The authors' work was supported by a grant from Ministry of Science and Technology (MOST 103-2320-B-002-068-MY2), the National Health Research Institute (NHRI-EX104-10418SC), and National Taiwan University (NTU 104R4000).

All animal experiments were conducted in accordance with the Guide for the Care and Use of Laboratory Animals, published by the US National Institutes of Health (NIH publication no. 85-23, revised 1996). This protocol was approved by and in accordance with the guidelines set forth by the Institutional Animal Care and Use Committee at National Taiwan University.
1. Animal Surgery
<ol>
	<li>Prepare a 22 G syringe needle by blunting the tip of the needle on a honing stone. Using pliers, plicate the needle to a right angle.</li>
	<li>Before surgery, prepare the required surgical instruments and materials, as well as a recovery cage. Autoclave all instruments and surgical supplies before use.</li>
	<li>Maintain the rats around 200 g and keep them under 12 hr light/dark cycles at a controlled temperature (21 &#177; 2 &#176;C) with free access to food and water. Include at least 6 rats in each group. Anesthetize the rats with pentobarbital (75 mg/kg in 0.5 ml, i.p.) or another appropriate anesthetic agent. Confirm the depth of anesthesia by testing the tail reflex. 
	NOTE: The absence of tail reflex is an indicator of adequate anesthesia.</li>
	<li>Place a rat in supine position on a surgery platform with a heating pad to maintain the body temperature. Shave the abdominal region of the rat with an animal hair clipper and hair remover lotion to avoid surgical contaminations. Scrub the cleanly-shaven abdomen with betadine or another cleansing reagent before surgery. 
	NOTE: It is important to maintain a sterile field throughout the procedure.</li>
	<li>Make a 2 cm incision along the midline of the abdomen with a scalpel. Using normal saline, keep the abdominal organ moist during the surgery. Displace the digestive organs carefully to the side using cotton balls to expose the inferior vena cava that lies in the posterior peritoneal region. Identify the abdominal aorta, which lies juxtaposed to and usually on the left of the inferior vena cava. 
	NOTE: The abdominal aorta is the vessel that pulsates in time with the heart rate.</li>
	<li>Pierce the peritoneum with a pair of forceps to uncover the vessels beneath. Gently isolate the abdominal aorta adjacent to the renal arteries and pass an 8 cm-long 4-0 silk suture underneath the abdominal aorta between the origins of the right and left renal arteries.</li>
	<li>Make a loose double knot with the suture; leave a 3 mm diameter loop, and place the blunted and bent 22 G needle inside the loop. Tighten the knot around the aorta and the needle, and then remove the needle immediately to achieve a 0.7 mm diameter constriction.</li>
	<li>Close the abdominal cavity with 6-0 absorbable suture material. Suture the muscle or skin incisions with simple interrupted sutures. To prevent infection, scrub the surgical site with an iodine tincture.</li>
	<li>Observe the animal carefully until it regains sufficient consciousness, as indicated by free movement and food intake. Do not leave an animal unattended until it has regained sufficient consciousness to maintain sternal recumbency. To prevent post-surgery pain, treat the rat with acetaminophen (300 mg/kg in 0.5 ml, i.p.). 
	NOTE: Users should administer analgesics as approved by institutional policies.</li>
</ol>
2. Tissue and Blood Sample Collection
<ol>
	<li>At 10 weeks post-surgery, weigh the rat and anesthetize it with pentobarbital (75 mg/kg in 0.5 ml, i.p.). Before surgery, confirm the depth of anesthesia by testing its tail reflex. Place the rat on a metal tray.</li>
	<li>Make a 2 cm incision along the midline of the neck using a scalpel. Displace the muscles carefully with forceps to expose the trachea. Observe carefully to identify the carotid arteries, which are parallel to the trachea and pulsate in time with the heart rate.</li>
	<li>Collect the blood from the carotid artery into a blood collecting tube coated with EDTA. Immediately centrifuge the blood for 15 min at 2,000 x g and collect the plasma. Store the blood plasma at -80 &#176;C until needed.</li>
	<li>Make a 5 cm incision at the thoracic region, around the midline of xyphoid process. Pierce the diaphragm with sharp forceps. Using a pair of scissors, cut and remove the rib cage along the mid-clavicular lines on both sides to expose the heart. Excise the heart carefully along the cardiac and vascular borders. Remove the heart gently without grabbing the tissue.</li>
	<li>Mount the heart on a modified Langendorff perfusion apparatus by tying the aortic trunk to the perfusion needle. Perfuse the heart with Krebs buffer (containing 110 mM NaCl, 2.6 mM KCl, 1.2 mM KH2PO4, 1.2 mM MgSO4, 25 mM NaHCO3, and 11 mM glucose [pH 7.4]) to wash out the blood. Weigh the heart and calculate the heart-weight-to-body-weight ratio. Fix the heart with 4% paraformaldehyde on the ice. Remember to wear a mask, since paraformaldehyde vapor is toxic.</li>
</ol>
3. Tissue Fibrosis Quantification
<ol>
	<li>Place the paraformaldehyde-fixed heart tissue on a tissue sectioning device and cut 2 mm thick sections. Place the tissue sections in an embedding cassette. Dehydrate the tissue through a series of graded alcohol baths (50%, 75%, 95%, and 100% for 1 hr each).</li>
	<li>Infiltrate the tissue with xylene for 1 hr and finally in wax for 1 hr. Place the infiltrated tissue into an embedding cassette and embed with paraffin wax. Store the embedded tissues in paraffin blocks at room temperature until microtoming.</li>
	<li>Slice the embedded tissue into 4 &#181;m thick sections. Place the sections in a 45 &#186;C water bath. Dip a glass slide into the water bath at an angle and gradually approach the paraffin section edges to allow partial attachment to the slide.</li>
	<li>Move the slide in and out of the bath to remove potential air pockets under the tissue section and to facilitate better attachment. Dry the slides at 37 &#186;C for 1 hr and store them at room temperature for histological staining.</li>
	<li>Put the slide into a tank. Deparaffinize the slide with xylene for 30 min and rehydrate it in sequentially diluted alcohol (95%, 75%, and 50% for 3 min each) and finally in distilled water. Use adequate picrosirius red solution to completely cover the tissue sections for 1 hr. Rinse the slides in a 0.5% acetic acid solution for two changes, and then perform two rinses in absolute alcohol.</li>
	<li>Air-dry the slide and mount the slide in synthetic resin with a coverslip. Photograph the slide in a visible light field. 
	NOTE: The red area in the photograph shows a picrosirius red positive zone under a microscope at 200X magnification. Calculate the percentage of the picrosirius red positive zone over the total area, which indicates the extent of fibrosis11.</li>
</ol>
4. Blood Troponin Quantification
<ol>
	<li>Quantify plasma troponin levels using an enzyme-linked immunosorbent assay (ELISA). Assay each sample in duplicate. Load 50 &#181;l of blood plasma and 50 &#181;l of an antibody cocktail into the appropriate wells. Seal the plate and incubate for 1 hr at room temperature on a plate shaker at 400 rpm. 
	NOTE: Cardiac troponin in the plasma is a marker for cardiac injury.</li>
	<li>Aspirate the liquid and wash each well with 250 &#181;l of wash buffer three times. After the last wash, invert the plate and blot it against clean paper towels to remove excessive liquid.</li>
	<li>Add 100 &#181;l of tetramethylbenzidine substrate to each well and incubate for 10 min in the dark on a plate shaker at 400 rpm. Add 100 &#181;l of stop solution to each well. Shake the plate on a plate shaker for 1 min to mix. Record the optical density (OD) at 450 nm. 
	NOTE: The troponin concentration is proportionate to the OD value.</li>
</ol>

