Name: puncture-induced iris neovascularization as a mouse model of rubeosis iridis
Uploaded: 2018-03-08T15:00:00
Description: Watch this Scientific Journal Video about Puncture-Induced Iris Neovascularization as a Mouse Model of Rubeosis Iridis at JoVE.com

The authors thank Linnea Tankred and Diana Rydholm for animal husbandry.

BALB/c mouse pups of either sex were used in accordance with the statement for the Use of Animals in Ophthalmologic and Vision Research, and the protocols were approved by Stockholm&#39;s Committee for Ethical Animal Research. Mice were housed in litters, together with the nursing mother, with a 12 h day/night cycle, free access to food and water, and monitored daily.
NOTE: For the surgical procedure, mice were kept under anesthesia with volatile isoflurane. Ocular ointments are discouraged du...

<ol>
	<li>Morrison, J. C., Van Buskirk, E. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Anterior+collateral+circulation+in+the+primate+eye.">Anterior collateral circulation in the primate eye.</a> Ophthalmology. 90 (6), 707-715 (1983).</li><li>Dreyfuss, J. L., Giordano, R. J., Regatieri, C. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ocular+Angiogenesis.">Ocular Angiogenesis.</a> J Ophthalmol. 2015, 892043 (2015).</li><li>Breuss, J. M., Uhrin, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=VEGF-initiated+angiogenesis+and+the+uPA/uPAR+system.">VEGF-initiated angiogenesis and the uPA/uPAR system.</a> Cell Adh Migr. 6 (6), 535-615 (2012).</li><li>Rodrigues, G. 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=Neovascular+glaucoma:+a+review.">Neovascular glaucoma: a review.</a> Int J Retina Vitreous. 2, 26 (2016).</li><li>Stahl, 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=The+mouse+retina+as+an+angiogenesis+model.">The mouse retina as an angiogenesis model.</a> Invest Ophth Vis Sci. 51 (6), 2813-2826 (2010).</li><li>DiPietro, L. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Angiogenesis+and+wound+repair:+when+enough+is+enough.">Angiogenesis and wound repair: when enough is enough.</a> J Leukocy Biol. 100 (5), 979-984 (2016).</li><li>Eming, S., Brachvogel, B., Odorisio, T., Koch, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regulation+of+angiogenesis:+Wound+healing+as+a+model.">Regulation of angiogenesis: Wound healing as a model.</a> Prog Histochem Cytoc. 42 (3), 115-170 (2007).</li><li>Beaujean, O., Locri, F., Aronsson, M., Kvanta, A., Andr&#233;, H. <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+in+vivo+model+of+puncture-induced+iris+neovascularization.">A novel in vivo model of puncture-induced iris neovascularization.</a> PloS One. 12 (6), e0180235 (2017).</li><li>Zudaire, E., Gambardella, L., Kurcz, C., Vermeren, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Computational+Tool+for+Quantitative+Analysis+of+Vascular+Networks.">A Computational Tool for Quantitative Analysis of Vascular Networks.</a> PloS One. 6 (11), (2011).</li><li>Dorrell, M., Uusitalo-Jarvinen, H., Aguilar, E., Friedlander, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ocular+neovascularization:+basic+mechanisms+and+therapeutic+advances.">Ocular neovascularization: basic mechanisms and therapeutic advances.</a> Surv Ophthalmol. 52 Suppl 1, S3-S19 (2007).</li><li>Kvanta, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ocular+angiogenesis:+the+role+of+growth+factors.">Ocular angiogenesis: the role of growth factors.</a> Acta Ophthalmol. 84 (3), 282-288 (2006).</li><li>Salman, A. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intrasilicone+Bevacizumab+Injection+for+Iris+Neovascularization+after+Vitrectomy+for+Proliferative+Diabetic+Retinopathy.">Intrasilicone Bevacizumab Injection for Iris Neovascularization after Vitrectomy for Proliferative Diabetic Retinopathy.</a> Ophthalmic Res. 49 (1), 20-24 (2013).</li><li>Jeong, Y. C., Hwang, Y. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Etiology+and+Features+of+Eyes+with+Rubeosis+Iridis+among+Korean+Patients:+A+Population-Based+Single+Center+Study.">Etiology and Features of Eyes with Rubeosis Iridis among Korean Patients: A Population-Based Single Center Study.</a> PloS One. 11 (8), e0160662 (2016).</li><li>Speier, S., Nyqvist, D., K&#246;hler, M., Caicedo, A., Leibiger, I. B., Berggren, P. -. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Noninvasive+high-resolution+in+vivo+imaging+of+cell+biology+in+the+anterior+chamber+of+the+mouse+eye.">Noninvasive high-resolution in vivo imaging of cell biology in the anterior chamber of the mouse eye.</a> Nat Protoc. 3 (8), 1278-1286 (2008).</li><li>Stefansson, E., Landers, M. B., Wolbarsht, M. L., Klintworth, G. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neovascularization+of+the+Iris+-+an+Experimental-Model+in+Cats.">Neovascularization of the Iris - an Experimental-Model in Cats.</a> Invest Ophth Vis Sci. 25 (3), 361-364 (1984).</li><li>Nork, T. M., Tso, M., Duvall, J., Hayreh, S. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cellular+Mechanisms+of+Iris+Neovascularization+Secondary+to+Retinal+Vein+Occlusion.">Cellular Mechanisms of Iris Neovascularization Secondary to Retinal Vein Occlusion.</a> Arch Ophthalmol-Chic. 107 (4), 581-586 (1989).</li><li>Hjelmeland, L. M., Stewart, M. W., Li, J. W., Toth, C. A., Burns, M. S., Landers, M. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+Experimental-Model+of+Ectropion+Uveae+and+Iris+Neovascularization+in+the+Cat.">An Experimental-Model of Ectropion Uveae and Iris Neovascularization in the Cat.</a> Invest Ophth Vis Sci. 33 (5), 1796-1803 (1992).</li><li>Tolentino, M. J., Miller, J. W., Gragoudas, E. S., Chatzistefanou, K., Ferrara, N., Adamis, A. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vascular+endothelial+growth+factor+is+sufficient+to+produce+iris+neovascularization+and+neovascular+glaucoma+in+a+nonhuman+primate.">Vascular endothelial growth factor is sufficient to produce iris neovascularization and neovascular glaucoma in a nonhuman primate.</a> Arch Ophthalmol-Chic. 114 (8), 964-970 (1996).</li><li>Paula, J. 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=Rabbit+Rubeosis+Iridis+Induced+by+Intravitreal+Latex-derived+Angiogenic+Fraction.">Rabbit Rubeosis Iridis Induced by Intravitreal Latex-derived Angiogenic Fraction.</a> Curr Eye Res. 36 (9), 857-859 (2011).</li><li>Takei, A., Ekstr&#246;m, 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=Gene+Transfer+of+Prolyl+Hydroxylase+Domain+2+Inhibits+Hypoxia-inducible+Angiogenesis+in+a+Model+of+Choroidal+Neovascularization.">Gene Transfer of Prolyl Hydroxylase Domain 2 Inhibits Hypoxia-inducible Angiogenesis in a Model of Choroidal Neovascularization.</a> Sci Rep. 7, 42546 (2017).</li></ol>

