Name: is my mouse pregnant? high-frequency ultrasound assessment
Uploaded: 2021-03-18T14:00:00
Description: Watch this Scientific Journal Video about Is My Mouse Pregnant? High-Frequency Ultrasound Assessment at JoVE.com

All the steps in this protocol follow the Guide for the Care and Use of Laboratory Animals published by the National Institutes of Health and have been approved by the Institutional Animal Care and Use Committee of New York University Grossman School of Medicine.
1. Mating of mice for timed pregnancies
<ol>
	<li>Pair the appropriate female mouse (usually a heterozygote) in a cage with the appropriate male mouse (usually a heterozygote) for overnight mating.</li>
	<li>Separate the mice the ne...

<ol>
	<li>Bogue, 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=Mouse+Phenome+Database:+an+integrative+database+and+analysis+suite+for+curated+empirical+phenotype+data+from+laboratory+mice.">Mouse Phenome Database: an integrative database and analysis suite for curated empirical phenotype data from laboratory mice.</a> Nucleic Acids Research. 46, 843-850 (2018).</li><li>Ito, R., Takahashi, T., Ito, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Humanized+mouse+models:+Application+to+human+diseases.">Humanized mouse models: Application to human diseases.</a> Journal of Cellular Physiology. 233 (5), 3723-3728 (2018).</li><li>Law, M., Shaw, D. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mouse+Genome+Informatics+(MGI)+is+the+international+resource+for+information+on+the+laboratory+mouse.">Mouse Genome Informatics (MGI) is the international resource for information on the laboratory mouse.</a> Methods in Molecular Biology. 1757, 141-161 (2018).</li><li>Rydell-T&#246;rm&#228;nen, K., Johnson, J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+applicability+of+mouse+models+to+the+study+of+human+disease.">The applicability of mouse models to the study of human disease.</a> Methods in Molecular Biology. 1940, 3-22 (2019).</li><li>Hinton, R. B., Yutzey, K. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Heart+valve+structure+and+function+in+development+and+disease.">Heart valve structure and function in development and disease.</a> Annual Reviews of Physiology. 73, 29-46 (2011).</li><li>Dickinson, M. 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=High-throughput+discovery+of+novel+developmental+phenotypes.">High-throughput discovery of novel developmental phenotypes.</a> Nature. 537 (7621), 508-514 (2016).</li><li>Tam, P. P. 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=Formation+of+the+embryonic+head+in+the+mouse:+attributes+of+a+gene+regulatory+network.">Formation of the embryonic head in the mouse: attributes of a gene regulatory network.</a> Current Topics in Developmental Biology. 117, 497-521 (2016).</li><li>Palis, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hematopoietic+stem+cell-independent+hematopoiesis:+emergence+of+erythroid,+megakaryocyte,+and+myeloid+potential+in+the+mammalian+embryo.">Hematopoietic stem cell-independent hematopoiesis: emergence of erythroid, megakaryocyte, and myeloid potential in the mammalian embryo.</a> FEBS Letters. 590 (22), 3965-3974 (2016).</li><li>Behringer, R., Gertsenstein, M., Nagy, K. V., Nagy, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Selecting+female+mice+in+estrus+and+checking+plugs.">Selecting female mice in estrus and checking plugs.</a> Cold Spring Harbor Protocols. 2016 (8), (2016).</li><li>Heyne, G. W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+simple+and+reliable+method+for+early+pregnancy+detection+in+inbred+mice.">A simple and reliable method for early pregnancy detection in inbred mice.</a> Journal of the American Association for Laboratory Animal Science. 54 (4), 368-371 (2015).</li><li>Finlay, J. B., Liu, X., Ermel, R. W., Adamson, T. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Maternal+weight+gain+as+a+predictor+of+litter+size+in+Swiss+Webster,+C57BL/6J,+and+BALB/cJ+mice.">Maternal weight gain as a predictor of litter size in Swiss Webster, C57BL/6J, and BALB/cJ mice.</a> Journal of the American Association for Laboratory Animal Science. 54 (6), 694-699 (2015).</li><li>Zhou, Y. Q., 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=Applications+for+multifrequency+ultrasound+biomicroscopy+in+mice+from+implantation+to+adulthood.">Applications for multifrequency ultrasound biomicroscopy in mice from implantation to adulthood.</a> Physiological Genomics. 