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H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transverse+aortic+constriction+in+mice.">Transverse aortic constriction in mice.</a> J Vis Exp. , e1729 (2010).</li><li>Schaefer, 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=A+New+Animal+Model+for+Investigation+of+Mechanical+Unloading+in+Hypertrophic+and+Failing+Hearts:+Combination+of+Transverse+Aortic+Constriction+and+Heterotopic+Heart+Transplantation.">A New Animal Model for Investigation of Mechanical Unloading in Hypertrophic and Failing Hearts: Combination of Transverse Aortic Constriction and Heterotopic Heart Transplantation.</a> PLoS One. 11, e0148259 (2016).</li><li>Rodriguez-Iturbe, B., Quiroz, Y., Kim, C. H., Vaziri, N. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hypertension+induced+by+aortic+coarctation+above+the+renal+arteries+is+associated+with+immune+cell+infiltration+of+the+kidneys.">Hypertension induced by aortic coarctation above the renal arteries is associated with immune cell infiltration of the kidneys.</a> Am J Hypertens. 18, 1449-1456 (2005).</li><li>Ku, H. C., Lee, S. Y., Yang, K. C., Kuo, Y. H., Su, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Modification+of+Caffeic+Acid+with+Pyrrolidine+Enhances+Antioxidant+Ability+by+Activating+AKT/HO-1+Pathway+in+Heart.">Modification of Caffeic Acid with Pyrrolidine Enhances Antioxidant Ability by Activating AKT/HO-1 Pathway in Heart.</a> PLoS One. 11, e0148545 (2016).</li><li>Bovill, J. 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The authors have nothing to disclose.

