Role of lipoperoxidation in the remodeling intensification induced by beta-carotene after infarction

The mechanisms involved in the biggest remodeling caused by the post-infarct beta-carotene are unknown. To analyze the role of lipoperoxidation in the ventricular remodeling after infarct of the myocardium in rats supplemented with beta-carotene. Rats were infarcted and divided into two groups: C (control) and BC (500mg/kg/regimen). After six months, echocardiogram and biochemical evaluation were performed. The t test was used, with 5% significance. The animals from BC group presented highest means of the diastolic (C = 1.57 +/- 0.4 mm(2)/g, BC = 2.09 +/- 0.3 mm(2)/g; p < 0.001) and systolic (C = 1.05 +/- 0.3 mm(2)/g, BC = 1.61 +/- 0.3 mm(2)/g; p < 0.001) areas of LV, which were adapted according to the rat's body weight. The systolic function of LV, evaluated by the area variation fraction, was lower in the animals supplemented with beta-carotene (C = 31.9 +/- 9.3%, BC = 23.6 +/- 5.1%; p = 0.006). The animals supplemented with beta-carotene presented higher values of the E/A relation (C = 2.7 +/- 2.5, BC = 5.1 +/- 2.8; p = 0.036). No differences were found between the groups concerning the cardiac levels of the GSH (C = 21 +/- 8 nmol/mg of protein, BC = 37 +/- 15 nmol/mg of protein; p = 0.086), GSSG (C = 0.4 (0.3-0.5) nmol/g of protein, BC = 0.8 (0.4-1.0; p = 0.19) of protein; p = 0.246) and lipoperoxides (C = 0.4 +/- 0.2 nmol/mg of tissue, BC = 0.2 +/- 0.1 nmol/mg of tissue; p = 0.086). The highest remodeling in infarcted rats supplemented with beta-carotene does not depend on the lipoperoxidation.