10 (2), 113-126 (2002).</li><li>Ji, R. P., Phoon, C. K. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Noninvasive+localization+of+nuclear+factor+of+activated+T+cells+c1-/-+mouse+embryos+by+ultrasound+biomicroscopy-Doppler+allows+genotype-phenotype+correlation.">Noninvasive localization of nuclear factor of activated T cells c1-/- mouse embryos by ultrasound biomicroscopy-Doppler allows genotype-phenotype correlation.</a> Journal of the American Society of Echocardiography. 18 (12), 1415-1421 (2005).</li><li>Kulandavelu, 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=Embryonic+and+neonatal+phenotyping+of+genetically+engineered+mice.">Embryonic and neonatal phenotyping of genetically engineered mice.</a> ILAR Journal. 47 (2), 103-117 (2006).</li><li>Mu, J., Slevin, J. C., Qu, D., McCormick, S., Adamson, S. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vivo+quantification+of+embryonic+and+placental+growth+during+gestation+in+mice+using+micro-ultrasound.">In vivo quantification of embryonic and placental growth during gestation in mice using micro-ultrasound.</a> Reproductive Biology and Endocrinology. 6, 34 (2008).</li><li>Phoon, C. K. L., Turnbull, D. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cardiovascular+imaging+in+mice.">Cardiovascular imaging in mice.</a> Current Protocols in Mouse Biology. 6 (1), 15-38 (2016).</li><li>Phoon, C. K. L., Turnbull, D. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ultrasound+biomicroscopy-Doppler+in+mouse+cardiovascular+development.">Ultrasound biomicroscopy-Doppler in mouse cardiovascular development.</a> Physiological Genomics. 14 (1), 3-15 (2003).</li><li>Peavey, M. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+novel+use+of+three-dimensional+high-frequency+ultrasonography+for+early+pregnancy+characterization+in+the+mouse.">A novel use of three-dimensional high-frequency ultrasonography for early pregnancy characterization in the mouse.</a> Journal of Visualized Experiments. (128), e56207 (2017).</li><li>Greco, 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=High+frequency+ultrasound+for+in+vivo+pregnancy+diagnosis+and+staging+of+placental+and+fetal+development+in+mice.">High frequency ultrasound for in vivo pregnancy diagnosis and staging of placental and fetal development in mice.</a> PLoS One. 8 (10), 77205 (2013).</li><li>Flores, L. E., Hildebrandt, T. B., K&#252;hl, A. A., Drews, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Early+detection+and+staging+of+spontaneous+embryo+resorption+by+ultrasound+biomicroscopy+in+murine+pregnancy.">Early detection and staging of spontaneous embryo resorption by ultrasound biomicroscopy in murine pregnancy.</a> Reproductive Biology and Endocrinology. 12, 38 (2014).</li><li>Norton, W. 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=Refinements+for+embryo+implantation+surgery+in+the+mouse:+comparison+of+injectable+and+inhalant+anesthesias+-+tribromoethanol,+ketamine+and+isoflurane+-+on+pregnancy+and+pup+survival.">Refinements for embryo implantation surgery in the mouse: comparison of injectable and inhalant anesthesias - tribromoethanol, ketamine and isoflurane - on pregnancy and pup survival.</a> Laboratory Animal. 50 (5), 335-343 (2016).</li><li>Thaete, L. G., Levin, S. I., Dudley, A. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Impact+of+anaesthetics+and+analgesics+on+fetal+growth+in+the+mouse.">Impact of anaesthetics and analgesics on fetal growth in the mouse.</a> Laboratory Animal. 47 (3), 175-183 (2013).</li><li>Phoon, C. K. 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=Tafazzin+knockdown+in+mice+leads+to+a+developmental+cardiomyopathy+with+early+diastolic+dysfunction+preceding+myocardial+noncompaction.">Tafazzin knockdown in mice leads to a developmental cardiomyopathy with early diastolic dysfunction preceding myocardial noncompaction.</a> Journal of the American Heart Association. 1 (2), (2012).</li></ol>

The most important first step in the imaging is to identify the vagina and then to determine the bifurcation of the uterine horn to the left and right. By following each uterine horn, the imager is less likely to mis-identify loops of the bowel as the uterus. Moreover, understanding the variations in the appearance of the bowel (with/without fecal matter) is important to distinguish these from the uterus; occasionally, fecal &#8220;balls&#8221; in bowel loops may mimic a gravid (pregnant) uterus. Although other authors h...