Hypertensive heart disease, a major health problem that contributes greatly to morbidity and mortality, can lead to cardiac hypertrophy and heart failure5. The pathogenesis and progression of hypertensive heart disease in humans is complex, so an appropriate animal model is critical to investigate the underlying mechanisms and to test novel therapeutics that aim to improve cardiac structure and function5. The abdominal aortic constriction model, which simulates chronic heart disease, is an effective...

Heart failure is a complex clinical syndrome, the symptoms of which include fatigue, dyspnea, exercise intolerance, and fluid retention in peripheral tissues. It is the leading cause of death in developed countries1. Aside from inherited cardiomyopathy caused by mutations in sarcomere proteins or ion channels2, myocardial dysfunction can be caused by a variety of medical conditions, including hypertension, valvular heart diseases, obesity, and diabetes3. Changes in myocardial structure, electrical conduction, and energy metabolism lead to inadequate cardiac pumping capacity to meet circulatory demands, which ultimately results in heart failure3,4. Investigating the mechanisms underlying heart failure, therefore, is critical in the field of cardiovascular research. Identifying molecular mechanisms leading to heart failure progression can eventually aid in the discovery of novel therapeutic targets or useful biomarkers1. It is therefore important to develop heart failure animal models that share key clinical features with heart failure in humans5.
Cardiac hypertrophy and remodeling plays a critical role in the development of heart failure. Hypertensive heart disease is the key contributing factor of cardiac hypertrophy and the maladaptive remodeling seen in human patients1. To mimic these human conditions, animal models are often established through surgical procedures. In particular, the transverse or abdominal aorta can be constricted to increase the resistance against the left ventricle, which ultimately leads to a pressure overload in the heart. This phenomenon usually results in cardiac hypertrophy, a physiological compensation of the cardiomyocytes to meet the functional demand of the cardiovascular system. However, the functional demand overrides the normal physiological compensatory mechanisms, leading to cardiac fibrosis and contractile impairment. Transverse aortic constriction (TAC) surgery often involves complicated procedures, including thoracotomy, mechanical ventilation, and separation of the thymus and fat tissue from the aortic arch. In contrast, abdominal aortic constriction requires simpler experimental techniques6-8. The abdominal aorta, between the left and right renal arteries, is constricted during the surgery. Cardiac hypertrophy and remodeling can be observed several weeks after the abdominal aortic constriction surgery6-8; they produce robust hypertensive heart disease similar to that generated by the transverse aortic constriction surgery9,10. Here, we describe a protocol to conduct abdominal aortic constriction in rats using an efficient, highly-reproducible, and minimally-invasive method. The abdominal aorta adjacent to the renal arteries is constricted by a 0.72 mm loop formed by a 4-0 silk thread. Ten weeks after the surgery, cardiac hypertrophy and remodeling can be observed. The rat model of abdominal aortic constriction-induced cardiac hypertrophy provides a platform for studying disease mechanisms and pathophysiology, as well as the development of potential therapeutics.

