Name: dissection of the mouse pancreas for histological analysis and metabolic profiling
Uploaded: 2017-08-19T14:00:00
Description: Watch this Scientific Journal Video about Dissection of the Mouse Pancreas for Histological Analysis and Metabolic Profiling at JoVE.com

MAK acknowledges support for this work from the National Institutes of Health / National Cancer Institute grant number - 1R15CA152985-01A1. This project has also been supported by the Miami University Undergraduate Research Award Program, the Miami University Doctorate-Undergraduate Opportunities for Scholarship Program and the Miami University Summer Scholars Program.

The procedures carried out in the video and described below have been approved by the Institutional Animal Care and Use Committee (IACUC) at Miami University.
1. Preparation and Stimulus Test
<ol>
	<li>Establish two distinct areas for the surgical procedure, the operating table and the post-operation table. Stage both areas with all materials and utensils necessary.
	<ol>
		<li>Stage the operating table under a vented hood. Arrange the table with the equipment in a manner that allows the con...

<ol>
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J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Differences+in+Survival+by+Histologic+Type+of+Pancreatic+Cancer.">Differences in Survival by Histologic Type of Pancreatic Cancer.</a> Cancer Epidemiol Biomarkers Prev. 14 (7), 1766-1773 (2005).</li><li>Jackson-Grusby, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Modeling+cancer+in+mice.">Modeling cancer in mice.</a> Oncogene. 21 (35), 5504-5514 (2002).</li><li>Heid, I., 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=Early+requirement+of+Rac1+in+a+mouse+model+of+pancreatic+cancer.">Early requirement of Rac1 in a mouse model of pancreatic cancer.</a> Gastroenterology. 141 (2), 719-730 (2011).</li><li>Hingorani, S. R., 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=Preinvasive+and+invasive+ductal+pancreatic+cancer+and+its+early+detection+in+the+mouse.">Preinvasive and invasive ductal pancreatic cancer and its early detection in the mouse.</a> Cancer cell. 4 (6), 437-450 (2003).</li><li>Shi, 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=KRAS2+Mutations+in+Human+Pancreatic+Acinar-Ductal+Metaplastic+Lesions+Are+Limited+to+Those+with+PanIN+Implications+for+the+Human+Pancreatic+Cancer+Cell+of+Origin.">KRAS2 Mutations in Human Pancreatic Acinar-Ductal Metaplastic Lesions Are Limited to Those with PanIN Implications for the Human Pancreatic Cancer Cell of Origin.</a> Mol Cancer Res. 7 (2), 230-236 (2009).</li><li>LaConti, J. 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=Distinct+serum+metabolomics+profiles+associated+with+malignant+progression+in+the+KrasG12D+mouse+model+of+pancreatic+ductal+adenocarcinoma.">Distinct serum metabolomics profiles associated with malignant progression in the KrasG12D mouse model of pancreatic ductal adenocarcinoma.</a> BMC Genomics. 16 (1), 1-10 (2015).</li><li>Ludwig, M. R., 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=Surveying+the+serologic+proteome+in+a+tissue-specific+kras(G12D)+knockin+mouse+model+of+pancreatic+cancer.">Surveying the serologic proteome in a tissue-specific kras(G12D) knockin mouse model of pancreatic cancer.</a> Proteomics. 16 (3), 516-531 (2016).</li><li>Taylor, D. K., Mook, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isoflurane+Waste+Anesthetic+Gas+Concentrations+Associated+with+the+Open-Drop+Method.">Isoflurane Waste Anesthetic Gas Concentrations Associated with the Open-Drop Method.</a> J Am Assoc Lab Anim Sci. 48 (1), 61-64 (2009).</li><li>Parasuraman, S., Raveendran, R., Kesavan, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Blood+sample+collection+in+small+laboratory+animals.">Blood sample collection in small laboratory animals.</a> J Pharmacol Pharmacother. 1 (2), 87-93 (2010).</li><li>Li, D. S., Yuan, Y. H., Tu, H. J., Liang, Q. L., Dai, L. 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S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Limbic+System+Participates+in+Mediating+the+Effects+of+General+Anesthetics.">Limbic System Participates in Mediating the Effects of General Anesthetics.</a> Neuropsychopharmacology. 31, 1177-1192 (2006).</li><li>Ijichi, 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=Aggressive+pancreatic+ductal+adenocarcinoma+in+mice+caused+by+pancreas-specific+blockade+of+transforming+growth+factor-&#946;+signaling+in+cooperation+with+active+Kras+expression.">Aggressive pancreatic ductal adenocarcinoma in mice caused by pancreas-specific blockade of transforming growth factor-&#946; signaling in cooperation with active Kras expression.</a> Genes Dev. 20 (22), 3147-3160 (2006).</li><li>Abiatari, I., 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=Moesin-dependent+cytoskeleton+remodelling+is+associated+with+an+anaplastic+phenotype+of+pancreatic+cancer.">Moesin-dependent cytoskeleton remodelling is associated with an anaplastic phenotype of pancreatic cancer.</a> J Cell Mol Med. 14 (5), 1166-1179 (2010).</li><li>Goodpaster, A. M., Romick-Rosendale, L. E., Kennedy, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=a+Statistical+significance+analysis+of+nuclear+magnetic+resonance-based+metabonomics+data.">a Statistical significance analysis of nuclear magnetic resonance-based metabonomics data.</a> Analytical biochemistry. 401, 134-143 (2010).</li><li>Yadav, D., 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=Idiopathic+Tumefactive+Chronic+Pancreatitis:+Clinical+Profile,+Histology,+and+Natural+History+After+Resection.">Idiopathic Tumefactive Chronic Pancreatitis: Clinical Profile, Histology, and Natural History After Resection.</a> Clin Gastroenterol Hepatol. 1 (2), 129-135 (2003).</li></ol>

