This model was developed with financial support from the Ministry of Science and Technology, Taiwan (MOST 109-2320-B-030-006-MY3).

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). The study protocol was approved by and in accordance with the guidelines of the Institutional Animal Care and Use Committee at Fu-Jen Catholic University.
1. Preparation before surgery
<ol>
	<li>Preparation of saline wet cotton balls
	<ol>
		<li>Put on a surgical mask and gloves.</li>
		<li>Pinch off a small portion of sterile cotton and roll it to form a ball. Repeat this procedure.</li>
		<li>Dip the cotton balls in sterile 0.9% saline and squeeze out excess saline.</li>
		<li>Store the cotton balls in a clean box sterilized with 75% ethanol.</li>
	</ol>
	</li>
	<li>Preparation of holding hooks.
	<ol>
		<li>Put on a surgical mask and gloves.</li>
		<li>Sterilize clips and rubber bands with 75% ethanol.</li>
		<li>Bend the clips into the shape of a hook for the chest wall and tissue.</li>
		<li>Connect the bent clips with one, two, or three rubber bands to ensure the tension from the wound of the surgical window is wide enough for LAD ligation.</li>
		<li>Prepare and store at least five homemade hooks in a clean box sterilized with 75% ethanol.</li>
	</ol>
	</li>
	<li>Preparation of a ligation loop.
	<ol>
		<li>Place the middle of a 7-0 silk stitch in the 1/2 circle size 3 spring eye of a tapered nonswaged surgical needle.</li>
	</ol>
	</li>
	<li>Preparation of a snare loop controller
	<ol>
		<li>Cut a 5-mm polyethylene (PE)-10 tube using scissors.</li>
		<li>Heat and soften the tube under flame to smooth both of its edges.</li>
	</ol>
	</li>
	<li>Preparing the rats
	<ol>
		<li>Select 8-week-old Sprague-Dawley male rats with a minimum weight of 250 g.</li>
		<li>House and maintain the rats under a 12 h light/dark cycle at a controlled temperature (21 &#176;C &#177; 2 &#176;C) with free access to food, standard mouse pellets, and tap water.</li>
		<li>Anesthetize the rats with pentobarbital (50 mg/kg, administered intraperitoneally). 
		NOTE: Additional anesthetic (pentobarbital, 30 mg/kg) should be administered after every hour.</li>
		<li>Check the rats&#39; reflexes by pinching the tail and hind feet to ensure that the animal is sufficiently anesthetized.</li>
		<li>Open the tissue between two cartridge rings below the glottis using scissors and insert a 3 cm PE-10 tube to act as an endotracheal tube25.</li>
		<li>Connect the endotracheal tube to a ventilator manually.</li>
		<li>Inspect the animal&#39;s thoracic movement synchronized with the respiration cycle to ensure the lungs are adequately ventilated.</li>
		<li>Open the neck region and cannulate the jugular vein26.</li>
	</ol>
	</li>
</ol>
2. LAD ligation
<ol>
	<li>Put on a surgical mask and gloves.</li>
	<li>Touch the chest and find the manubrium and sternal angle (the junction of the manubrium and sternum body).</li>
	<li>Identify the left-side rib that connects with the sternal angle (rib A) by touching manually.</li>
	<li>Identify the intercostal space immediately below rib A. Use fine-tip forceps to gently lift the skin close to the intercostal space, and then use a surgical scalpel with a blade to create a 1 cm oblique incision along the skin tension lines from the point approximately 5 mm to the left of the sternal body.</li>
	<li>Use curved forceps to gently separate the skin and muscle layers from the incision. Hook the muscle layers outside the left anterior chest wall downward with bent clips to expose the ribs underneath.</li>
	<li>Identify the rib below rib A (rib B). Cut rib B with a blunt scissor from the middle of the rib cartilage (approximately 2-3 mm from the sternal body). Gently touch and compress the wound with a saline wet cotton ball for several seconds if bleeding occurs.</li>
	<li>Open the thorax carefully from the cut of rib B with four bent clips. Each bent clip should hook the intercostal muscle and ribs to gently spread the chest wall in four directions (namely, upper then left, upper then right, left downward, and right downward) and create a rectangular surgical window.</li>
	<li>Hook gently against the left lung and other adjacent tissues covering the pericardium with another bent clip to prevent accidental tissue damage during the procedure.</li>
	<li>Expose the heart by gently removing the thin pericardium with forceps. Identify the 1st branch of the left main coronary artery (LMCA), which is usually between the pulmonary artery and left auricle. The LMCA and LAD present as a superficial bright red line that runs from the edge of the left auricle toward the apex.</li>
	<li>Use the prepared surgical needle to create an open ligation loop by inserting and passing the silk stitch under the LAD at a location immediately distal to the 1st branch of the LMCA in the direction from the left toward the right side of the LAD to avoid accidentally puncturing the left auricle. With a single suture, the open loop is created. Gently swab the surface of the heart to visualizethe coronary arteries if the LAD is invisible because of fluid or blood covering the surface of the heart.</li>
	<li>Hold one side of the suture and gently separate the needle from the suture using a needle holder.</li>
	<li>Insert the two ends of the silk suture on one side of the open loop into the circle on the other side to form a snare loop.</li>
	<li>Insert the two ends of the silk suture of the snare loop into the prepared snare controller before closing the loop.</li>
	<li>Slide the snare loop controller along the silk suture while gently stretching the silk to close the snare loop. Cease the coronary flow of the LAD to induce temporary myocardial ischemia for 1 h.</li>
	<li>Hold the silk to fix the position of the snare loop controller with Kelly forceps once the loop has been tied securely. Place the other end of the Kelly forceps on the surgical table during LAD ligation.</li>
	<li>Cover the surgical window with saline wet cotton balls during LAD ligation.</li>
	<li>Open the Kelly forceps.</li>
	<li>Release the snare loop controller for reperfusion of the coronary flow for 2 h.</li>
	<li>Resect the heart along the base and vascular borders carefully and avoid grabbing the tissue. 
	NOTE: Euthanize the rat with CO2&#160;at a flow rate of 40% &#160;cage volume/min.</li>
</ol>

