Name: a syngeneic murine model of endometriosis using naturally cycling mice
Uploaded: 2020-11-24T15:00:00
Description: Watch this Scientific Journal Video about A Syngeneic Murine Model of Endometriosis using Naturally Cycling Mice at JoVE.com

We would like to thank the members of the Reizes laboratory for their critical review and insights during preparation of the manuscript, as well as the Imaging and Histology cores at Lerner Research Institute for their assistance in data collection and data analysis. This work was supported through an internal grant funding through the Research Program Committee at Cleveland Clinic and by an external grant through the Society for Reproductive Investigation and Bayer. Research in the Reizes Laboratory is also funded through VeloSano Bike to Cure, Center of Research Excellence in Gynecologic Cancer, and through The Laura J. Fogarty Endowed Chair for Uterine Cancer Research. Cleveland Clinic owns the copyright permission for&#160;Figure 1&#160;and&#160;Figure 2.

NOTE: The use of animals in this study was approved by the Institutional Animal Care and Use Committee (IACUC) at the Cleveland Clinic Lerner Research Institute. All publicly available animal care and use standards were performed following guidelines by the National Institutes of Health.&#160;This procedure is utilizing aseptic techniques. The Petri dish is sterile. The PBS/saline used is sterile. The surgical instruments for necropsy and tissue dissection are sterilized via autoclave. We use 70% EtOH on the instruments ...

