title: Histological Quantification of Chronic Myocardial Infarct in Rats.
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.
authors.affiliation: Cardiology, Department of Medicine, University of Fribourg.
authors.forename: Jérémy
authors.initials: J
authors.lastname: Valentin
authors.affiliation: Cardiology, Department of Medicine, University of Fribourg.
authors.forename: Aurélien
authors.initials: A
authors.lastname: Frobert
authors.affiliation: Cardiology, Department of Medicine, University of Fribourg.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Ajalbert
authors.affiliation: Cardiology, Department of Medicine, University of Fribourg.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Cook
authors.affiliation: Cardiology, Department of Medicine, University of Fribourg; marie-noelle.giraud@unifr.ch.
authors.forename: Marie-Noëlle
authors.initials: MN
authors.lastname: Giraud
mesh_terms: D000818:Animals; D005355:Fibrosis / Q000473:pathology*; D006352:Heart Ventricles; D017379:Hypertrophy, Left Ventricular / Q000209:etiology; D009203:Myocardial Infarction / Q000473:pathology* / Q000503:physiopathology; D010210:Papillary Muscles; D051381:Rats; D016277:Ventricular Function, Left / Q000502:physiology; D020257:Ventricular Remodeling