The authors declare that there is no conflict of interest regarding the publication of this article.

The proposed protocol has several distinctive features, such as identifying the exact position for LAD ligation, creating a gadget to control a snare loop in a single suture, and supporting a modified surgical maneuver to reduce tissue damage, thus enabling researchers to ligate the LAD accurately, securely, and consistently, as well as control the state of the snare loop instantly for acute myocardial IR research.
The location of LAD ligation influences the area and size of the myocardial inf...

Ischemic heart disease is a leading cause of death worldwide1,2. In addition to the control of modifiable risk factors for preventing the development of coronary heart disease, therapeutic strategies are crucially required for acute coronary syndrome3,4. Cardiogenic shock and fatal arrhythmia in acute ST-segment elevation myocardial infarction (STEMI) have been found to increase the likelihood of in-hospital mortality5,6,7,8. Primary percutaneous coronary intervention (PCI) is the preferred treatment for STEMI9,10,11; however, the therapeutic effects have a ceiling when the door-to-balloon time is &#60;90 min12,13. Additional strategies are required for further improving the clinical outcomes of the disease14,15,16,17,18,19.
An acute myocardial ischemia- reperfusion (IR) experiment involving left anterior descending artery (LAD) ligation in rats is one of the animal models comparable to the clinical scenario wherein short door-to-balloon times are required for patients with STEMI to rescue the heart from ischemic damage. However, surgery-induced STEMI in small animals is often technically challenging because it is a complex operation associated with high mortality and high variation in infarction size20,21,22,23,24. To overcome the technical challenge, the present study developed a comprehensive and effective animal model in rats (because they are larger than mice) to establish a reliable and reproducible acute myocardial IR research protocol through technical modification. The proposed protocol results in fewer surgical complications, less tissue damage, and less likelihood of mortality during surgery. Additionally, a procedure was used to measure the infarct size and area at risk (AAR) and, thus, verify the quality of the study results. The proposed protocol can be used to investigate the pathophysiological processes of acute myocardial IR stress to develop new therapeutic strategies against the damage.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Evan&#8217;s blue</td>
			<td>Sigma Aldrich</td>
			<td>E2129</td>
			<td></td>
		</tr>
		<tr>
			<td>Forceps</td>
			<td>Shinva</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Pentobarbital</td>
			<td>Sigma Aldrich</td>
			<td>1507002</td>
			<td></td>
		</tr>
		<tr>
			<td>Scalpel blades</td>
			<td>Shinva</td>
			<td>s2646</td>
			<td></td>
		</tr>
		<tr>
			<td>Scalpel handles</td>
			<td>Shinva</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Silk sutures</td>
			<td>SharpointTM</td>
			<td>DC-2150N</td>
			<td></td>
		</tr>
		<tr>
			<td>Surgical needle</td>
			<td>AnchorTM</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Triphenyltetrazolium chloride (TTC) solution</td>
			<td>Solarbio</td>
			<td>T8170-1</td>
			<td></td>
		</tr>
		<tr>
			<td>Ventilator</td>
			<td>Harvard Rodent Ventilator</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