The mouse is the preferred mammalian model for many human diseases and biological processes1,2,3,4. Research in developmental biology often requires staged-pregnant mice to determine evolving processes at various timepoints5,6,7,8. Moreover, optimal and effective breeding of model mice requires an assessment of timed pregnancies, particularly when investigators are studying the effects of a gene mutation on development. Typically, investigators mate heterozygous mice overnight, look for a vaginal plug early the next morning, and hope that a pregnancy ensues9. Determining intrauterine loss typically starts with checking a newborn litter for Mendelian ratios of genotypes, then working backwards by sacrificing pregnant mice at various gestational stages, and recovering the embryos. Investigators may determine weight gain as a metric of a positive pregnancy10,11; however, especially with genetically-engineered mice, the litters may be very small and subsequently resorbed when there is intrauterine loss due to which the weight gain may not be obvious (particularly early in pregnancy, ~E6.5&#8211;8.5). A mouse may appear falsely pregnant due, for example, to a benign abdominal tumor. In essence, one works &#8220;blind&#8221;.
High-resolution ultrasound biomicroscopy allows for direct visualization of the gravid uterus and developing mouse embryos12,13,14,15,16. Although we had initially developed methods to assess embryonic mouse cardiovascular physiology16,17, we recognized the utility of this imaging modality to streamline our mouse breeding. Specifically, we no longer had to wait to &#8220;see&#8221; if a mouse were pregnant, based on either the obvious weight gain or delivery of a litter; we could determine the gravid state and re-mate mice quickly if the dam was not pregnant. Moreover, intrauterine losses could also be easily imaged, and a timeline of loss could be determined without sacrificing the mouse (see Figure 1 for a schematic). Time, valuable model mice, and funds can thus be saved.

<table>
	<tbody>
		<tr>
			<td>Depilatory cream</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Ethanol, 70%</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Fur clippers</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Gauze or KimWipes</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Isoflurane</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Medical oxygen (optional)</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Medical tape</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Mouse imaging system (including anesthesia set-up and imaging platform)</td>
			<td>Fujifilm Visual Sonics</td>
			<td>Various</td>
			<td>Any system with 40 MHz center-frequency ultrasound transducer probe</td>
		</tr>
		<tr>
			<td>Razor blade (not a safety razor)</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Scale (to weigh mouse)</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Ultrasound gel</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

is my mouse pregnant? high-frequency ultrasound assessment

The mouse is the mammalian animal model of choice for many human diseases and biological processes. Developmental biology often requires staged-pregnant mice to determine evolving processes at various timepoints. Moreover, optimal and efficient breeding of model mice requires an assessment of timed pregnancies. Most commonly, mice are mated overnight, and the presence of a vaginal plug is determined; however, the positive predictive value of this technique is suboptimal, and one needs to wait to know if the mouse is truly pregnant. High-resolution ultrasound biomicroscopy is an effective and efficient tool for imaging: 1) Whether a mouse is pregnant; 2) What gestational stage the mouse has reached; and 3) Whether there are intrauterine losses. In addition to the embryos and fetuses, the investigator must also recognize common artifacts in the abdominal cavity so as not to mistake these for a gravid uterus. This article provides a protocol for imaging along with illustrative examples.

This protocol will allow an investigator to determine confidently whether a mouse is pregnant, including during the early stages and to determine whether there are obvious prenatal embryonic or fetal losses without needing to sacrifice the pregnant dam. This protocol is especially useful when breeding genetically engineered mice; typically, heterozygous x heterozygous crosses to yield homozygous offspring leads to failure of proper development, which causes prenatal lethality. Figure 1 depic...

Watch this Scientific Journal Video about Is My Mouse Pregnant? High-Frequency Ultrasound Assessment at JoVE.com

Is My Mouse Pregnant? High-Frequency Ultrasound Assessment

High-resolution ultrasound can help streamline experiments requiring timed-pregnant mice by determining the state of pregnancy, gestational age, and pregnancy losses. Presented here is a protocol to illustrate methods to assess mouse pregnancies as well as potential pitfalls (image artifacts) that may mimic pregnancy.

