Supported by NIH 1P01HL089407-01A1 (Lawrence, PI), Animal Core A,NIH 1 K01 HL080962-01A2 (Myers, PI).

1. Mouse Anesthesia Procedures
<ol>
 <li>Animals are removed from their cage and placed in an anesthetic pre-operative induction chamber for gas induction at 2% isoflurane and 100% oxygen at a flow rate of 0.5 liters per minute (vaporizer controlled).</li>
 <li>Mice are sedated in the anesthetic induction chamber, removed from chamber and the ventral abdomen is shaved with electric clippers, or maintained within the chamber if a hair depilatory is used (1 min).</li>
 <li>While still under sedation, they are weighed, the eyes are lubricated with sterile opthalmic ointment and, then placed in dorsal recumbancy on a warm water circulating heating device under general anesthesia with a nose cone using isoflurane and oxygen. At this point the oxygen rate is reduced to 0.2 liters per minute.</li>
 <li>The abdomen is sprayed with chlorhexidine solution (chlorhexidine diacetate is rapidly bacterialcidal and persistent) and wiped with sterile gauze three times or until the surgical site is clean.</li>
</ol>
2. Mouse Micro-surgical and Recovery Procedures
<ol>
 <li>A ventral midline incision (2 cm) is made with iris scissors through the skin and abdominal wall exposing the abdomen. A sterile saline soaked 2x2 in gauze is used to reflect the intestines to the animal's left side. A mouse restrainer is put in place allowing visualization of the inferior vena cava (IVC).</li>
 <li>At this point, the isoflurane is reduced to a maintenance level of 2% and the oxygen rate remains at 0.2 liters per minute for the remainder of the surgical procedure.</li>
 <li>Blunt dissection is facilitated using a sterile applicator swab and extra delicate iris half curved tissue forceps. Care must be taken in handling mouse tissues for they are extremely fragile.</li>
 <li>All IVC side branches, from the renal veins to the iliac bifurcation, are ligated with 7-0 non-reactive prolene sutures. Back branches remained patent.</li>
 <li>In the electrolytic IVC model (EIM), a 25G stainless-steel needle, attached to a silver coated copper wire (KY-30-1-GRN, Electrospec, Dover, NJ) is inserted into the exposed caudal IVC, (Figure 1) and positioned against the anterior wall (anode).</li>
 <li>Another wire is implanted subcutaneously completing the circuit (cathode).</li>
 <li>A current of 250 &mu;Amps over 15 minutes was applied using a Grass S48 square wave stimulator and a constant current unit (Grass Technologies, An Astro-Med, Inc.,West Warwick, RI). The direct current results in the formation of toxic products of electrolysis that erode the endothelial surface of the IVC promoting a thrombogenic environment and subsequent thrombus formation.</li>
 <li>After 15 minutes, the needle is removed and a cotton swab is held gently in contact with the area to prevent bleeding</li>
 <li>In sham animals, the needle is placed into the IVC and then removed, without application of the current.</li>
 <li>The laparotomy site is closed in a two-layer fashion. Our laboratory uses 5-0 vicryl, a synthetic suture, in a continuous pattern to close the abdominal wall. Adhesive skin glue is used to close the skin. There are no external sutures for removal.</li>
 <li>Mice are then recovered in an individual mouse cage, closely
observed post-operatively (45 minutes to 2 hours) under a heating lamp
(min distance 24 inches away from cage), then returned to their
original housing units. Pain medication and anti-inflammatory agents
can be used if it does not interfere
with study objective. Scientific justification to withhold pain
medications, veterinary, and ICUCA approval are needed. Our laboratory
has found that Buprenorphine,0.05-0.1 mg/kg SQ is an excellent pre-
and post-operative analgesic for mice. In addition, Lidocaine at
4mg/kg (0.4 ml/kg of a 1% solution) can be infused in the incision
site when systemic analgesics may confound experimental results.</li>
 <li>We typically do not experience post-operative adverse effects due
to DVT. However, adverse post- operative effects can include
spontaneous anesthetic death, surgical blood loss, and partial paresis
due to nerve trauma. Animals that are slow to recover can be fed
nutria gel or have moist chow placed on the floor of the cage to
facilitate the animal's recovery. Animals with sever post- operative
complications should be humanely euthanized.</li>
<li>At the assigned time point, euthanasia is performed humanely in
accordance with the recommendations set forth by the American
Veterinary Medical Association Guidelines on Euthanasia for rodents.</li>
</ol>
3. Representative Results
The EIM is a model that forms thrombus in the presence of continuous blood flow. The following figures show parameters investigated in this novel model.
 <img src="/files/ftp_upload/2737/2737fig1.jpg" alt="Figure 1" /> 
 Figure 1 definesthe anatomical area in where a 25G stainless-steel needle, attached to a silver coated copper wire (KY-30-1-GRN, Electrospec, Dover, NJ) is inserted. Note that a lymphatic node is almost present and helps as a landmark to find the caudal IVC.
 <img src="/files/ftp_upload/2737/2737fig2.jpg" alt="Figure 2" /> 
 Figure 2: Thrombus weight 2 days after EIM in different strains. As expected, thrombus weight was lower in PAI-1 KO mice and larger in hypercoagulable Delta CT mice (^CT).
 <img src="/files/ftp_upload/2737/2737fig3.jpg" alt="Figure 3" /> 
 Figure 3: Soluble P-selectin, a maker for deep vein thrombosis, was measured in different strains. The lowest levels were found in PAI-1 KO mice whereas the highest levels were found in hypercoagulable delta CT mice.
 <img src="/files/ftp_upload/2737/2737fig4.jpg" alt="Figure 4" /> 
 Figure 4 Correlation between thrombus weight and soluble P-selectin was found in different strains. Of note, in the group that generated the shorter thrombus size, the soluble P-selectin detected was the lowest (PAI-1 KO mice). In the group that generated the largest thrombus size, the soluble P-selectin detected was the highest (hypercoagulable delta CT).
 <img src="/files/ftp_upload/2737/2737fig5.jpg" alt="Figure 5" /> 
 Figure 5: In order to demonstrate presence of blood flow, ultrasound was performed in mice undergoing EIM. Figure 5 shows the ultrasound performed in a mouse 2 days after EIM. Then the specimen was harvest. Note the that the thrombus shape suggest thrombus formation in presence of flow

