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A Refined Approach to Permanent Coronary Artery Ligation in Rats: Enhancing Outcomes and Reducing Animal Burden
Cardio & Organ Systems (COST), Biomedical Research Institute, UHasselt, Agoralaan, 3590 Diepenbeek, Belgium
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Animals 2026, 16(1), 99; https://doi.org/10.3390/ani16010099 (registering DOI)
Submission received: 17 November 2025
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Revised: 16 December 2025
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Accepted: 22 December 2025
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Published: 29 December 2025
(This article belongs to the Section Animal Welfare)
Simple Summary
Rodent models continue to be used for studying heart attacks and developing new therapies. However, the standard surgical method to induce a heart attack in rats, achieved by permanently tying off a coronary artery, often causes high mortality and variable results. We refined this procedure to increase survival outcomes, reproducibility, and to reduce animal burden. The refinements include improved surgical access to the heart while avoiding lung injury, continuous monitoring of temperature and heart rate, and timely adjustments of retractors and anesthetic depth to prevent cardiac complications. With these improvements, we eliminated surgical mortality and achieved consistent heart attacks, thereby increasing both scientific reliability and animal welfare.
Abstract
Rodents models of myocardial infarction (MI) continue to be frequently used in preclinical cardiovascular research, despite alternative approaches being on the rise. The commonly used coronary artery permanent ligation (PL) approach is often hampered by substantial perioperative mortality and variable success rates. We optimized the rat PL protocol by relying exclusively on isoflurane inhalation anesthesia by introducing a standardized intubation setup, maintaining strict control of body temperature throughout surgery, and surgical technique refinements. The latter included gentle mobilization of the Pectoralis major and thymus, a medial thoracotomy through the third intercostal space, and the use of a reference ligature to facilitate reliable identification and ligation of the left anterior descending coronary artery (LAD). Cardiac rhythm was continuously monitored, and extubation was carefully timed to reduce complications. With this protocol, perioperative mortality was reduced to zero and successful ligation was obtained in 94% of animals (n = 172). Echocardiography and histology confirmed consistent induction of infarcts. By lowering invasiveness and improving survival and reproducibility, the refined PL method enhances both the reliability of preclinical research and compliance with the 3Rs, representing a meaningful step forward for studies in cardiac regeneration.
