Name: identification and dissection of diverse mouse adipose depots
Uploaded: 2019-07-11T12:30:00
Description: Watch this Scientific Journal Video about Identification and Dissection of Diverse Mouse Adipose Depots at JoVE.com

O.A.M. is supported by NIH grants DK062876 and DK092759; D.P.B. is supported by the University of Michigan Medical Scientist Training Program (T32GM007863), University of Michigan Training Program in Organogenesis (T32HD007605), University of Michigan Rackham Merit Fellowship, and Tylenol Future Care Fellowship.

All animal procedures are performed with the approval of the Institutional Animal Care and Use Committee (IACUC) of the University of Michigan.
1. Euthanization
NOTE: For the purpose of this video protocol, 4 to 6 month-old C57BL/6J mice are used.
<ol>
	<li>Place the mouse in an isoflurane vaporizer chamber and adjust the isoflurane flow rate to 5% or greater. Continue isoflurane exposure until one minute after breathing stops. Then remove the mou...

<ol>
	<li>Cinti, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+adipose+organ+at+a+glance.">The adipose organ at a glance.</a> Disease Models &amp; Mechanisms. 5 (5), 588-594 (2012).</li><li>Rosen, E. D., Spiegelman, B. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=What+we+talk+about+when+we+talk+about+fat.">What we talk about when we talk about fat.</a> Cell. 156 (1-2), 20-44 (2014).</li><li>Sanchez-Gurmaches, J., Guertin, D. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adipocyte+lineages:+tracing+back+the+origins+of+fat.">Adipocyte lineages: tracing back the origins of fat.</a> Biochimica et Biophysica Acta. 1842 (3), 340-351 (2014).</li><li>Bagchi, D. P., Forss, I., Mandrup, S., MacDougald, O. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=SnapShot:+Niche+Determines+Adipocyte+Character+I.">SnapShot: Niche Determines Adipocyte Character I.</a> Cell Metabolism. 27 (1), 264-264 (2018).</li><li>Tchkonia, T., 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=Mechanisms+and+metabolic+implications+of+regional+differences+among+fat+depots.">Mechanisms and metabolic implications of regional differences among fat depots.</a> Cell Metabolism. 17 (5), 644-656 (2013).</li><li>Kajimura, S., Spiegelman, B. M., Seale, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Brown+and+Beige+Fat:+Physiological+Roles+beyond+Heat+Generation.">Brown and Beige Fat: Physiological Roles beyond Heat Generation.</a> Cell Metabolism. 22 (4), 546-559 (2015).</li><li>Frontini, A., Cinti, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Distribution+and+development+of+brown+adipocytes+in+the+murine+and+human+adipose+organ.">Distribution and development of brown adipocytes in the murine and human adipose organ.</a> Cell Metabolism. 11 (4), 253-256 (2010).</li><li>Zhang, F., 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=An+Adipose+Tissue+Atlas:+An+Image-Guided+Identification+of+Human-like+BAT+and+Beige+Depots+in+Rodents.">An Adipose Tissue Atlas: An Image-Guided Identification of Human-like BAT and Beige Depots in Rodents.</a> Cell Metabolism. 27, 252-262 (2018).</li><li>Sanchez-Gurmaches, J., Guertin, D. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adipocytes+arise+from+multiple+lineages+that+are+heterogeneously+and+dynamically+distributed.">Adipocytes arise from multiple lineages that are heterogeneously and dynamically distributed.</a> Nature Communications. 5, 4099 (2014).</li><li>Li, Z., Hardij, J., Bagchi, D. P., Scheller, E. L., MacDougald, O. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development,+regulation,+metabolism+and+function+of+bone+marrow+adipose+tissues.">Development, regulation, metabolism and function of bone marrow adipose tissues.</a> Bone. 110, 134-140 (2018).</li><li>Scheller, E. L., Cawthorn, W. P., Burr, A. A., Horowitz, M. C., MacDougald, O. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Marrow+Adipose+Tissue:+Trimming+the+Fat.">Marrow Adipose Tissue: Trimming the Fat.</a> Trends in Endocrinology &amp; Metabolism. 27 (6), 392-403 (2016).</li><li>Alexander, 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=Dermal+white+adipose+tissue:+a+new+component+of+the+thermogenic+response.">Dermal white adipose tissue: a new component of the thermogenic response.</a> The Journal of Lipid Research. 56 (11), 2061-2069 (2015).</li><li>Kruglikov, I. L., Scherer, P. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dermal+Adipocytes:+From+Irrelevance+to+Metabolic+Targets?.">Dermal Adipocytes: From Irrelevance to Metabolic Targets?.</a> Trends in Endocrinology &amp; Metabolism. 27 (1), 1-10 (2016).</li><li>Iacobellis, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Local+and+systemic+effects+of+the+multifaceted+epicardial+adipose+tissue+depot.">Local and systemic effects of the multifaceted epicardial adipose tissue depot.</a> Nature Reviews Endocrinology. 11 (6), 363-371 (2015).</li><li>Addison, O., Marcus, R. L., LaStayo, P. C., Ryan, A. