to use a low GATOS research LGR 13 carbon isotope analyzer.Collecting samples for four hours gives reproducible 13 carbon dioxide kinetics, which reflect the rate of gastric emptying. Curve fitting. Using non-linear regression allows calculation of half emptying times.This procedure is suitable for the follow-up of mice with chronic disease. In this particular study, we use female non-obese diabetic, N-O-D-L-T-J mice, which are a model for human type one diabetes. Prior to analysis, all mice are allowed to habituate in the testing chambers to minimize stress levels.Since a delay in gastric emptying is a characteristic indicator of stress and mice, Non habituated mice continue to move around for about one hour after transfer to the chamber and defecate and urinate. Frequently the mice are considered successfully habituated when they quickly settle into their new environment. Upon transfer into the chamber, after a brief period of exploration, the habituated mice will rest quietly in the chamber.In habituated mice gastric emptying test results should show a difference of less than 10%intra mouse variability. Once trained and ready for gastric emptying, the mice must be fasted the day prior to the experiment. The mice are fasted overnight on a metal mesh bottom fasting rack.To prevent phasia, make sure they have free access to drinking water. Diabetic mice should not be fasted more than 16 hours. Consistency is extremely important during a gastric MCN experiment.Factors such as handling the mice the same way, fasting the mice at the same time every day, checking glucose levels and administering insulin at the same time each day. As a user wearing the same cologne and the same lab coat every day is extremely important cause all of these factors will change the gastric MTN data. The materials we use for the preparation of the egg meal are an egg OC acid, a glass beaker, a falcon tube, and a bent end spatula.Start with weighing out five grams of egg yolk in a 50 milliliter falcon tube. Next, add 10 microliters of okin NOIC acid with a concentration of two microliters per gram to the Falcon tube containing the egg and mix vigorously with the spatula in the falcon tube. For one minute, the egg is then transferred to a glass beaker and heated over a buns and burner until it coagulates and its consistency is suitable.To make small balls, this typically takes about 30 seconds. The balls of egg yolk should weigh 0.2 grams per mouse. It is important to keep the cumulative dose constant in all the mice.Our range for acceptable cumulative dose recovery is 55 to 100%Start by setting up the gastric emptying chambers. Use clean chambers and covers that have been air dried.Also. Any tubes connecting the chamber to the analyzer or the carbon dioxide air supply should be moisture free.Moisture can interfere with the signal red by the analyzer. Connect the chambers to the inlet tubes that provide hydrocarbon scrubbed airflow. It is important that this air is always consistent because any variation in the carbon dioxide amount could change the baseline value.Then connect the outlet tubes from the chambers to the machine, close the tubes and turn on the airflow. Apply a very small amount of Vaseline at the end of the covers so they close and are easily and securely sealed. This tight seal is necessary to collect all the carbon dioxide produced by the mice.Weigh the mice using a small mouse holder to reduce stress levels. Body weight is determined as a measure of their continuing good health. Then place each mouse in the appropriate chamber.It is important to have the air flowing into the chambers at this time. Each mouse is implanted with a tracking device. The data on the mouse's weight, blood glucose and treatments are tracked using a software database that uses this number.We use software that allows us to automatically link the mouse ID number directly to the store data. This, of course, can also be done manually. To start the measurement, allow the mice to acclimate to the chambers before adjusting the air levels.Once the mice appear calm, which may take a few minutes, adjust the airflow rate for each mouse chamber. This may be different for each mouse. Typically, the airflow is adjusted at the beginning of the experiment to make sure that exhaled carbon dioxide reaches levels detectable by whatever equipment is being used, and to make sure that the level stays low enough to ensure healthy air turnover.We use initial carbon dioxide levels between 1000 and 1500 parts per million if having difficulty with adjustments, check for air leaks. Next, repeat the process for each of the chambers and watch for another round of measurements to see if adjustments made to airflow have corrected the carbon dioxide level. It is important to obtain a steady baseline reading prior to the feeding of the mice.When this is achieved, give the egg meal to the first mouse and record the time each mouse receives their food. We run the procedure for four hours to obtain enough values for fitting the 13 carbon dioxide enrichment curve for each mouse. Check on the mice every 30 to 60 minutes to make sure that the carbon dioxide levels are still safe.For the mice, our machine measures 12 carbon dioxide, 13 carbon dioxide and water concentrations every 25 seconds. Therefore, 12 mice can be simultaneously analyzed with a five minute interval between readings. If manually sampling or using another device, make sure your readings are obtained at a minimum of five to 10 minute intervals.Prepare new boxes containing food before the end of the test so the mice can start eating immediately after the test is Over. This graph represents the data points of a mouse with normal gastric emptying. It shows a fraction of 13 carbon that is recovered in the exhaled air expressed as a percentage of the administered dose per hour expressed as a function of time.The data points are fitted by a curve with the following equation. Why is the percentage of the 13 carbon recovered in the breath per hour and a B and CA regression constant? The T half is calculated by putting the parameters of this curve into the inverse gamma function as established in a previous study in our lab, the normal gastric half emptying time for a non-diabetic NOD mouse age nine to 15 weeks ranges from 62 to 1 31 minutes as represented by the gray box.The blue curve is from a mouse with an accelerated gastric emptying with a T half value of 40 minutes, and the red curve is from a mouse with a delayed gastric emptying with a T half value of 168 minutes. In conclusion, this video demonstrates how to measure solid gastric emptying by means of a non-invasive breath test. In mice, we showed how to prepare the animals for testing the making of the food and the collection of the data.This method of measuring solid gastric emptying with the administration of 13 carbon OCT oak acid was previously reported for humans, and we adapted the protocol for use in mice. This protocol provides us with a valuable method to repeatedly measure gastric emptying in the same mouse, which allows for the investigation of gastric emptying for the study of long-term diseases. There are several future applications of this method.For example, the testing of different drugs for the treatment of diabetic gastroparesis.