left anterior descending coronary artery ligation for ischemia-reperfusion research: model improvement via technical modifications and quality control

Coronary heart disease is the leading cause of death globally. Complete cessation of blood flow in coronary arteries causes ST-segment elevation myocardial infarction (STEMI), resulting in cardiogenic shock and fatal arrhythmia, which are associated with high mortality. Primary coronary intervention (PCI) for recanalizing the coronary artery significantly improves the outcomes of STEMI, but advancements made in shortening the door-to-balloon time have failed to reduce in-hospital mortality, suggesting that additional therapeutic strategies are required. Left anterior descending coronary artery (LAD) ligation in rats is an animal model for acute myocardial IR research that is comparable to the clinical scenario in which rapid coronary recanalization through PCI is used for STEMI; however, PCI-induced STEMI is a technically challenging and complicated operation associated with high mortality and great variation in infarction size. We identified the ideal position for LAD ligation, created a gadget to control a snare loop, and supported a modified surgical maneuver, thereby reducing tissue damage, to establish a reliable and reproducible acute myocardial ischemia-reperfusion (IR) research protocol for rats. This is a non-survival surgery. We also propose a method for validating the quality of study results, which is a critical step for determining the accuracy of subsequent biochemical analyses.

At the end of myocardial ischemia and reperfusion, the quality of LAD ligation should be assessed before further biochemical or molecular analyses.
The sufficiency of LAD occlusion through ligation was determined by injecting 1 mL of 2% Evan&#39;s blue dye through the central venous catheter. Then, the myocardium with coronary perfusion was stained blue compared with the non-perfused region, which remained red (Figure 1A). The red region is the AAR of myocardial i...

Watch this Scientific Journal Video about Left Anterior Descending Coronary Artery Ligation for Ischemia-Reperfusion Research: Model Improvement via Technical Modifications and Quality Control at JoVE

Left Anterior Descending Coronary Artery Ligation for Ischemia-Reperfusion Research: Model Improvement via Technical Modifications and Quality Control

Herein, we present a protocol focusing on the quality control of the left anterior descending coronary artery ligation by technically modifying the traditional procedure in rats for acute myocardial ischemia-reperfusion research.

Coronary heart disease is the leading cause of death globally. Complete cessation of blood flow in coronary arteries causes ST-segment elevation ...

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3.1K Views.  Fu Jen Catholic University. Herein, we present a protocol focusing on the quality control of the left anterior descending coronary artery ligation by technically modifying the traditional procedure in rats for acute myocardial ischemia-reperfusion research.