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			<td height="21" style="height:21px;width:223px;">22-Gauge syringe needle&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;</td>
			<td style="width:139px;">&#160;&#160; BD Biosciences&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;</td>
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			<td height="21" style="height:21px;width:223px;">EDTA Blood Collection Tubes</td>
			<td style="width:139px;">&#160;&#160; BD Biosciences&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;</td>
			<td style="width:119px;">REF365974</td>
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			<td style="width:139px;">Sigma Aldrich&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;</td>
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			<td height="21" style="height:21px;width:223px;">Paraformaldehyde&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;</td>
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			<td height="21" style="height:21px;width:223px;">Acetaminophen</td>
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			<td height="21" style="height:21px;width:223px;">Cardiac troponin kit&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;</td>
			<td style="width:139px;">&#160;Abcam&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;</td>
			<td style="width:119px;">ab200016</td>
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			<td height="42" style="height:42px;width:223px;">Imagequant</td>
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			<td height="21" style="height:21px;width:223px;">Langendorff&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;</td>
			<td style="width:139px;">&#160;ADInstruments&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;</td>
			<td style="width:119px;">ML870B2</td>
			<td></td>
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a model of cardiac remodeling through constriction of the abdominal aorta in rats

Heart failure is one of the leading causes of death worldwide. It is a complex clinical syndromethat includes fatigue, dyspnea, exercise intolerance, and fluid retention. Changes in myocardial structure, electrical conduction, and energy metabolism develop with heart failure, leading to contractile dysfunction, increased risk of arrhythmias, and sudden death. Hypertensive heart disease is one of the key contributing factors of cardiac remodeling associated with heart failure. The most commonly-used animal model mimicking hypertensive heart disease is created via surgical interventions, such as by narrowing the aorta. Abdominal aortic constriction is a useful experimental technique to induce a pressure overload, which leads to heart failure. The surgery can be easily performed, without the need for chest opening or mechanical ventilation. Abdominal aortic constriction-induced cardiac pathology progresses gradually, making this model relevant to clinical hypertensive heart failure. Cardiac injury and remodeling can be observed 10 weeks after the surgery. The method described here provides a simple and effective approach to produce a hypertensive heart disease animal model that is suitable for studying disease mechanisms and for testing novel therapeutics.

10 weeks after the abdominal aortic constriction surgery, the resulting cardiac pathology was analyzed. The cardiac histology was measured by calculating the ratio of the heart weight to the body weight and by detecting the amount of collagen in the heart. Cardiac injury was confirmed by measuring plasma cardiac troponin concentration.
As shown in Figure 1A, the cardiac size was enlarged after abdominal aortic c...

Watch this Scientific Journal Video about A Model of Cardiac Remodeling Through Constriction of the Abdominal Aorta in Rats at JoVE.com

A Model of Cardiac Remodeling Through Constriction of the Abdominal Aorta in Rats

A rat model of abdominal aortic constriction that induces cardiac hypertrophy and remodeling is described. An efficient, highly-reproducible, and minimally-invasive method is used to provide a simple yet useful platform for research in myocardial hypertrophy and dysfunction.

Heart failure is one of the leading causes of death worldwide. It is a complex clinical syndromethat includes fatigue, dyspnea, exercise intolerance, and ...

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9.9K Views.  National Taiwan University. A rat model of abdominal aortic constriction that induces cardiac hypertrophy and remodeling is described. An efficient, highly-reproducible, and minimally-invasive method is used to provide a simple yet useful platform for research in myocardial hypertrophy and dysfunction.