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intermuscular+Fat:+A+Review+of+the+Consequences+and+Causes.">Intermuscular Fat: A Review of the Consequences and Causes.</a> International Journal of Endocrinology. 2014, 1-11 (2014).</li><li>Pond, C. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adipose+tissue+and+the+immune+system.">Adipose tissue and the immune system.</a> Prostaglandins, Leukotrienes, and Essential Fatty Acids. 73 (1), 17-30 (2005).</li><li>Kloppenburg, A. I. -. F. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+emerging+player+in+knee+osteoarthritis:+the+infrapatellar+fat+pad.">An emerging player in knee osteoarthritis: the infrapatellar fat pad.</a> Arthritis Research &amp; Therapy. 15 (225), 1-9 (2013).</li><li>Mann, A., Thompson, A., Robbins, N., Blomkalns, A. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Localization,+Identification,+and+Excision+of+Murine+Adipose+Depots.">Localization, Identification, and Excision of Murine Adipose Depots.</a> Journal of Visualized Experiments. (94), e52174 (2014).</li><li>Casteilla, L., Cousin, B., Calise, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Choosing+an+adipose+tissue+depot+for+sampling:+factors+in+selection+and+depot+specificity.">Choosing an adipose tissue depot for sampling: factors in selection and depot specificity.</a> Methods in Molecular Biology. 155, 1-22 (2008).</li><li>de Jong, J. M., Larsson, O., Cannon, B., Nedergaard, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+stringent+validation+of+mouse+adipose+tissue+identity+markers.">A stringent validation of mouse adipose tissue identity markers.</a> American Journal of Physiology-Endocrinology and Metabolism. 308 (12), E1085-E1105 (2015).</li><li>Cinti, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+adipose+organ.">The adipose organ.</a> Prostaglandins, Leukotrienes, and Essential Fatty Acids. 73 (1), 9-15 (2005).</li><li>Parlee, S. D., Lentz, S. I., Mori, H., MacDougald, O. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantifying+size+and+number+of+adipocytes+in+adipose+tissue.">Quantifying size and number of adipocytes in adipose tissue.</a> Methods in Enzymology. 537, 93-122 (2014).</li><li>Scheller, E. L., 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=Region-specific+variation+in+the+properties+of+skeletal+adipocytes+reveals+regulated+and+constitutive+marrow+adipose+tissues.">Region-specific variation in the properties of skeletal adipocytes reveals regulated and constitutive marrow adipose tissues.</a> Nature Communications. 6, 7808 (2015).</li><li>Scheller, E. L., 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=Use+of+osmium+tetroxide+staining+with+microcomputerized+tomography+to+visualize+and+quantify+bone+marrow+adipose+tissue+in+vivo.">Use of osmium tetroxide staining with microcomputerized tomography to visualize and quantify bone marrow adipose tissue in vivo.</a> Methods in Enzymology. 537, 123-139 (2014).</li><li>Lukjanenko, L., Brachat, S., Pierrel, E., Lach-Trifilieff, E., Feige, J. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genomic+profiling+reveals+that+transient+adipogenic+activation+is+a+hallmark+of+mouse+models+of+skeletal+muscle+regeneration.">Genomic profiling reveals that transient adipogenic activation is a hallmark of mouse models of skeletal muscle regeneration.</a> PLoS One. 8 (8), e71084 (2013).</li><li>Pagano, A. F., 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=Muscle+Regeneration+with+Intermuscular+Adipose+Tissue+(IMAT)+Accumulation+Is+Modulated+by+Mechanical+Constraints.">Muscle Regeneration with Intermuscular Adipose Tissue (IMAT) Accumulation Is Modulated by Mechanical Constraints.</a> PLoS One. 10 (12), e0144230 (2015).</li><li>Khan, I. 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=Intermuscular+and+perimuscular+fat+expansion+in+obesity+correlates+with+skeletal+muscle+T+cell+and+macrophage+infiltration+and+insulin+resistance.">Intermuscular and perimuscular fat expansion in obesity correlates with skeletal muscle T cell and macrophage infiltration and insulin resistance.</a> International Journal of Obesity. 39 (11), 1607-1618 (2015).</li><li>Sulston, R. 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=Increased+Circulating+Adiponectin+in+Response+to+Thiazolidinediones:+Investigating+the+Role+of+Bone+Marrow+Adipose+Tissue.">Increased Circulating Adiponectin in Response to Thiazolidinediones: Investigating the Role of Bone Marrow Adipose Tissue.</a> Frontiers in Endocrinology. 7, 128 (2016).</li></ol>

As the importance of the diverse molecular and functional characteristics of discrete adipocyte clusters is increasingly recognized, it is crucial that investigators within the field uniformly identify and excise adipose depots for further analyses. To date, few protocols exist for standardized localization and isolation of the wide range of mouse adipose depots. Previously published methods are focused primarily on one or two depots and lack the details necessary for uniform identification and excision by different inve...

