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

Summary

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.

Abstract

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.

Introduction

Ischemic heart disease is a leading cause of death worldwide^1,2. 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 syndrome^3,4. Cardiogenic shock and fatal arrhythmia in acute ST-segment elevation myocardial infarction (STEMI) have been found to increase the likelihood of in-hospital mortality^5,6,7,8.....

Protocol

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

1. Preparation of saline wet cotton balls
   1. Put on a surgical mask and gloves.
   2. Pinch off a small portion of sterile cotton and roll it to form a ball. Repeat this procedure.
   3. Dip the cotton balls in ste....

Results

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'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 infar.......

Discussion

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.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Evan’s blue	Sigma Aldrich	E2129
Forceps	Shinva
Pentobarbital	Sigma Aldrich	1507002
Scalpel blades	Shinva	s2646
Scalpel handles	Shinva
Silk sutures	SharpointTM	DC-2150N
Surgical needle	AnchorTM
Triphenyltetrazolium chloride (TTC) solution	Solarbio	T8170-1
Ventilator	Harvard Rodent Ventilator