Efeitos do betacaroteno e do tabagismo sobre a remodelação cardíaca pós-infarto do miocárdio

Abstract

Objective: To analyze the effects of beta-carotene on the ventricular remodeling process following myocardial infarction (MI) in rats exposed to cigarette smoke. Methods: After acute myocardial infarction (AMI), the animals were divided into four groups: 1) Group C, 24 animals that were given standard diet; 2) Group BC, 26 animals that were given beta-carotene; 3) Group ECS, 26 animals that were given standard diet and were exposed to cigarette smoke; and 4) Group BC+ECS, 20 animals that were given beta-carotene and were exposed to cigarette smoke. After six months, a morphofunctional study was performed. We used a 5% significance level. Results: As regards diastolic areas (DA) and systolic areas (SA), the values for the BC group were higher than those for the C group. If DA/body weight (BW) and SA/BW are considered, the values for group BC+ECS were higher than the values for group C. As regards the fractional area change, we observed significant differences between ECS (lower values) and C (higher values) and between BC (lower values) and C (higher values). Differences between groups regarding infarction size were not observed. The ECS group presented higher values for myocyte cross-section area (MCA) than control animals. Additionally, the BC+ECS group presented higher MCA values than the BC, ECS and C groups. Conclusion: After myocardial infarction, smoking and beta-carotene intensified the heart remodeling process; harmful effects of the remodeling process were heightened when the two treatments were used in conjunction.