Adipose tissues play critical roles in whole-body homeostasis, including storage and release of energy in response to local and global needs, thermoregulation, and secretion of adipokines to regulate energy balance, metabolism and immune responses1,2. Adipocytes are distributed throughout the body in discrete depots, and in some cases serve specialized roles within their microenvironments3,4,5. Historically, the study of adipose tissue has centered on white adipose tissue (WAT), and its role in maintaining energy homeostasis. Most adipocytes are distributed throughout the body in subcutaneous and visceral WAT depots. The characteristics of these depots are important for differential susceptibility to metabolic diseases. Subcutaneous adipocytes, located beneath the skin, have been associated with protective metabolic effects5. Visceral adipocytes, which surround the vital organs and are contained within the gonadal, perirenal, retroperitoneal, omental and pericardial depots, are commonly linked to metabolic disorders, including type 2 diabetes and cardiovascular disease2. Brown adipose tissues (BAT) have also been studied extensively. Brown and brown-like adipocytes express uncoupling protein 1 (UCP1) and play important roles in adaptive thermogenesis and glucose homeostasis6,7. Classical brown adipocytes are contained in the interscapular BAT depot8. Clusters of brown adipocytes are also found in other locations, including supraclavicular, infra/subscapular, cervical, paravertebral and periaortic depots8,9.
In addition to their location in major WAT and BAT depots, adipocytes exist in discrete niches throughout the body4, where they may perform specialized functions within their respective microenvironments. For example, bone marrow adipose tissue (BMAT) serves as a lipid reservoir, is a major source of circulating adiponectin, and closely interacts with osteoblasts, osteoclasts, and hematopoietic cells10,11. Dermal adipocytes contribute to widespread processes, including wound healing, immune response, thermoregulation, and hair follicle growth12,13. Further, epicardial adipocytes may produce several adipokines and chemokines that exert local and systemic effects on the development and progression of coronary artery disease14. Expansion of inter/intramuscular WAT has been positively correlated with increased adiposity, systemic insulin resistance, and decreased muscular strength and mobility15. In addition, popliteal adipocytes serve as a lipid reservoir for lymphatic expansion during infection16. While the specific roles of different articular depots are generally unknown, the Hoffa depot (infrapatellar) within the knee is now thought to contribute to pathologies, including anterior knee pain and osteoarthritis17.
Whereas regional differences in adipocyte character and function are under intense study, the field is currently limited by the lack of a standardized protocol for the identification and dissection of diverse mouse depots. Previously published methods have typically described the isolation of one or two specific depots and lack the level of detail required for uniform excision18,19. The protocol described in this manuscript provides a comprehensive guide for the specific anatomic locations and isolation steps of many different mouse adipose depots. Although WAT depots are the primary focus of this manuscript, the excision of interscapular BAT is also described in detail. Adipose tissues excised using this protocol can be used for a wide variety of experimental endpoints, including&#160;explant studies, histology, and gene expression analyses.
The goal of this manuscript is to provide investigators with a detailed protocol to clearly and precisely identify and isolate both prominent and less-studied mouse adipose depots (Figure 1). This resource will facilitate a more complete investigation of the developmental, molecular, and functional characteristics of adipocytes within diverse niches.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/59499/59499fig1.jpg" /> 
Figure 1: Schematic depiction of mouse adipose depots dissected in this protocol. This image has been adapted from Bagchi et al., 20184. <a href="https://www.jove.com/files/ftp_upload/59499/59499fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