In the present protocol, a novel method for induction of iris vascular response by uveal puncture is presented. The puncture triggers wound healing mechanisms and promotes vascular responses in the iris10,11. This is in agreement with ocular pathologies, such as PDR and NVG, where exacerbated angiogenic responses from the retina in the posterior segment of the eye culminate in the clinical condition of rubeosis iridis, an increased vascularization of the iris<sup...

The iris, together with the ciliary body and the choroid, comprises the uvea, which is the most vascularized tissue of the eye. Iris vasculature is essential in maintaining homeostasis in the anterior chamber of the eye. As a result of abundant anastomotic connections between arteries and veins, iris blood vessels provide nutrients and supply of oxygen not only to the iris itself, but to the entire anterior segment of the eye1.
The formation of new blood vessels, or angiogenesis from pre-existing ones, is fundamental in physiological processes, such as development and wound healing2. Angiogenesis is finely regulated by a multitude of canonical factors, such as vascular endothelial growth factor (VEGF) and plasminogen activator inhibitor (PAI), as well as multiple inflammatory factors, and an imbalance of these factors can lead to pathologic angiogenesis3.
In the eye, neovascularization is the cause of sight-threatening diseases, such as proliferative diabetic retinopathy (PDR) and neovascular glaucoma (NVG). In these ocular diseases, the focal neovascularization is commonly located in retinal tissues, yet the imbalance in inflammatory and angiogenic factors in both the posterior and anterior ocular chambers of the eye has been associated with rubeosis iridis, the clinical term for iris pathological neoangiogenesis4. These pathologies indicate the capability of the adult iris to undergo angiogenesis. In mice, ocular vasculature is immature after birth and continues maturation postpartum. This peculiarity of development is exploited in the mouse model of oxygen-induced retinopathy, a model that closely mimics the clinical condition of retinopathy of prematurity5. In addition, angiogenesis and inflammation play a pivotal role in wound healing mechanisms6, and wound healing itself has been associated with angiogenesis models7.
In this study, we describe a model of puncture-induced iris neovascularization. Uveal punctures are performed near the outer limit of the limbus, which induce iris neovascularization by triggering the wound healing system. Due to the transparency of the cornea, iris vasculature can be analyzed easily in vivo by noninvasive methods. Punctured eyes present an increase of vascular bed in the iris, which has been associated with an increase of plasminogen activating and inflammatory markers8. The presented model has great potential as a new tool to study angiogenesis and screening angiogenic compounds, and allows direct in vivo visualization of the angiogenic processes.

