Name: body composition and metabolic caging analysis in high fat fed mice
Uploaded: 2018-05-24T14:00:00
Description: Watch this Scientific Journal Video about Body Composition and Metabolic Caging Analysis in High Fat Fed Mice at JoVE.com

Agradecemos a equipe da pesquisa médica de Alfred e equipe de serviços de educação delegacia Animal (AS AMREP) por sua assistência e cuidado com os ratos utilizados neste estudo e para o apoio do regime de apoio operacional de infraestrutura do estado vitoriano Governo.

Todos os experimentos descritos foram aprovados por Alfred médico pesquisa educação delegacia Animal Comitê de ética (AMREP AEC) e ratos foram fornecidos cuidado humano em consonância com a saúde nacional e Conselho de pesquisa médica (NHMRC) da Austrália orientações sobre Experimentação animal. Os animais foram administrados seus prescrita dieta e água ad libitum e alojados em um ambiente de temperatura controlada (~ 21-22 ° C) com uma luz de 12 h e 12 h-escuro ciclo. Sete semanas velhos camundon...

<ol>
	<li>Chen, W., Wilson, J. L., Khaksari, M., Cowley, M. A., Enriori, P. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Abdominal+fat+analyzed+by+DEXA+scan+reflects+visceral+body+fat+and+improves+the+phenotype+description+and+the+assessment+of+metabolic+risk+in+mice.">Abdominal fat analyzed by DEXA scan reflects visceral body fat and improves the phenotype description and the assessment of metabolic risk in mice.</a> Am J Physiol Endocrinol Metab. 303 (5), E635-E643 (2012).</li><li>Kovner, I., Taicher, G. Z., Mitchell, A. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Calibration+and+validation+of+EchoMRI+whole+body+composition+analysis+based+on+chemical+analysis+of+piglets,+in+comparison+with+the+same+for+DXA.">Calibration and validation of EchoMRI whole body composition analysis based on chemical analysis of piglets, in comparison with the same for DXA.</a> Int J Body Compos Res. 8 (1), 17-29 (2010).</li><li>EchoMRI. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Software User Manual: Whole body composition analyzer. , (2016).</li><li>Columbus Instruments. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Oxymax for Windows User Manual. , (2014).</li><li>Tschop, M. H., 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=A+guide+to+analysis+of+mouse+energy+metabolism.">A guide to analysis of mouse energy metabolism.</a> Nat Methods. 9 (1), 57-63 (2011).</li><li>Speakman, J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Measuring+energy+metabolism+in+the+mouse+-+theoretical,+practical,+and+analytical+considerations.">Measuring energy metabolism in the mouse - theoretical, practical, and analytical considerations.</a> Front Physiol. 4, (2013).</li><li>Swoap, S. J., 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=Vagal+tone+dominates+autonomic+control+of+mouse+heart+rate+at+thermoneutrality.">Vagal tone dominates autonomic control of mouse heart rate at thermoneutrality.</a> Am J Physiol Heart Circ Physiol. 294 (4), H1581-H1588 (2008).</li><li>Tian, X. Y., 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=Thermoneutral+housing+accelerates+metabolic+inflammation+to+potentiate+atherosclerosis+but+not+insulin+resistance.">Thermoneutral housing accelerates metabolic inflammation to potentiate atherosclerosis but not insulin resistance.</a> Cell Metab. 23 (1), 165-178 (2016).</li><li>Giles, D. A., 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=Thermoneutral+housing+exacerbates+nonalcoholic+fatty+liver+disease+in+mice+and+allows+for+sex-independent+disease+modeling.">Thermoneutral housing exacerbates nonalcoholic fatty liver disease in mice and allows for sex-independent disease modeling.</a> Nat Med. 23 (7), 829-838 (2017).</li><li>Lee, M. W., 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=Activated+type+2+innate+lymphoid+cells+regulate+beige+fat+biogenesis.">Activated type 2 innate lymphoid cells regulate beige fat biogenesis.</a> Cell. 160 (1-2), 74-87 (2015).</li><li>Kusminski, C. M., 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=MitoNEET-driven+alterations+in+adipocyte+mitochondrial+activity+reveal+a+crucial+adaptive+process+that+preserves+insulin+sensitivity+in+obesity.">MitoNEET-driven alterations in adipocyte mitochondrial activity reveal a crucial adaptive process that preserves insulin sensitivity in obesity.</a> Nat Med. 18 (10), 1539-1549 (2012).</li><li>Judex, 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=Quantification+of+adiposity+in+small+rodents+using+micro-CT.">Quantification of adiposity in small rodents using micro-CT.</a> Methods. 50 (1), 14-19 (2010).</li><li>Chaurasia, B., 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=Adipocyte+ceramides+regulate+subcutaneous+adipose+browning,+inflammation,+and+metabolism.">Adipocyte ceramides regulate subcutaneous adipose browning, inflammation, and metabolism.</a> Cell Metab. 24 (6), 820-834 (2016).</li><li>Matthews, V. B., 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=Interleukin-6-deficient+mice+develop+hepatic+inflammation+and+systemic+insulin+resistance.">Interleukin-6-deficient mice develop hepatic inflammation and systemic insulin resistance.</a> Diabetologia. 53 (11), 2431-2441 (2010).</li><li>Tschop, M., Smiley, D. L., Heiman, M. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ghrelin+induces+adiposity+in+rodents.">Ghrelin induces adiposity in rodents.</a> Nature. 407 (6806), 908-913 (2000).</li><li>Garcia, M. C., 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=Mature-onset+obesity+in+interleukin-1+receptor+I+knockout+mice.">Mature-onset obesity in interleukin-1 receptor I knockout mice.</a> Diabetes. 55 (5), 1205-1213 (2006).</li><li>Kowalski, G. M., Bruce, C. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+regulation+of+glucose+metabolism:+Implications+and+considerations+for+the+assessment+of+glucose+homeostasis+in+rodents.">The regulation of glucose metabolism: Implications and considerations for the assessment of glucose homeostasis in rodents.</a> Am J Physiol Endocrinol Metab. 307 (10), E859-E871 (2014).</li><li>McGuinness, O. P., Ayala, J. E., Laughlin, M. R., Wasserman, D. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=NIH+experiment+in+centralized+mouse+phenotyping:+the+Vanderbilt+experience+and+recommendations+for+evaluating+glucose+homeostasis+in+the+mouse.">NIH experiment in centralized mouse phenotyping: the Vanderbilt experience and recommendations for evaluating glucose homeostasis in the mouse.</a> Am J Physiol Endocrinol Metab. 297 (4), E849-E855 (2009).</li></ol>