Video: Left Anterior Descending Coronary Artery Ligation for Ischemia-Reperfusion Research: Model Improvement via Technical Modifications and Quality Control

Coronary Artery Ligation and Intramyocardial Injection in a Murine Model of Infarction

Mouse models are a valuable tool for studying acute injury and chronic remodeling of the myocardium in vivo. With the advent of genetic modifications to the whole organism or the myocardium and an array of biological and/or synthetic materials, there is great potential for any combination of these to assuage the extent of acute ischemic injury and impede the onset of heart failure pursuant to myocardial remodeling. 
Here we present the methods and materials used to reliably perform this microsurgery and the modifications involved for temporary (with reperfusion) or permanent coronary artery occlusion studies as well as intramyocardial injections. The effects on the heart that can be seen during the procedure and at the termination of the experiment in addition to histological evaluation will verify efficacy. 
Briefly, surgical preparation involves anesthetizing the mice, removing the fur on the chest, and then disinfecting the surgical area. Intratracheal intubation is achieved by transesophageal illumination using a fiber optic light. The tubing is then connected to a ventilator. An incision made on the chest exposes the pectoral muscles which will be cut to view the ribs. For ischemia/reperfusion studies, a 1 cm piece of PE tubing placed over the heart is used to tie the ligature to so that occlusion/reperfusion can be customized. For intramyocardial injections, a Hamilton syringe with sterile 30gauge beveled needle is used. When the myocardial manipulations are complete, the rib cage, the pectoral muscles, and the skin are closed sequentially. Line block analgesia is effected by 0.25% marcaine in sterile saline which is applied to muscle layer prior to closure of the skin. The mice are given a subcutaneous injection of saline and placed in a warming chamber until they are sternally recumbent. They are then returned to the vivarium and housed under standard conditions until the time of tissue collection. At the time of sacrifice, the mice are anesthetized, the heart is arrested in diastole with KCl or BDM, rinsed with saline, and immersed in fixative. Subsequently, routine procedures for processing, embedding, sectioning, and histological staining are performed. 
Nonsurgical intubation of a mouse and the microsurgical manipulations described make this a technically challenging model to learn and achieve reproducibility. These procedures, combined with the difficulty in performing consistent manipulations of the ligature for timed occlusion(s) and reperfusion or intramyocardial injections, can also affect the survival rate so optimization and consistency are critical.

Numerous genetic manipulations and/or intramyocardial injections of genes, proteins, cells, and/or biomaterials are superimposed upon the dimension of time in studies of acute ischemia/ reperfusion injury and chronic remodeling in mice. This video illustrates the microsurgical procedures for ischemia/reperfusion, permanent coronary artery ligation, and intramyocardial injection studies.

Mouse models are a valuable tool for studying acute injury and chronic remodeling of the myocardium in vivo.  With the advent of genetic modifications to ...

Modified Technique for Coronary Artery Ligation in Mice

Myocardial infarction (MI) is one of the most important causes of mortality in humans1-3. In order to improve morbidity and mortality in patients with MI we need better knowledge about pathophysiology of myocardial ischemia. This knowledge may be valuable to define new therapeutic targets for innovative cardiovascular therapies4. Experimental MI model in mice is an increasingly popular small-animal model in preclinical research in which MI is induced by means of permanent or temporary ligation of left coronary artery (LCA)5. In this video, we describe the step-by-step method of how to induce experimental MI in mice.
The animal is first anesthetized with 2% isoflurane. The unconscious mouse is then intubated and connected to a ventilator for artificial ventilation. The left chest is shaved and 1.5 cm incision along mid-axillary line is made in the skin. The left pectoralis major muscle is bluntly dissociated until the ribs are exposed. The muscle layers are pulled aside and fixed with an eyelid-retractor. After these preparations, left thoracotomy is performed between the third and fourth ribs in order to visualize the anterior surface of the heart and left lung. The proximal segment of LCA artery is then ligated with a 7-0 ethilon suture which typically induces an infarct size ~40% of left ventricle. At the end, the chest is closed and the animals receive postoperative analgesia (Temgesic, 0.3 mg/50 ml, ip). The animals are kept in a warm cage until spontaneous recovery.

The surgical procedure used to induce experimental myocardial infarction in mice begins with left thoracotomy between the third and the fourth ribs in order to visualize the anterior surface of the heart and left lung. The left coronary artery is ligated, the chest is closed and the mouse is allowed to recover spontaneously.

Myocardial infarction (MI) is one of the most important causes of mortality in humans1-3. In order to improve morbidity and mortality in patients with MI ...