Video: A Model of Cardiac Remodeling Through Constriction of the Abdominal Aorta in Rats

Chronic Constriction of the Sciatic Nerve and Pain Hypersensitivity Testing in Rats

Chronic neuropathic pain, resulting from damage to the central or peripheral nervous system, is a prevalent and debilitating condition, affecting 7-18% of the population1,2. Symptoms include spontaneous (tingling, burning, electric-shock like) pain, dysaesthesia, paraesthesia, allodynia (pain resulting from normally non-painful stimuli) and hyperalgesia (an increased response to painful stimuli). The sensory symptoms are co-morbid with behavioural disabilities, such as insomnia and depression. To study chronic neuropathic pain several animal models mimicking peripheral nerve injury have been developed, one of the most widely used is Bennett and Xie's (1988) unilateral sciatic nerve chronic constriction injury (CCI)3 (Figure 1). Here we present a method for performing CCI and testing pain hypersensitivity.
CCI is performed under anaesthesia, with the sciatic nerve on one side exposed by making a skin incision, and cutting through the connective tissue between the gluteus superficialis and biceps femoris muscles. Four chromic gut ligatures are tied loosely around the sciatic nerve at 1 mm intervals, to just occlude but not arrest epineural blood flow. The wound is closed with sutures in the muscle and staples in the skin. The animal is then allowed to recover from surgery for 24 hrs before pain hypersensitivity testing begins.
For behavioural testing, rats are placed into the testing apparatus and are allowed to habituate to the testing procedure. The area tested is the mid-plantar surface of the hindpaw (Figure 2), which falls within the sciatic nerve distribution. Mechanical withdrawal threshold is assessed by mechanically stimulating both injured and uninjured hindpaws using an electronic dynamic plantar von Frey aesthesiometer or manual von Frey hairs4. The mechanical withdrawal threshold is the maximum pressure exerted (in grams) that triggers paw withdrawal. For measurement of thermal withdrawal latency, first described by Hargreaves et al (1988), the hindpaw is exposed to a beam of radiant heat through a transparent glass surface using a plantar analgesia meter5,6. The withdrawal latency to the heat stimulus is recorded as the time for paw withdrawal in both injured and uninjured hindpaws. Following CCI, mechanical withdrawal threshold, as well as thermal withdrawal latency in the injured paw are both significantly reduced, compared to baseline measurements and the uninjured paw (Figure 3). The CCI model of peripheral nerve injury combined with pain hypersensitivity testing provides a model system to investigate the effectiveness of potential therapeutic agents to modify chronic neuropathic pain. In our laboratory, we utilise CCI alongside thermal and mechanical sensitivity of the hindpaws to investigate the role of neuro-immune interactions in the pathogenesis and treatment of neuropathic pain.

Due to the simplicity of surgery and the robust behavioural outcome, chronic constriction of the sciatic nerve is one of the pre-eminent animal models of neuropathic pain. Within 24 hrs following surgery, pain hypersensitivity is established and can be quantitatively measured using a von Frey aesthesiometer (mechanical test) and plantar analgesia meter (thermal test).

Chronic neuropathic pain, resulting from damage to the central or peripheral nervous system, is a prevalent and debilitating condition, affecting 7-18% of ...

Orthotopic Liver Transplantation in Rats

Clinical progress in the field of liver transplantation has been largely supported by animal models1,2. Since the publication of the first orthotopic rat liver transplantation in 1979 by Kamada et al.3, this model has remained the gold standard despite various proposed alternative techniques4. Nevertheless, its broader use is limited by its steep learning curve5.
In this video paper, we show a simple and easy-to-establish revision of Kamada's two-cuff technique. The suprahepatic vena cava anastomosis is performed manually with a running suture, and the vena porta and infrahepatic vena cava anastomoses are performed utilizing a quick-linker cuff system6. Manufacturing the quick-linker kit is shown in a separate video paper.

We present an easy-to-establish revision of the classical two-cuff technique for orthotopic liver transplantation in rat.

Clinical progress in the field of liver transplantation has been largely supported by animal models1,2. Since the publication of the first orthotopic rat ...