Passos críticos
Os protocolos descritos neste documento fornecem um exemplo de formas de composição corporal de medida e vários parâmetros metabólicos em ratos utilizando um analisador de composição do corpo e um animal metabólico, sistema de monitoramento. Para ambas as técnicas, é criticamente importante garantir que as máquinas estão trabalhando de forma otimizada, e para isso, é imperativo que o pesquisador realiza um teste de sistema para o analisador de com...

Metabolismo sustenta muitos aspectos de celular normal, órgão e fisiologia de todo o corpo. Por conseguinte, no cenário de diversas patologias, alterações no metabolismo podem contribuir diretamente para a condição subjacente ou podem ser adversamente afetadas como um efeito colateral da patologia. Tradicionalmente, metabólica pesquisas e estudos em balanço energético concentraram no campo da obesidade e doenças relacionadas, tais como resistência à insulina, pré-diabetes, intolerância à glicose, diabetes e doenças cardiovasculares. Esta pesquisa se justifica, dada a crescente prevalência de tais condições em todo o mundo e o indivíduo, da sociedade, e os custos económicos dessas condições infligem. Como tal, o desenvolvimento de estratégias de prevenção e novas terapias para a obesidade do alvo é uma meta constante em laboratórios de pesquisa ao redor do mundo e modelos pré-clínicos do mouse são fortemente invocados para estes estudos.
Embora pesar ratos fornece uma avaliação confiável de ganho de peso ou perda, ele não fornece um colapso dos diferentes componentes que formam a composição do corpo inteiro (massa gorda, massa magra, água livre bem como outros componentes, como o pelo e as garras). A pesagem de almofadas de gordura após a conclusão dos estudos, uma vez que o mouse é falecido fornece uma medida exata de diferentes depósitos de gordura, mas só pode fornecer dados para um único momento. Como consequência, muitas vezes é necessário se inscrever várias coortes para investigar o desenvolvimento da obesidade ao longo do tempo, significativamente crescente número de animais, tempo e custos. A utilização da absortometria de raio-x de dupla energia (DEXA) fornece uma abordagem para avaliar o conteúdo de tecido gordo e magro corpo e permite que o pesquisador obter dados de uma forma longitudinal. No entanto, o procedimento exige ratos anestesiados1, e episódios repetidos de anestesia podem impactar o acúmulo de tecido adiposo ou afetar outros aspectos da regulação metabólica. EchoMRI utiliza a ressonância magnética nuclear em materiais para medir a massa gorda e magra, a água livre e conteúdo total de água. Isto é possível devido à criação do contraste entre os componentes de diferentes tecidos, com diferenças na duração, amplitude e a distribuição espacial das frequências de rádio geradas permitindo a definição e quantificação de cada tipo de tecido. Esta técnica é vantajosa, pois é não-invasivo, rápido, simples, não requer anestesia ou radiação e, importante, foi positivamente validado contra análise química2.
Uma consideração chave de obesidade e investigação com ele relacionada é a equação de equilíbrio de energia. Enquanto o acúmulo de gordura é mais complicado do que puramente energia (ingestão de alimentos) versus energia para fora (gasto de energia), são fatores vitais para ser capaz de medir. Gasto energético diário é o total de quatro diferentes componentes: (1) despesas de energia basal (taxa metabólica de repouso); (2) o gasto de energia devido ao efeito térmico do consumo de alimentos; (3) a energia necessária para a termorregulação; e (4) a energia gasta na atividade física. Como despesa de energia gera calor, medir a produção de calor por um animal (conhecido como calorimetria direta) pode ser usado para avaliar o gasto de energia. Alternativamente, medição de inspirado e expirado a concentrações de O2 e CO2, permitindo a determinação de todo o corpo O2 consumo e produção de CO2 , pode ser utilizado como uma forma de medir indiretamente (indireta Calorimetria) produção de calor e, consequentemente, calcular o gasto de energia. Um aumento na ingestão de alimentos ou uma diminuição no gasto de energia irá predispor ratos para ganho de peso e observações de mudanças nesses parâmetros podem fornecer informações úteis de prováveis mecanismos de ação em particulares modelos de obesidade. Um parâmetro metabólico relacionado de interesse é a relação de troca respiratória (RER), um indicador da proporção de substrato/combustível (ou seja, carboidrato ou gordura) está passando por metabolismo e sendo utilizado para produzir energia. Consequentemente, medição de ingestão de alimentos (energia consumida) combinado com níveis de atividade física, O consumo de2 , RER e gasto de energia pode fornecer uma compreensão ampla do perfil metabólico do organismo. Um método para coletar tais dados é usar um animal de laboratório completo sistema (moluscos), que se baseia o método de calorimetria indireta para medir o gasto de energia e tem a capacidade adicional de determinar os níveis de atividade física (feixe de monitoramento quebras) e ingestão de alimentos através de escalas incorporado na câmara de medição.
Neste protocolo, nós fornecemos uma descrição direta do uso de um analisador de composição do corpo para avaliar a composição corporal em ratos e um sistema de monitoramento animal metabólico para medir aspectos do metabolismo. Considerações e limitações para essas técnicas serão discutidas bem como sugeridos métodos de análise, interpretação e representação de dados.

