Development and Long-Term Follow-Up of an Experimental Model of Myocardial Infarction in Rabbits

Abstract

A chronic model of acute myocardial infarction was developed to study the mechanisms involved in adverse postinfarction ventricular remodeling. In an acute myocardial infarction (AMI), the left circumflex coronary artery of New Zealand White rabbits (n = 9) was occluded by ligature for 1 h, followed by reperfusion. A specific care protocol was applied before, during, and after the intervention, and the results were compared with those of a sham operated group (n = 7). After 5 weeks, programmed stimulation and high-resolution mapping were performed on isolated and perfused hearts using the Langendorff technique. The infarct size determined by 2,3,5-triphenyltetrazolium chloride inside of the area at risk (thioflavin-S) was then determined. The area at risk was similar in both groups (54.33% (experimental infarct group) vs. 58.59% (sham group), ns). The infarct size was 73.16% as a percentage of the risk area. The experimental infarct group had a higher inducibility of ventricular arrhythmias (100% vs. 43% in the sham group, p = 0.009). A reproducible chronic experimental model of myocardial infarction is presented in which the extent and characteristics of the lesions enable the study of the vulnerability to develop ventricular arrhythmias because of the remodeling process that occurs during cardiac tissue repair.

Experimental Animal Models in Heart Disease

“…In rodents, surgical interventions remain more straightforward than microsurgical methods. More critically, rabbit cardiac physiology resembles human cardiac physiology more than mice or rats (14). Indeed, cellular electrophysiology and Ca++ transport in rabbits are more similar to those in humans than in rats or mice (15).…”

Crafting a Rigorous, Clinically Relevant Large Animal Model of Chronic Myocardial Ischemia: What Have We Learned in 20 Years?

“…Although this has permitted electrophysiologic insights to be derived from such models [26,27], the robust endogenous collateral coronary network possessed by guinea pigs differs from humans in providing the species with a correspond-ing bulwark against ischemic disease and thus limits their applicability to the study of chronic myocardial ischemia [28]. Another species utilized in small animal models is the rabbit, the hearts of which possess coronary anatomical and electrophysiological similarity to the hearts of humans, including a paucity of collateral circulation and a corresponding reliability of infarct induction [29]. Given this, as well as the analogous development of atherosclerotic lesions in rabbits to the process as it occurs in humans, it is not surprising that these animals have been used for many decades in cardiovascular research [30][31][32].…”