Significance with Respect to Existing Methods 
While other informal videos of mouse dissections exist, this video article provides the first professional quality, peer reviewed, visual demonstration of all of the detailed steps required for extraction and harvesting of the mouse pancreas by dissection10. With the pancreas being a main organ for metabolic activity and insulin production, dissection and harvesting of the pancreas allows for the preservation of the physiological...

The mouse has emerged as an important animal model of human pancreatic cancer1,2. In the Ptf1acre/+;LSL-KrasG12D/+ mouse model, the Kristen rat sarcoma (K-Ras) oncogene is activated exclusively in the pancreas, resulting in initiation of precancerous lesions in the pancreas, known as pancreatic intraepithelial neoplasias (PanINs), that progress to pancreatic ductal adenocarcinomas, commonly referred to as PDACs3. This mouse model system provides one of the best available animal models for human pancreatic cancer4,5, with the additional advantage that the PanINs emerge within the first five months of life and frequently progress to PDAC within a single year4,5, whereas pancreatic cancer most frequently occurs in humans 60-70 years of age.
Extraction of the pancreas by dissection from the Ptf1acre/+;LSL-KrasG12D/+ mice at various ages allows for detailed longitudinal histological examination of cancer development in the pancreas, ranging from the earliest PanIN stages through the progression to PDAC3,4,5. Harvesting the pancreas at ages ranging from five to fifteen months can also be used to prepare tissue extracts to characterize global changes in pancreas4 metabolism that occur during the transition from healthy to diseased tissue6,7.
This article presents a complete visual guide of the steps required to perform a mouse pancreas extraction and provides guidelines for storage of a pancreas for further analysis. This guide will be equally valuable for individuals conducting research on other pancreatic diseases, including type I diabetes, and should be especially useful to students and investigators new to research involving harvesting of the mouse pancreas using dissection for metabolic profiling or histological analyses.

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			<td style="width:167px;">The glass jar used in the video has been discontinued.&#160; This is its replacement.</td>
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			<td>The glass jar lid used in the video has been discontinued.&#160; This is its replacement.</td>
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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.

Figure 1 shows an overview of the operating environment area and Figure 2 shows the post operation area. While this setting provides the minimal amount of equipment and staging, individuals may choose to alter this to best suit individual needs. The protocol should be optimized according to the specific needs of the experiment. This procedure is conducted in a manner that terminates the life of a mouse, requiring proper euthaniza...