<ol>
	<li>Zondervan, K. T., Becker, C. M., Missmer, S. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Endometriosis.">Endometriosis.</a> England Journal of Medicine. 382 (13), 1244-1256 (2020).</li><li>Schwartz, K., Llarena, N. C., Rehmer, J. M., Richards, E. G., Falcone, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+role+of+pharmacotherapy+in+the+treatment+of+endometriosis+across+the+lifespan.">The role of pharmacotherapy in the treatment of endometriosis across the lifespan.</a> Expert Opinion on Pharmacotherapy. 21 (8), 893-903 (2020).</li><li>Giudice, L. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Clinical+practice.+Endometriosis.">Clinical practice. 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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=Pathophysiology+and+immune+dysfunction+in+endometriosis.">Pathophysiology and immune dysfunction in endometriosis.</a> BioMed Research International. 2015, (2015).</li><li>Falcone, T., Flyckt, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Clinical+management+of+endometriosis.">Clinical management of endometriosis.</a> Obstetrics and Gynecology. 131 (3), 557-571 (2018).</li><li>Vercellini, P., 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=Association+between+endometriosis+stage,+lesion+type,+patient+characteristics+and+severity+of+pelvic+pain+symptoms:+a+multivariate+analysis+of+over+1000+patients.">Association between endometriosis stage, lesion type, patient characteristics and severity of pelvic pain symptoms: a multivariate analysis of over 1000 patients.</a> Human Reproduction. 22 (1), 266-271 (2007).</li><li>Bulun, S. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Endometriosis.">Endometriosis.</a> Endocrine Reviews. 40 (4), 1048-1079 (2019).</li><li>Brueggmann, 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=Novel+three-dimensional+in+vitro+models+of+ovarian+endometriosis.">Novel three-dimensional in vitro models of ovarian endometriosis.</a> Journal of Ovarian Research. 7, 17 (2014).</li><li>Dodds, K. N., Beckett, E. A. H., Evans, S. F., Hutchinson, M. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lesion+development+is+modulated+by+the+natural+estrous+cycle+and+mouse+strain+in+a+minimally+invasive+model+of+endometriosis.">Lesion development is modulated by the natural estrous cycle and mouse strain in a minimally invasive model of endometriosis.</a> Biology of Reproduction. 97 (6), 810-821 (2017).</li><li>Martinez, J., Bisbal, V., Marin, N., Cano, A., G&#243;mez, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Noninvasive+monitoring+of+lesion+size+in+a+heterologous+mouse+model+of+endometriosis.">Noninvasive monitoring of lesion size in a heterologous mouse model of endometriosis.</a> Journal of Visualized Experiments: JoVE. (144), (2019).</li><li>Pelch, K. E., Sharpe-Timms, K. L., Nagel, S. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mouse+model+of+surgically-induced+endometriosis+by+auto-transplantation+of+uterine+tissue.">Mouse model of surgically-induced endometriosis by auto-transplantation of uterine tissue.</a> Journal of Visualized Experiments: JoVE. (59), e3396 (2012).</li><li>Nishimoto-Kakiuchi, 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=Spontaneous+endometriosis+in+cynomolgus+monkeys+as+a+clinically+relevant+experimental+model.">Spontaneous endometriosis in cynomolgus monkeys as a clinically relevant experimental model.</a> Human Reproduction. 33 (7), 1228-1236 (2018).</li><li>Nair, H. 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=An+efficient+model+of+human+endometriosis+by+induced+unopposed+estrogenicity+in+baboons.">An efficient model of human endometriosis by induced unopposed estrogenicity in baboons.</a> Oncotarget. 7 (10), 10857-10869 (2016).</li><li>Lagan&#224;, A. 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=Translational+animal+models+for+endometriosis+research:+a+long+and+windy+road.">Translational animal models for endometriosis research: a long and windy road.</a> Annals of Translational Medicine. 6 (22), 431 (2018).</li><li>Bellofiore, N., 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=First+evidence+of+a+menstruating+rodent:+the+spiny+mouse+(Acomys+cahirinus).">First evidence of a menstruating rodent: the spiny mouse (Acomys cahirinus).</a> Amercian Journal of Obstetrics and Gynecology. 216 (1), 1-11 (2017).</li><li>Bruner-Tran, K. L., Mokshagundam, S., Herington, J. L., Ding, T., Osteen, K. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rodent+models+of+experimental+endometriosis:+identifying+mechanisms+of+disease+and+therapeutic+targets.">Rodent models of experimental endometriosis: identifying mechanisms of disease and therapeutic targets.</a> Current Women's Health Reviews. 14 (2), 173-188 (2018).</li><li>Bilotas, M. 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=Interplay+between+endometriosis+and+pregnancy+in+a+mouse+model.">Interplay between endometriosis and pregnancy in a mouse model.</a> PloS One. 10 (4), 0124900 (2015).</li><li>Peterse, 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=Of+mice+and+women:+a+laparoscopic+mouse+model+for+endometriosis.">Of mice and women: a laparoscopic mouse model for endometriosis.</a> Journal of Minimally Invasive Gynecology. 25 (4), 578-579 (2018).</li><li>Richards, E. G., 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=KLF11+is+an+epigenetic+mediator+of+DRD2/dopaminergic+signaling+in+endometriosis.">KLF11 is an epigenetic mediator of DRD2/dopaminergic signaling in endometriosis.</a> Reproductive Sciences. 224 (8), 1129-1138 (2017).</li><li>Jones, R. L., Lang, S. A., Kendziorski, J. A., Greene, A. D., Burns, K. A. <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+a+Mouse+Model+of+Experimentally+Induced+Endometriosis+to+Evaluate+and+Compare+the+Effects+of+Bisphenol+A+and+Bisphenol+AF+Exposure.">Use of a Mouse Model of Experimentally Induced Endometriosis to Evaluate and Compare the Effects of Bisphenol A and Bisphenol AF Exposure.</a> Environmental Health Perspectives. 126 (12), 127004 (2018).</li><li>Greaves, E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+novel+mouse+model+of+endometriosis+mimics+human+phenotype+and+reveals+insights+into+the+inflammatory+contribution+of+shed+endometrium.">A novel mouse model of endometriosis mimics human phenotype and reveals insights into the inflammatory contribution of shed endometrium.</a> The American Journal of Pathology. 184 (7), 1930-1939 (2014).</li><li>Nothnick, W. B., Graham, A., Holbert, J., Weiss, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=miR-451+deficiency+is+associated+with+altered+endometrial+fibrinogen+alpha+chain+expression+and+reduced+endometriotic+implant+establishment+in+an+experimental+mouse+model.">miR-451 deficiency is associated with altered endometrial fibrinogen alpha chain expression and reduced endometriotic implant establishment in an experimental mouse model.</a> PloS One. 9 (6), 100336 (2014).</li></ol>

Our study demonstrates that endometriosis can be reliably induced in mice without requiring use of ovariectomy and/or survival surgery, and that ectopic endometrial lesions can be identified and quantified using a standardized survey of the abdomen and histologic analysis.
Many murine studies of endometriosis utilize surgically induced endometriosis in which donor endometrium is sutured in place to t...