<table border="0" cellpadding="0" cellspacing="0" width="1053">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:251px;">4 in 1 system</td>
			<td style="width:157px;">EchoMRI</td>
			<td style="width:275px;">4 in 1 system</td>
			<td style="width:371px;">Whole body composition analyser</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;">Canola oil test sample (COSTS)</td>
			<td>EchoMRI</td>
			<td style="width:275px;">Mouse-specific (contact company for cat number)</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Animal specimen holder&#160;</td>
			<td>EchoMRI</td>
			<td style="width:275px;">103-E56100R</td>
			<td style="width:371px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:251px;">Delimiter&#160;</td>
			<td>EchoMRI</td>
			<td style="width:275px;">600-E56100D</td>
			<td style="width:371px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">12 chamber system</td>
			<td>Columbus Instruments</td>
			<td>Custom built</td>
			<td>Metabolic Caging System; includes control program</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Drierite</td>
			<td>Fisher Scientific</td>
			<td>238988</td>
			<td>CLAMS consumable</td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;">Calibration gas tank</td>
			<td>Air Liquide</td>
			<td>Mixed to order</td>
			<td>Gas calibration (0.5% CO2, 20.5% O2, balance nitrogen).&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Normal chow diet</td>
			<td>Specialty Feeds</td>
			<td>Irradiated mouse and rat diet</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">High fat diet</td>
			<td>Specialty Feeds</td>
			<td>SF04-001</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Balance</td>
			<td>Mettler Toledo</td>
			<td>PL202-S</td>
			<td>Balance for weighing mice</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">TexQ Disinfectant spray</td>
			<td>TexWipe</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Hydrogen Peroxide cleaning solution</td>
			<td>TexWipe</td>
			<td>TX684</td>
			<td></td>
		</tr>
	</tbody>
</table>

body composition and metabolic caging analysis in high fat fed mice

Alterações de composição corporal (massa gorda ou magra), parâmetros metabólicos, tais como o consumo de oxigênio de todo o corpo, a despesa de energia e a utilização de substrato e comportamentos tais como a ingestão de alimentos e atividade física podem fornecer informações importantes a respeito os mecanismos subjacentes da doença. Dada a importância da composição corporal e metabolismo para o desenvolvimento da obesidade e suas sequelas subsequentes, é necessário tomar medidas precisas desses parâmetros no cenário de pesquisa pré-clínica. Os avanços da tecnologia sobre as passado poucas décadas tornaram possível derivar dessas medidas em modelos de roedores em uma forma não-invasiva e longitudinal. Por conseguinte, estas medidas metabólicas provaram ser úteis ao avaliar a resposta das manipulações genéticas (por exemplo nocaute ou transgénicos ratos, viral knock-down ou superexpressão de genes), triagem de drogas experimentais/composto e dietéticos, intervenções de atividade física ou comportamental. Aqui, descrevemos os protocolos usados para medir a composição corporal e parâmetros metabólicos usando um animal sistema em alimentados com comida e altos gordo dieta-alimentou ratos de monitoramento.

Os resultados observados na Figura 3 exibem uma típica mudança nos parâmetros de composição do corpo com alta gordura alimentar, medida através de EchoMRI. No início do estudo não houve diferença em qualquer parâmetro medido (Figura 3A-F). No entanto, após apenas 1 semana de alta gordura alimentar, houve um aumento significativo no peso corporal, massa gorda e percentagem de massa gorda no grupo HFD (<...

