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Updated: Mar 9, 2026
Histological Quantification of Chronic Myocardial Infarct in Rats
Published on: December 11, 2016
Histological Quantification of Chronic Myocardial Infarct in Rats
Jérémy Valentin1, Aurélien Frobert1, Guillaume Ajalbert1
1Cardiology, Department of Medicine, University of Fribourg.
Insights
Standardizing infarct size quantification in myocardial infarction (MI) models is crucial. This study presents a precise method using systematic heart sampling and image analysis for accurate assessment, aiding research into new MI therapies.
Area of Science:
- Cardiovascular Research
- Pathology
- Animal Models
Background:
- Myocardial infarction (MI) involves cardiomyocyte death and subsequent cardiac remodeling.
- Current methods for quantifying infarct size in animal models lack standardization, hindering research comparability.
- Accurate infarct size assessment is vital for developing therapies to reduce infarct expansion and remodeling.
Purpose of the Study:
- To establish a standardized and accurate method for quantifying infarct size in rat hearts post-myocardial infarction.
- To validate the use of the expansion index (EI) for assessing left ventricular remodeling.
Main Methods:
- A systematic sampling protocol for harvested rat hearts was developed.
- Trichromatic stained histological sections were analyzed from base to apex.
- Image analysis techniques were employed for quantification, including calculation of the expansion index (EI).
Main Results:
- The proposed method enables accurate quantification of infarct size.
- The expansion index (EI) effectively assesses left ventricular remodeling post-MI.
- Standardized protocols are essential for reproducible infarct size assessment.
Conclusions:
- A reliable and standardized method for infarct size quantification has been established.
- This protocol facilitates accurate assessment of therapeutic interventions targeting MI.
- The expansion index provides valuable insights into cardiac remodeling dynamics after MI.
Abstract:
Myocardial infarction is defined as cardiomyocyte death due to prolonged ischemia; an inflammatory response and scar formation (fibrosis) follow the ischemic injury. Following the initial acute phase, chronic remodeling of the left ventricle (LV) modifies the structure and function of the heart. Permanent coronary ligation in small animals has been widely used as a reference model for a chronic model of MI. Thinning of the infarcted wall progressively develops to transmural fibrosis. Histological assessment of infarct size is commonly performed; nevertheless, a standardization of the methods for quantification is missing. Indeed, important methodological aspects, such as the number of sections analyzed and the sampling and quantification methods, are usually not described and therefore preclude comparison across investigations. Too often, quantification is performed on a single section obtained at the level of the papillary muscles. Because novel strategies aimed at reducing infarct expansion and remodeling are under investigation, there is an important need for the standardization of accurate heart sampling protocols. We describe an accurate method to quantify the infarct size using a systematic sampling of harvested rat heart and image analyses of trichromatic stained histological sections obtained from base to apex. We also provide evidence that calculating the expansion index (EI) allowed for infarct size assessment, taking into account changes of the left ventricle throughout the remodeling.