Watch this Scientific Journal Video about Dissection of the Mouse Pancreas for Histological Analysis and Metabolic Profiling at JoVE.com

Dissection of the Mouse Pancreas for Histological Analysis and Metabolic Profiling

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.

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

The primary goal of this video article is to provide detailed visual instructions outlining the dissection of a mouse pancreas. The instructions should be useful to researchers who study mouse models of human pancreatic diseases and who need to harvest the mouse pancreas by dissection for histological analysis or metabolic profiling. The video article also provides detailed instructions to perform a terminal blood collection using a heart puncture procedure.Displayed is a operating table with the needed supplies. These include one glass jar with lid, one 15 mL falcon tube, one pair of surgical scissors, one squeeze bottle of 70%ethanol, two foam boards, two forceps, two one mL 21 gauge syringes, two 50 mL falcon tubes, one centrifuge tube, one cryo-vial, four surgical pads, ten pins, a dispenser of sterilizing wipes and a sharps container. Displayed is the post-operating table with the needed supplies.These include one analytical balance, one four liter Dewar of liquid nitrogen, a shallow wide mouth Dewar, a floating microtube rack, one pair of surgical scissors, two forceps, five cryo-vials and a dispenser of sterile wipes. To perform euthanasia, the mouse is first placed in the glass jar containing a gauze pad soaked with a few drops of isoflurane, and then covered with the lid until the mouse becomes unconscious, which typically takes about one minute. The mouse is then removed from the glass jar and a foot pinch test is performed to ensure that the mouse cannot experience discomfort.If the foot pinch test fails, the mouse is returned to the glass jar and the lid replaced until the foot pinch test can be performed successfully. Place the mouse on its back and pin the limbs of the mouse to the surgical foam board and wet the ventral side of the mouse with 70%ethanol. Pinch the fur near the urethral opening with the forceps and slightly pull upward.Make an incision through the abdominal cavity, starting from the urethral opening, up the midline and ending at the chin. Near the starting point of the initial incision, grab one side of the fur and make another incision downward and diagonal toward the back paw. Repeat this in the same manner on the opposite side.Locate the heart to perform the terminal heart puncture. To do this, grasp the sternum with the forceps and cut into the diaphragm. Quickly cut upward through the ribcage and remove the cut portion to expose the beating heart.Once the heart is located, remove the pericardium and perform the terminal heart puncture with the syringe. For optimal blood collection, use the plunger of the needle to mimic the pumping action of the heart and avoid drawing too quickly. Dispel the blood into the centrifuge tube and dispose of the syringe into the sharps container.After the heart puncture is performed, euthanasia is carried out by removing the attachments connecting the heart. Locate the stomach on the left side of the mouse. The pancreas has the appearance of a diffuse lighter color tissue that is attached to the stomach and duodenum and all along the small and large intestines and is attached to the spleen.Begin to gently separate the pancreas from the stomach and duodenum by using the forceps. Continue to separate the pancreas from the small intestine continuing from the jejunum and ileum sections and finally to the cecum and large intestine. At the cecum, reposition the forceps and continue separation of the pancreas along the remaining colon towards the rectum.At this point, it is convenient to cut and remove the section from the stomach to the region of the colon immediately preceding the rectum. Locate the pancreas and attached spleen. Slide the pancreas towards the right side of the mouse.Cut the remaining connections between the pancreas and thoracic cavity to fully detach the pancreas and adjoined spleen. Remove the pancreas and spread it out to examine. If desired, other organs may be removed at this point.After extraction, the samples are moved to the post operative area. Each organ will be weighed and then placed into their respective cryo-vial. Record any observed irregularities.Once the organs are in cryo-vials, place them into the floating microtube rack and then into the Dewar with liquid nitrogen. After snap freezing, the organ should be stored at minus 80 degrees Celsius for long-term storage. All of the dissection tools used should be sanitized using the sterilizing wipes.The falcon tube lined with the isoflurane soaked surgical pad should be capped. The surgical pad on the foam board should be replaced with a fresh surgical pad. Portions of the mouse that were not collected should be disposed of according to the facility's animal disposal policy.The following items should be handled accordingly. Once these items are properly stored, a multitude of experiments can be conducted and include, but are not limited to, fluorescence microscopy, hematoxylin and eosin histology, immunohistochemistry, mass spectrometry, and nuclear magnetic resonance spectroscopy. With the pancreas being a primary organ for metabolic activity and insulin production, this procedure allows for the preservation of the physiological characteristics.By isolating the pancreas, future analysis may be conducted on the sample. This procedure allows for the comparison and study of interactions from other tissues within the same organism, within the same timeframe.

