This work was supported by grants from the National Natural Science Foundation of China (82073851 to Sun) and the National China Postdoctoral Science Foundation (2021M690074 to Lin).

All procedures were performed according to the Guide for the Care and Use of Laboratory Animals published by the US National Institutes of Health (NIH Publication No. 85-23, revised in 1996) and were approved by the Animal Ethics Committee of Nanfang Hospital, Southern Medical University (Guangzhou, China). Healthy male C57BL/6J mice (8-10 weeks old; body weight, 25-30 g) were obtained from the Animal Center of Southern Medical University. Female mice can also be used, but mixing both genders is not recommended due to th...

<ol>
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The authors have nothing to disclose.

Sicard and colleagues from France first reported a mouse model of RVI in 2019, which described the surgical process and focused on the interaction between LV and RV after RVI9. However, to date, no study has reported using this model for further studies. A more detailed procedure would be helpful for researchers to use the mouse model of RVI for investigation. In contrast to the report by Sicard et al.9, we provided step-by-step information for model generation and strategy...

The right ventricle (RV), long thought to be a simple tube connected to the pulmonary artery, has been wrongfully neglected for many years1. However, there has been an increasing interest in RV function recently since it plays an essential role in hemodynamic disorders2,3 and may serve as an independent risk predictor of cardiovascular disease4,5,6,7. RV diseases include RV infarction (RVI), pulmonary artery hypertension, and valvular disease8. In contrast to the immense interest in pulmonary artery hypertension, RVI has remained neglected7,9.
RVI, usually accompanied by inferior-posterior myocardial infarction10,11, is caused by right coronary artery (RCA) occlusion. According to clinical investigations, severe RVI likely induces hemodynamic disturbances and arrhythmias, such as hypotension, bradycardia, and atrioventricular block, associated with higher hospital morbidity and mortality12,13,14. RV function could recover spontaneously to a certain extent even in the absence of reperfusion15,16. Several morphological and functional differences exist between the left ventricle (LV) and RV17. RV is believed to be more resistant to ischemia than LV8, partially due to the more extensive collateral circulation formation after RVI. Clarifying the differences between LV infarction (LVI) and RVI and identifying the underlying mechanisms would provide new therapeutic targets for cardiac regeneration and ischemic heart failure. However, owing to the difficulty associated with&#160;RVI mouse model generation, basic research on RVI is mainly limited.
A large animal model of RVI has been generated by ligating RCA in swine18, which is easier to operate because of the visible RCA. Compared with the large animal model, the mouse model has the following advantages: more accessibility in gene manipulation, lower economic cost, and shorter experimental period19,20. Although a mouse RVI model focusing on the influence of RVI on LV function was reported previously, the detailed steps of the procedure, the difficulties and key points of operation, and the model characteristics such as hemodynamic changes were not fully introduced9,21.
This article provides detailed surgical procedures for generating a mouse model of RVI. Moreover, this model was characterized by echocardiographic measurement, invasive hemodynamic evaluation, and histological analysis. Furthermore, a coronary vasculature cast was performed to observe the coronary arterial arrangement in RV. The technique introduced in this paper would help beginners to quickly grasp the generation of the mouse RVI model with acceptable operation mortality and reliable evaluation approaches. The mouse model of RVI would help research the mechanisms of right heart failure and seek new therapeutic targets of RV remodeling.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>2,3,5-triphenyltetrazolium chloride</td>
			<td>Sigma</td>
			<td>T8877</td>
			<td>For TTC staining</td>
		</tr>
		<tr>
			<td>Animal Mini Ventilator</td>
			<td>Havard</td>
			<td>Type 845</td>