Endometriosis is an enigmatic disease of the female reproductive tract with significant financial and health burdens on women1,2. The etiology of endometriosis is not completely understood, and multiple explanations have been proposed including coelomic metaplasia, embryonic M&#252;llerian rests, recruitment of bone marrow derived progenitor cells, and retrograde menstruation3. While multiple aspects of these proposed mechanisms may be involved, and no single explanation can account for all forms of the disease, the leading model of endometriosis pathogenesis is retrograde menstruation. Retrograde menstruation is the passage of menstrual effluent through the fallopian tubes and into the peritoneal cavity; it is estimated that 90% of menstruating women regularly undergo retrograde menstruation4,5. Given this commonplace phenomenon of retrograde menstruation, why endometriosis develops only in a subset of women is unclear5. To better understand the etiology of this disease, direct human studies are not feasible and animal studies are warranted.
Endometriosis is a challenge both to treat and to study. Prevalence of the disease is not known but estimated to be 10%1. While some advanced types of endometriosis may be accurately identified through noninvasive imaging, a definitive diagnosis is only achieved through histopathological analysis of surgically obtained biopsy specimens; lesions that visually appear to be diseased, may in fact be fibrosis or scarring from other causes6. Severity and extent of disease does not correlate with symptomatology7.
Endometriosis lesions consist of heterogeneous cell types and populations which interact in complex ways within the microenvironment, therefore, limiting the usefulness of cellular models8,9. In vivo models exist, but these have inherent challenges and limitations10,11,12. Primate models are ideal but are often not feasible13,14,15. Few non-primate mammals menstruate and develop endometriosis spontaneously16. Rodent models of endometriosis exist but each have limitations17. Many of these models require survival surgery to suture or implant endometrial tissue into the donor recipient wall or bowel, adding technical complexity, need for anesthesia, and confounding immune factors from the surgery itself18,19,20. In addition, many models require ovariectomy and estrogen supplementation; while increasing lesion yield, this adds time, expense, and additional survival surgery. Intraperitoneal (IP) injection models do not require anesthesia or survival surgery, and these models logically simulate retrograde menstruation better than suturing models21,22,23. Most IP models, however, are subject to more variability in lesion location due to the random dispersal of endometrial fragments following injection and therefore to more bias in lesion identification and measurement.
Here we present a murine model of endometriosis that integrates several features of existing endometriosis models into a novel, simplified, and efficient system that relies on microscopic quantification in lieu of subjective grading.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
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			<td>Supplies for injecting PMSG into donor mouse</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>1 mL Tuberculin syringe with 27G needle</td>
			<td>Fisher Scientific</td>
			<td>14-826-87</td>
			<td></td>
		</tr>
		<tr>
			<td>Pregnant mare serum gonadotropin</td>
			<td>Sigma-Aldrich</td>
			<td>9002-70-4</td>
			<td></td>
		</tr>
		<tr>
			<td>Supplies for necropsy of donor mouse and tissue processing</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>6&#8221; serrated forceps, curved tip</td>
			<td>Electron Microscopy Sciences</td>
			<td>72993-6C</td>
			<td></td>
		</tr>
		<tr>
			<td>70% ethanol solution</td>
			<td>Pharmco</td>
			<td>33000HPLCCS4L</td>
			<td>70% solution dilute ethyl acetate 200 proof</td>
		</tr>
		<tr>
			<td>Analytical balance</td>
			<td>Mettler Toledo</td>
			<td>ME54TE</td>
			<td></td>
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			<td>Carbon dioxide</td>
			<td>TriGas Supplier</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Dissecting tray</td>
			<td>Fisher Scientific</td>
			<td>S14000</td>
			<td></td>
		</tr>
		<tr>
			<td>No. 10 disposable scalpel</td>
			<td>Fisher Scientific</td>
			<td>NC9999403</td>
			<td></td>
		</tr>
		<tr>
			<td>Scissors, curved</td>
			<td>Electron Microscopy Sciences</td>
			<td>72941</td>
			<td></td>
		</tr>
		<tr>
			<td>Scissors, straight</td>
			<td>Electron Microscopy Sciences</td>
			<td>72940</td>
			<td></td>
		</tr>
		<tr>
			<td>Stereo microscope</td>
			<td>Leica Microsystems</td>
			<td>Leica SE 4</td>
			<td>For tissue dissection</td>
		</tr>
		<tr>
			<td>Sterile phosphate buffered saline (PBS)</td>
			<td>Institutional core facility supplies</td>
			<td></td>
			<td></td>
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			<td>Surgical instrument sterilization tray</td>
			<td>Electron Microscopy Sciences</td>
			<td>66112-02</td>
			<td></td>
		</tr>
		<tr>
			<td>Tissue culture dishes</td>
			<td>Fisher Scientific</td>
			<td>08-772E</td>
			<td></td>
		</tr>
		<tr>
			<td>Weighing dishes</td>
			<td>Fisher Scientific</td>
			<td>02-202-103</td>
			<td></td>
		</tr>
		<tr>
			<td>Supplies for injecting into recipient mouse</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
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			<td>1 cc syringe</td>
			<td>BD Biosciences</td>
			<td>301025</td>
			<td></td>
		</tr>
		<tr>
			<td>18 G needle</td>
			<td>Fisher Scientific</td>
			<td>148265d</td>
			<td></td>
		</tr>
		<tr>
			<td>200 uL pipette tip</td>
			<td>Fisher Scientific</td>
			<td>02-707-422</td>
			<td></td>
		</tr>
		<tr>
			<td>Double distilled water</td>
			<td>Institutional core facility supplies</td>
			<td></td>
			<td></td>
		</tr>
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			<td>Latex bulb</td>
			<td>Fisher Scientific</td>
			<td>03-448-21</td>
			<td></td>
		</tr>
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			<td>Micro cover glass slip</td>
			<td>VWR</td>
			<td>48366-067</td>
			<td></td>
		</tr>
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			<td>Microscope slide</td>
			<td>Fisher Scientific</td>
			<td>12-544-7</td>
			<td></td>
		</tr>
		<tr>
			<td>Standard light microscope</td>
			<td>Leica Microsystems</td>
			<td>DM IL</td>
			<td>For evaluating vaginal cytology smears</td>
		</tr>
		<tr>
			<td>Supplies for harvesting tissue from recipient mouse</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>10% Buffered formalin</td>
			<td>Fisher Scientific</td>
			<td>SF100-4</td>
			<td></td>
		</tr>
		<tr>
			<td>Biopsy foam pads</td>
			<td>Fisher Scientific</td>
			<td>22-038-222</td>
			<td></td>
		</tr>
		<tr>
			<td>Precision Digital Calipers</td>
			<td>Electron Microscopy Sciences</td>
			<td>62065-40</td>
			<td></td>
		</tr>
		<tr>
			<td>Processing/embedding cassettes</td>
			<td>Fisher Scientific</td>
			<td>22-272416</td>
			<td></td>
		</tr>
	</tbody>
</table>