A Murine Model of Myocardial Ischemia-reperfusion Injury through Ligation of the Left Anterior Descending Artery

Acute or chronic myocardial infarction (MI) are cardiovascular events resulting in high morbidity and mortality. Establishing the pathological mechanisms at work during MI and developing effective therapeutic approaches requires methodology to reproducibly simulate the clinical incidence and reflect the pathophysiological changes associated with MI. Here, we describe a surgical method to induce MI in mouse models that can be used for short-term ischemia-reperfusion (I/R) injury as well as permanent ligation. The major advantage of this method is to facilitate location of the left anterior descending artery (LAD) to allow for accurate ligation of this artery to induce ischemia in the left ventricle of the mouse heart. Accurate positioning of the ligature on the LAD increases reproducibility of infarct size and thus produces more reliable results. Greater precision in placement of the ligature will improve the standard surgical approaches to simulate MI in mice, thus reducing the number of experimental animals necessary for statistically relevant studies and improving our understanding of the mechanisms producing cardiac dysfunction following MI. This mouse model of MI is also useful for the preclinical testing of treatments targeting myocardial damage following MI.

We introduce a surgical method to induce experimental ischemia/reperfusion (I/R) injury to simulate myocardial infarction (MI) in mouse models that allows for more clarity in positioning of the ligation on the left anterior descending artery (LAD) to increase the reproducibility of MI experiments in mice.

Acute or chronic myocardial infarction (MI) are cardiovascular events resulting in high morbidity and mortality. Establishing the pathological mechanisms ...

Permanent Ligation of the Left Anterior Descending Coronary Artery in Mice: A Model of Post-myocardial Infarction Remodelling and Heart Failure

Heart failure is a syndrome in which the heart fails to pump blood at a rate commensurate with cellular oxygen requirements at rest or during stress. It is characterized by fluid retention, shortness of breath, and fatigue, in particular on exertion. Heart failure is a growing public health problem, the leading cause of hospitalization, and a major cause of mortality. Ischemic heart disease is the main cause of heart failure.
Ventricular remodelling refers to changes in structure, size, and shape of the left ventricle. This architectural remodelling of the left ventricle is induced by injury (e.g., myocardial infarction), by pressure overload (e.g., systemic arterial hypertension or aortic stenosis), or by volume overload. Since ventricular remodelling affects wall stress, it has a profound impact on cardiac function and on the development of heart failure. A model of permanent ligation of the left anterior descending coronary artery in mice is used to investigate ventricular remodelling and cardiac function post-myocardial infarction. This model is fundamentally different in terms of objectives and pathophysiological relevance compared to the model of transient ligation of the left anterior descending coronary artery. In this latter model of ischemia/reperfusion injury, the initial extent of the infarct may be modulated by factors that affect myocardial salvage following reperfusion. In contrast, the infarct area at 24 hr after permanent ligation of the left anterior descending coronary artery is fixed. Cardiac function in this model will be affected by 1) the process of infarct expansion, infarct healing, and scar formation; and 2) the concomitant development of left ventricular dilatation, cardiac hypertrophy, and ventricular remodelling.
Besides the model of permanent ligation of the left anterior descending coronary artery, the technique of invasive hemodynamic measurements in mice is presented in detail.

Heart failure is the leading cause of hospitalization and a major cause of mortality. A model of permanent ligation of the left anterior descending coronary artery in mice is applied to investigate ventricular remodelling and cardiac dysfunction post-myocardial infarction. The technique of invasive hemodynamic measurements in mice is presented.

Heart failure is a syndrome in which the heart fails to pump blood at a rate commensurate with cellular oxygen requirements at rest or during stress. It ...

Murine Left Anterior Descending (LAD) Coronary Artery Ligation: An Improved and Simplified Model for Myocardial Infarction

Ischemic heart disease (IHD), or acute coronary syndrome (ACS), is one of the leading causes of death in the United States. IHD is characterized by reduced blood supply to the heart, resulting in the loss of oxygen to and the ensuing necrosis of the heart muscle. The MI model has gained popularity for its use as a short-term ischemia-reperfusion model and a long-term permanent ligation model. Below, we describe a reliable method for the permanent ligation of the LAD. With mouse genetic engineering technology becoming more advanced, and with an increasing availability of quality murine surgical instruments, the mouse has become a popular model for MI surgeries. Our surgical model incorporates the use of an easily reversible anesthetic for the rapid recovery of the mouse; a minimally invasive endotracheal intubation without involving a tracheotomy; and a thoracentesis through the original thoracotomy site without creating an additional incision in the chest, as is done in some other methods, to effectively remove excess blood and air from the chest cavity. This method is comparatively less invasive than other methods, which dramatically reduces surgical and post-surgical complications and mortality and improves reproducibility.