			<td>For artificial ventilation</td>
		</tr>
		<tr>
			<td>Animal ultrasound system VEVO2100</td>
			<td>Visual Sonic</td>
			<td>VEVO2100</td>
			<td>Measurement for Doppler flow velocity and AS plaque</td>
		</tr>
		<tr>
			<td>Batson&#8217;s #17 Anatomical Corrosion Kit</td>
			<td>Polyscience Inc</td>
			<td>7349</td>
			<td>For vasculature casting</td>
		</tr>
		<tr>
			<td>buprenorphine</td>
			<td>Isoreag</td>
			<td>1134630-70-8</td>
			<td>For reduce the pain of mice after surgery</td>
		</tr>
		<tr>
			<td>C57BL/6J mice + D29A1A2:D27</td>
			<td>Animal Center of South Medical University</td>
			<td>-</td>
			<td>For the generation of mouse RVI model</td>
		</tr>
		<tr>
			<td>Camera</td>
			<td>Sangnond</td>
			<td></td>
			<td>For taking photograph</td>
		</tr>
		<tr>
			<td>Cold light illuminator</td>
			<td>Olympus</td>
			<td>ILD-2</td>
			<td>Light for operation</td>
		</tr>
		<tr>
			<td>electrocardiograph</td>
			<td>ADI Instrument</td>
			<td>ADAS1000</td>
			<td>For recording electrocardiogram</td>
		</tr>
		<tr>
			<td>hair removal cream</td>
			<td>Reckitt Benchiser</td>
			<td>RQ/B 33 Type 2</td>
			<td>Remove mouse hair</td>
		</tr>
		<tr>
			<td>Heat pad- thermostatic surgical system (ALC-HTP-S1)</td>
			<td>SHANGHAI ALCOTT BIOTECH CO</td>
			<td>ALC-HTP-S1</td>
			<td>Heating</td>
		</tr>
		<tr>
			<td>Hematoxylin-eosin dye</td>
			<td>Leagene</td>
			<td>DH0003</td>
			<td>Hematoxylin-eosin staining</td>
		</tr>
		<tr>
			<td>Heparin sodium salt</td>
			<td>Macklin</td>
			<td>H837056</td>
			<td>For heparization</td>
		</tr>
		<tr>
			<td>Isoflurane</td>
			<td>RWD life science</td>
			<td>R510-22</td>
			<td>Inhalant anaesthesia</td>
		</tr>
		<tr>
			<td>Lab made spatula</td>
			<td></td>
			<td></td>
			<td>Work as a laryngoscope</td>
		</tr>
		<tr>
			<td>Lab made tracheal cannula</td>
			<td></td>
			<td></td>
			<td>For intubation</td>
		</tr>
		<tr>
			<td>Matrx VIP 3000 Isofurane Vaporizer</td>
			<td>Midmark Corporation</td>
			<td>VIP 3000</td>
			<td>Anesthetization</td>
		</tr>
		<tr>
			<td>Medical nylon suture (5-0)</td>
			<td>Ningbo Medical Needle Co.</td>
			<td>5-0</td>
			<td>For chest close</td>
		</tr>
		<tr>
			<td>Microsurgical elbow tweezers</td>
			<td>RWD life science</td>
			<td>F11021-11</td>
			<td>For surgery</td>
		</tr>
		<tr>
			<td>Microsurgical scissors</td>
			<td>NAPOX</td>
			<td>MB-54-1</td>
			<td>For arteriotomy</td>
		</tr>
		<tr>
			<td>Millar Catheter</td>
			<td>AD Instruments, Shanghai</td>
			<td>1.0F</td>
			<td>Measurement of pressure gradient</td>
		</tr>
		<tr>
			<td>MS400D ultrasonic probe</td>
			<td>Visual Sonic</td>
			<td>MS400D</td>
			<td>Measurement for Doppler flow velocity and AS plaque</td>
		</tr>
		<tr>
			<td>needle forceps</td>
			<td>Visual Sonic</td>
			<td>F31006-12</td>
			<td>For surgery</td>
		</tr>
		<tr>
			<td>nitroglycerin</td>
			<td>BEIJING YIMIN MEDICINE Co</td>
			<td></td>
			<td>For dilating coronary artery</td>
		</tr>
		<tr>
			<td>Ophthalmic scissors</td>
			<td>RWD life science</td>
			<td>S11022-14</td>
			<td>For surgery</td>
		</tr>
		<tr>
			<td>Pentobarbital sodium salt</td>
			<td>Merck</td>
			<td>25MG</td>
			<td>Anesthetization</td>
		</tr>
		<tr>
			<td>PowerLab Multi-Directional Physiological Recording System</td>
			<td>AD Instruments, Shanghai</td>
			<td>4/35</td>
			<td>Pressure recording</td>
		</tr>
		<tr>
			<td>Precision electronic balance</td>
			<td>Denver Instrument</td>
			<td>TB-114</td>
			<td>Weighing scale</td>
		</tr>
		<tr>
			<td>Silk suture (8-0)</td>
			<td>Ningbo Medical Needle Co.</td>
			<td>6-0</td>
			<td>coronary artery ligation</td>
		</tr>
		<tr>
			<td>Small animal microsurgery equipment</td>
			<td>Napox</td>
			<td>MA-65</td>
			<td>Surgical instruments</td>
		</tr>
		<tr>
			<td>tissue forceps</td>
			<td>Visual Sonic</td>
			<td>F-12007-10</td>
			<td>For surgery</td>
		</tr>
		<tr>
			<td>tissue scissor</td>
			<td>Visual Sonic</td>
			<td>S13052-12</td>
			<td>Open chest for hemodynamic measurement</td>
		</tr>
		<tr>
			<td>Transmission Gel</td>
			<td>Guang Gong pai</td>
			<td>250ML</td>
			<td>preparation for Echocardiography measurement</td>
		</tr>
		<tr>
			<td>Vascular Clamps</td>
			<td>Visual Sonic</td>
			<td>R31005-06</td>
			<td>For blocking blood from aorta</td>
		</tr>
	</tbody>
</table>