a syngeneic murine model of endometriosis using naturally cycling mice

Endometriosis is a leading cause of pelvic pain and infertility. It is defined by the presence of endometrial tissue in extrauterine locations. The development of novel therapies and diagnostic tools for endometriosis has been limited due in part to challenges in studying the disease. Outside of primates, few mammals menstruate, and none develop spontaneous endometriosis. Rodent models are popular but require artificial induction of endometriosis, with many utilizing either immunocompromised mice or surgically induced disease. Recently, more attention has been given to models involving intraperitoneal injection. We present a murine model of endometriosis that integrates several features of existing endometriosis models into a novel, simplified system that relies on microscopic quantification in lieu of subjective grading. In this model, we perform hormonal stimulation of donor mice, intraperitoneal injection, systematic abdominal survey and tissue harvest, and histologic quantification that can be performed and verified at any time after necropsy. This model requires minimal resources and training; does not require expertise by lab technicians in murine survival surgery or in the identification of gross endometriotic lesions; can be used in immunocompromised, immunocompetent, and/or mutant mice; and reliably creates endometriotic lesions that are histologically consistent with human endometriotic disease.

For an initial proof of concept experiment, donor endometrium from RFP mice was injected into wildtype recipient mice. H&#38;E staining revealed histopathologic confirmation of classic architecture of endometriosis lesion (Figure 3A). Fluorescent microscopy confirmed that the observed lesion in question originated from the donor (Figure 3B).
The second experiment was performed using 10 wildtype C57BL/6J donors and 10 recipients. An ad...

Watch this Scientific Journal Video about A Syngeneic Murine Model of Endometriosis using Naturally Cycling Mice at JoVE.com

A Syngeneic Murine Model of Endometriosis using Naturally Cycling Mice

Many rodent models of endometriosis are limited by technical complexity, reproducibility, and/or need for immunocompromised animals or special reporter mice. We present a simplified system of lesion induction using any experimental mouse with an independently verifiable, objective scoring system and with no requirement for ovariectomy or survival surgery.

Endometriosis is a leading cause of pelvic pain and infertility. It is defined by the presence of endometrial tissue in extrauterine locations. The ...