dissection-mouse-pancreas-for-histological-analysis-metabolic

Research

JoVE Journal

Medicine

Dissection of Human Vitreous Body Elements for Proteomic Analysis

The vitreous is an optically clear, collagenous extracellular matrix that fills the inside of the eye and overlies the retina. 1,2 Abnormal interactions between vitreous substructures and the retina underlie several vitreoretinal diseases, including retinal tear and detachment, macular pucker, macular hole, age-related macular degeneration, vitreomacular traction, proliferative vitreoretinopathy, proliferative diabetic retinopathy, and inherited vitreoretinopathies. 1,2 The molecular composition of the vitreous substructures is not known. Since the vitreous body is transparent with limited surgical access, it has been difficult to study its substructures at the molecular level. We developed a method to separate and preserve these tissues for proteomic and biochemical analysis. The dissection technique in this experimental video shows how to isolate vitreous base, anterior hyaloid, vitreous core, and vitreous cortex from postmortem human eyes. One-dimensional SDS-PAGE analyses of each vitreous component showed that our dissection technique resulted in four unique protein profiles corresponding to each substructure of the human vitreous body. Identification of differentially compartmentalized proteins will reveal candidate molecules underlying various vitreoretinal diseases.

This video shows an effective technique for differentiating and dissecting the various semi-transparent structures of the human vitreous body in post mortem eyes.

The vitreous is an optically clear, collagenous extracellular matrix that fills the inside of the eye and overlies the retina. 1,2 Abnormal interactions ...

Whole Vitreous Humor Dissection for Vitreodynamic Analysis

The authors propose an effective technique to isolate whole, intact vitreous core and cortex from post mortem enucleated porcine eyes. While previous studies have shown the results of such dissections, the detailed steps have not been described, precluding researchers outside the field from replicating their methods. Other studies harvest vitreous either through aspiration, which does not maintain the vitreous structure anatomy, or through partial dissection, which only isolates the vitreous core. The proposed method isolates the whole vitreous body, with the vitreous core and cortex intact, while maintaining vitreous anatomy and structural integrity. In this method, a full thickness scleral flap in an enucleated porcine eye is first created and through this, the choroid tissue can be separated from the sclera. The scleral flap is then expanded and the choroid is completely separated from the sclera. Finally the choroid-retina tissue is peeled off the vitreous to leave an isolated intact vitreous body. The proposed vitreous dissection technique can be used to study physical properties of the vitreous humor. In particular, this method has significance for experimental studies involving drug delivery, vitreo-retinal oxygen transport, and intraocular convection.

The goal of this protocol is to show an effective technique to isolate whole, intact vitreous core and cortex from post mortem enucleated porcine eyes.

The authors propose an effective technique to isolate whole, intact vitreous core and cortex from post mortem enucleated porcine eyes. While previous ...

Surgical Injury to the Mouse Pancreas through Ligation of the Pancreatic Duct as a Model for Endocrine and Exocrine Reprogramming and Proliferation

Expansion of pancreatic beta cells in vivo or ex vivo, or generation of beta cells by differentiation from an embryonic or adult stem cell, can provide new expandable sources of beta cells to alleviate the donor scarcity in human islet transplantation as therapy for diabetes. Although recent advances have been made towards this aim, mechanisms that regulate beta cell expansion and differentiation from a stem/progenitor cell remain to be characterized. Here, we describe a protocol for an injury model in the adult mouse pancreas that can function as a tool to study mechanisms of tissue remodeling and beta cell proliferation and differentiation. Partial duct ligation (PDL) is an experimentally induced injury of the rodent pancreas involving surgical ligation of the main pancreatic duct resulting in an obstruction of drainage of exocrine products out of the tail region of the pancreas. The inflicted damage induces acinar atrophy, immune cell infiltration and severe tissue remodeling. We have previously reported the activation of Neurogenin (Ngn) 3 expressing endogenous progenitor-like cells and an increase in beta cell proliferation after PDL. Therefore, PDL provides a basis to study signals involved in beta cell dynamics and the properties of an endocrine progenitor in adult pancreas. Since, it still remains largely unclear, which factors and pathways contribute to beta cell neogenesis and proliferation in PDL, a standardized protocol for PDL will allow for comparison across laboratories.

