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

Summary

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.

Abstract

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.

Introduction

Animal models of myocardial infarction (MI) are important in research of the complex pathophysiology of ischemic heart disease¹. Ischemia-reperfusion (I/R) injury is a major contributor the myocardial damage generated during MI. The initial ischemia injury produced by occlusion of the coronary circulation can be minimized in MI patients by the use of angioplasty to restore perfusion in a timely fashion. While this intervention has greatly reduced the number of deaths due to acute MI, restoration of blood flow into the ischemic area results in I/R injury that leads to death of cardiomyocytes. This loss of myocardial mass contributes to decreased cardiac outp....

Protocol

This animal protocol was approved by and is in accordance with the guidelines and regulations set forth by the Institutional Animal Care and Use Committee (IACUC) at The Ohio State University. All policies developed by the local IACUC are in compliance with the Animal Experimentation Guide developed by Office of Laboratory Animal Welfare at the National Institutes of Health.

1. Anesthesia and Endotracheal Intubation

1. Autoclave all instruments and surgical supplies before use. Wear sterile, single use surgical gloves throughout the procedure. Maintain a sterile field throughout the procedure. Use of a sterile drape is suggest....

Results

Following 24 hours of reperfusion, analysis of infarct size and the area-at-risk (AAR), by phthalo blue dye and triphenyl tetrazolium chloride (TTC), ligation of the LAD can be confirmed by observing blanching of myocardial tissue distal to the suture as well as dysfunction of the anterior wall. Reperfusion can be verified by the return of red color to the myocardial tissue and the demonstration of some recovery of anterior wall motion.

Infarct areas (white) should be distinguishable from area.......

Discussion

Mouse myocardial ischemia-reperfusion models are an effective method for cardiovascular research to simulate clinical acute or chronic heart disease^13,14. Significant effort has been applied to develop and refine surgical approaches that produce ischemic events and reperfusion damage in the hearts of several different animal types. While there are particular advantages to the use of different animals systems, the mouse has characteristics that have led to extensive interest in producing myocardial I/R in the m.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
PhysioSuite with RightTemp Homeothermic Warming	Kent Scientific Corp	PS-RT
Light source	Zeiss	KL 1500 LCD
Mouse Heart Slicer Matrix	Zivic Miller	HSMS001-1
Micro Tray - Base, Lid, & Mat (6.0 x 10 x 0.75)	Fine Science Tools	6100A
2,3,5-Triphenyltetrazolium chloride	Sigma Aldrich	T8877
Buprenorphine (Buprenex Injectable)	Reckitt Benkiser Healthcare	NDC 12496-0757-1
bupivacaine	Hospira	NDC 0409-1163-01
Isoflurane	Abbott	NDC 5260-04-05
Betadine Soultion	Purdue Pharma	25655-41-8
Mouse Cardiac Troponin T(cTnT) ELISA	Kamiya Biomedical Company	KT-58997
Fine Scissors	Fine Science Tools	14040-10
Dumont #5 Forceps	Fine Science Tools	11251-30
Dumont #3 Forceps	Fine Science Tools	11231-30
Castroviejo Micro Needle Holders	Fine Science Tools	12060-01
Slim Elongated Needle Holder	Fine Science Tools	12005-15
Round Handled Needle Holders	Fine Science Tools	12075-12
Omano Trinocular Stereoscope	Microscope.com	OM99-V6
SB2 Boom Stand with Universal Arm	Microscope.com	V6
Tracheal Tube, 0.5 mm, 1/16 in Y	Kent Scientific Corp	RSP05T16
Anesthesia Systems for Rodents and Small Animals	VetEquip, Inc	901807
4-0 silk taper suture	Sharpoint™ Products	DC-2515N
6-0 silk taper suture	Sharpoint™ Products	DC-2150N