Our mirroring model of endometriosis is a simplified and efficient system that integrates the best features of existing models. And perhaps most importantly, relies on microscopic quantification in lieu of subjective grading. Modeling endometriosis can be difficult because there can be many confounding factors and sources of bias.In our approach, endometriosis is induced without ovariectomy or survival surgery. And the endometrial lesions are objectively quantified. These Innovations provide a highly reliable and reproducible animal model of endometriosis that can be used to further endometriosis disease research.To facilitate ongoing estrous cycling, place urine soaked bedding from a male mouse cage into the recipient female mouse cage periodically throughout development, and again at 72 hours before endometrial tissue transplant. When the donor female mice are between 22 to 24 days old, use a one milliliter syringe equipped with a 25 to 27 gauge needle to subcutaneously inject two international units of pregnant mare serum gonadotropin in 200 microliters of sterile saline into the lower mouse abdomen. 38 to 42 hours after injection, use dissecting scissors to make a shallow transverse incision through the skin and subcutaneous tissue of the euthanized mouse at the midline and use blunt traction to open the skin on either side of the incision.Before removing the uterus, trim the adjacent connective tissue and transact each uterine horn just below its respective fallopian tubes, then transect the cervix to allow removal of the entire uterus and block. Inspect the uterus carefully, removing any additional peripheral fat or connective tissue and place the uterus in a droplet of cold PBS on a Petri dish for weighing. Transect each horn across the uterine fundus as close to the fundus as possible and place the dish under a dissecting microscope.Placing one blade of the dissecting scissors inside the lumen of the first horn, cut along the major axis of the tube keeping in mind, which side is this serosa and which side is the epithelium. Then use forceps to grasp and peel away the endometrial layer and mince the tissue into 10 to 12, one by one millimeter fragments. Alternatively, mince the tissue into one by one millimeter pieces without separating off the myometrium.Then place the tissues into 500 microliters of saline in a new Petri dish and harvest the endometrium from the second uterine horn as demonstrated. For peritoneal delivery of the tissue fragments into the recipient animal, use the blunt end of a one milliliter syringe to collect the tissue pieces. A total volume of one milliliter of tissue and saline should be collected.Attach an 18 gauge needle to the syringe and gently depress the plunger to load the fluid into the needle. A mock injection into the Petri dish can be performed to ensure that all of the tissue will pass through the needle tip. Either before or after the injection, use a bulb syringe to administer 10 microliters of saline to obtain a vaginal smear of the recipient animal for estrous cycle documentation.Holding the syringe at a 45 degree angle, intraperitoneally inject the fragments. If fragments remain after the injection, draw an additional 200 microliters of saline into the syringe to allow the rest of the pragmatists to be injected. Once you're assured of no bleeding or complications, place the mouse back in the home cage with a normal diet.Approximately 21 days after fragment injection, spray the recipient mouse abdomen was 70%ethanol, intent the skin to allow creation of a superficial subcutaneous incision to bluntly open the abdomen. Perform a complete survey of the abdominal wall and peritoneum, pancreas and mesenteric fat and para uterine connective fat and tissue for gross lesions. Harvest each region of tissue entirely and place the dissected tissue samples into an appropriate labeled cassette for formalin fixation and processing according to standard protocols.Then section the formalin blocks onto two slides per tissue area at two uniform depths. To score the endometriosis lesions, scan the tissue sections at a 40 times magnification and archive the slides. After scanning, use an appropriate digital slide reading software program to define and mark the longest distance between the edges of each endometriosis lesion.A continuous lesion is defined by glands surrounded by stroma. The line does not necessarily traverse only the endometriosis tissue, but the two end points must be connected by continuous stroma and or glands. Make a second line, 90 degrees across the first line as demonstrated.If multiple non-contiguous lesions are encountered, give each their own X and Y measurements. Calculate the final score for each slide as the summation of the areas of each lesion and use the larger of the scores from the two sections on each slide as the final score for that tissue region. Then total the scores from each region to give the final microscopic score for that animal.In this representative sample, histopathologic analysis after donor endometrium injection revealed a classic architecture of endometriosis lesion. Fluorescent microscopy of the tissue sample confirmed that the lesion originated from the donor. It is important to note that the macroscopic examination for lesions alone is not sufficient for the quantification of the endometriosis disease burden as the gross lesions observed in these representative samples were ultimately determined not to be endometriosis upon histological examination.Collection of all the tissue within the designated regions reduces bias by allowing for a systematic, objective approach to lesion quantification. Once this reliable and reproducible model has been achieved, researchers can use it to investigate a multitude of endometriosis pathways and therapies.

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Medicine

Mouse Model of Surgically-induced Endometriosis by Auto-transplantation of Uterine Tissue