This protocol describes an injury model involving the surgical ligation of the pancreatic duct in the adult mouse pancreas, resulting in severe injury that establishes an environment that allows beta cell neogenesis and proliferation. This model can be used as a tool to study mechanisms involved in beta cell formation.

Expansion of pancreatic beta cells in vivo or ex vivo, or generation of beta cells by differentiation from an embryonic or adult stem cell, can provide ...

Do's and Don'ts in the Preparation of Muscle Cryosections for Histological Analysis

Histological evaluation of muscle biopsies has served as an indispensable tool in the understanding of the development and progression of pathology of neuromuscular disorders. However, in order to do so, proper care needs to be taken when excising and preserving tissues to achieve optimal staining. One method of tissue preservation involves fixing tissues in formaldehyde and then embedding them with paraffin wax. This method preserves morphology well and allows for long-term storage at RT but is cumbersome and requires handling of toxic chemicals. Further, formaldehyde fixation results in antigen cross-linking, which necessitates antigen retrieval protocols for effective immunostaining. On the contrary, frozen sectioning does not require fixation and thus retains biological antigen conformation. This method also provides a distinct advantage in quick turn around time, making it especially useful in situations needing quick histological evaluation like intraoperative surgical biopsies. Here we describe the most effective method of preparing muscle biopsies for visualization with different histological and immunological stains.

Do&#039;s and Don&#039;ts in the Preparation of Muscle Cryosections for Histological Analysis

Here we demonstrate the most efficient methods for freezing, embedding, cryosectioning, and staining of muscle biopsies to avoid freezing artifacts.

Histological evaluation of muscle biopsies has served as an indispensable tool in the understanding of the development and progression of pathology of ...

Mouse Model for Pancreas Transplantation Using a Modified Cuff Technique

Mouse models have several advantages in transplantation research, including easy handling, a variety of genetically well-defined strains, and the availability of the widest range of molecular probes and reagents to perform in vivo as well as in vitro studies. Based on our experience with various murine transplantation models, we developed a heterotopic pancreas transplantation model in mice with the intent to analyze mechanisms underlying severe ischemia reperfusion injury-associated early graft damage. In contrast to previously described techniques using suture techniques, herein we describe a new procedure using a non-suture cuff technique. 
In recent years, we have performed more than 300 pancreas transplantations in mice with an overall success rate of &gt;90%, a success rate never described before in mouse pancreas transplantation. The backbone of this non-suture cuff technique for graft revascularization consists of two major steps: (I) pulling the recipient vessel over a polyethylene/polyamide cuff and fixing it with a circumferential ligature, and (II) placing the donor vessel over the everted recipient vessel and fixing it with a second circumferential ligature. The resultant continuity of the endothelial layer results in less thrombogenic lesions with high patency rates and, finally, high success rates.
In this model, arterial anastomosis is achieved by pulling the abdominal aorta of the donor graft over the everted common carotid artery of the recipient animal. Venous drainage of the graft is achieved by pulling the portal vein of the graft over the everted external jugular vein of the recipient. This manuscript provides details and crucial steps of the organ recovery and organ implantation procedures, which will allow researchers with microsurgical skills to perform the transplantation successfully in their laboratories.

Among abdominal solid organ transplantation, pancreatic grafts are prone to develop severe ischemia reperfusion injury-associated graft damage, leading eventually to early graft loss. This protocol describes a model of murine pancreas transplantation using a non-suture cuff technique, ideally suited for analyzing these early, deleterious damages.

Mouse models have several advantages in transplantation research, including easy handling, a variety of genetically well-defined strains, and the ...

