Modification on acute myocardial infarction model through left anterior descending coronary artery ligation: An experimental study on rats (Rattus norvegicus) using readily available materials

Abstract

Background and Aim: Several difficulties are involved in creating models for myocardial infarction (MI) in animals, such as low survival rates after acute MI, complicated techniques in creating animal models, complexities in confirming acute MI incidence, and complex surgical tools needed in the process. This study aimed to develop an animal model for acute MI using Wistar rats utilizing simple instruments that are readily available in standard animal laboratories. Materials and Methods: We induced MI in 48 Wistar rats using the left anterior descending coronary artery ligation modification technique without tracheal incision and ventilator. This ligation technique was performed 1-2 mm distal to the left atrial appendage. MI occurrence was evaluated using heart enzyme parameters 24 h post-ligation and histological studies of the infarcted area 6 weeks after the ligation. Rats were divided into the coronary artery ligation group and sham group. Results: Of the 48 rats, 24 (50%) died within 24 h post-ligation, but no further deaths occurred in the next follow-up period of 6 weeks. The average infarct size in six rats within 24 h of ligation was 35%±5.7%. The serum glutamic oxaloacetic transaminase level of the group treated with coronary artery ligation was statistically significantly higher than that of the sham group (p=0.000). Conclusion: We developed an MI rat model with consistent infarction size, in which the long-term death of rats was not observed. Our ligation technique for an MI rat model can be a reference for experimental settings without ventilators for small animals.