Watch this Scientific Journal Video about Body Composition and Metabolic Caging Analysis in High Fat Fed Mice at JoVE.com

Body Composition and Metabolic Caging Analysis in High Fat Fed Mice

Composição corporal e análise de enjaulamento metabólico em ratos de alta gordura Fed

Este protocolo descreve o uso de um analisador de composição do corpo e sistema de monitoramento animal metabólico para caracterizar a composição corporal e parâmetros metabólicos em camundongos. Um modelo de obesidade induzido pelo alto teor de gordura alimentar é usado como um exemplo para a aplicação dessas técnicas.

Alterations to body composition (fat or lean mass), metabolic parameters such as whole-body oxygen consumption, energy expenditure, and substrate ...

The goal if this procedure is to collect body composition and metabolic measurements from mice such as fat and lean mass percentages and energy expenditure. This methods can help answer important questions regarding mice metabolism such as, how fat are my mice? And why are my mice so fat?The main advantage with this techniques is that they can be completed in living conscious mice and therefore can be repeated numerous times through out a study. Prior to scanning mice perform a system test on the body composition analyzer machine once the machine has warmed up for a few hours. Use the standards called Canola Oil System Test Sample or COSTS.Open the system software then click the System Test toolbar button or by pressing alt+Y on the keyboard. Before starting the test, put the correct standard inside the gantry of the system. Then run the diagnostic test following the system prompts as needed.After the system has passed the test proceed with the diagnosis of a mouse. Now put the mouse in a holder. A red opaque holder is the least stressful.Position the holder at a 45 degree angle and insert the mouse. Then slowly and carefully raise the holder until it is vertical. Next insert a delimiter into the holder to limit the movement of the mouse.In some circumstances, with extremely active mice, it may be necessary to manually secure the delimiter. Now within the software select a folder to save the data to and create a filename. Next if necessary, reduce the amount of random noise in the fat and lean measurements by increasing the number of Primary Accumulations of the scan.Usually however, the default settings will give the necessary level of precision. If data for free water and total water aren't needed, then turn off the water stage by using the appropriate toggle. This will significantly speed up the scan.Now initiate the scan my selecting Start Scan or by pressing F5 on the keyboard. Enter all relevant data about the animal and press OK or F5 to commence the scan which will take about a minute. After collecting the data return the animal back to its cage.Always safely clean the acrylic holder between uses such as with warm soapy water. Later, once all of the animals have been scanned export the data for further analysis and collation. Before beginning, make sure the machine has been on for over two hours.In the Animal Monitoring System, open the control program and select the Oxymax utility option from the tool menu to initiate the pumps. Then check the desiccant and replace it with fresh dry material if needed. Also, check the condition of the ammonia trap and soda lime and replace it if needed.Next, connect the calibration gas tank to the system using a regulator and hose. Then open the valve and output five to 10 PSI of gas. Next in the software, select Calibration from the Tools menu and check that the sample and reference flows are at precisely 0.4 liters per minute.Then check that the zirconia oxygen sensor is heated to 725 degrees Celsius give or take one degree Celsius. Next make certain that the sample and reference drier and air pumps are all ON and double check that the calibration gas is attached and tuned on. Now proceed with the calibration and as needed slightly adjust the OFFSET control on the front of the zirconia oxygen sensor to achieve an oxygen ratio value within acceptable limits.After successfully calibrating the oxygen and carbon dioxide sensors, detach the gas standard and read the oxygen levels of atmospheric gas which should be about 20.92. If measuring food intake, consider using powdered mouse diet. Then load the food hopper by depressing the spring loaded platform.Next fill the water bottles and organize the food. Now weigh and inspect the health of the mice before proceeding to assemble the chambers. Next place the food hopper on the balance.Above it, place the chamber with the perforated platform. Then carefully place the mouse in the chamber and attach a lid using the front and back clips. Then fasten on the water bottle to complete the set-up.Now set up the next mouse and after all the mice are ready, double check the chamber lids, mice, and water. To run the experiment, select Experimental File Open from the menu. Then select the appropriate template.Next, under Setup, define the parameters of the experiment that should be recorded and deselect any chambers not in use. Then select the location for the experiment to be saved. If food intake is to be measured, tare the scales.Then start the capturing of data by selecting Run in the Experiment menu. The first 24 hours can be used as an acclamation phase and the next 24 plus hours, used for data analysis. At least twice a day, check on the animals and the data collection.Make certain each has access to food and water and look for signs of distress such as digging of the perforated flooring. In the software check the real time data collection. Go to the Metabolic tab to look at oxygen consumption, RER and energy expenditure.O2IN should read between 20.90 and 20.94 CO2IN should read approximately 0.04 RER should read between 0.7 and one the flow rate should be at a constant 0.5 to 0.6 liters per minute. Under the Activity tab, real time data on beam breaks is displayed. Under the Feeding tabs, real time data on food consumption is displayed.To finish the experiment, select Stop from the Experiment menu and export the results as CSV files for analysis. Then inspect the health of the mice, weigh them, and then return them to their home cages. In the following graphs, the black squares represent mice fed the high fat diet and the black circles represent the mice fed the standard chow diet.Changes in body composition parameters caused by high fat feeding were measured via EchoMRI using the described procedures. After one week on the high fat diet, there was a significant weight gain which increased by three weeks. The weight change could be clearly attributed to a change in fat mass.It was not due to a change in lean mass, free water content or total water content. In the following bar graphs, the white columns represent the chow fed mice and the black columns represent the high fat fed mice. V02 measurements when normalized to animal mass showed no changes after the three week period.Similarly energy expenditure measurements when normalized to animal mass showed no changes. Physical activity measured by beam breaks, varied by time of day but was the same for both groups. Food intake was not different when normalized to body mass.This amount is significantly more energy intake with the high fat diet. Once established as it is non invasive the body composition analysis can be conducted on a daily basis if necessary. While extended animal metabolic monitoring sessions may be considered more stressful to the mice due to the social isolation, these analysis can also be performed numerous times within a The implications of these techniques extend towards identifying therapeutic targets for obesity and metabolic disorders such as type two diabetes by the careful metabolic phenotyping of mice in regards to genetic manipulations or drug treatments.Ultimately not only can these methods provide insights for obesity but also for other conditions such as mass models of sarcopenia, cancer cachexia, muscular dystrophy or widi dystrophy.