<table>
	<tbody>
		<tr>
			<td>Bonn eye scissors</td>
			<td>Bausch &#38; Lomb</td>
			<td>23060</td>
			<td></td>
		</tr>
		<tr>
			<td>Clayman-Vannas curved scissors</td>
			<td>Bausch &#38; Lomb</td>
			<td>E3383 C</td>
			<td></td>
		</tr>
		<tr>
			<td>Clayman-Vannas straight scissors</td>
			<td>Bausch &#38; Lomb</td>
			<td>E3383 S</td>
			<td></td>
		</tr>
		<tr>
			<td>Objective adapter for camera</td>
			<td>Handcrafted</td>
			<td>N/A</td>
			<td>Or any system that allows adapting a camera to the microscope</td>
		</tr>
		<tr>
			<td>Heating Pad 100-110 watts</td>
			<td>Non Applicable</td>
			<td>N/A</td>
			<td>Available in pet/veterinarian stores</td>
		</tr>
		<tr>
			<td>Hypodermic 30g beveled needle</td>
			<td>KDM GmBH germany</td>
			<td>911914</td>
			<td></td>
		</tr>
		<tr>
			<td>Iphone 4S</td>
			<td>Apple</td>
			<td>Non Applicable</td>
			<td>Or other high resolution image acquistion device</td>
		</tr>
		<tr>
			<td>Isoflurane</td>
			<td>Baxter</td>
			<td>KDG 9623</td>
			<td></td>
		</tr>
		<tr>
			<td>McPherson tying forceps</td>
			<td>Bausch &#38; Lomb</td>
			<td>E1815 S</td>
			<td></td>
		</tr>
		<tr>
			<td>Micro tying forceps</td>
			<td>Bausch &#38; Lomb</td>
			<td>63140</td>
			<td></td>
		</tr>
		<tr>
			<td>Minims tetracaine hydrochloride</td>
			<td>Bausch &#38; Lomb</td>
			<td>N/A</td>
			<td>1 % (w/v) Eye Drops</td>
		</tr>
		<tr>
			<td>Neutral-buffered formalin</td>
			<td>Bioreagens</td>
			<td>0018-40</td>
			<td></td>
		</tr>
		<tr>
			<td>Normal saline solution</td>
			<td>Fresenius Kabi</td>
			<td>210352</td>
			<td>0.9 % (w/v) NaCl in injectable water</td>
		</tr>
		<tr>
			<td>Phosphate-buffered saline</td>
			<td>ThermoFisher Scientific</td>
			<td>10010023</td>
			<td>Balanced and buffered PBS pH 7.4</td>
		</tr>
		<tr>
			<td>Petri dish 10 cm</td>
			<td>Starstedt</td>
			<td>83.3902</td>
			<td></td>
		</tr>
		<tr>
			<td>Petri dish 3 cm</td>
			<td>Starstedt</td>
			<td>83.3900</td>
			<td></td>
		</tr>
		<tr>
			<td>Safe Seal Tube 2.0 mL</td>
			<td>Starstedt</td>
			<td>72.685.200</td>
			<td>Or any eppendorf style tubes</td>
		</tr>
		<tr>
			<td>TC plate 96-well</td>
			<td>Starstedt</td>
			<td>83.3924</td>
			<td></td>
		</tr>
		<tr>
			<td>Transfer pipette 3.5 mL</td>
			<td>Starstedt</td>
			<td>86.1171</td>
			<td>Or any other Pasteur pipette style</td>
		</tr>
		<tr>
			<td>Univentor 400 anesthesia unit</td>
			<td>Univentor Limited</td>
			<td>N/A</td>
			<td>Or equivalent flow regulator with induction chamber and mask for volatile anesthesia</td>
		</tr>
		<tr>
			<td>Wild M650 surgical microscope</td>
			<td>Wild Heerbrugg</td>
			<td>N/A</td>
			<td>Or other surgical or magnifying stereoscope</td>
		</tr>
	</tbody>
</table>