Murine Left Anterior Descending LAD Coronary Artery Ligation: An Improved and Simplified Model for Myocardial Infarction

We provide a reliable method for left anterior descending artery (LAD) ligation in a mouse model. This method is comparatively less invasive than other methods, involving endotracheal intubation, a left-sided thoracotomy approach, and thoracentesis. This method can be used as a model for both acute and chronic myocardial infarction (MI).

Ischemic heart disease (IHD), or acute coronary syndrome (ACS), is one of the leading causes of death in the United States. IHD is characterized by ...

Direct Re-implantation of Left Coronary Artery into the Aorta in Adults with Anomalous Origin of Left Coronary Artery from the Pulmonary Artery (ALCAPA)

Anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) is a rare congenital anomaly which is one of leading causes of myocardial ischemia and infarction in children. If left untreated, it results in a 90% mortality rate in the first year of life. In patients who survive to the adulthood, the coronary steal phenomenon and retrograde left-sided coronary flow provide a substrate for chronic subendocardial ischemia, which may lead to left ventricular dysfunction, ischemic mitral regurgitation, malignant ventricular arrhythmias, and sudden cardiac death. The average age of life-threatening presentation is 33 years and of sudden cardiac death 31 years. Therefore, surgical correction is highly recommended as soon as the diagnosis is made, regardless of age. In adult-type ALCAPA originating from the right-facing sinus of the pulmonary artery, direct re-implantation of the ALCAPA into the aorta is the more physiologically sound repair technique to re-establish the dual-coronary perfusion system and is recommended. This protocol describes the technique of direct re-implantation of adult-type ALCAPA into the aorta.

Direct Re-implantation of Left Coronary Artery into the Aorta in Adults with Anomalous Origin of Left Coronary Artery from the Pulmonary Artery ALCAPA

Surgical correction of ALCAPA is highly recommended, regardless of age or the degree of intercoronary collateralization. This protocol presents a technique for the direct re-implantation of adult-type ALCAPA into the aorta to re-establish the dual-coronary perfusion. Whenever feasible, direct re-implantation is preferred to other surgical correction techniques.

Anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) is a rare congenital anomaly which is one of leading causes of myocardial ...

Evaluation of Coronary Flow Reserve After Myocardial Ischemia Reperfusion in Rats

Coronary artery disease is the leading cause of death worldwide. After an acute myocardial infarction, early and successful myocardial intervention via recanalization of the coronary artery is the most effective strategy for reducing the size of ischemic myocardium. The coronary microvasculature cannot be visualized and imaged&#160;in vivo, but there are several invasive and noninvasive techniques that can be used to assess parameters which depend directly on coronary microvascular function. The endothelial function after ischemia reperfusion can be assessed also at the level of the coronary circulation via the coronary flow reserve (CFR).&#160;In this study, peak velocity of left anterior descending (LAD) coronary arteries was measured in rats in vivo via Transthoracic Doppler Echocardiography during resting and stress challenge (induced by Dobutamine). A normal heart can increase its coronary blood flow up to four times above the resting values during stress induction. Following ischemia reperfusion, we found a significantly diminished CFR, which can be used as a marker of coronary microvascular dysfunction. CFR has opened a window on the importance of microvascular dysfunction and has been shown to predict cardiovascular risk independent of whether the severe obstructive disease is present.

Coronary flow reserve (CFR), is defined as the ratio of maximal coronary blood flow to the resting coronary blood flow. We present a protocol for evaluating CFR in rats via ultrasound, which offers the opportunity to predict cardiovascular risk factors in the absence of obstructive coronary disease.

Coronary artery disease is the leading cause of death worldwide. After an acute myocardial infarction, early and successful myocardial intervention via ...