generation and characterization of right ventricular myocardial infarction induced by permanent ligation of the right coronary artery in mice

Right ventricular infarction (RVI) is a common presentation in clinical practice. Severe RVI can lead to fatal hemodynamic dysfunction and arrhythmia. In contrast to the extensively used mouse myocardial infarction (MI) model generated by left coronary artery ligation, the RVI mouse model is rarely employed due to the difficulty associated with model generation. Research on the mechanisms and treatment of RVI-induced RV remodeling and dysfunction requires animal models to mimic the pathophysiology of RVI in patients. This study introduces a feasible procedure for RVI model generation in C57BL/6J mice. Further, this model was characterized based on the following: infarct size evaluation at 24 h after MI, assessment of cardiac remodeling and function with echocardiography, RV hemodynamics assessment, and histology of the infarct zone at 4 weeks after RVI. In addition, a coronary vasculature cast was performed to observe the coronary arterial arrangement in RV. This mouse model of RVI would facilitate the research on mechanisms of right heart failure and seek new therapeutic targets of RV remodeling.

In this study, mice were randomly assigned to the RVI (n = 11) or sham operation (n = 11) group. The coronary cast in 2 normal mouse hearts is shown in Figure 1A. In response to RCA ligation, ST-segment elevation was seen in lead III of the ECG (Figure 1B). Moreover, 2,3,5-triphenyl tetrazolium chloride (TTC) staining showed that the infarct area accounts for 45% of the RV free wall at 24 h postoperatively (Figure 1C,D</stro...

Watch this Scientific Journal Video about Generation and Characterization of Right Ventricular Myocardial Infarction Induced by Permanent Ligation of the Right Coronary Artery in Mice at JoVE.com

Generation and Characterization of Right Ventricular Myocardial Infarction Induced by Permanent Ligation of the Right Coronary Artery in Mice

There are several differences between the right and left ventricles. However, the pathophysiology of right ventricular infarction (RVI) has not been clarified. In the present protocol, a reproducible method for RVI mouse model generation is introduced, which may provide a means to explain the mechanism of RVI.

Right ventricular infarction (RVI) is a common presentation in clinical practice. Severe RVI can lead to fatal hemodynamic dysfunction and arrhythmia. In ...