puncture-induced iris neovascularization as a mouse model of rubeosis iridis

We describe a model of puncture-induced iris neovascularization as a general model for noninvasive evaluation of angiogenesis. The model is also relevant for targeting neovascular glaucoma, a sight-threatening complication of diabetic retinopathy. This method is based on the induction of iris vascular response by a series of self-sealing uveal punctures on BALB/c mice and takes advantage of the postpartum maturation of mouse ocular vasculature. Mouse pups undergo uveal punctures from postnatal day 12.5, when the pups naturally open their eyes, until postnatal day 24.5. Due to the transparency of the cornea, iris vasculature can be analyzed easily through time by noninvasive in vivo methods. Furthermore, the semitransparent iris of BALB/c mice can be flatmounted for detailed immunohistologic analysis with minimal non-specific background staining. In this model, angiogenesis is mainly driven by the inflammatory and plasminogen activating systems. The puncture-induced model is the first to induce iris neovascularization in small rodents, and has the advantage of allowing direct noninvasive in vivo analysis of the angiogenic process. Moreover, the model can be combined with angiogenic modulating substances, which highlights its potential in the study of angiogenesis with an in vivo perspective.

Albino BALB/c mouse pups at P12.5 were subjected to uveal punctures, repeated every fourth day (experimental day 0, 4, 8, 12), until P24.5. At P27.5, mice were euthanized and irises carefully dissected (experimental day 15). Pictures of mouse eyes were taken with a camera attached to a surgical stereoscope before every puncture series in each experimental day to assess noninvasive evaluation of the iris vascular response. Uveal punctures induce a vascular response from the iris by trigger...

Watch this Scientific Journal Video about Puncture-Induced Iris Neovascularization as a Mouse Model of Rubeosis Iridis at JoVE.com

Puncture-Induced Iris Neovascularization as a Mouse Model of Rubeosis Iridis

Iris neovascularization, a common complication of ischemic retinal disease, may lead to sight-threatening neovascular glaucoma. Here, we describe a murine protocol for inducing experimental iris neovascularization that may be used for noninvasive evaluation of angiogenesis-modulating substances.

We describe a model of puncture-induced iris neovascularization as a general model for noninvasive evaluation of angiogenesis. The model is also relevant ...

The overall goal of this procedure is to induce iris vasculature, which allows direct in-vivo visualization of angiogenic processes. This method can help answer key questions in the ophthalmology field, particularly in neovascular diseases. The main advantage of this technique is that it utilizes albino mice to allow for directing vivo visualization of the blood vessels.Through this method can give insight into ocular neovascular disease. It can also be applied as a general model of angiogenesis, such as testing for new angiogenic therapies. Visual demonstration of this method is critical, as the iris dissection is challenging because of the small size of the mouse eye.With practice, however, it can be mastered. After anesthetizing a P12.5 mouse and preparing it for the procedure, put it in the lateral recumbancy position under a stereoscope and confirm the mask is well positioned. The eye should fill the field of view.Clear focus of the eye is imperative. Next, using small tying forceps in the non-dominant hand, carefully protrude the eye by applying downward pressure to the eyelids, dorsal and ventral to the eye. Keeping a firm hold on the eyelid helps.Before proceeding, photo document the vasculature at 40X. Next, use the stereoscope to locate the corneal limbus. The limbus of albino BALB/c mice can be easily identified as the circular vascular plexus posterior to the cornea.Now, in the dominant hand, hold a 30 gauge beveled needle and use it to perform a small uveal puncture near the posterior limbal limit of the uvea between the ciliary body and the ora serrata. Make the puncture using only the tip of the needle and no more than half the bevel. Avoid rupturing the lens.The puncture should be self-sealing but still allow for intra-ocular injection of study substances through the wound. Next, perform a second uveal puncture in the opposite site of the eye. Optimize the punctures to be at the most dorsal and most ventral positions.Repeat the uveal punctures at the same two positions every four days until P24.5. And prior to repeating the puncture, always check for traumatic cataract. After enucleating the eye and fixing it as described in the text protocol, remove the fixative solution and rinse the eye three times with fresh PBS.Then, place the eye on a smooth, dry surface with the anterior chamber upwards. Next, insert a beveled 30 gauge needle posterior to the limbus to make an entry point. Then, secure the anterior segment with small tying forceps and use Clayman-Vannas straight scissors to cut around the limbus while rotating the eye.Using partial cuts can make the process easier. When completed, the posterior segment of the eye should release. Next, position the anterior segment downward to expose the lens.Remove the lens carefully by grabbing it with small forceps and pulling upwards. Now, position the anterior segment with the cornea facing down and with the cut perpendicular to the field of view. Then, gently grab the tissue posterior to the ciliary body using small tying forceps in the non-dominant hand.Clayman-Vannas straight scissors to trim just anterior to the ciliary body with the goal of removing the trabecular meshwork and isolating the iris. The iris should then move within the cornea. Next, use small tying forceps to grip the cornea and carefully transfer the anterior eye cup to a 96-well plate containing 200 microliters of PBS.Maintain the grip on the cornea and continue dissecting the iris by flushing the tissue with PBS. If needed, a 30 gauge needle can be used to help displace the iris. Now, remove the cornea using the small tying forceps.The isolated iris can then be stored in PBS at four degrees Celsius temporarily until it is experimented upon. Albino BALB/c mice at P12.5 were subjected to uveal punctures repeated every fourth day until P24.5, as described. Due to the transparency of the cornea and the melanin deficiency of BALB/c mice, iris vasculature is readily visible in P16.5 pups and intensifies throughout the duration of the protocol.At P27.5, mice were euthanized and their irises were carefully dissected. The punctures induced a vascular response from the iris by triggering the wound healing system. Immunohistochemistry was performed against PECAM1.The resulting stain showed an increase in overall vasculature in irises of punctured eyes compared to controls. After watching this video, you should have a good understanding of how to induce iris angiogenesis and successfully isolate the mouse iris. Following this procedure, other methods like QBCR can be performed in order to answer additional molecular and cellular questions such as testing the efficacy of pro-angiogenic or anti-angiogenic substances.After its development, this technique has paved the way for researchers to explore neovascular diseases by in-vivo, non-invasive methods using small rodents as a model.