Endometriosis is a chronic, painful disease whose etiology remains unknown. Furthermore, treatment of endometriosis can require laparoscopic removal of lesions, and/or chronic pharmaceutical management of pain and infertility symptoms. The cost associated with endometriosis has been estimated at 22 billion dollars per year in the United States1. To further our understanding of mechanisms underlying this enigmatic disease, animal models have been employed. Primates spontaneously develop endometriosis and therefore primate models most closely resemble the disease in women. Rodent models, however, are more cost effective and readily available2. The model that we describe here involves an autologous transfer of uterine tissue to the intestinal mesentery (Figure 1) and was first developed in the rat3 and later transferred to the mouse4. The goal of the autologous rodent model of surgically-induced endometriosis is to mimic the disease in women. We and others have previously shown that the altered gene expression pattern observed in endometriotic lesions from mice or rats mirrors that observed in women with the disease5,6. One advantage of performing the surgery in the mouse is that the abundance of transgenic mouse strains available can aid researchers in determining the role of specific components important in the establishment and growth of endometriosis. An alternative model in which excised human endometrial fragments are introduced to the peritoneum of immunocompromised mice is also widely used but is limited by the lack of a normal immune system which is thought to be important in endometriosis2,7. Importantly, the mouse model of surgically induced endometriosis is a versatile model that has been used to study how the immune system8, hormones9,10 and environmental factors11,12 affect endometriosis as well as the effects of endometriosis on fertility13 and pain14.

A description of the surgical induction of endometriosis in mice and rats by auto-transplantation of uterine tissue to the arterial cascade of the intestinal mesentery.

Endometriosis is a chronic, painful disease whose etiology remains unknown. Furthermore, treatment of endometriosis can require laparoscopic removal of ...

Murine Model of Wound Healing

Wound healing and repair are the most complex biological processes that occur in human life. After injury, multiple biological pathways become activated. Impaired wound healing, which occurs in diabetic patients for example, can lead to severe unfavorable outcomes such as amputation. There is, therefore, an increasing impetus to develop novel agents that promote wound repair. The testing of these has been limited to large animal models such as swine, which are often impractical. Mice represent the ideal preclinical model, as they are economical and amenable to genetic manipulation, which allows for mechanistic investigation. However, wound healing in a mouse is fundamentally different to that of humans as it primarily occurs via contraction. Our murine model overcomes this by incorporating a splint around the wound. By splinting the wound, the repair process is then dependent on epithelialization, cellular proliferation and angiogenesis, which closely mirror the biological processes of human wound healing. Whilst requiring consistency and care, this murine model does not involve complicated surgical techniques and allows for the robust testing of promising agents that may, for example, promote angiogenesis or inhibit inflammation. Furthermore, each mouse acts as its own control as two wounds are prepared, enabling the application of both the test compound and the vehicle control on the same animal. In conclusion, we demonstrate a practical, easy-to-learn, and robust model of wound healing, which is comparable to that of humans.

A murine model of cutaneous wound healing that can be used to assess therapeutic compounds in physiological and pathophysiological settings.

Wound healing and repair are the most complex biological processes that occur in human life. After injury, multiple biological pathways become activated. ...

Murine Cervical Heart Transplantation Model Using a Modified Cuff Technique

Mouse models are of special interest in research since a wide variety of monoclonal antibodies and commercially defined inbred and knockout strains are available to perform mechanistic in vivo studies. While heart transplantation models using a suture technique were first successfully developed in rats, the translation into an equally widespread used murine equivalent was never achieved due the technical complexity of the microsurgical procedure. In contrast, non-suture cuff techniques, also developed initially in rats, were successfully adapted for use in mice1-3. This technique for revascularization involves two major steps I) everting the recipient vessel over a polyethylene cuff; II) pulling the donor vessel over the formerly everted recipient vessel and holding it in place with a circumferential tie. This ensures a continuity of the endothelial layer, short operating time and very high patency rates4.
Using this technique for vascular anastomosis we performed more than 1,000 cervical heart transplants with an overall success rate of 95%. For arterial inflow the common carotid artery and the proximal aortic arch were anastomosed resulting in a retrograde perfusion of the transplanted heart. For venous drainage the pulmonary artery of the graft was anastomosed with the external jugular vein of the recipient5.
Herein, we provide additional details of this technique to supplement the video.

The murine cervical heart transplantation model is well suited for immunological as well as ischemia reperfusion injury studies. We modified the procedure using a non-suture cuff technique and performed more than 1,000 successful transplants with this approach.
Herein, we provide additional details of this technique to supplement the video.

Mouse models are of special interest in research since a wide variety of monoclonal antibodies and commercially defined inbred and knockout strains are ...

A Murine Model of Subarachnoid Hemorrhage

In this video publication a standardized mouse model of subarachnoid hemorrhage (SAH) is presented. Bleeding is induced by endovascular Circle of Willis perforation (CWp) and proven by intracranial pressure (ICP) monitoring. Thereby a homogenous blood distribution in subarachnoid spaces surrounding the arterial circulation and cerebellar fissures is achieved. Animal physiology is maintained by intubation, mechanical ventilation, and continuous on-line monitoring of various physiological and cardiovascular parameters: body temperature, systemic blood pressure, heart rate, and hemoglobin saturation. Thereby the cerebral perfusion pressure can be tightly monitored resulting in a less variable volume of extravasated blood. This allows a better standardization of endovascular filament perforation in mice and makes the whole model highly reproducible. Thus it is readily available for pharmacological and pathophysiological studies in wild type and genetically altered mice.