body-composition-and-metabolic-caging-analysis-in-high-fat-fed-mice

Research

JoVE Journal

Medicine

Hyperinsulinemic-euglycemic Clamps in Conscious, Unrestrained Mice

Type 2 diabetes is characterized by a defect in insulin action. The hyperinsulinemic-euglycemic clamp, or insulin clamp, is widely considered the "gold standard" method for assessing insulin action in vivo. During an insulin clamp, hyperinsulinemia is achieved by a constant insulin infusion. Euglycemia is maintained via a concomitant glucose infusion at a variable rate. This variable glucose infusion rate (GIR) is determined by measuring blood glucose at brief intervals throughout the experiment and adjusting the GIR accordingly. The GIR is indicative of whole-body insulin action, as mice with enhanced insulin action require a greater GIR. The insulin clamp can incorporate administration of isotopic 2[14C]deoxyglucose to assess tissue-specific glucose uptake and [3-3H]glucose to assess the ability of insulin to suppress the rate of endogenous glucose appearance (endoRa), a marker of hepatic glucose production, and to stimulate the rate of whole-body glucose disappearance (Rd).
The miniaturization of the insulin clamp for use in genetic mouse models of metabolic disease has led to significant advances in diabetes research. Methods for performing insulin clamps vary between laboratories. It is important to note that the manner in which an insulin clamp is performed can significantly affect the results obtained. We have published a comprehensive assessment of different approaches to performing insulin clamps in conscious mice1 as well as an evaluation of the metabolic response of four commonly used inbred mouse strains using various clamp techniques2. Here we present a protocol for performing insulin clamps on conscious, unrestrained mice developed by the Vanderbilt Mouse Metabolic Phenotyping Center (MMPC; URL: www.mc.vanderbilt.edu/mmpc). This includes a description of the method for implanting catheters used during the insulin clamp. The protocol employed by the Vanderbilt MMPC utilizes a unique two-catheter system3. One catheter is inserted into the jugular vein for infusions. A second catheter is inserted into the carotid artery, which allows for blood sampling without the need to restrain or handle the mouse. This technique provides a significant advantage to the most common method for obtaining blood samples during insulin clamps which is to sample from the severed tip of the tail. Unlike this latter method, sampling from an arterial catheter is not stressful to the mouse1. We also describe methods for using isotopic tracer infusions to assess tissue-specific insulin action. We also provide guidelines for the appropriate presentation of results obtained from insulin clamps.

The hyperinsulinemic-euglycemic clamp, or insulin clamp, is the gold standard for assessing insulin action in vivo. A method for performing insulin clamps in mice is described. This includes a method for arterial catheterization that permits experiments to be performed in conscious, unrestrained mice with minimal stress.

Hiperinsulinêmico euglicêmico-Clamps em Consciente, Ratos Unrestrained

Type 2 diabetes is characterized by a defect in insulin action. The hyperinsulinemic-euglycemic clamp, or insulin clamp, is widely considered the "gold ...

Medicina

Protocol for Long Duration Whole Body Hyperthermia in Mice

Hyperthermia is a general term used to define the increase in core body temperature above normal. It is often used to describe the increased core body temperature that is observed during fever. The use of hyperthermia as an adjuvant has emerged as a promising procedure for tumor regression in the field of cancer biology. For this purpose, the most important requirement is to have reliable and uniform heating protocols. We have developed a protocol for hyperthermia (whole body) in mice. In this protocol, animals are exposed to cycles of hyperthermia for 90 min followed by a rest period of 15 min. During this period mice have easy access to food and water. High body temperature spikes in the mice during first few hyperthermia exposure cycles are prevented by immobilizing the animal. Additionally, normal saline is administered in first few cycles to minimize the effects of dehydration. This protocol can simulate fever like conditions in mice up to 12-24 hr. We have used 8-12 weeks old BALB/Cj female mice to demonstrate the protocol.

This paper describes a protocol for whole body hyperthermia in mice that can stimulate fever like conditions up to 12-24 hr.

Protocolo para Longa Duração Hipertermia corpo inteiro em Ratos

Hyperthermia is a general term used to define the increase in core body temperature above normal. It is often used to describe the increased core body ...