puncture-induced-iris-neovascularization-as-mouse-model-rubeosis

Research

JoVE Journal

Medicine

A Mouse Model of in Utero Transplantation

The transplantation of stem cells and viruses in utero has tremendous potential for treating congenital disorders in the human fetus. For example, in utero transplantation (IUT) of hematopoietic stem cells has been used to successfully treat patients with severe combined immunodeficiency.1,2 In several other conditions, however, IUT has been attempted without success.3 Given these mixed results, the availability of an efficient non-human model to study the biological sequelae of stem cell transplantation and gene therapy is critical to advance this field. We and others have used the mouse model of IUT to study factors affecting successful engraftment of in utero transplanted hematopoietic stem cells in both wild-type mice4-7 and those with genetic diseases.8,9 The fetal environment also offers considerable advantages for the success of in utero gene therapy. For example, the delivery of adenoviral10, adeno-associated viral10, retroviral11, and lentiviral vectors12,13 into the fetus has resulted in the transduction of multiple organs distant from the site of injection with long-term gene expression. in utero gene therapy may therefore be considered as a possible treatment strategy for single gene disorders such as muscular dystrophy or cystic fibrosis. Another potential advantage of IUT is the ability to induce immune tolerance to a specific antigen. As seen in mice with hemophilia, the introduction of Factor IX early in development results in tolerance to this protein.14 
In addition to its use in investigating potential human therapies, the mouse model of IUT can be a powerful tool to study basic questions in developmental and stem cell biology. For example, one can deliver various small molecules to induce or inhibit specific gene expression at defined gestational stages and manipulate developmental pathways. The impact of these alterations can be assessed at various timepoints after the initial transplantation. Furthermore, one can transplant pluripotent or lineage specific progenitor cells into the fetal environment to study stem cell differentiation in a non-irradiated and unperturbed host environment.
The mouse model of IUT has already provided numerous insights within the fields of immunology, and developmental and stem cell biology. In this video-based protocol, we describe a step-by-step approach to performing IUT in mouse fetuses and outline the critical steps and potential pitfalls of this technique.

A Mouse Model of in Utero Transplantation

The mouse model of in utero transplantation is a versatile tool that can be used to study the potential clinical applications of stem cell transplantation and gene therapy in the fetus. In this protocol, we present a general approach to performing this technique

The transplantation of stem cells and viruses in utero has tremendous potential for treating congenital disorders in the human fetus.  For example, in ...

Mouse Complete Stasis Model of Inferior Vena Cava Thrombosis

Venous thromboembolism (VTE) includes both deep vein thrombosis (DVT) and pulmonary embolism (PE). In the United States (U.S.), the high morbidity and mortality rates make VTE a serious health concern 1-2. After heart disease and stroke, VTE is the third most common vascular disease 3. In the U.S. alone, there is an estimated 900,000 people affected each year, with 300,000 deaths occurring annually 3. A reliable in vivo animal model to study the mechanisms of this disease is necessary.
The advantages of using the mouse complete stasis model of inferior vena cava thrombosis are several. The mouse model allows for the administration of very small volumes of limited availability test agents, reducing costs dramatically. Most promising is the potential for mice with gene knockouts that allow specific inflammatory and coagulation factor functions to be delineated. Current molecular assays allow for the quantitation of vein wall, thrombus, whole blood, and plasma for assays. However, a major concern involving this model is the operative size constraints and the friability of the vessels. Also, due to the small IVC sample weight (mean 0.005 grams) it is necessary to increase animal numbers for accurate statistical analysis for tissue, thrombus, and blood assays such as real-time polymerase chain reaction (RT-PCR), western blot, enzyme-linked immunosorbent (ELISA), zymography, vein wall and thrombus cellular analysis, and whole blood and plasma assays 4-8.
The major disadvantage with the stasis model is that the lack of blood flow inhibits the maximal effect of administered systemic therapeutic agents on the thrombus and vein wall.