A standardized mouse model of subarachnoid hemorrhage by intraluminal Circle of Willis perforation is described. Vessel perforation and subarachnoid bleeding are monitored by intracranial pressure monitoring. In addition various vital parameters are recorded and controlled to maintain physiologic conditions.

In this video publication a standardized mouse model of subarachnoid  hemorrhage (SAH) is presented. Bleeding is induced by endovascular Circle of  Willis ...

A Preclinical Murine Model of Hepatic Metastases

Numerous murine models have been developed to study human cancers and advance the understanding of cancer treatment and development. Here, a preclinical, murine pancreatic tumor model of hepatic metastases via a hemispleen injection of syngeneic murine pancreatic tumor cells is described. This model mimics many of the clinical conditions in patients with metastatic disease to the liver. Mice consistently develop metastases in the liver allowing for investigation of the metastatic process, experimental therapy testing, and tumor immunology research.

A preclinical, murine model of hepatic metastases performed via a hemispleen injection technique.

Numerous murine models have been developed to study human cancers and advance the understanding of cancer treatment and development. Here, a preclinical, ...

A "Patient-Like" Orthotopic Syngeneic Mouse Model of Hepatocellular Carcinoma Metastasis

The majority of cancer-related deaths are caused by the metastasis of the cancer rather than the primary tumor itself. Yet, the underlying mechanisms of cancer metastasis are still unclear. Animal models are essential for elucidating the mechanisms and for evaluating novel strategies for the treatment of metastatic cancers. Here, an in-depth description of a &#8220;patient-like&#8221; orthotopic syngeneic mouse model for exploring the mechanisms of metastasis of solid organ tumors is provided. The survival surgical implantation of BNL 1ME A.7R.1 mouse hepatocellular carcinoma cells directly into the liver (the organ of origin) of the inbred wild-type immune competent laboratory mouse strain, BALB/c is described. The success and reproducibility of this methodology recommends it for widespread use in elucidating the biological mechanisms of solid organ cancer metastasis.

The metastatic spread of cancer is the major cause of cancer-related deaths. We provide an in-depth description of our survival surgery methodology for establishing a &#8220;patient-like&#8221; orthotopic syngeneic mouse model system for studying the mechanisms of metastasis in solid organ tumors.

The majority of cancer-related deaths are caused by the metastasis of the cancer rather than the primary tumor itself. Yet, the underlying mechanisms of ...

Injection of Syngeneic Murine Melanoma Cells to Determine Their Metastatic Potential in the Lungs

Approximately 90% of human cancer deaths are linked to metastasis. Despite the prevalence and relative harm of metastasis, therapeutics for treatment or prevention are lacking. We report a method for the establishment of pulmonary metastases in mice, useful for the study of this phenomenon. Tail vein injection of B57BL/6J mice with B16-BL6 is among the most used models for melanoma metastases. Some of the circulating tumor cells establish themselves in the lungs of the mouse, creating "experimental" metastatic foci. With this model it is possible to measure the relative effects of therapeutic agents on the development of cancer metastasis. The difference in enumerated lung foci between treated and untreated mice indicates the efficacy of metastases neutralization. However, prior to the investigation of a therapeutic agent, it is necessary to determine an optimal number of injected B16-BL6 cells for the quantitative analysis of metastatic foci. Injection of too many cells may result in an overabundance of metastatic foci, impairing proper quantification and overwhelming the effects of anti-cancer therapies, while injection of too few cells will hinder the comparison between treated and controls.

Metastasis plays a profound role in the virulence of cancer, accounting for an estimated 90% of deaths. We report a protocol for a metastatic melanoma model in mice that is useful for determining the efficacy of therapeutic agents against this clinical phenomenon.

Approximately 90% of human cancer deaths are linked to metastasis.  Despite the prevalence and relative harm of metastasis, therapeutics for treatment or ...