<ol>
	<li>Diaz, J. A., Hawley, A. E., Alvarado, C. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Thrombogenesis+with+continuous+blood+flow+in+the+inferior+vena+cava.+A+novel+mouse+model.">Thrombogenesis with continuous blood flow in the inferior vena cava. A novel mouse model.</a> Thromb Haemost. 104, 366-375 (2010).</li><li>Eitzman, D. T., Westrick, R. J., Nabel, E. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Plasminogen+activator+inhibitor-1+and+vitronectin+promote+vascular+thrombosis+in+mice.">Plasminogen activator inhibitor-1 and vitronectin promote vascular thrombosis in mice.</a> Blood. 95, 577-580 (2000).</li><li>Myers, D., Farris, D., Hawley, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Selectins+influence+thrombosis+in+a+mouse+model+of+experimental+deep+venous+thrombosis.">Selectins influence thrombosis in a mouse model of experimental deep venous thrombosis.</a> J Surg Res. 108, 212-221 (2002).</li><li>Myers, D. D., Hawley, A. E., Farris, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=P-selectin+and+leukocyte+microparticles+are+associated+with+venous+thrombogenesis.">P-selectin and leukocyte microparticles are associated with venous thrombogenesis.</a> J Vasc Surg. 38, 1075-1089 (2003).</li><li>Pierangeli, S. S., Barker, J. H., Stikovac, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+human+IgG+antiphospholipid+antibodies+on+an+in+vivo+thrombosis+model+in+mice.">Effect of human IgG antiphospholipid antibodies on an in vivo thrombosis model in mice.</a> Thromb Haemost. 71, 670-674 (1994).</li><li>Pierangeli, S. S., Liu, X. W., Barker, J. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Induction+of+thrombosis+in+a+mouse+model+by+IgG,+IgM+and+IgA+immunoglobulins+from+patients+with+the+antiphospholipid+syndrome.">Induction of thrombosis in a mouse model by IgG, IgM and IgA immunoglobulins from patients with the antiphospholipid syndrome.</a> Thromb Haemost. 74, 1361-1367 (1995).</li></ol>

No conflicts of interest declared.