<table>
	<tbody>
		<tr>
			<td>10% neutral buffered formalin</td>
			<td>Fisher Scientific</td>
			<td>22-110-869</td>
			<td></td>
		</tr>
		<tr>
			<td>24-well plates, untreated</td>
			<td>Sigma-Aldrich</td>
			<td>CLS3738</td>
			<td></td>
		</tr>
		<tr>
			<td>70% ethanol (dilute from 95%)</td>
			<td>Fisher Scientific</td>
			<td>04-355-226</td>
			<td></td>
		</tr>
		<tr>
			<td>Dissecting forceps with curved tips</td>
			<td>VWR</td>
			<td>89259-946</td>
			<td></td>
		</tr>
		<tr>
			<td>Dissecting pan</td>
			<td>Carolina Biological Supply Company</td>
			<td>629004</td>
			<td></td>
		</tr>
		<tr>
			<td>Dissecting scissors (sharp/blunt tip)</td>
			<td>VWR</td>
			<td>82027-588</td>
			<td></td>
		</tr>
		<tr>
			<td>Gauze sponges</td>
			<td>Vitality Medical</td>
			<td>2634</td>
			<td>Curity 4 x 4 inch gauze sponge, 12 ply</td>
		</tr>
		<tr>
			<td>Handi-Pins for dissection</td>
			<td>Carolina Biological Supply Company</td>
			<td>629132</td>
			<td></td>
		</tr>
		<tr>
			<td>Iris scissors (straight)</td>
			<td>VWR</td>
			<td>470018-890</td>
			<td></td>
		</tr>
		<tr>
			<td>Isoflurane</td>
			<td>VetOne</td>
			<td>501017</td>
			<td></td>
		</tr>
		<tr>
			<td>Scalpel</td>
			<td>VWR</td>
			<td>100499-578</td>
			<td>Feather scalpel handle with blade, disposable</td>
		</tr>
	</tbody>
</table>

identification and dissection of diverse mouse adipose depots

Adipose tissues are complex organs with a wide array of functions, including storage and mobilization of energy in response to local and global needs, uncoupling of metabolism to generate heat, and secretion of adipokines to regulate whole-body homeostasis and immune responses. Emerging research is identifying important regional differences in the developmental, molecular, and functional profiles of adipocytes located in discrete depots throughout the body. Different properties of the depots are medically relevant since metabolic diseases often demonstrate depot-specific effects. This protocol will provide investigators with a detailed anatomic atlas and dissection guide for the reproducible and accurate identification and excision of diverse mouse adipose tissues. Standardized dissection of discrete adipose depots will allow detailed comparisons of their molecular and metabolic characteristics and contributions to local and systemic pathologic states under various nutritional and environmental conditions.

Successful identification and isolation of various mouse adipose depots can be achieved using the protocol described above. The gross anatomical locations of subcutaneous (A, E-F), brown (B), visceral (C, D, G-J), and popliteal (K) depots are shown in Figure 2.
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/59499/59499fig2.jpg" /> 
Figure 2: Gross anatomical locations of mou...

Watch this Scientific Journal Video about Identification and Dissection of Diverse Mouse Adipose Depots at JoVE.com

Identification and Dissection of Diverse Mouse Adipose Depots

Adipocytes exist in discrete depots and have diverse roles within their unique microenvironments. As regional differences in adipocyte character and function are uncovered, standardized identification and isolation of depots is crucial for advancement of the field. Herein, we present a detailed protocol for the excision of various mouse adipose depots.

Adipose tissues are complex organs with a wide array of functions, including storage and mobilization of energy in response to local and global needs, ...

A standardized methodology for identifying and dissecting adipose depots throughout the body is critical for the investigation of differences in the character and function of adipocytes within discrete anatomical niches. The main advantage of this technique is that it is a reliable and accurate method for identifying and excising both common and less studied rodent adipose depots. For the identification and isolation of interscapular BAT, use iris scissors to cut horizontally along the bottom edge of the anterior subcutaneous tissue of a euthanized mouse following the natural border of the depot.Make two vertical incisions along the lateral edges of the depot following the natural borders of the tissue. Use forceps to carefully flip up the depot to reveal the butterfly-shaped interscapular brown adipose tissue embedded within the white adipose tissue. Then carefully dissect the BAT away from the surrounding WAT.Store adipose tissues in appropriate containers for downstream analysis. For the identification and isolation of posterior subcutaneous WAT, place the mouse into the supine position and secure the animal's limbs. Use forceps to lift up the skin at the base of the sternum and make a one millimeter skin incision.Insert one blade of the iris scissors into the cut and make a four to five centimeter midline skin incision beginning at the base of the sternum and ascending to the base of the tail. Next, make two one centimeter horizontal incisions at the top of the initial vertical incision extending laterally from the midline. Use the forceps to carefully peel back the skin from the peritoneal cavity, use the leg to locate the posterior subcutaneous WAT which should remain associated with the skin.Pin the outstretched skin and completely excise the triangular inguinal WAT depot from the base of the hindlimb ventrally across the groin. For visceral WAT depot identification and isolation, use forceps to lift up the thin peritoneal cavity wall at the base of the sternum and make a one millimeter incision in the tented tissue. Insert one blade of the iris scissors into the cut and make a four to five centimeter descending vertical incision from the top of the peritoneal cavity to the rectum.Make two one centimeter horizontal incisions at the top and bottom of the vertical incision extending laterally from the midline and use the forceps to peel back the peritoneum to expose the abdominal cavity contents. Then pin the outstretched peritoneum to the dissection pan to harvest the WAT depots contained within the peritoneal cavity. For the identification and isolation of visceral gonadal WAT, locate the gonads and use forceps to lift up the associated gonadal WAT, then use iris scissors to carefully excise the WAT from the gonads.To excise the perirenal depot, locate the kidney and use forceps to lift up the renal tissue. Pull the kidney to the midline to see a clear division between the perirenal and retroperitoneal depots and excise the WAT directly associated with the kidneys. Then remove the adrenal glands located above the kidneys from the WAT.For retroperitoneal WAT identification and isolation, lift the kidney to the midline again and use iris scissors to carefully dissect the retroperitoneal WAT from the posterior peritoneal wall. To isolate the popliteal WAT, place the patella against the dissection pan taking care that the popliteal fossa at the back of the knee is facing upward. Use the iris scissors to carefully remove the skin from the base of the hindlimb to the foot.Use the iris scissors to make a cut at the inferior border of the medial and lateral heads of the gastrocnemius muscle, use the forceps to lift up the muscle to reveal the triangular popliteal depot. Then use iris scissors to excise the depot along the natural tissue borders. Here, the gross anatomical locations of mouse subcutaneous, brown, visceral, and popliteal depots are shown.The histological characteristics of the subcutaneous, brown, visceral, popliteal, constitutive, and regulated marrow adipose, intramuscular, and infrapatellar adipose depots can be evaluated by standard Hematoxylin and Eosin staining protocols. The adipose tissues isolated using this protocol can be used for a wide variety of experimental endpoints including histological analysis, molecular studies, and gene and protein expression analysis. Field-wide standardization of the identification of diverse adipose depots will undoubtedly help us further our understanding of their molecular and metabolic characteristics and their differential contributions to both local and systematic pathological states.