Carotid Artery Infusions for Pharmacokinetic and Pharmacodynamic Analysis of Taxanes in Mice

When proposing the use of a drug, drug combination, or drug delivery into a novel system, one must assess the pharmacokinetics of the drug in the study model. As the use of mouse models are often a vital step in preclinical drug discovery and drug development1-8, it is necessary to design a system to introduce drugs into mice in a uniform, reproducible manner. Ideally, the system should permit the collection of blood samples at regular intervals over a set time course. The ability to measure drug concentrations by mass-spectrometry, has allowed investigators to follow the changes in plasma drug levels over time in individual mice1, 9, 10. In this study, paclitaxel was introduced into transgenic mice as a continuous arterial infusion over three hours, while blood samples were simultaneously taken by retro-orbital bleeds at set time points. Carotid artery infusions are a potential alternative to jugular vein infusions, when factors such as mammary tumors or other obstructions make jugular infusions impractical. Using this technique, paclitaxel concentrations in plasma and tissue achieved similar levels as compared to jugular infusion. In this tutorial, we will demonstrate how to successfully catheterize the carotid artery by preparing an optimized catheter for the individual mouse model, then show how to insert and secure the catheter into the mouse carotid artery, thread the end of the catheter out through the back of the mouse&#8217;s neck, and hook the mouse to a pump to deliver a controlled rate of drug influx. Multiple low volume retro-orbital bleeds allow for analysis of plasma drug concentrations over time.

This method was developed with the goal of delivering a steady drug solution via the carotid artery, to assess the pharmacokinetics of novel drugs in mouse models.

Infusões artéria carótida para farmacocinéticas e farmacodinâmicas Análise de taxanos em Ratos

When proposing the use of a drug, drug combination, or drug delivery into a novel system, one must assess the pharmacokinetics of the drug in the study ...

Dissection of the Mouse Pancreas for Histological Analysis and Metabolic Profiling

We have been investigating the pancreas specific transcription factor, 1a cre-recombinase; lox-stop-lox- Kristen rat sarcoma, glycine to aspartic acid at the 12 codon (Ptf1acre/+;LSL-KrasG12D/+) mouse strain as a model of human pancreatic cancer. The goal of our current studies is to identify novel metabolic biomarkers of pancreatic cancer progression. We have performed metabolic profiling of urine, feces, blood, and pancreas tissue extracts, as well as histological analyses of the pancreas to stage the cancer progression. The mouse pancreas is not a well-defined solid organ like in humans, but rather is a diffusely distributed soft tissue that is not easily identified by individuals unfamiliar with mouse internal anatomy or by individuals that have little or no experience performing mouse organ dissections. The purpose of this article is to provide a detailed step-wise visual demonstration to guide novices in the removal of the mouse pancreas by dissection. This article should be especially valuable to students and investigators new to research that requires harvesting of the mouse pancreas by dissection for metabolic profiling or histological analyses.

This video article provides a detailed demonstration of the procedures required to successfully remove the pancreas from a mouse by dissection for histological analysis and metabolic profiling.

Dissecação do pâncreas Mouse para análise histológica e perfis metabólicos

We have been investigating the pancreas specific transcription factor, 1a cre-recombinase; lox-stop-lox- Kristen rat sarcoma, glycine to aspartic acid at ...

Semi-automated Analysis of Mouse Skeletal Muscle Morphology and Fiber-type Composition

For years, distinctions between skeletal muscle fiber types were best visualized by myosin-ATPase staining. More recently, immunohistochemical staining of myosin heavy chain (MyHC) isoforms has emerged as a finer discriminator of fiber-type. Type I, type IIA, type IIX and type IIB fibers can now be identified with precision based on their MyHC profile; however, manual analysis of these data can be slow and down-right tedious. In this regard, rapid, accurate assessment of fiber-type composition and morphology is a very desirable tool. Here, we present a protocol for state-of-the-art immunohistochemical staining of MyHCs in frozen sections obtained from mouse hindlimb muscle in concert with a novel semi-automated algorithm that accelerates analysis of fiber-type and fiber morphology. As expected, the soleus muscle displayed staining for type I and type IIA fibers, but not for type IIX or type IIB fibers. On the other hand, the tibialis anterior muscle was composed predominantly of type IIX and type IIB fibers, a small fraction of type IIA fibers and little or no type I fibers. Several image transformations were used to generate probability maps for the purpose of measuring different aspects of fiber morphology (i.e., cross-sectional area (CSA), maximal and minimal Feret diameter). The values obtained for these parameters were then compared with manually-obtained values. No significant differences were observed between either mode of analysis with regards to CSA, maximal or minimal Feret diameter (all p &#62; 0.05), indicating the accuracy of our method. Thus, our immunostaining analysis protocol may be applied to the investigation of effects on muscle composition in many models of aging and myopathy.

Immunohistochemical staining of myosin heavy chain isoforms has emerged as the state-of-the-art discriminator of skeletal muscle fiber-type (i.e., type I, type IIA, type IIX, type IIB). Here, we present a staining protocol along with a novel semi-automated algorithm that facilitates rapid assessment of fiber-type and fiber morphology.