The mouse is the mammalian animal model of choice for many human diseases and biological processes. Developmental biology often requires staged-pregnant ...

High resolution ultrasound can help streamline experiments requiring timed pregnant mice by determining the state of pregnancy, gestational age, and pregnancy losses. This protocol demonstrates how to assess mouse pregnancies and identify potential image artifacts that may mimic pregnancy. To begin, identify the bladder on the screen.Scanning caudally from the bladder, identify the vagina. When the ultrasound transducer is positioned midline and low on the abdomen, the bladder and vagina are visible. Then scanning slowly and smoothly in a cranial direction, identify the bifurcation of the vagina into the left and right uterine horns.Survey the left and right uterine horns. Up to mid-gestation, the mouse embryos will be positioned along the right and left peripheries. As they grow, the more distal portions of the uterus and their corresponding embryos will turn outwards and dorsally.This protocol is especially useful when breeding genetically engineered mice. Typically, heterozygous with heterozygous crosses to yield homozygous offspring lead to failure of proper development, causing prenatal lethality. Mouse embryos at various stages of development are shown here.Early stage mouse embryos, dead embryos, or resorbed embryos may resemble other organs in the abdomen or feces in the intestines, while intestinal loops may mimic the non-gravid uterus. Some investigators prefer to use a stage mounted transducer, such as shown in this image, but we prefer the handheld method of scanning, since this allows for fast and efficient imaging throughout the abdomen.

Research

JoVE Journal

Developmental Biology

Contrast Imaging in Mouse Embryos Using High-frequency Ultrasound

Ultrasound contrast-enhanced imaging can convey essential quantitative information regarding tissue vascularity and perfusion and, in targeted ...

Assessment of Endothelial Cell Migration After Exposure to Toxic Chemicals

Exposure to chemical substances (including alkylating chemical warfare agents like sulfur and nitrogen mustards) cause a plethora of clinical symptoms ...

Assessment of Maternal Vascular Remodeling During Pregnancy in the Mouse Uterus

The placenta mediates the exchange of factors such as gases and nutrients between mother and fetus and has specific demands for supply of blood from the ...

A Novel Use of Three-dimensional High-frequency Ultrasonography for Early Pregnancy Characterization in the Mouse

High-frequency ultrasonography (HFUS) is a common method to non-invasively monitor the real-time development of the human fetus in utero. The mouse is ...

Fetal Mouse Cardiovascular Imaging Using a High-frequency Ultrasound (30/45MHZ) System

Fetal Mouse Cardiovascular Imaging Using a High-frequency Ultrasound 30/45MHZ System

Congenital heart defects (CHDs) are the most common cause of childhood morbidity and early mortality. Prenatal detection&#160;of the underlying molecular ...

High Frequency Ultrasound for the Analysis of Fetal and Placental Development In Vivo

High Frequency Ultrasound for the Analysis of Fetal and Placental Development In Vivo

Ultrasound imaging is a widespread method used to detect organ anomalies and tumors in human and animal tissues. The method is non-invasive, harmless, and ...

Fluorimetric Techniques for the Assessment of Sperm Membranes

Standard spermiograms describing sperm quality are mostly based on the physiological and visual parameters, such as ejaculate volume and concentration, ...

Assessment of Ultrastructural Neuroplasticity Parameters After In Utero Transduction of the Developing Mouse Brain and Spinal Cord

The present study combines in utero transduction with transmission electron microscopy (TEM) aiming at a precise morphometrical analysis of ...

Assessment of Oxidative Damage in the Primary Mouse Ocular Surface Cells/Stem Cells in Response to Ultraviolet-C (UV-C) Damage

Assessment of Oxidative Damage in the Primary Mouse Ocular Surface Cells/Stem Cells in Response to Ultraviolet-C UV-C Damage

The ocular surface is subjected to regular wear and tear due to various environmental factors. Exposure to UV-C radiation constitutes an occupational ...

Human Egg Maturity Assessment and Its Clinical Application

The optimal timing of intracytoplasmic sperm injection (ICSI) is of a serious concern for fertility programs because untimely sperm entry diminishes the ...