ABC | Volume 114, Nº1, January 2019

Original Article Alegre et al. Açaí and myocardial ischemia-reperfusion in rats Arq Bras Cardiol. 2020; 114(1):78-86 Western blot The expression of the proteins involved in the regulation of the oxidative stress pathway is shown in Figure 2. There was no difference in the expression of total and phosphorylated NF- κ B, total and acetylated FOXO1, SIRT1 and Nrf-2. Also, no differences were observed in the NF-kB phosphorylated/total or the FOXO1 acetylated/total ratios. Isolated heart study There was no difference between the groups regarding the initial volume of the balloon, the maximum systolic pressure reached, or +dP/dt, which represents systolic function. Group A presented worse –dP/dt than C, signifying impairment of the diastolic function in the rats that received açaí supplementation. The areas under the curves in the diastolic pressure-volume relationship did not differ between groups (Figure 3). Discussion Myocardial ischemia-reperfusion injury is one of the leading causes of death worldwide, and it remains a situation for which current clinical therapies are surprisingly deficient. 26 Irreversible myocardial injury progresses with increased duration of ischemia; therefore, rapid restoration of blood flow to the ischemic area is essential to save the viable myocardium. 1 Reperfusion, however, can induce death of cardiomyocytes regardless of the ischemic episode by a process known as reperfusion injury. 1,5,27 Decreased reperfusion injury is a key target in the battle to preserve cardiac function in patients with acute myocardial infarction. During ischemia-reperfusion, changes such as the release of cytokines, interaction between leukocytes and endothelial cells and production of reactive nitrogen/oxygen species and free radicals (ERs) 27 occur in cellular metabolism, which can lead to oxidative damage. ERs are generated from various Figure 1 – Myocardial infarcted area after global myocardial ischemia-reperfusion. Figure shows left ventricles sections stained with triphenyltetrazolium chloride 1%. White area represents the infarcted myocardium. C: control group; A: açaí group; There is no difference between groups (p = 0.710). 60 50 40 30 20 10 0 C A % myocardial infarcted area Table 2 – Myocardial oxidative stress marker and antioxidant enzymes activity after global ischemia-reperfusion C (n = 9) A (n = 10) p-value LH (nmol/g tissue) 330 ± 33 208 ± 22 < 0.001 CAT (μmol/g of tissue) 58.5 ± 6.4 70.0 ± 8.9 0.005 SOD (nmol/mg of protein) 5.7 ± 0.4 8.1 ± 0.7 < 0.001 GSH-Px (nmol/mg of tissue) 20.2 ± 3.3 32.8 ± 4.7 < 0.001 C: control group; A: açaí group; LH: lipid hydroperoxide; CAT: catalase; SOD superoxide dismutase; GSH-Px: glutathione peroxidase. Values are expressed as the means ± standard deviation; p-value: t test. 81