Right ventricular is more resistant to ischemia than the left one. We introduced a technique to generate a right ventricular infection model, which can clarify the pathophysiological mechanism during the development of a right ventricular infarction. We located the right coronary artery through vascular costing and defined the ligation area which is critical for successfully generating a mouse right ventricular infarction model.Demonstrating the procedure will be Linhai Ruo, a poster doctor from my laboratory. Place the mouse supine on a pad and ensure the depth of anesthesia by the absence of a toe withdrawal response. Fix its incisors with a suture and immobilize the limbs with adhesive tape.Remove hair from the neck to xiphoid with a depilatory cream. Pull out the tongue slightly with tweezers, lift the mandible with a tongue depressor to expose the glottis. And perform intra tracheal intubation by inserting a 22 gauge cannula into the glottis.Connect the electrocardiography electrodes to the mouse limbs correctly, and record the ECG. To open the chest, make a one centimeter long incision in the skin, parallel to the third right rib with ophthalmic scissors. Determine the third intercostal space again, and ensure adequate space according to the sternum angle.Separate and cut the pectoralis major and pectoralis minor muscles with scissors and micro forceps above the third intercostal space. After that, bluntly separate the intercostal muscle with elbow forceps to expose the surgical field, then incise the pericardium. Lift the right atrium with sterile cotton and ligate the right coronary artery with a sterile 8-0 nylon thread, with a ligation range of three to five millimeters.After ligating the right coronary artery, note the monitoring ECG lead 3, showing ST-segment elevation. Remove the cotton and suture muscles and skin with a sterile 5-0 nylon thread. Then place the mouse on the heating pad to promote recovery.Place the mouse in the supine position on an ultrasonic platform for animal fixation and ultrasonic operation. Tape its claws to the electrode to obtain an ECG recording, through a system attached to the ultrasonic machine. Remove the hair from the mouse's chest with a depilatory cream and apply ultrasound gel to the skin of the chest.Set the platform to the horizontal position. Orient the transducer parallel to the left leg and obtain the left ventricular long axis image. Rotate the probe 90 degrees clockwise to obtain the left ventricle short access view.Press the cine store button to save the images. Tilt the upper left of the platform at the lowest point. Move down the transducer vertically, maintaining its position over the upper abdomen and below the mouse's diaphragm under B-Mode.Adjust the platform position slightly by rotating its X and Y axis until the right ventricle, right atrium, left atrium and left ventricle are seen on the screen. And save the image by pressing cine store or frame button. Press M-Mode.After the two X indicator line appears locate the indicator line at the tricuspid valve orifice, to obtain the movement of the tricuspid annual plane. Press M-Mode again. Press the cine store or frame store button to save data and images.Tilt the left side of the platform at the lowest point. Place the probe at a 30 degrees angle to the horizontal axis along the right anterior axillary line. Rotate the X and Y axis of the platform to display the right ventricle.Press the M-Mode button and locate the indicator line at the septum hyperechoic point, to obtain the M-Mode image of the right ventricle interface. Press the M-Mode button again. Press the cine store button to save the picture.Perform tracheal intubation and set the parameter of the animal ventilator. Make a one centimeter bilateral incision on the skin above the xiphoid process and transect the diaphragm and rib with ophthalmic scissors to expose the heart. Puncture the right ventricular free wall with a 32 gauge needle.Remove the needle and press the wound with cotton to staunch bleeding. Insert the tip of the catheter into the right ventricle through the puncture site, and push the catheter forward, slowly. Adjust the position of the tip to obtain a typical RV pressure wave form, shown on a monitor and recording system.After 10 minutes of stabilization, record the data of RV systolic blood pressure, RV and diastolic pressure, and RV maximum right ventricular pressure rising decreasing rate. Click on the select button to select cardiac cycles for calculation. And then click on analyzed button to calculate the mean values of the selected cycles.Place the animal supine on the pad and intubate for artificial ventilation. Open the chest with surgical scissors and expose the heart. Make a three millimeter notch with ophthalmic scissors on the right atria and perfuse the heart with 5mL of normal saline through the cardiac apex with an injector.Block the blood from the aorta with an aortic clamp. And perfuse 0.1mL of 1 mg/mL nitroglycerin, through the cardiac apex with an injector to dilate the coronary artery. Perfuse the heart with a 1mL cast reagent through the cardiac apex and wait two to three hours.Erode the heart with 50%sodium hydroxide for two to three days. And remove the muscle tissue or connective tissue by rinsing with normal saline. After RCA ligation, ST-segment elevation was seen in lead 3 of the ECG.2, 3, 5-Triphenyltetrazolium chlorid staining showed that the infarct area accounts for 45%of the RV free wall, 24 hours postoperatively. Echocardiography showed that the RV internal dimension at the end of diastole, increased in the RV1. And it was more than two times in the Sham group.RV fraction shortening, RV ejection fraction, and tricuspid annular plane systolic excursion were significantly smaller in the RVI. The RV by LV area ratio increased by approximately 50%RV hemodynamic measurement showed that in the RVI group, right ventricular systolic blood pressure, the maximum and minimum rising rate of RV pressure, RV contractility, were significantly smaller. Right ventricular and diastolic pressure and the exponential time constant of RV relaxation index, were considerably more significant than those in the Sham group.An RV aneurysm was visible in the infarcted area. The heart weight to body weight ratio and heart weight to tibia length ratio in the RVI group were slightly larger. Masson staining indicated significant fibrosis in the RV free wall.And seldomly, fibrosis occurred in the septum of RVI group. In contrast, a few surviving cardiomyocytes were in the infarct area. It is crucial expose the ligation area and grasp the inserted needle's depth and the range to increase the success and the survival rates.

generation-characterization-right-ventricular-myocardial-infarction

Research

JoVE Journal

Medicine

2.9K Views.  The First Clinical College of Dalian Medical University. Right ventricular is more resistant to ischemia than the left one. We introduced a technique to generate a right ventricular infection model, which can clarify the pathophysiological mechanism during the development of a right ventricular infarction. We located the right coronary artery through vascular costing and defined the ligation area which is critical for successfully generating a mouse right ventricular infarction model.Demonstrating the procedure will be Linhai Ruo, a poster d...