assessment-gastric-emptying-non-obese-diabetic-mice-using-13c

Research

JoVE Journal

Medicine

This video introduces how to perform an oral glucose tolerance test on a laboratory mouse.

Oral Glucose Tolerance Test (OGTT): Measuring Glucose Metabolism in Mice

The in vivo measurement of smooth muscle contractions along the gastrointestinal tract of laboratory animals remains a powerful, though underutilized, technique. Flexible, dual element strain gages are not commercially available and require fabrication. This protocol describes the construction of reliable, inexpensive strain gages for acute or chronic implantation in rodents.

Fabrication and Implantation of Miniature Dual-element Strain Gages for Measuring In Vivo Gastrointestinal Contractions in Rodents.

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.

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

The current article describes the generation and metabolic characterization of high-fat diet-fed mice as a model of diet-induced insulin resistance and obesity. It further features detailed protocols to perform the oral glucose tolerance test and the insulin tolerance test, monitoring whole-body alterations of glucose metabolism in vivo.

Study of In Vivo Glucose Metabolism in High-fat Diet-fed Mice Using Oral Glucose Tolerance Test (OGTT) and Insulin Tolerance Test (ITT)

The incidence of obesity is rising and increases the risk of chronic lung diseases. To establish the underlying mechanisms and preventive strategies, well-defined animal models are needed. Here, we provide three methods (glucose-tolerance-test, body plethysmography, and lung fixation) to study the effect of obesity on pulmonary outcomes in mice.

Intraperitoneal Glucose Tolerance Test, Measurement of Lung Function, and Fixation of the Lung to Study the Impact of Obesity and Impaired Metabolism on Pulmonary Outcomes

The current article describes a detailed protocol for isocaloric 2:1 intermittent fasting to protect and treat against obesity and impaired glucose metabolism in wild-type and ob/ob mice.

Assessment of the Metabolic Effects of Isocaloric 2:1 Intermittent Fasting in Mice

This study describes the direct measurement of hepatic glucose production in a polycystic ovary syndrome mouse model by using a stable isotopic glucose tracer via tail vein in both fasting and glucose-rich states in tandem.

Evaluation of Hepatic Glucose Production in a Polycystic Ovary Syndrome Mouse Model

This protocol introduces two methods for image acquisition in gastric ultrasonography. Additionally, tips are provided for interpreting this information to assist in medical decision-making.

Gastric Point of Care Ultrasound in Adults: Image Acquisition and Interpretation

A test battery (IMAP) for performing an in-depth assessment of auditory and cognitive abilities contributing to listening skills is described. It is quick to administer, child-friendly and free from linguistic confounds. Stimulus generation and protocol management are controlled via a software platform (IHR-STAR) to ensure replicable procedures.

Making Sense of Listening: The IMAP Test Battery

Ammonia is an important physiologic metabolite relevant to various disease and wellness states. It is also a difficult molecule to measure in breath, which demands particular precautions be taken to obtain accurate results. Not all factors influencing ammonia are known, but progress can be difficult without accounting for these factors.

Fast and Accurate Exhaled Breath Ammonia Measurement

Learn a non-invasive breath test method to measure gastric emptying in mice using [13C]-octanoic acid. This technique enables repeated measurements for studying gastroparesis progression.

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

Explore More Videos