Ascending Aortic Constriction in Rats for Creation of Pressure Overload Cardiac Hypertrophy Model

Ascending aortic constriction is the most common and successful surgical model for creating pressure overload induced cardiac hypertrophy and heart failure. Here, we describe a detailed surgical procedure for creating pressure overload and cardiac hypertrophy in rats by constriction of the ascending aorta using a small metallic clip. After anesthesia, the trachea is intubated by inserting a cannula through a half way incision made between two cartilage rings of trachea. Then a skin incision is made at the level of the second intercostal space on the left chest wall and muscle layers are cleared to locate the ascending portion of aorta. The ascending aorta is constricted to 50&#8211;60% of its original diameter by application of a small sized titanium clip. Following aortic constriction, the second and third ribs are approximated with prolene sutures. The tracheal cannula is removed once spontaneous breathing was re-established. The animal is allowed to recover on the heating pad by gradually lowering anesthesia. The intensity of pressure overload created by constriction of the ascending aorta is determined by recording the pressure gradient using trans-thoracic two dimensional Doppler-echocardiography. Overall this protocol is useful to study the remodeling events and contractile properties of the heart during the gradual onset and progression from compensated cardiac hypertrophy to heart failure stage.

We describe a stepwise procedure for creating pressure overload and left ventricular hypertrophy in Wistar rats by constriction of the ascending aorta using a small metallic clip. This model is extensively used for studying remodeling changes during cardiac hypertrophy and for identifying and evaluating strategies for regression of such changes.

Ascending aortic constriction is the most common and successful surgical model for creating pressure overload induced cardiac hypertrophy and heart ...

Assessment of Right Ventricular Structure and Function in Mouse Model of Pulmonary Artery Constriction by Transthoracic Echocardiography

Emerging clinical data support the notion that RV dysfunction is critical to the pathogenesis of cardiovascular disease and heart failure1-3. Moreover, the RV is significantly affected in pulmonary diseases such as pulmonary artery hypertension (PAH). In addition, the RV is remarkably sensitive to cardiac pathologies, including left ventricular (LV) dysfunction, valvular disease or RV infarction4. To understand the role of RV in the pathogenesis of cardiac diseases, a reliable and noninvasive method to access the RV structurally and functionally is essential.
A noninvasive trans-thoracic echocardiography (TTE) based methodology was established and validated for monitoring dynamic changes in RV structure and function in adult mice. To impose RV stress, we employed a surgical model of pulmonary artery constriction (PAC) and measured the RV response over a 7-day period using a high-frequency ultrasound microimaging system. Sham operated mice were used as controls. Images were acquired in lightly anesthetized mice at baseline (before surgery), day 0 (immediately post-surgery), day 3, and day 7 (post-surgery). Data was analyzed offline using software.
Several acoustic windows (B, M, and Color Doppler modes), which can be consistently obtained in mice, allowed for reliable and reproducible measurement of RV structure (including RV wall thickness, end-diastolic&#160;and end-systolic dimensions), and function (fractional area change, fractional shortening, PA peak velocity, and peak pressure gradient) in normal mice and following PAC.
Using this method, the pressure-gradient resulting from PAC was accurately measured in real-time using Color Doppler mode and was comparable to direct pressure measurements performed with a Millar high-fidelity microtip catheter. Taken together, these data demonstrate that RV measurements obtained from various complimentary views using echocardiography are reliable, reproducible and can provide insights regarding RV structure and function. This method will enable a better understanding of the role of RV cardiac dysfunction.

Right ventricle (RV) dysfunction is critical to the pathogenesis of cardiovascular disease, yet limited methodologies are available for its evaluation. Recent advances in ultrasound imaging provide a noninvasive and accurate option for longitudinal RV study. Herein, we detail a step-by-step echocardiographic method using a murine model of RV pressure overload.

Emerging clinical data support the notion that RV dysfunction is critical to the pathogenesis of cardiovascular disease and heart failure1-3. Moreover, ...