The mouse is an excellent research tool for in vivo experiments. Thus, the development of mouse models that closely mimic diseases or pathological conditions are necessary. Several venous thrombosis mouse models have been used to study DVT including: photochemical (2), stasis (3-4) and mechanical trauma (5-6). However, none of these models use an internal endothelial stimulus to generate thrombus in the presence of continuous blood flow. The EIM, using electrolytic stimulus within the IVC, promotes venous thrombogenesis by endothelial activation in the presence of blood flow (1). It is technically simple, easily reproducible and has a high survival rate (99%). Despite the fact that an electrical current is used to create the electrolysis, heat is not generated (1). The EIM model closely simulates clinical DVT, and therefore serves as a valuable tool for studying the intrinsic mechanisms of thrombus formation and resolution. The EIM model is also useful for the advancement of new therapeutic approaches against thrombosis disease.

<table border="1">
 <tbody>
 <tr>
 <th>Name of the reagent</th>
 <th>Company</th>
 <th>Catalogue number</th>
 <th>Comments (optional)</th>
 </tr>
 <tr>
 <td>DMEM</td>
 <td>Invitrogen</td>
 <td>ABCD1234</td>
 <td>&nbsp;</td>
 </tr>
 </tbody>
</table>

electrolytic inferior vena cava model (eim) of venous thrombosis

Animal models serve a vital role in deep venous thrombosis (DVT) research in order to study thrombus formation, thrombus resolution and to test potential therapeutic compounds (1). New compounds to be utilized in the treatment and prevention of DVT are currently being developed. The delivery of potential therapeutic antagonist compounds to an affected thrombosed vein has been problematic. In the context of therapeutic applications, a model that uses partial stasis and consistently generates thrombi within a major vein has been recently established. The Electrolytic Inferior vena cava Model (EIM) is mouse model of DVT that permits thrombus formation in the presence of continuous blood flow. This model allows therapeutic agents to be in contact with the thrombus in a dynamic fashion, and is more sensitive than other models of DVT (1). In addition, this thrombosis model closely simulates clinical situations of thrombus formation and is ideal to study venous endothelial cell activation, leukocyte migration, venous thrombogenesis, and to test therapeutic applications (1). The EIM model is technically simple, easily reproducible, creates consistent thrombi sizes and allows for a large sample (i.e. thrombus and vein wall) which is required for analytical purposes.

Watch this Scientific Journal Video about Electrolytic Inferior Vena Cava Model EIM of Venous Thrombosis at JoVE.com

Electrolytic Inferior Vena Cava Model EIM of Venous Thrombosis

The electrolytic induction of endothelial activation to the internal surface of the Inferior Vena Cava results in venous type thrombus formation due to endothelial activation and partial blood stasis, two components of Virchow's triad.

Electrolytic Inferior Vena Cava Model (EIM) of Venous Thrombosis

Animal models serve a vital role in deep venous thrombosis (DVT) research in order to study thrombus formation, thrombus resolution and to test potential ...

electrolytic-inferior-vena-cava-model-eim-of-venous-thrombosis

Research

JoVE Journal

Medicine

17.0K Views.  University of Michigan. The electrolytic induction of endothelial activation to the internal surface of the Inferior Vena Cava results in venous type thrombus formation due to endothelial activation and partial blood stasis, two components of Virchow's triad.