Semi automatizados de análise da morfologia do músculo esquelético de rato e composição de fibra-tipo

For years, distinctions between skeletal muscle fiber types were best visualized by myosin-ATPase staining. More recently, immunohistochemical staining of ...

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

Obesity represents the most important single risk factor in the pathogenesis of type 2 diabetes, a disease which is characterized by a resistance to insulin-stimulated glucose uptake and a gross decompensation of systemic glucose metabolism. Despite considerable progress in the understanding of glucose metabolism, the molecular mechanisms of its regulation in health and disease remain under-investigated, while novel approaches to prevent and treat diabetes are urgently needed. Diet derived glucose stimulates the pancreatic secretion of insulin, which serves as the principal regulator of cellular anabolic processes during the fed-state and thus balances blood glucose levels to maintain systemic energy status. Chronic overfeeding triggers meta-inflammation, which leads to alterations in peripheral insulin receptor-associated signaling and thus reduces the sensitivity to insulin-mediated glucose disposal. These events ultimately result in elevated fasting glucose and insulin levels as well as a reduction in glucose tolerance, which in turn serve as important indicators of insulin resistance. Here, we present a protocol for the generation and metabolic characterization of high-fat diet (HFD)-fed mice as a frequently used model of diet-induced insulin resistance. We illustrate in detail the oral glucose tolerance test (OGTT), which monitors the peripheral disposal of an orally administered glucose load and insulin secretion over time. Additionally, we present a protocol for the insulin tolerance test (ITT) to monitor whole-body insulin action. Together, these methods and their downstream applications represent powerful tools to characterize the general metabolic phenotype of mice as well as to specifically assess alterations in glucose metabolism. They may be especially useful in the broad research field of insulin resistance, diabetes and obesity to provide a better understanding of pathogenesis as well as to test the effects of therapeutic interventions.

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

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.

Estudo do metabolismo in vivo da glicose em camundongos alimentados com dieta de alto teor em gordura usando o teste oral de tolerância à glicose (OGTT) e o teste de tolerância à insulina (ITT)

Obesity represents the most important single risk factor in the pathogenesis of type 2 diabetes, a disease which is characterized by a resistance to ...

Incorporation of a Survivable Liver Biopsy Procedure in Mice to Assess Non-alcoholic Steatohepatitis (NASH) Resolution

Clinical trials assessing therapies for the treatment of non-alcoholic steatohepatitis (NASH) involve a baseline and end of study liver biopsy, and assessment of improvement in disease endpoints, often reflected as a percent of each treatment arm that improved, worsened or remained unchanged. Traditional preclinical rodent studies for putative NASH therapies are often limited by not knowing the level of liver disease/NASH present at the start of therapeutic intervention, instead of randomizing treatment groups on easily measurable endpoints such as body weight, metabolic status or similar. Here, we describe a liver biopsy technique in a diet-induced NASH mouse model, for the assessment of baseline liver disease in order to exclude mice that do not exhibit fibrosis and to equally distribute animals with similar fibrosis between treatment groups. These levels can then be compared to the terminal, post-intervention levels for a truer understanding of in vivo pharmacological effects and thus more accurately reflect clinical trial design strategies. The mouse is properly anesthetized and prepared for the surgery using sterile conditions. A small incision is made in the upper abdomen and the left lateral lobe of the liver is exposed. A wedge of the liver is surgically removed, and a similar-sized piece of absorbable gelatin is put in its place to stop any bleeding. The mouse is surgically sutured and stapled closed and will recover back to normal within 1 day. The entire process takes 5-10 min per mouse. Here we exemplify the utility of this procedure by leveraging the pre-study biopsy to assess the impact of the glucagon-like peptide-1 (GLP-1) receptor agonist liraglutide on NASH endpoints in mice.

Incorporation of a Survivable Liver Biopsy Procedure in Mice to Assess Non-alcoholic Steatohepatitis NASH Resolution

In clinical settings, a liver biopsy is used to assess stages of non-alcoholic steatohepatitis (steatosis, inflammation, hepatocyte ballooning, and fibrosis). Here, we illustrate a survivable liver biopsy in mice which can be used for histological analyses to enable assessment of therapeutic agents in a manner more aligned with clinical trials.

Incorporação de um procedimento de biópsia hepática Survivable em ratos para avaliar a resolução esteatohepatite não-alcoólica (NASH)

Clinical trials assessing therapies for the treatment of non-alcoholic steatohepatitis (NASH) involve a baseline and end of study liver biopsy, and ...

Quantitative Analysis of Cellular Composition in Advanced Atherosclerotic Lesions of Smooth Muscle Cell Lineage-Tracing Mice

Atherosclerosis remains the leading cause of death worldwide and, despite countless preclinical studies describing promising therapeutic targets, novel interventions have remained elusive. This is likely due, in part, to a reliance on preclinical prevention models investigating the effects of genetic manipulations or pharmacological treatments on atherosclerosis development rather than the established disease. Also, results of these studies are often confounding because of the use of superficial lesion analyses and a lack of characterization of lesion cell populations. To help overcome these translational hurdles, we propose an increased reliance on intervention models that employ investigation of changes in cellular composition at a single cell level by immunofluorescent staining and confocal microscopy. To this end, we describe a protocol for testing a putative therapeutic agent in a murine intervention model including a systematic approach for animal dissection, embedding, sectioning, staining, and quantification of brachiocephalic artery lesions. In addition, due to the phenotypic diversity of cells within late-stage atherosclerotic lesions, we describe the importance of using cell-specific, inducible lineage tracing mouse systems and how this can be leveraged for unbiased characterization of atherosclerotic lesion cell populations. Together, these strategies may assist vascular biologists to more accurately model therapeutic interventions and analyze atherosclerotic disease and will hopefully translate into a higher rate of success in clinical trials.