Visualization of Streptococcus pneumoniae within Cardiac Microlesions and Subsequent Cardiac Remodeling

During bacteremia Streptococcus pneumoniae can translocate across the vascular endothelium into the myocardium and form discrete bacteria-filled microscopic lesions (microlesions) that are remarkable due to the absence of infiltrating immune cells. Due to their release of cardiotoxic products, S. pneumoniae within microlesions are thought to contribute to the heart failure that is frequently observed during fulminate invasive pneumococcal disease in adults. Herein is demonstrated a protocol for experimental mouse infection that leads to reproducible cardiac microlesion formation within 30 hr. Instruction is provided on microlesion identification in hematoxylin &#38; eosin stained heart sections and the morphological distinctions between early and late microlesions are highlighted. Instruction is provided on a protocol for verification of S. pneumoniae within microlesions using antibodies against pneumococcal capsular polysaccharide and immunofluorescent microscopy. Last, a protocol for antibiotic intervention that rescues infected mice and for the detection and assessment of scar formation in the hearts of convalescent mice is provided. Together, these protocols will facilitate the investigation of the molecular mechanisms underlying pneumococcal cardiac invasion, cardiomyocyte death, cardiac remodeling as a result of exposure to S. pneumoniae, and the immune response to the pneumococci in the heart.

Visualization of Streptococcus pneumoniae within Cardiac Microlesions and Subsequent Cardiac Remodeling

Streptococcus pneumoniae forms discrete non-purulent microscopic lesions in the heart. Outlined is the protocol for a murine model of cardiac microlesion formation. Instruction is provided on microlesion visualization using microscopy, discrimination between early and late microlesions, and methods to detect cardiac remodeling in hearts of convalescent animals.

During bacteremia Streptococcus pneumoniae can translocate across the vascular endothelium into the myocardium and form discrete bacteria-filled ...

Assessment of Cardiac Morphological and Functional Changes in Mouse Model of Transverse Aortic Constriction by Echocardiographic Imaging

Transverse aortic constriction (TAC) in mice has been used as a valuable model to study mechanisms of cardiac hypertrophy and heart failure1. A reliable noninvasive method is essential to assess real-time cardiac morphological and functional changes in animal models of heart disease. Transthoracic echocardiography represents an important tool for noninvasive assessment of cardiac structure and function2. Here we used a high-resolution ultrasound imaging system to monitor myocardial remodeling and heart failure progression over time in a mouse model of TAC. B-mode, M-mode, and Doppler imaging were used to precisely assess cardiac hypertrophy, ventricular dilatation, and functional deterioration in mice following TAC. Color and pulse wave (PW) Doppler imaging was used to noninvasively measure pressure gradient across the aortic constriction created by TAC and to assess transmitral blood flow in mice. Thus transthoracic echocardiographic imaging provides comprehensive noninvasive measurements of cardiac dimensions and function in mouse models of heart disease.

The goal of this protocol is to noninvasively assess cardiac structural and functional changes in a mouse model of heart disease created by transverse aortic constriction, using B- and M-mode echocardiography and color/pulse wave Doppler imaging.

Transverse aortic constriction (TAC) in mice has been used as a valuable model to study mechanisms of cardiac hypertrophy and heart failure1. A reliable ...

Balloon-based Injury to Induce Myointimal Hyperplasia in the Mouse Abdominal Aorta

The use of animal models is essential for a better understanding of MH, one major cause for arterial stenosis.In this article, we demonstrate a murine balloon denudation model, which is comparable with established vessel injury models in large animals. The aorta denudation model with balloon catheters mimics the clinical setting and leads to comparable pathobiological and physiological changes. Briefly, after performing a horizontal incision in the aorta abdominalis, a balloon catheter will be inserted into the vessel, inflated, and introduced retrogradely. Inflation of the balloon will lead to intima injury and overdistension of the vessel. After removing the catheter, the aortic incision will be closed with single stiches. The model shown in this article is reproducible, easy to perform, and can be established quickly and reliably. It is especially suitable for evaluating expensive experimental therapeutic agents, which can be applied in an economical fashion. By using different knockout-mouse strains, the impact of different genes on MH development can be assessed.

This article demonstrates a murine model to study the development of myointimal hyperplasia (MH) after aortic balloon injury.

The use of animal models is essential for a better understanding of MH, one major cause for arterial stenosis.In this article, we demonstrate a murine ...