Video: Electrolytic Inferior Vena Cava Model EIM of Venous Thrombosis

Microsurgical Venous Pouch Arterial-Bifurcation Aneurysms in the Rabbit Model: Technical Aspects

For ruptured human cerebral aneurysms endovascular embolization has become an equivalent alternative to aneurysm clipping.1 However, large clinical trials have shown disappointing long-term results with unacceptable high rates of aneurysm recanalization and delayed aneurysm rupture.2 To overcome these problems, animal experimental studies are crucial for the development of better endovascular devices.3-5
Several animal models in rats, rabbits, canines and swine are available.6-8 Comparisons of the different animal models showed the superiority of the rabbit model with regard to hemodynamics and comparability of the coagulation system and cost-effectiveness.9-11 
The venous pouch arterial bifurcation model in rabbits is formed by a venous pouch sutured into an artificially created true bifurcation of both common carotid arteries (CCA). The main advantage of this model are true bifurcational hemodynamics.12 The major drawbacks are the sofar high microsurgical technical demands and high morbidity and mortality rates of up to 50%.13 These limitations have resulted in less frequent use of this aneurysm model in the recent years. These shortcomings could be overcome with improved surgical procedures and modified peri- and postoperative analgetic management and anticoagulation.14-16 Our techniques reported in this paper demonstrate this optimized technique for microsurgical creation of arterial bifurcation aneurysms.

An optimized technique for the microsurgical creation of arterial bifurcation aneurysms mimicking bifurcation human cerebral aneurysms is described. A venous pouch is sutured into an artificially created true bifurcation of both common carotid arteries. Facilitated microsurgical techniques and aggressive postoperative anticoagulation and analgesia lead to minimized morbidity rates and high aneurysm patency rates.

For ruptured human cerebral aneurysms endovascular embolization has become an equivalent alternative to aneurysm clipping.1 However, large clinical trials ...

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 ...

Implantation of Inferior Vena Cava Interposition Graft in Mouse Model

Biodegradable scaffolds seeded with bone marrow mononuclear cells (BMCs) are often used for reconstructive surgery to treat congenital cardiac anomalies. The long-term clinical results showed excellent patency rates, however, with significant incidence of stenosis. To investigate the cellular and molecular mechanisms of vascular neotissue formation and prevent stenosis development in tissue engineered vascular grafts (TEVGs), we developed a mouse model of the graft with approximately 1 mm internal diameter. First, the TEVGs were assembled from biodegradable tubular scaffolds fabricated from a polyglycolic acid nonwoven felt mesh coated with &#949;-caprolactone and L-lactide copolymer. The scaffolds were then placed in a lyophilizer, vacuumed for 24 hr, and stored in a desiccator until cell seeding. Second, bone marrow was collected from donor mice and mononuclear cells were isolated by density gradient centrifugation. Third, approximately one million cells were seeded on a scaffold and incubated O/N. Finally, the seeded scaffolds were then implanted as infrarenal vena cava interposition grafts in C57BL/6 mice. The implanted grafts demonstrated excellent patency (&#62;90%) without evidence of thromboembolic complications or aneurysmal formation. This murine model will aid us in understanding and quantifying the cellular and molecular mechanisms of neotissue formation in the TEVG.

To improve our knowledge of cellular and molecular neotissue formation, a murine model of the TEVG was recently developed. The grafts were implanted as infrarenal vena cava interposition grafts in C57BL/6 mice. This model achieves similar results to those achieved in our clinical investigation, but over a far shortened time-course.

Biodegradable scaffolds seeded with bone marrow mononuclear cells (BMCs) are often used for reconstructive surgery to treat congenital cardiac anomalies. ...

Orthotopic Injection of Breast Cancer Cells into the Mammary Fat Pad of Mice to Study Tumor Growth.