We propose a standardized protocol to characterize the cellular composition of late-stage murine atherosclerotic lesions including systematic methods of animal dissection, tissue embedding, sectioning, staining, and analysis of brachiocephalic arteries from atheroprone smooth muscle cell lineage tracing mice.

Análise quantitativa da composição celular em lesões ateroscleróticas avançadas de ratos de rastreamento de linhagem celular músculo liso

Atherosclerosis remains the leading cause of death worldwide and, despite countless preclinical studies describing promising therapeutic targets, novel ...

Vinyl Chloride and High-Fat Diet as a Model of Environment and Obesity Interaction

Vinyl chloride (VC), an abundant environmental contaminant, causes steatohepatitis at high levels, but is considered safe at lower levels. Although several studies have investigated the role of VC as a direct hepatotoxicant, the concept that VC modifies sensitivity of the liver to other factors, such as nonalcoholic fatty liver disease (NAFLD) caused by high-fat diet (HFD) is novel. This protocol describes an exposure paradigm to evaluate the effects of chronic, low-level exposure to VC. Mice are acclimated to low-fat or high-fat diet one week prior to the beginning of the inhalation exposure and remain on these diets throughout the experiment. Mice are exposed to VC (sub-OSHA level: &#60;1 ppm) or room air in inhalation chambers for 6 hours/day, 5 days/week, for up to 12 weeks. Animals are monitored weekly for body weight gain and food consumption. This model of VC exposure causes no overt liver injury with VC inhalation alone. However, the combination of VC and HFD significantly enhances liver disease. A technical advantage of this co-exposure model is the whole-body exposure, without restraint. Moreover, the conditions more closely resemble a very common human situation of a combined exposure to VC with underlying nonalcoholic fatty liver disease and therefore support the novel hypothesis that VC is an environmental risk factor for the development of liver damage as a complication of obesity (i.e., NAFLD). This work challenges the paradigm that the current exposure limits of VC (occupational and environmental) are safe. The use of this model can shed new light and concern on the risks of VC exposure. This model of toxicant-induced liver injury can be used for other volatile organic compounds and to study other interactions that may impact the liver and other organ systems.

The goal of this protocol was to develop a murine model of low-level toxicant exposure that does not cause overt liver injury but rather exacerbates pre-existing liver damage. This paradigm better recapitulates human exposure and the subtle changes that occur upon exposure to toxicant concentrations that are considered safe.

Cloreto de vinil e dieta rica em gordura como modelo de interação ambiental e obesidade

Vinyl chloride (VC), an abundant environmental contaminant, causes steatohepatitis at high levels, but is considered safe at lower levels. Although ...

Segmentation and Linear Measurement for Body Composition Analysis using Slice-O-Matic and Horos

Body composition is associated with risk of disease progression and treatment complications in a variety of conditions. Therefore, quantification of skeletal muscle mass and adipose tissues on Computed Tomography (CT) and/or Magnetic Resonance Imaging (MRI) may inform surgery risk evaluation and disease prognosis. This article describes two quantification methods originally described by Mourtzakis et al. and Avrutin et al.: tissue segmentation and linear measurement of skeletal muscle. Patients' cross-sectional image at the midpoint of the third lumbar vertebra was obtained for both measurements. For segmentation, the images were imported into Slice-O-Matic and colored for skeletal muscle, intramuscular adipose tissue, visceral adipose tissue, and subcutaneous adipose tissue. Then, surface areas of each tissue type were calculated using the tag surface area function. For linear measurements, the height and width of bilateral psoas and paraspinal muscles at the level of the third lumbar vertebra are measured and the calculation using these four values yield the estimated skeletal muscle mass. Segmentation analysis provides quantitative, comprehensive information about the patients' body composition, which can then be correlated with disease progression. However, the process is more time-consuming and requires specialized training. Linear measurements are an efficient and clinic-friendly tool for quick preoperative evaluation. However, linear measurements do not provide information on adipose tissue composition. Nonetheless, these methods have wide applications in a variety of diseases to predict surgical outcomes, risk of disease progression and inform treatment options for patients.

Segmentation and linear measurements quantify skeletal muscle mass and adipose tissues using Computed Tomography and/or Magnetic Resonance Imaging images. Here, we outline the use of Slice-O-Matic software and Horos image viewer for rapid and accurate analysis of body composition. These methods can provide important information for prognosis and risk stratification.

Segmentação e Medição Linear para Análise de Composição Corporal usando Slice-O-Matic e Horos

Body composition is associated with risk of disease progression and treatment complications in a variety of conditions. Therefore, quantification of ...