Echocardiographic and Histological Examination of Cardiac Morphology in the Mouse

An increasing number of genetically modified mouse models has become available in recent years. Moreover, the number of pharmacological studies performed in mice is high. Phenotypic characterization of these mouse models also requires the examination of cardiac function and morphology. Echocardiography and magnetic resonance imaging (MRI) are commonly used approaches to characterize cardiac function and morphology in mice. Echocardiographic and MRI equipment specialized for use in small rodents is&#160;expensive and requires a dedicated space. This protocol describes cardiac measurements in mice using a clinical echocardiographic system with a 15 MHz human vascular probe. Measurements are performed on anesthetized adult mice. At least three image sequences are recorded and analyzed for each animal in M-mode in the parasternal short-axis view. Afterwards, cardiac histological examination is performed, and cardiomyocyte diameters are determined on hematoxylin-eosin- or wheat germ agglutinin (WGA)-stained paraffin sections. Vessel density is determined morphometrically after Pecam-1 immunostaining. The protocol has been applied successfully to pharmacological studies and different genetic animal models under baseline conditions, as well as after experimental myocardial infarction by the permanent ligation of the left anterior descending coronary artery (LAD). In our experience, echocardiographic investigation is limited to anesthetized animals and is feasible in adult mice weighing at least 25 g.

Echocardiographic examination is frequently used in mice. Expensive high-resolution ultrasound devices have been developed for this purpose. This protocol describes an affordable echocardiographic procedure combined with histological morphometric analyses to determine cardiac morphology.

An increasing number of genetically modified mouse models has become available in recent years. Moreover, the number of pharmacological studies performed ...

Dissection and Explant Culture of Murine Allantois for the In Vitro Analysis of Allantoic Attachment

The placenta is essential for the growth and development of mammalian embryos. For this reason, numerous genetic alterations and likely also environmental insults that disturb placenta development or function can cause early pregnancy loss in mice and humans. Nevertheless, simple in vitro assays to screen for potential effects on placenta formation are lacking. Here, we focus on modeling the first and critical step in placenta formation, which consists of the attachment of the allantois to the chorion. We describe a method to rapidly assess the attachment of allantoic explants on immobilized &#945;4&#946;1 integrin, which serves as a chorio-mimetic substrate.This in vitro approach enables a qualitative evaluation of the attachment and spreading behavior of multiple allantois explants at different consecutive time points. The protocol may be used to investigate the effect of targeted mouse mutations, drugs, or various environmental factors that have been linked to pregnancy complications or fetal loss on allantois attachment ex vivo.

Dissection and Explant Culture of Murine Allantois for the In Vitro Analysis of Allantoic Attachment

We describe an in vitro assay to model chorioallantoic attachment, the first step in placenta formation. The protocol demonstrates the dissection and explant culture of murine allantoides on immobilized &#945;4&#946;1 integrin. Allantois attachment is evaluated microscopically at pre-determined time points.

The placenta is essential for the growth and development of mammalian embryos. For this reason, numerous genetic alterations and likely also environmental ...

Quantitative Micro-CT Analysis of Aortopathy in a Mouse Model of &#946;-aminopropionitrile-induced Aortic Aneurysm and Dissection

Aortic aneurysm and dissection is associated with significant morbidity and mortality in the population and can be highly lethal. While animal models of aortic disease exist, in vivo imaging of the vasculature has been limited. In recent years, micro-computerized tomography (micro-CT) has emerged as a preferred modality for imaging both large and small vessels both in vivo and ex vivo. In conjunction with a method of vascular casting, we have successfully used micro-CT to characterize the frequency and distribution of aortic pathology in &#946;-aminopropionitrile-treated C57/Bl6 mice. Technical limitations of this method include variations in the quality of the perfusion introduced by poor animal preparation, the application of proper methodologies for vessel size quantification, and the non-survivability of this procedure. This article details a methodology for the intravascular perfusion of a lead-based radiopaque silicone rubber for the quantitative characterization of aortopathy in a mouse model of aneurysm and dissection. In addition to visualizing aortic pathology, this method may be used for examining other vascular beds in vivo or vascular beds removed post-mortem.