identification-and-dissection-of-diverse-mouse-adipose-depots

Research

JoVE Journal

Biology

Dissection of 6.5 dpc Mouse Embryos

Analysis of gene expression patterns during early stages of mammalian embryonic development can provide important clues about gene function, cell-cell interaction and signaling mechanisms that guide embryonic patterning. However, dissection of the mouse embryo from the decidua shortly after implantation can be a challenging procedure, and detailed step-by-step documentation of this process is lacking.

Here we demonstrate how post-implantation (6.5 dpc) embryos are isolated by first dissecting the uterus of a pregnant mouse (detection of the vaginal plug was designated day 0.5 poist coitum) and subsequently dissecting the embryo from maternal decidua. The dissection of Reichert's membrane is described as well as the removal of the ectoplacental cone.

Isolation of postimplantation-stage embryos allows one to study gene patterning and analyze cell-lineage decision making processes during embryonic development, but proper dissection of the early embryo can be challenging. This protocol describes a method for isolating early primitive-streak-stage embryos (~6.5 days post coitum [dpc]).

Analysis of gene expression patterns during early stages of mammalian embryonic development can provide important clues about gene function, cell-cell ...

Dissection of Hippocampal Dentate Gyrus from Adult Mouse

The hippocampus is one of the most widely studied areas in the brain because of its important functional role in memory processing and learning, its remarkable neuronal cell plasticity, and its involvement in epilepsy, neurodegenerative diseases, and psychiatric disorders. The hippocampus is composed of distinct regions; the dentate gyrus, which comprises mainly granule neurons, and Ammon's horn, which comprises mainly pyramidal neurons, and the two regions are connected by both anatomic and functional circuits. Many different mRNAs and proteins are selectively expressed in the dentate gyrus, and the dentate gyrus is a site of adult neurogenesis; that is, new neurons are continually generated in the adult dentate gyrus. To investigate mRNA and protein expression specific to the dentate gyrus, laser capture microdissection is often used. This method has some limitations, however, such as the need for special apparatuses and complicated handling procedures. In this video-recorded protocol, we demonstrate a dissection technique for removing the dentate gyrus from adult mouse under a stereomicroscope. Dentate gyrus samples prepared using this technique are suitable for any assay, including transcriptomic, proteomic, and cell biology analyses. We confirmed that the dissected tissue is dentate gyrus by conducting real-time PCR of dentate gyrus-specific genes, tryptophan 2,3-dioxygenase (TDO2) and desmoplakin (Dsp), and Ammon's horn enriched genes, Meis-related gene 1b (Mrg1b) and TYRO3 protein tyrosine kinase 3 (Tyro3). The mRNA expressions of TDO2 and Dsp in the dentate gyrus samples were detected at obviously higher levels, whereas Mrg1b and Tyro3 were lower levels, than those in the Ammon's horn samples. To demonstrate the advantage of this method, we performed DNA microarray analysis using samples of whole hippocampus and dentate gyrus. The mRNA expression of TDO2 and Dsp, which are expressed selectively in the dentate gyrus, in the whole hippocampus of alpha-CaMKII+/- mice, exhibited 0.037 and 0.10-fold changes compared to that of wild-type mice, respectively. In the isolated dentate gyrus, however, these expressions exhibited 0.011 and 0.021-fold changes compared to that of wild-type mice, demonstrating that gene expression changes in dentate gyrus can be detected with greater sensitivity. Taken together, this convenient and accurate dissection technique can be reliably used for studies focused on the dentate gyrus.