Murine Distal Colostomy, A Novel Model of Diversion Colitis in C57BL/6 Mice

Diversion colitis (DC) is a frequent clinical condition occurring in patients with bowel segments excluded from the fecal stream as a result of a diverting enterostomy. The etiology of this disease remains ill-defined but appears to differ from that of classical inflammatory bowel diseases such as Crohn's disease and ulcerative colitis. Research aimed to decipher the pathophysiological mechanisms leading to the development of this disease has been severely hampered by the lack of an appropriate murine model. This protocol generates a murine model of DC that facilitates the study of the immune system's role and its interaction with the microbiome in the development of DC. In this model using C57BL/6 animals, distal parts of the colon are excluded from the fecal stream by creating a distal colostomy, triggering the development of mild to moderate inflammation in the excluded bowel segments and reproducing the hallmark lesions of human DC with a moderate systemic inflammatory response. In contrast to the rat model, a large number of genetically-modified murine models on the C57BL/6 background are available. The combination of these animals with our model allows the potential roles of individual cytokines, chemokines, or receptors of bioactive molecules (e.g., interleukin (IL)-17; IL-10, chemokine CXCL13, chemokine receptors CXCR5 and CCR7, and the sphingosine-1-phosphate receptor 4) to be assessed in the pathogenesis of DC. The availability of congenic mouse strains on the C57BL/6 background largely facilitates transfer experiments to establish the roles of distinct cell types involved in the etiology of DC. Finally, the model offers the opportunity to assess the influences of local interventions (e.g., modification of the local microbiome or local anti-inflammatory therapy) on mucosal immunity in affected and non-affected bowel segments and the on systemic immune homeostasis.

Murine distal colostomy provides a murine model for human diversion colitis, a predominantly lymphocytic colitis in colon segment excluded from the fecal stream.

Diversion colitis (DC) is a frequent clinical condition occurring in patients with bowel segments excluded from the fecal stream as a result of a ...

Isometric Contractility Measurement of the Mouse Mesenteric Artery Using Wire Myography

The wire myograph technique is used to assess the contractility of vascular smooth muscles in response to depolarization, GPCR agonists/inhibitors and drugs. It is widely used in many studies on the physiological functions of vascular smooth muscle, the pathogenesis of vascular diseases such as hypertension, and the development of smooth muscle relaxant drugs. The mouse is a widely used model animal with a large pool of disease models and genetically modified strains. We introduced this method to measure the isometric contraction of mouse mesenteric artery in detail. A 1.4-mm segment of mouse mesenteric resistance artery was isolated and mounted on a myograph chamber by passing two steel wires through its lumen. After equilibration and normalization steps, the vessel segment was potentiated by a high-K+ solution twice prior to the contraction assay. As an example of the application of this method in drug development, we measured the relaxant effect of a novel natural substance, neoliensinine, isolated from a Chinese herb, embryos of the lotus seed (Nelumbo nucifera Gaertn.) on mouse mesenteric arteries. The vessel segments mounted on the myograph chamber were stimulated with a high-K+ solution. When the force tension reached a stable sustained phase, cumulative doses of neoliensinine were added to the chamber. We found that neoliensinine had a dose-dependent relaxant effect on smooth muscle contraction, thus suggesting that it bears potential activity against hypertension. In addition, as the vessel segment can survive at least 4 hours after mounting and maintain contractility induced by the high-K+ solution for many times, we suggest that the wire myograph system may be used for the time-consuming process of drug screening.

The wire myograph technique is used to investigate vascular smooth muscle functions and screen new drugs. We report a detailed protocol for measuring the isometric contractility of the mouse mesenteric artery and for screening new relaxants of vascular smooth muscle.

The wire myograph technique is used to assess the contractility of vascular smooth muscles in response to depolarization, GPCR agonists/inhibitors and ...

Murine Cervical Aortic Transplantation Model using a Modified Non-Suture Cuff Technique

With the introduction of powerful immunosuppressive protocols, distinct advances are possible in the prevention and therapy of acute rejection episodes. However, only minor improvement in the long-term results of transplanted solid organs could be observed over the past decades. In this context, chronic allograft vasculopathy (CAV) still represents the leading cause of late organ failure in cardiac, renal and pulmonary transplantation.
Thus far, the underlying pathogenesis of CAV development remains unclear, explaining why effective treatment strategies are presently missing and emphasizing a need for relevant experimental models in order to study the underlying pathophysiology leading to CAV formation. The following protocol describes a murine heterotopic cervical aortic transplantation model using a modified non-suture cuff technique. In this technique, a segment of the thoracic aorta is interpositioned in the right common carotid artery. With the use of the non-suture cuff technique, an easy to learn and reproducible model can be established, minimizing the possible heterogeneity of sutured vascular micro anastomoses.

Here, we present a protocol of heterotopic aortic transplantation in mice using the non-suture cuff technique in a cervical murine model. This model can be used to study the underlying pathology of chronic allograft vasculopathy (CAV) and can help evaluate new therapeutic agents in order to prevent its formation.

With the introduction of powerful immunosuppressive protocols, distinct advances are possible in the prevention and therapy of acute rejection episodes. ...