The mouse complete stasis model of inferior vena cava thrombosis yields quantifiable amounts of vein wall tissue and thrombus. It has proven useful for evaluating interactions between the vein wall and the occlusive thrombus and in assessing the progression from acute to chronic inflammation.

Venous thromboembolism (VTE) includes both deep vein thrombosis (DVT) and pulmonary embolism (PE).  In the United States (U.S.), the high morbidity and ...

Rapid Point-of-Care Assay of Enoxaparin Anticoagulant Efficacy in Whole Blood

There is the need for a clinical assay to determine the extent to which a patient's blood is effectively anticoagulated by the low-molecular-weight-heparin (LMWH), enoxaparin. There are also urgent clinical situations where it would be important if this could be determined rapidly. The present assay is designed to accomplish this. We only assayed human blood samples that were spiked with known concentrations of enoxaparin. The essential feature of the present assay is the quantification of the efficacy of enoxaparin in a patient's blood sample by degrading it to complete inactivity with heparinase. Two blood samples were drawn into Vacutainer tubes (Becton-Dickenson; Franklin Lakes, NJ) that were spiked with enoxaparin; one sample was digested with heparinase for 5 min at 37 &deg;C, the other sample represented the patient's baseline anticoagulated status. The percent shortening of clotting time in the heparinase-treated sample, as compared to the baseline state, yielded the anticoagulant contribution of enoxaparin. We used the portable, battery operated Hemochron 801 apparatus for measurements of clotting times (International Technidyne Corp., Edison, NJ). The apparatus has 2 thermostatically controlled (37 &deg;C) assay tube wells. We conducted the assays in two types of assay cartridges that are available from the manufacturer of the instrument. One cartridge was modified to increase its sensitivity. We removed the kaolin from the FTK-ACT cartridge by extensive rinsing with distilled water, leaving only the glass surface of the tube, and perhaps the detection magnet, as activators. We called this our minimally activated assay (MAA). The use of a minimally activated assay has been studied by us and others. 2-4 The second cartridge that was studied was an activated partial thromboplastin time (aPTT) assay (A104). This was used as supplied from the manufacturer. The thermostated wells of the instrument were used for both the heparinase digestion and coagulation assays. The assay can be completed within 10 min. The MAA assay showed robust changes in clotting time after heparinase digestion of enoxaparin over a typical clinical concentration range. At 0.2 anti-Xa I.U. of enoxaparin per ml of blood sample, heparinase digestion caused an average decrease of 9.8% (20.4 sec) in clotting time; at 1.0 I.U. per ml of enoxaparin there was a 41.4% decrease (148.8 sec). This report only presents the experimental application of the assay; its value in a clinical setting must still be established.

Demonstration of a rapid quantitative assay of the inhibition of blood coagulation by the low-molecular-weight-heparin, enoxaparin. The contribution of enoxaparin is assessed by removing its influence through digestion with heparinase. A fuller description of the assay is detailed in our published paper.1 The assay still requires clinical confirmation.

There is the need for a clinical assay to determine the extent to which a patient's blood is effectively anticoagulated by the ...

Intraductal Injection of LPS as a Mouse Model of Mastitis: Signaling Visualized via an NF-&kappa;B Reporter Transgenic

Animal models of human disease are necessary in order to rigorously study stages of disease progression and associated mechanisms, and ultimately, as pre-clinical models to test interventions. In these methods, we describe a technique in which lipopolysaccharide (LPS) is injected into the lactating mouse mammary gland via the nipple, effectively modeling mastitis, or inflammation, of the gland. This simulated infection results in increased nuclear factor kappa B (NF-&kappa;B) signaling, as visualized through bioluminescent imaging of an NF-&kappa;B luciferase reporter mouse1.
Our ultimate goal in developing these methods was to study the inflammation associated with mastitis in the lactating gland, which often includes redness, swelling, and immune cell infiltration2,3. Therefore, we were keenly aware that incision or any type of wounding of the skin, the nipple, or the gland in order to introduce the LPS could not be utilized in our methods since the approach would likely confound the read-out of inflammation. We also desired a straight-forward method that did not require specially made hand-drawn pipettes or the use of micromanipulators to hold these specialized tools in place. Thus, we determined to use a commercially available insulin syringe and to inject the agent into the mammary duct of an intact nipple. This method was successful and allowed us to study the inflammation associated with LPS injection without any additional effects overlaid by the process of injection. In addition, this method also utilized an NF-&kappa;B luciferase reporter transgenic mouse and bioluminescent imaging technology to visually and quantitatively show increased NF-&kappa;B signaling within the LPS-injected gland4.
These methods are of interest to researchers of many disciplines who wish to model disease within the lactating mammary gland, as ultimately, the technique described here could be utilized for injection of a number of substances, and is not limited to only LPS.