A dissection technique for removal of the dentate gyrus from adult mouse under a stereomicroscope was demonstrated in this video-recorded protocol.

The hippocampus is one of the most widely studied areas in the brain because of its important functional role in memory processing and learning, its ...

In vivo Imaging and Therapeutic Treatments in an Orthotopic Mouse Model of Ovarian Cancer

Human cancer and response to therapy is better represented in orthotopic animal models. This paper describes the development of an orthotopic mouse model of ovarian cancer, treatment of cancer via oral delivery of drugs, and monitoring of tumor cell behavior in response to drug treatment in real time using in vivo imaging system. In this orthotopic model, ovarian tumor cells expressing luciferase are applied topically by injecting them directly into the mouse bursa where each ovary is enclosed. Upon injection of D-luciferin, a substrate of firefly luciferase, luciferase-expressing cells generate bioluminescence signals. This signal is detected by the in vivo imaging system and allows for a non-invasive means of monitoring tumor growth, distribution, and regression in individual animals. Drug administration via oral gavage allows for a maximum dosing volume of 10 mL/kg body weight to be delivered directly to the stomach and closely resembles delivery of drugs in clinical treatments. Therefore, techniques described here, development of an orthotopic mouse model of ovarian cancer, oral delivery of drugs, and in vivo imaging, are useful for better understanding of human ovarian cancer and treatment and will improve targeting this disease.

In vivo Imaging and Therapeutic Treatments in an Orthotopic Mouse Model of Ovarian Cancer

Orthotopic animal models of ovarian cancer replicate better human disease and therefore enhance our understanding of cancer progression and tumor response to therapy. A mouse model receives an intrabursal injection of luciferase-expressing ovarian tumor cells. Treatment is administered via oral gavage. Tumor growth is monitored by in vivo imaging system.

Human cancer and response to therapy is better represented in orthotopic animal models.  This paper describes the development of an orthotopic mouse model ...

Preparation of Adipose Progenitor Cells from Mouse Epididymal Adipose Tissues

Obesity and metabolic disorders such as diabetes, heart disease, and cancer, are all associated with dramatic adipose tissue remodeling. Tissue-resident adipose progenitor cells (APCs) play a key role in adipose tissue homeostasis and can contribute to the tissue pathology. The growing use of single cell analysis technologies &#8211; including single-cell RNA-sequencing and single-cell proteomics &#8211; is transforming the stem/progenitor cell field by permitting unprecedented resolution of individual cell expression changes within the context of population- or tissue-wide changes. In this article, we provide detailed protocols to dissect mouse epididymal adipose tissue, isolate single adipose tissue-derived cells, and perform fluorescence activated cell sorting (FACS) to enrich for viable Sca1+/CD31-/CD45-/Ter119- APCs. These protocols will allow investigators to prepare high quality APCs suitable for downstream analyses such as single cell RNA sequencing.

We present a simple method to isolate highly viable adipose progenitor cells from mouse epididymal fat pads using fluorescence activated cell sorting.

Obesity and metabolic disorders such as diabetes, heart disease, and cancer, are all associated with dramatic adipose tissue remodeling. Tissue-resident ...

Efficient Dissection and Culture of Primary Mouse Retinal Pigment Epithelial Cells

Eye disorders affect millions of people worldwide, but the limited availability of human tissues hinders their study. Mouse models are powerful tools to understand the pathophysiology of ocular diseases because of their similarities with human anatomy and physiology. Alterations in the retinal pigment epithelium (RPE), including changes in morphology and function, are common features shared by many ocular disorders. However, successful isolation and culture of primary mouse RPE cells is very challenging. This paper is an updated audiovisual version of the protocol previously published by Fernandez-Godino et al. in 2016 to efficiently isolate and culture primary mouse RPE cells. This method is highly reproducible and results in robust cultures of highly polarized and pigmented RPE monolayers that can be maintained for several weeks on Transwells. This model opens new avenues for the study of the molecular and cellular mechanisms underlying eye diseases. Moreover, it provides a platform to test therapeutic approaches that can be used to treat important eye diseases with unmet medical needs, including inherited retinal disorders and macular degenerations.

This protocol, which was originally reported by Fernandez-Godino et al. in 20161, describes a method to efficiently isolate and culture mouse RPE cells, which form a functional and polarized RPE monolayer within one week on Transwell plates. The procedure takes approximately 3 hours.

Eye disorders affect millions of people worldwide, but the limited availability of human tissues hinders their study. Mouse models are powerful tools to ...