Murine Myocardial Infarction Model using Permanent Ligation of Left Anterior Descending Coronary Artery

Myocardial infarction (MI) and acute coronary diseases are among the most prominent causes of death in population with western lifestyle. The murine models of MI with permanent ligation of left-anterior descending (LAD) coronary artery closely mimics MI in humans. Murine models benefit from the extensive genetic engineering available nowadays. Here we propose a reproducible murine surgical model of myocardial infarction by permanent LAD coronary ligation. Our technique comprises anesthesia with ketamine/xylazine that can be rapidly reversed by administration of an antagonist, intubation without tracheotomy for mechanical-assisted ventilation, ventilation with application of extrinsic positive end-expiratory pressure (PEEP) to avoid alveolar collapse, a thoracotomy method limiting to the minimum surgical lesions made to skeletal muscles, and lung inflation without thoracentesis. This method is sparsely invasive, reproducible and reduces post-surgery mortality and complications.

Herein we describe a surgical procedure showing how to achieve permanent ligation of the left-anterior descending coronary artery in mice. This model is of high relevance to investigate the pathophysiology of myocardial infarction and the concomitant biological processes.

Myocardial infarction (MI) and acute coronary diseases are among the most prominent causes of death in population with western lifestyle. The murine ...

Left Coronary Artery Ligation: A Surgical Murine Model of Myocardial Infarction

Ischemic heart disease and subsequent myocardial infarction (MI) is one of the leading causes of mortality in the United States and around the world. In order to explore the pathophysiological changes after myocardial infarction and design future treatments, research models of MI are required. Permanent ligation of the left coronary artery (LCA) in mice is a popular model to investigate cardiac function and ventricular remodeling post MI. Here we describe a less invasive, reliable, and reproducible surgical murine MI model by permanent ligation of the LCA. Our surgical model comprises of an easily reversible general anesthesia, endotracheal intubation that does not require a tracheotomy, and a thoracotomy. Electrocardiography and troponin measurement should be performed to ensure MI. Echocardiography at day 28 after MI will discern heart function and heart failure parameters. The degree of cardiac fibrosis can be evaluated by Masson's trichrome staining and cardiac MRI. This MI model is useful for studying the pathophysiological and immunological alterations after MI.

Presented here is a surgical procedure for permanent ligation of the left coronary artery in mice. This model can be used to investigate the pathophysiology and associated inflammatory response after myocardial infarction.

Ischemic heart disease and subsequent myocardial infarction (MI) is one of the leading causes of mortality in the United States and around the world. In ...

Rodent Model of Intestinal Ischemia-Reperfusion Injury via Occlusion of the Superior Mesenteric Artery

Intestinal ischemia-reperfusion injury (IRI) is associated with a myriad of conditions in both veterinary and human medicine. Intestinal IRI conditions, such as gastric dilatation volvulus (GDV), mesenteric torsion, and colic, are observed in animals such as dogs and horses. An initial interruption of blood flow causes tissues to become ischemic. Although necessary to salvage viable tissue, subsequent reperfusion can induce further injury. The main mechanism responsible for IRI is free radical formation upon reperfusion and reintroduction of oxygen into damaged tissue, but there are many other components involved. The resulting local and systemic effects often impart a poor prognosis. 
Intestinal IRI has been the subject of extensive research over the past 50 years. An in vivo rodent model in which the base of the superior mesenteric artery (SMA) is temporarily ligated is currently the most common method used to study intestinal IRI. Here, we describe a model of intestinal IRI utilizing isoflurane anesthesia in 21% O2 medical air that yields reproducible injury, as demonstrated by consistent histopathology of the small intestines. Tissue injury was also assessed in the colon, liver, and kidneys.

We describe how to generate a widely used surgical model of intestinal ischemia-reperfusion injury (IRI) in rodents. The procedure involves occlusion of the superior mesenteric artery followed by the restoration of blood flow. This model is useful for studies investigating occlusive causes of intestinal IRI in both veterinary and human medicine.

Intestinal ischemia-reperfusion injury (IRI) is associated with a myriad of conditions in both veterinary and human medicine. Intestinal IRI conditions, ...