Breast cancer growth can be studied in mice using a plethora of models. Genetic manipulation of breast cancer cells may provide insights into the functions of proteins involved in oncogenic progression or help to discover new tumor suppressors. In addition, injecting cancer cells into mice with different genotypes might provide a better understanding of the importance of the stromal compartment. Many models may be useful to investigate certain aspects of disease progression but do not recapitulate the entire cancerous process. In contrast, breast cancer cells engraftment to the mammary fat pad of mice better recapitulates the location of the disease and presence of the proper stromal compartment and therefore better mimics human cancerous disease. In this article, we describe how to implant breast cancer cells into mice orthotopically and explain how to collect tissues to analyse the tumor milieu and metastasis to distant organs. Using this model, many aspects (growth, angiogenesis, and metastasis) of cancer can be investigated simply by providing a proper environment for tumor cells to grow.

Cancer is a complex disease that is influenced by the tissue surrounding the tumor as well as local pro- and anti-inflammatory mediators. Therefore, orthotropic injection models, rather than subcutaneous models may be useful to study cancer progression in a manner that better mimics human pathology.

Breast cancer growth can be studied in mice using a plethora of models. Genetic manipulation of breast cancer cells may provide insights into the ...

Ferric Chloride-induced Thrombosis Mouse Model on Carotid Artery and Mesentery Vessel

Severe thrombosis and its ischemic consequences such as myocardial infarction, pulmonary embolism and stroke are major worldwide health issues. The ferric chloride injury is now a well-established technique to rapidly and accurately induce the formation of thrombi in exposed veins or artery of small and large diameter. This model has played a key role in the study of the pathophysiology of thrombosis, in the discovery and validation of novel antithrombotic drugs and in the understanding of the mechanism of action of these new agents. Here, the implementation of this technique on a mesenteric vessel and carotid artery in mice is presented. The method describes how to label circulating leukocytes and platelets with a fluorescent dye and to observe, by intravital microscopy on the exposed mesentery, their accumulation at the injured vessel wall which leads to the formation of a thrombus. On the carotid artery, the occlusion caused by the clot formation is measured by monitoring the blood flow with a Doppler probe.

The FeCl3 induced thrombosis model in mice is described herein. A method to monitor thrombus growth by intravital microscopy observation on a mesenteric vessel and by blood flow measurement in the carotid artery is presented.

Severe thrombosis and its ischemic consequences such as myocardial infarction, pulmonary embolism and stroke are major worldwide health issues. The ferric ...

Patch Angioplasty in the Rat Aorta or Inferior Vena Cava

Pericardial patches are commonly used in vascular surgery to close vessels. To facilitate studies of the neointimal hyperplasia that forms on the patch, we developed a rat model of patch angioplasty that can be used in either a vein or an artery, creating a patch venoplasty or a patch arterioplasty, respectively. Technical aspects of this model are discussed. The infra-renal IVC or aorta are dissected and then clamped proximally and distally. A 3 mm venotomy or arteriotomy is performed in the infrarenal inferior vena cava or aorta of 6 to 8 week-old Wistar rats. A bovine pericardial patch (3 mm x 1.5 mm x 0.6 mm) is then used to close the site using a 10-0 nylon suture. Compared to arterial patches, venous patches show increased neointimal thickness on postoperative day 7. This novel model of pericardial patch angioplasty can be used to examine neointimal hyperplasia on vascular biomaterials, as well as to compare the differences between the arterial and venous environments.

We have established a model of pericardial patch angioplasty that can be used in either small-diameter veins or arteries. This model can be used to compare venous and arterial neointimal hyperplasia formation.

Pericardial patches are commonly used in vascular surgery to close vessels. To facilitate studies of the neointimal hyperplasia that forms on the patch, ...

A Rat Model of Orthotopic Liver Transplantation Using a Novel Magnetic Anastomosis Technique for Suprahepatic Vena Cava Reconstruction