Intraductal Injection of LPS as a Mouse Model of Mastitis: Signaling Visualized via an NF-&amp;kappa;B Reporter Transgenic

Described here is a technique in which lipopolysaccharide is injected into the lactating mouse mammary gland via the nipple to simulate mastitis, a condition commonly caused by bacterial infection. Lipopolysaccharide injection results in increased nuclear factor kappa B (NF-&kappa;B) signaling, visualized through bioluminescent imaging of an NF-&kappa;B luciferase reporter mouse.

Animal models of human disease are necessary in order to rigorously study stages of disease progression and associated mechanisms, and ultimately, as ...

The In ovo CAM-assay as a Xenograft Model for Sarcoma

Sarcoma is a very rare disease that is heterogeneous in nature, all hampering the development of new therapies. Sarcoma patients are ideal candidates for personalized medicine after stratification, explaining the current interest in developing a reproducible and low-cost xenotransplant model for this disease. The chick chorioallantoic membrane is a natural immunodeficient host capable of sustaining grafted tissues and cells without species-specific restrictions. In addition, it is easily accessed, manipulated and imaged using optical and fluorescence stereomicroscopy. Histology further allows detailed analysis of heterotypic cellular interactions.
This protocol describes in detail the in ovo grafting of the chorioallantoic membrane with fresh sarcoma-derived tumor tissues, their single cell suspensions, and permanent and transient fluorescently labeled established sarcoma cell lines (Saos-2 and SW1353). The chick survival rates are up to 75%. The model is used to study graft- (viability, Ki67 proliferation index, necrosis, infiltration) and host (fibroblast infiltration, vascular ingrowth) behavior. For localized grafting of single cell suspensions, ECM gel provides significant advantages over inert containment materials. The Ki67 proliferation index is related to the distance of the cells from the surface of the CAM and the duration of application on the CAM, the latter determining a time frame for the addition of therapeutic products.

The In ovo CAM-assay as a Xenograft Model for Sarcoma

The in ovo chorioallantoic membrane (CAM) is grafted with fresh sarcoma-derived tumor tissues, their single cell suspensions, and permanent and transient fluorescently labeled established sarcoma cell lines. The model is used to study graft- (viability, Ki67 proliferation index, necrosis, infiltration) and host (fibroblast infiltration, vascular ingrowth) behavior.

Sarcoma is a very rare disease that is heterogeneous in nature, all hampering the development of new therapies. Sarcoma patients are ideal candidates for ...

An Alkali-burn Injury Model of Corneal Neovascularization in the Mouse

Under normal conditions, the cornea is avascular, and this transparency is essential for maintaining good visual acuity. Neovascularization (NV) of the cornea, which can be caused by trauma, keratoplasty or infectious disease, breaks down the so called &lsquo;angiogenic privilege' of the cornea and forms the basis of multiple visual pathologies that may even lead to blindness. Although there are several treatment options available, the fundamental medical need presented by corneal neovascular pathologies remains unmet. In order to develop safe, effective, and targeted therapies, a reliable model of corneal NV and pharmacological intervention is required. Here, we describe an alkali-burn injury corneal neovascularization model in the mouse. This protocol provides a method for the application of a controlled alkali-burn injury to the cornea, administration of a pharmacological compound of interest, and visualization of the result. This method could prove instrumental for studying the mechanisms and opportunities for intervention in corneal NV and other neovascular disorders.

Neovascularization (NV) of the cornea can complicate multiple visual pathologies. Utilizing a controlled, alkali-burn injury model, a quantifiable level of corneal NV can be produced for mechanistic study of corneal NV and evaluation of potential therapies for neovascular disorders.

Under normal conditions, the cornea is avascular, and this transparency is essential for maintaining good visual acuity. Neovascularization (NV) of the ...