A Closed-chest Model to Induce Transverse Aortic Constriction in Mice

Research on cardiac hypertrophy and heart failure is frequently based on pressure overload mouse models induced by TAC. The standard procedure is to perform a partial thoracotomy to visualize the transverse aortic arch. However, the surgical trauma caused by the thoracotomy in open-chest models changes the respiratory physiology as the ribs are dissected and left unattached after chest closure. To prevent this, we established a minimally invasive, closed chest approach via lateral thoracotomy. Herein we approach the aortic arch via the 2nd intercostal space without entering the chest cavities, leaving the mouse with a less traumatic injury to recover from. We perform this operation using standard laboratory settings for open chest TAC procedures with equal survival rates. Apart from maintaining physiological breathing patterns due to the closed chest approach, the mice seem to benefit by showing rapid recovery, as the less invasive technique appears to facilitate a fast healing process and to reduce immune response after trauma.

Here, we present a protocol of Transverse Aortic constriction (TAC) via a lateral thoracotomy. This technique is a minimally invasive, closed chest surgical procedure aiming to simulate pressure overload and heart failure in mice utilizing standard TAC laboratory settings.

Research on cardiac hypertrophy and heart failure is frequently based on pressure overload mouse models induced by TAC. The standard procedure is to ...

Ultrasound Imaging of the Thoracic and Abdominal Aorta in Mice to Determine Aneurysm Dimensions

Contemporary high-resolution ultrasound instruments have sufficient resolution to facilitate the measurement of mouse aortas. These instruments have been widely used to measure aortic dimensions in mouse models of aortic aneurysms. Aortic aneurysms are defined as permanent dilations of the aorta, which occur most frequently in the ascending and abdominal regions. Sequential measurements of aortic dimensions by ultrasound are the principal approach for assessing the development and progression of aortic aneurysms in vivo. Although many reported studies used ultrasound imaging to measure aortic diameters as a primary endpoint, there are confounding factors, such as probe position and cardiac cycle, that may impact the accuracy of data acquisition, analysis, and interpretation. The purpose of this protocol is to provide a practical guide on the use of ultrasound to measure the aortic diameter in a reliable and reproducible manner. This protocol introduces the preparation of mice and instruments, the acquisition of appropriate ultrasound images, and data analysis.

Ultrasound imaging has become a common modality to determine the luminal dimensions of thoracic and abdominal aortic aneurysms in mice. This protocol describes the procedure to acquire reliable and reproducible two-dimensional ultrasound images of the ascending and abdominal aorta in mice.

Contemporary high-resolution ultrasound instruments have sufficient resolution to facilitate the measurement of mouse aortas. These instruments have been ...

Implantation of Human-Sized Coronary Stents into Rat Abdominal Aorta Using a Trans-Femoral Access

Percutaneous coronary intervention (PCI), combined with the deployment of a coronary stent, represents the gold standard in interventional treatment of coronary artery disease. In-stent restenosis (ISR) is determined by an excessive proliferation of neointimal tissue within the stent and limits the long-term success of stents. A variety of animal models have been used to elucidate pathophysiological processes underlying in-stent restenosis (ISR), with the porcine coronary and the rabbit iliac artery models being the most frequently used. Murine models provide the advantages of high throughput, ease of handling and housing, reproducibility, and a broad availability of molecular markers. The apolipoprotein E deficient (apoE-/- ) mouse model has been widely used to study cardiovascular diseases. However, stents must be miniaturized to be implanted into mice, involving important changes of their mechanical and (potentially) biological properties. The use of apoE-/- rats can overcome these shortcomings as apoE-/- rats allow for the evaluation of human-sized coronary stents while at the same time providing an atherogenic phenotype. This makes them an excellent and reliable model to investigate ISR after stent implantation. Here, we describe, in detail, the implantation of commercially available human coronary stents into the abdominal aorta of rats with an apoE-/- background using a trans-femoral access.

This protocol describes the implantation of human coronary stents into the abdominal aorta of rats with an apoE-/- background using a trans-femoral access. Compared with other animal models, murine models carry the advantages of high throughput, reproducibility, ease of handling and housing, and a broad availability of molecular markers.

Percutaneous coronary intervention (PCI), combined with the deployment of a coronary stent, represents the gold standard in interventional treatment of ...