Quantitative Micro-CT Analysis of Aortopathy in a Mouse Model of &amp;#946;-aminopropionitrile-induced Aortic Aneurysm and Dissection

This article describes a detailed methodology of using a radiopaque lead-based silicone rubber to perfuse the murine vasculature for aortic diameter quantification in a mouse model of aortic aneurysm and dissection.

Aortic aneurysm and dissection is associated with significant morbidity and mortality in the population and can be highly lethal. While animal models of ...

Mechanisms Underlying Gut Hormone Secretion Using the Isolated Perfused Rat Small Intestine

The gut is the largest endocrine organ of the body, producing more than 15 different peptide hormones that regulate appetite and food intake, digestion, nutrient absorption and distribution, and post-prandial glucose excursions. Understanding the molecular mechanisms that regulate gut hormone secretion is fundamental for understanding and translating gut hormone physiology. Traditionally, the mechanisms underlying gut hormone secretion are either studied in vivo (in experimental animals or humans) or using gut hormone-secreting primary mucosal cell cultures or cell lines. Here, we introduce an isolated perfused rat small intestine as an alternative method for studying gut hormone secretion. The virtues of this model are that it relies on the intact gut, meaning that it recapitulates most of the physiologically important parameters responsible for the secretion in in vivo studies, including mucosal polarization, paracrine relationships and routes of perfusion/stimulus exposure. In addition, and unlike in vivo studies, the isolated perfused rat small intestine allows for almost complete experimental control and direct assessment of secretion. In contrast to in vitro studies, it is possible to study both the magnitude and the dynamics of secretion and to address important questions, such as what stimuli cause secretion of different gut hormones, from which side of the gut (luminal or vascular) is secretion stimulated, and to analyze in detail molecular sensors underlying the secretory response. In addition, the preparation is a powerful model for the study of intestinal absorption and details regarding the dynamics of intestinal absorption including the responsible transporters.

Here, we present a powerful and physiological model to study the molecular mechanisms underlying gut hormone secretion and intestinal absorption &#8212; the isolated perfused rat small intestine.

The gut is the largest endocrine organ of the body, producing more than 15 different peptide hormones that regulate appetite and food intake, digestion, ...

Location, Dissection, and Analysis of the Murine Stellate Ganglion

The autonomic nervous system is a substantial driver of cardiac electrophysiology. Especially&#160;the role of its sympathetic branch is an ongoing matter of investigation in the pathophysiology of ventricular arrhythmias (VA). Neurons in the stellate ganglia (SG)&#160;&#8211;&#160;bilateral star-shaped structures of the sympathetic chain &#8211;&#160;are an important component of the sympathetic infrastructure. The SG are a recognized target for&#160;treatment via cardiac sympathetic denervation in patients with therapy-refractory VA. While neuronal remodeling and glial activation in the SG have been described in patients with VA, the underlying cellular and molecular processes that potentially precede the onset of arrhythmia are only insufficiently understood and should be elucidated to improve autonomic modulation. Mouse models allow us to study sympathetic neuronal remodeling, but identification of the murine SG is challenging for the inexperienced investigator. Thus, in-depth cellular and molecular biological studies of the murine SG are lacking for many common cardiac diseases. Here, we describe a basic repertoire for dissecting and studying the SG in adult mice for analyses at RNA level (RNA isolation for gene expression analyses, in situ hybridization), protein level (immunofluorescent whole mount staining), and cellular level (basic morphology, cell size measurement). We present potential solutions to overcome challenges in the preparation technique, and how to improve staining via quenching of autofluorescence. This allows for the visualization of neurons as well as glial cells via established markers in order to determine cell composition and remodeling processes. The methods presented here allow characterizing the SG to gain further information on autonomic dysfunction in mice prone to VA and can be complemented by additional techniques investigating neuronal and glial components of the autonomic nervous system in the heart.

Pathophysiological changes in the cardiac autonomic nervous system, especially in its sympathetic branch, contribute to the onset and maintenance of ventricular arrhythmias. In the present protocol, we show how to characterize murine stellate ganglia to improve the understanding of the underlying molecular and cellular processes.

The autonomic nervous system is a substantial driver of cardiac electrophysiology. Especially&#160;the role of its sympathetic branch is an ongoing matter ...