Induction and Diverse Assessment Indicators of Experimental Autoimmune Encephalomyelitis

Multiple sclerosis (MS) is a typical autoimmune disease of the central nervous system (CNS) characterized by inflammatory infiltration, demyelination, and axonal damage. Currently, there are no measures to cure MS completely, but multiple disease-modifying therapies (DMT) are available to control and mitigate disease progression. There are significant similarities between the CNS pathological features of experimental autoimmune encephalomyelitis (EAE) and MS patients. EAE has been widely used as a representative model to determine MS drugs' efficacy and explore the development of new therapies for MS disease. Active induction of EAE in mice has a stable and reproducible effect and is particularly suitable for studying the effects of drugs or genes on autoimmune neuroinflammation. The method of immunizing C57BL/6J mice with myelin oligodendrocyte glycoprotein (MOG35-55) and the daily assessment of disease symptoms using a clinical scoring system is mainly shared. Given the complex etiology of MS with diverse clinical manifestations, the existing clinical scoring system can't satisfy the assessment of disease treatment. To avoid the shortcomings of a single intervention, new indicators to assess EAE based on clinical manifestations of anxiety-like moods and osteoporosis in MS patients are created to provide a more comprehensive assessment of MS treatment.

The present protocol describes the induction of experimental autoimmune encephalomyelitis in a mouse model using myelin oligodendrocyte glycoprotein and monitoring the disease process using a clinical scoring system. Experimental autoimmune encephalomyelitis-related symptoms are analyzed using mouse femur micro-computed tomography analysis and open field test to assess the disease process comprehensively.

Multiple sclerosis (MS) is a typical autoimmune disease of the central nervous system (CNS) characterized by inflammatory infiltration, demyelination, and ...

Isolation and Identification of Vascular Endothelial Cells from Distinct Adipose Depots for Downstream Applications

Vascular endothelial cells lining the wall of the vascular system play important roles in a variety of physiological processes, including vascular tone regulation, barrier functions, and angiogenesis. Endothelial cell dysfunction is a hallmark predictor and major driver for the progression of severe cardiovascular diseases, yet the underlying mechanisms remain poorly understood. The ability to isolate and perform analyses on endothelial cells from various vascular beds in their native form will give insight into the processes of cardiovascular disease. This protocol presents the procedure for the dissection of mouse subcutaneous and mesenteric adipose tissues, followed by isolation of their respective arterial vasculature. The isolated arteries are then digested using a specific cocktail of digestive enzymes focused on liberating functionally viable endothelial cells. The digested tissue is assessed by flow cytometry analysis using CD31+/CD45&#8722; cells as markers for positive endothelial cell identification. Cells can be sorted for immediate downstream functional assays or used to generate primary cell lines. The technique of isolating and digesting arteries from different vascular beds will provide options for researchers to evaluate freshly isolated vascular cells&#160;from arteries of interest and allow them to perform a wide range of functional tests on specific cell types.

This protocol details a method for the dissection of mouse adipose depots and the isolation and digestion of respective arteries to liberate and then identify the endothelial cell population. Freshly isolated cells used in downstream applications will advance the understanding of vascular cell biology and the mechanisms of vascular dysfunction.

Vascular endothelial cells lining the wall of the vascular system play important roles in a variety of physiological processes, including vascular tone ...

Adipose Tissue-Derived Stem Cell Isolation and Characterization

Isolation and Identification of Mesenchymal Stem Cells Derived from Adipose Tissue of Sprague Dawley Rats

Adult mesenchymal cells have revolutionized molecular and cell biology in recent decades. They can differentiate into different specialized cell types, in addition to their great capacity for self-renewal, migration, and proliferation. Adipose tissue is one of the least invasive and most accessible sources of mesenchymal cells. It has also been reported to have higher yields compared to other sources, as well as superior immunomodulatory properties. Recently, different procedures for obtaining adult mesenchymal cells from different tissue sources and animal species have been published. After evaluating the criteria of some authors, we standardized a methodology that is applicable to different purposes and easily reproducible. A pool of stromal vascular fraction (SVF) from perirenal and epididymal adipose tissue allowed us to develop primary cultures with optimal morphology and functionality. The cells were observed adhered to the plastic surface for 24 h, and exhibited a fibroblast-like morphology, with prolongations and a tendency to form colonies. Flow cytometry (FC) and immunofluorescence (IF) techniques were used to assess the expression of the membrane markers CD105, CD9, CD63, CD31, and CD34. The ability of adipose-derived stem cells (ASCs) to differentiate into the adipogenic lineage was also assessed using a cocktail of factors (4 &#181;M insulin, 0.5 mM 3-methyl-iso-butyl-xanthine, and 1 &#181;M dexamethasone). After 48 h, a gradual loss of fibroblastoid morphology was observed, and at 12 days, the presence of lipid droplets positive to oil red staining was confirmed. In summary, a procedure is proposed to obtain optimal and functional ASC cultures for application in regenerative medicine.