The rat model of orthotopic liver transplantation (OLT) is essential for transplant research. It is a very sophisticated animal model and requires a steep learning curve. The introduction of the cuff technique for anastomosis of the portal vein (PV) and infrahepatic vena cava (IHVC) has significantly simplified the transplant procedure in rats. However, due to the short anterior wall of the recipients' suprahepatic vena cava (SHVC), the cuff technique is very difficult to use for the reconstruction of the SHVC. Most researchers in this field still use the hand-suture technique for SHVC reconstruction, which makes it the bottleneck step in rat orthotopic liver transplantation. The magnetic anastomosis technique (i.e., magnamosis) is a method of connecting two vessels using the attractive force between two magnets. Our recent study has shown that the magnetic anastomosis technique is superior to the hand-suture technique for SHVC reconstruction in rats. In this article, we show a step-by-step protocol for SHVC reconstruction in rats using the novel magnetic anastomosis technique. In this model, the reconstruction of the PV and IHVC was performed by the standard cuff technique, while the reconstruction of the bile duct (BD) was performed by a stent technique. The hepatic re-arterialization was not performed. The magnetic anastomosis technique made SHVC reconstruction much easier and significantly shortened the anphepatic phase. After a reasonable learning curve, even researchers without advanced microsurgical skills can produce reliable and reproducible results using this rat model of OLT.

The reconstruction of the suprahepatic vena cava (SHVC) remains a difficult step in rat orthotopic liver transplantation. In this article, we show a step-by-step protocol for SHVC reconstruction in rats using a novel magnetic anastomosis technique.

The rat model of orthotopic liver transplantation (OLT) is essential for transplant research. It is a very sophisticated animal model and requires a steep ...

Ferric Chloride-induced Canine Carotid Artery Thrombosis: A Large Animal Model of Vascular Injury

Occlusive arterial thrombosis leading to cerebral ischemic stroke and myocardial infarction contributes to ~13 million deaths every year globally. Here, we have translated a vascular injury model from a small animal into a large animal (canine), with slight modifications that can be used for pre-clinical screening of prophylactic and thrombolytic agents. In addition to the surgical methods, the modified protocol describes the step-by-step methods to assess carotid artery canalization by angiography, detailed instructions to process both the brain and carotid artery for histological analysis to verify carotid canalization and cerebral hemorrhage, and specific parameters to complete an assessment of downstream thromboembolic events by utilizing magnetic resonance imaging (MRI). In addition, specific procedural changes from the previously well-established small animal model necessary to translate into a large animal (canine) vascular injury are discussed.

Here, we present the modifications necessary to a well characterized and commonly used small animal ferric chloride-induced (FeCl3) carotid artery injury model for use in a large animal vascular injury model. The resulting model can be utilized for pre-clinical trial assessment of both prophylactic and thrombolytic pharmacological and mechanical interventions.

Occlusive arterial thrombosis leading to cerebral ischemic stroke and myocardial infarction contributes to ~13 million deaths every year globally. Here, ...

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 Model of Central Venous Stenosis using Aortocaval Fistula with an Outflow Stenosis

Central venous stenosis is an important entity contributing to arteriovenous fistula (AVF) failure. A murine AVF model was modified to create a partial ligation of the inferior vena cava (IVC) in the outflow of the fistula, mimicking central venous stenosis. Technical aspects of this model are introduced. The aorta and IVC are exposed, following an abdominal incision. The infra-renal aorta and IVC are dissected for proximal clamping, and the distal aorta is exposed for puncture. The IVC at the midpoint between the left renal vein and the aortic bifurcation is carefully dissected to place an 8-0 suture beneath the IVC. After clamping the aorta and IVC, an AVF is created by puncturing the infra-renal aorta through both walls into the IVC with a 25 G needle, followed by ligating a 22 G intra-venous (IV) catheter and IVC together. The catheter is then removed, creating a reproducible venous stenosis without occlusion. The aorta and IVC are unclamped after confirming primary hemostasis. This novel model of central vein stenosis is easy to perform, reproducible, and will facilitate studies on AVF failure.

An aortocaval fistula was created by puncturing the murine infra-renal aorta through both walls into the inferior vena cava and was followed by creation of a stenosis in its outflow via partial ligation of the inferior vena cava. This reproducible model can be used to study central venous stenosis.

Central venous stenosis is an important entity contributing to arteriovenous fistula (AVF) failure. A murine AVF model was modified to create a partial ...