Cardioprotective effect of preconditioning is more efficient than postconditioning in rats submitted to cardiac ischemia and reperfusion1.

José Gustavo Padrão Tavares,Paolo Ruggero Errante,Murched Omar Taha,Renato Ribeiro Nogueira Ferraz,Francisco Sandro Menezes-Rodrigues,Ênio Rodrigues Vasques,Afonso Caricati-Neto,Tânia Carmem Peñaranda Govato

doi:10.1590/s0102-865020180070000004

Abstract

To investigate the cardioprotective effects of ischemic preconditioning (preIC) and postconditioning (postIC) in animal model of cardiac ischemia/reperfusion. Adult rats were submitted to protocol of cardiac ischemia/reperfusion (I/R) and randomized into three experimental groups: cardiac I/R (n=33), preCI + cardiac I/R (n=7) and postCI + cardiac I/R (n=8). After this I/R protocol, the incidence of ventricular arrhythmia (VA), atrioventricular block (AVB) and lethality (LET) was evaluated using the electrocardiogram (ECG) analysis. After reestablishment of coronary blood flow, we observed variations of the ECG trace with increased incidence of ventricular arrhythmia (VA) (85%), atrioventricular block (AVB) (79%), and increase of lethality (70%) in cardiac I/R group. The comparison between I/R + preIC group with I/R group demonstrated significant reduction in VA incidence to 28%, AVB to 0% and lethality to 14%. The comparison of I/R + postIC group with I/R group was observed significance reduction in AVB incidence to 25% and lethality to 25%. The preconditioning strategies produce cardioprotection more efficient that postconditioning against myocardial dysfunctions and lethality by cardiac ischemia and reperfusion.

Highlights

The coronary reperfusion therapy constitutes the major therapeutic strategy to salvage the myocardium from tissue injury following prolonged ischemia in acute myocardial infarction (AMI) patients[1,2,3]
Strategies to limit myocardial damage in acute myocardial infarction include, in addition to early reperfusion, the improvement of the endogenous resistance of cardiac cells to blood deprivation, which can be obtained by stimulating its survival mechanisms that function as a molecular adaptation to ischemic stress[2]
Cardiac I/R group showed changes in the ECG tracing from the 5 minutes of first ischemic arrhythmias corresponded to ventricular arrhythmia (VA) and atrioventricular block (AVB) in most animals tested occurred, and the rest of animals tested showed no arrhythmias during ischemia

Summary

Introduction

The coronary reperfusion therapy constitutes the major therapeutic strategy to salvage the myocardium from tissue injury following prolonged ischemia in acute myocardial infarction (AMI) patients[1,2,3]. Strategies to limit myocardial damage in acute myocardial infarction include, in addition to early reperfusion, the improvement of the endogenous resistance of cardiac cells to blood deprivation, which can be obtained by stimulating its survival mechanisms that function as a molecular adaptation to ischemic stress[2]. Among these phenomena, we can mention the stunned and the hibernation of the myocardium. This protection is typically measure as prevention against arrhythmias, reduction in myocardial infarction size or better recovery of the electrical and contractile function of the heart[9]

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