Author Spotlight: Isolation and Identification of Mesenchymal Stem Cells Derived from Adipose Tissue of Sprague Dawley Rats  

This protocol describes a methodology for isolating and identifying adipose tissue-derived mesenchymal stem cells (MSCs) from Sprague Dawley rats.

Adult mesenchymal cells have revolutionized molecular and cell biology in recent decades. They can differentiate into different specialized cell types, in ...

Culturing Preadipocytes Isolated from Murine Perivascular Adipose Tissue

Isolation, Culture, and Adipogenic Induction of Stromal Vascular Fraction-derived Preadipocytes from Mouse Periaortic Adipose Tissue

Perivascular adipose tissue (PVAT) is an adipose tissue depot that surrounds blood vessels and exhibits the phenotypes of white, beige, and brown adipocytes. Recent discoveries have shed light on the central role of PVAT in regulating vascular homeostasis and participating in the pathogenesis of cardiovascular diseases. A comprehensive understanding of PVAT properties and regulation is of great importance for the development of future therapies. Primary cultures of periaortic adipocytes are valuable for studying PVAT function and the crosstalk between periaortic adipocytes and vascular cells. This paper presents an economical and feasible protocol for the isolation, culture, and adipogenic induction of stromal vascular fraction-derived preadipocytes from mouse periaortic adipose tissue, which can be useful for modeling adipogenesis or lipogenesis in vitro. The protocol outlines tissue processing and cell differentiation for culturing periaortic adipocytes from young mice. This protocol will provide the technological cornerstone at the bench side for the investigation of PVAT function.

Author Spotlight: The Significance of Isolation, Culture, and Adipogenic Induction of SVF-Derived Preadipocytes from Mouse Perivascular Adipose Tissue 

Here, we describe the isolation, culture, and adipogenic induction of stromal vascular fraction-derived preadipocytes from mouse periaortic adipose tissue, allowing for the study of perivascular adipose tissue function and its relationship with vascular cells.

Perivascular adipose tissue (PVAT) is an adipose tissue depot that surrounds blood vessels and exhibits the phenotypes of white, beige, and brown ...

Mouse Inner Ear Extraction and Stria Vascularis Dissection

To begin, identify the inner ear within the temporal bone of a euthanized mouse. Scrape away the cranial nerves using number 55 forceps. Then use number 55 forceps to dissect out the bulla and capsule, detaching them from surrounding bone.Remove any remaining soft tissue from the inner ear surface. For SV dissection, use number 55 forceps to hold the specimen by the vestibular portion with the cochlear facing up. Pierce through the cochlear bone at the apex using the same forceps.Scrape along the apical turn, applying gentle force to break away small pieces of the outer bone layer. Gently lift the bone and detach it from the lateral wall. Using number 55 forceps remove cochlear bone pieces from the apical and middle turns.Gently pushing down the lateral wall, pry and remove the bone wall pieces towards the middle turn to expose the lateral wall of the apical and middle turns. Push the apical turn lateral wall aside to expose the spiral ganglion. Detach the lateral wall of the apical and middle turns from the spiral ganglion along the outer hair cell layer.Then remove pieces of spiral ganglion from inside the cochlear. Detach the cochlear from the vestibular portion of the temporal bone by inserting the forceps into the round and oval window and pushing down towards the vestibule to have better access to the lateral wall of the basal turn. After the cochlear is detached remove the vestibular portion of the inner ear.Prioritize preserving as much of the strayer as possible. Continue removing til the bone of the middle turn is detached from the SV.Next, remove pieces of the remaining cochlear bone covering the basal turn. This can be accomplished by pushing the lateral wall layer under the bone to detach it.Pry and gently pull the tissue to remove the farthest basal part of the lateral wall being careful not to damage the soft tissue below. With the basal part of the lateral wall detached, separate the lateral wall from the remaining cochlear by tracing the forceps along the lateral wall. Gently brush the forceps between the bone and the remaining lateral wall until it reaches the apex.Then move the lateral wall to a fresh PBS. Lay the lateral wall flat revealing the SV as a darker layer of tissue on the internal side of the lateral wall. Gently pry the SV layer away from the lateral wall.Push aside the detached SV and advance the forceps along the lateral wall attempting to detach the SV as one long ribbon, trying not to squeeze the SV.Use a tissue scoop to collect the fragile tissue. Cochlear were dissected from adult mouse aged greater than or equal to postnatal day 30. Inner ear was extracted from the surrounding temporal bone.SV was exposed after the removal of bone covering the middle turn. The SV was fully separated from the lateral wall after dissection.