Influence of late N‐acetylcysteine administration on cardiac remodeling in long‐term follow‐up postinfarction rats (862.3)

Abstract

This study aimed to evaluate the influence of late N‐acetylcysteine (NAC) administration on cardiac remodeling in long‐term follow‐up postinfarction rats. Methods: Myocardial infarction (MI) was induced by left coronary occlusion. Four months later, rats were assigned to three groups: Sham (n=13), MI‐C (MI without treatment, n=16), and MI‐NAC (MI treated with N‐acetylcysteine, 120 mg/kg/day, n=16). Six months after surgery, cardiac structures and function were evaluated by transthoracic Doppler echocardiogram and rats were euthanized the next day. Infarct size was measured by histological analysis, and rats with small MI (< 30%) were excluded. Results: MI size did not differ between MI‐C and MI‐NAC groups (p>0.05; Student’s t test). Right ventricle (RV) and lung weight, RV/body weight (BW) and lung/BW ratios were similar between MI‐C and MI‐NAC and higher than Sham. Left ventricle diastolic diameter, left atrium (LA) diameter, and LA/BW ratio were higher in MI‐C than Sham and similar between MI‐C and MI‐NAC. The systolic function variables fractional area shortening and posterior wall shortening velocity were similar between MI‐C and MI‐NAC and both lower than Sham. Concerning diastolic function, E wave‐to‐A wave ratio was higher in MI‐C than in both Sham and MI‐NAC (Sham: 1.47±0.14; MI‐C: 4.83±2.41; MI‐NAC: 3.25±1.85; p<0.001, ANOVA and Bonferroni). Conclusion: Late N‐acetylcysteine treatment attenuates diastolic dysfunction in long‐term follow‐up postinfarction rats. Grant Funding Source: FAPESP and CNPq