Excitotoxic Stimulation of Brain Microslices as an In vitro Model of Stroke

Examining molecular mechanisms involved in neuropathological conditions, such as ischemic stroke, can be difficult when using whole animal systems. As such, primary or &#39;neuronal-like&#39; cell culture systems are commonly utilized. While&#160;these systems are relatively easy to work with, and are useful model systems in which various functional outcomes (such as cell death) can be readily quantified, the examined outcomes and pathways in cultured immature neurons (such as excitotoxicity-mediated cell death pathways) are not necessarily the same as those observed in mature brain, or in intact tissue. Therefore, there is the need to develop models in which cellular mechanisms in mature neural tissue can be examined. We have developed an in vitro technique that can be used to investigate a variety of molecular pathways in intact nervous tissue. The technique described herein utilizes rat cortical tissue, but this technique can be adapted to use tissue from a variety of species (such as mouse, rabbit, guinea pig, and chicken) or brain regions (for example, hippocampus, striatum, etc.). Additionally, a variety of stimulations/treatments can be used (for example, excitotoxic, administration of inhibitors, etc.). In conclusion, the brain slice model described herein can be used to examine a variety of molecular mechanisms involved in excitotoxicity-mediated brain injury.

Excitotoxic Stimulation of Brain Microslices as an In vitro Model of Stroke

We have developed a brain slice model which can be used to examine molecular mechanisms involved in excitotoxicity-mediated brain injury.&#160;This technique generates viable mature brain tissue and reduces animal numbers required for experimentation, whilst keeping the neuronal circuitry, cellular interactions, and postsynaptic compartments partly intact.

Examining molecular mechanisms involved in neuropathological conditions, such as ischemic stroke, can be difficult when using whole animal systems. As ...

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

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

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

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

A Mouse Model for Laser-induced Choroidal Neovascularization

The mouse laser-induced choroidal neovascularization (CNV) model has been a crucial mainstay model for neovascular age-related macular degeneration (AMD) research. By administering targeted laser injury to the RPE and Bruch&#8217;s membrane, the procedure induces angiogenesis, modeling the hallmark pathology observed in neovascular AMD. 
First developed in non-human primates, the laser-induced CNV model has come to be implemented into many other species, the most recent of which being the mouse. Mouse experiments are advantageously more cost-effective, experiments can be executed on a much faster timeline, and they allow the use of various transgenic models. The miniature size of the mouse eye, however, poses a particular challenge when performing the procedure. Manipulation of the eye to visualize the retina requires practice of fine dexterity skills as well as simultaneous hand-eye-foot coordination to operate the laser. However, once mastered, the model can be applied to study many aspects of neovascular AMD such as molecular mechanisms, the effect of genetic manipulations, and drug treatment effects. 
The laser-induced CNV model, though useful, is not a perfect model of the disease. The wild-type mouse eye is otherwise healthy, and the chorio-retinal environment does not mimic the pathologic changes in human AMD. Furthermore, injury-induced angiogenesis does not reflect the same pathways as angiogenesis occurring in an age-related and chronic disease state as in AMD.
Despite its shortcomings, the laser-induced CNV model is one of the best methods currently available to study the debilitating pathology of neovascular AMD. Its implementation has led to a deeper understanding of the pathogenesis of AMD, as well as contributing to the development of many of the AMD therapies currently available.

Here, we present the mouse laser-induced choroidal neovascularization (CNV) protocol, an experimental model that re-creates the vascular hallmarks of neovascular age-related macular degeneration (AMD). Once mastered, it can reliably and effectively induce CNV as a model system to test various experimental measures.

The mouse laser-induced choroidal neovascularization (CNV) model has been a crucial mainstay model for neovascular age-related macular degeneration (AMD) ...

Tachycardia-Induced Cardiomyopathy As a Chronic Heart Failure Model in Swine

A stable and reliable model of chronic heart failure is required for many experiments to understand hemodynamics or to test effects of new treatment methods. Here, we present such a model by tachycardia-induced cardiomyopathy, which can be produced by rapid cardiac pacing in swine.
A single pacing lead is introduced transvenously into fully anaesthetized healthy swine, to the apex of the right ventricle, and fixated. Its other end is then tunneled dorsally to the paravertebral region. There, it is connected to an in-house modified heart pacemaker unit that is then implanted in a subcutaneous pocket. 
After 4 - 8 weeks of rapid ventricular pacing at rates of 200 - 240 beats/min, physical examination revealed signs of severe heart failure - tachypnea, spontaneous sinus tachycardia, and fatigue. Echocardiography and X-ray showed dilation of all heart chambers, effusions, and severe systolic dysfunction. These findings correspond well to decompensated dilated cardiomyopathy and are also preserved after the cessation of pacing.
This model of tachycardia-induced cardiomyopathy can be used for studying the pathophysiology of progressive chronic heart failure, especially hemodynamic changes caused by new treatment modalities like mechanical circulatory supports. This methodology is easy to perform and the results are robust and reproducible.

Here, we present a protocol to produce tachycardia-induced cardiomyopathy in swine. This model represents a potent way to study the hemodynamics of progressive chronic heart failure and the effects of applied treatment.

A stable and reliable model of chronic heart failure is required for many experiments to understand hemodynamics or to test effects of new treatment ...