Induction of Myocardial Infarction and Myocardial Ischemia-Reperfusion Injury in Mice

Summary

Here we describe a simple and reproducible method that can induce myocardial infarction or myocardial ischemia-reperfusion injury in mice by precision ligation of the left anterior descending coronary artery through micromanipulation.

Abstract

Acute myocardial infarction is a common cardiovascular disease with high mortality. Myocardial reperfusion injury can counteract the beneficial effects of heart reflow and induce secondary myocardial injury. A simple and reproducible model of myocardial infarction and myocardial ischemia-reperfusion injury is a good tool for researchers. Here, a customizable method to create a myocardial infarction (MI) model and MIRI by precision ligation of the left anterior descending coronary artery (LAD) through micromanipulation is described. Accurate and reproducible ligature positioning of the LAD helps obtain consistent results for heart injury. ST-segment changes can help to identify model accuracy. The serum level of cardiac troponin T (cTnT) is used to assess the myocardial injury, cardiac ultrasound is employed to evaluate the myocardial systolic function, and Evans-Blue/triphenyl tetrazolium chloride staining is used to measure infarct size. In general, this protocol reduces procedure duration, ensures controllable infarct size, and improves mouse survival.

Introduction

Acute myocardial infarction (AMI) is a common cardiovascular disease worldwide and carries high mortality¹. Advances in technologies make early and efficacious revascularization available for AMI patients. After these treatments in some patients, myocardial ischemia-reperfusion injury (MIRI) can occur². Thus, it is of great significance to understand the mechanisms of actions and how to ameliorate MI/MIRI. Mice are widely used as models because of their low cost, rapid breeding time, and ease for making genetic alterations³. Scholars have developed different methods to model MIRI and MI in animal<....

Protocol

Animal studies have been approved by the Animal Care and Utilization Committee of Huazhong University of Science and Technology (Wuhan, China).

NOTE: Male C57BL/6J mice (8-10 weeks) are used as models. Mice have free access to food and water and are bred in specific pathogen-free conditions. The room is maintained under controlled temperature (22 °C ± 2 °C) and humidity (45%-65%). Mice are exposed to a 12-h light/dark environment at the Animal Care Facility of Tongji Medical School (Wuhan, China) according to the guidelines set by this institution. Use sterile microsurgical instruments and surgical supplies. Surgical gloves and masks are re....

Results

The experimental workflow is shown in Figure 1A. The researcher can schedule the time nodes according to the experimental design upon study initiation. The duration of LAD ligation is according to the research purpose. For MI, the research can ignore the reperfusion step. Cardiac ultrasound is available at different stages of the study because it is non-invasive, while Evans-Blue/TTC staining can be performed only when the mouse is sacrificed. For research that focuses on fibrosis and ventri.......

Discussion

In recent years, the creation of models for MI and MIRI in clinical and scientific research has developed rapidly^20,21. However, there are still some questions, such as the mechanisms of actions and how to ameliorate MI/MIRI, that must be resolved. Here, a modified protocol for establishing a murine model of MI and MIRI is described. Several key points must be considered carefully.

The first key point is endotracheal intubation. Some p.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
0.9 % sodium chloride solution	Kelun Industry Group,China		-
4% paraformaldehyde fixing solution	Servicebio,China	G1101	-
4-0 silk suture	Shanghai Pudong Jinhuan Medical Products,China	C412	-
8-0 suture	Shanghai Pudong Jinhuan Medical Products,China	H801	-
Buprenorphine	IsoReag,China	IR-11190	-
Camera	Canon,Japan	EOS 80D	-
Depilatory cream	Veet,French		-
Elecsys Troponin T hs STAT	Roche,Germany		-
Electrochemical luminescence immunoanalyzer	Roche,Germany	Elecsys 2010	-
Evans blue	Sigma,America	E2129	-
Eye scissors	Shanghai Medical Instruments,China	JC2303	-
Haemostatic forceps	Shanghai Medical Instruments,China	J31020	-
High frequency in vivo imaging systems	Visualsonics,Canada	Vevo2100	-
Ibuprofen	PerFeMiKer,China	CLS-12921	-
Intravenous catheter	Introcan,Germany	4254090B	-
Ketamine	Sigma-Aldrich,America	K2753	-
Medical alcohol	Huichang ,China		-
Microneedle holders	Shanghai Medical Instruments,China	WA2040	-
Microscopic shears	Shanghai Medical Instruments,China	WA1040	-
Microsurgical forceps	Shanghai Medical Instruments,China	WA3020	-
Mouse electrocardiograph	Techman,China	BL-420F	-
Needle holders	Shanghai Medical Instruments,China	JC3202	-
operating floor	Chico,China	ZK-HJPT	-
PE-10 tube	Huamei,China		-
Pentobarbital	Merck,America	1030001	-
Rodent Ventilator	Shanghai Alcott Biotech,China	ALC-V8S-P	-
Stereo microscope	Aomei Industry,China	SZM0745-STL3-T3	-
Surgical thermostatic heating pad	Globalebio, China	GE0-20W	-
Triphenyltetrazolium chloride	Servicebio,China	G1017	-
Xylazine	Huamaike Biochemicals and Life Science Research Prouducts,China	323004	-