Naringina exerce efeito cardioprotetor na injúria de isquemia-reperfusão em coração de rato através da redução do estresse oxidativo

• Ano de defesa: 2019
• Autor(a) principal: Araujo, Andreza Melo de
• Orientador(a): Vasconcelos, Carla Maria Lins de
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Programa de Pós-Graduação: Pós-Graduação em Ciências Fisiológicas
• Palavras-chave em Português: Coração; Isquemia; Reperfusão miocárdica; Flavonoides; Naringina; Isquemia-reperfusão; Estresse oxidativo; Ratos
• Palavras-chave em Inglês: Naringin; Ischemia-reperfusion; Heart; Oxidative stress; Rats
• Área do conhecimento CNPq: CIENCIAS BIOLOGICAS::FISIOLOGIA
• Link de acesso: http://ri.ufs.br/jspui/handle/riufs/12602

Cardiac ischemia-reperfusion (IR) injury leads to a decrease in myocardial oxygen supply and irreversible damage of heart. Reperfusion of artery is necessary to restore blood flow of heart, however, it may amplify myocardial injury. Studies have shown that natural compounds with antioxidant activity can minimize injury caused by IR injury. Then, naringin (NGR) is a flavonoid with antioxidant and anti-inflammatory activities and that reduces the risk of atherosclerosis. The aim of the study was to evaluate the cardioprotective effects of pre-treatment with NGR in hearts submitted to IR lesion. For this, male Wistar rats (N=60) were divided into 4 groups and pre-treated orally for 7 days: 1) Control (0.9% saline solution + 25% DMSO) without IR injury; 2) Vehicle + IR (0.9% saline + 25% DMSO) submitted to IR, 3) NGR + IR (0.9% saline + 25% DMSO + 25 mg/kg NGR) and 4) NAC + 9% + DMSO 25% + N-acetyl cysteine (NAC) 100 mg/kg). After the treatments, the hearts were mounted in Langendorff type retrograde perfusion system (constant flow 8 ml/min, 37oC) and subjected to global ischemia (30 min) followed by 60 min reperfusion. In all experimental groups, the electrocardiographic parameters (PRi, QTc, QRS and heart rate) (n=7) and contractile (left ventricular pressure developed), derived of contraction (+ dP/dt) and relaxation (-dP/dt) (n=10). Coronary pressure (CP), arrhythmia score, and lactate dehydrogenase (LDH) in the perfusate (n=5) were also evaluated. The evaluation of the oxidative stress of hearts was made based on the determination of the production of reactive oxygen species, lipid peroxidation (TBARS), catalase (CAT) and superoxide dismutase (SOD), total sulfhydryl groups (SH) and protein carbolation. The results showed that pre-treatment of the animals with NGR was able to restore the reduction of PDVE, + dP/dt and -dP/dt induced by IR. Similar result to NGR was also observed in the group treated with NAC. The heart rate was increased in NGR-treated animals when compared to vehicle+IR group. There was no significant difference in relation to CP between the experimental groups studied. Furthermore, on the electrocardiogram, it was not possible to detect T wave inversion and ST segment elevation in the hearts of animals treated with NGR. No change was observed in the PRi, QTc intervals and duration of the QRS complex between the experimental groups (n=7). Pretreatment of the animals with NGR attenuated the severity of the arrhythmias, decreasing the arrhythmia score from 21.4  2.48 a.u. (vehicle + IR) to 5.5  0.72 a.u. (NGR) associated to a decrease in the occurrence of more severe arrhythmias such as ventricular fibrillation. The results showed a reduction of 78% of LDH in the perfusate of animals pretreated with NGR, associated with a reduction of the infarct area to 10% when compared to vehicle+IR group (47%) (p< 0.05). The results show an increase in ROS production in the vehicle + IR group (1.61  0.30 a.u, p <0.05) when compared to the control group (1.0  0.14 a.u.) and reduction in the NRG+IR (1.11  0.10 a.u, p <0.05). Treatment of animals with NRG was able to restore CAT and SOD activities by 61% and 50%, respectively. The results showed a decrease in lipid peroxidation in the NRG + IR group (1.48 ± 0.47 nmol MDA/mg protein) in relation to vehicle + IR (3.38 ± 0.47 mmol MDA/mg protein) (p < 0.05). There was no change in the determination of total sulfhydryl groups (SH) and protein carbolation in the experimental groups evaluated. We conclude that NRG exerts cardioprotective effect against IR injury by reducing oxidative damage and restoring the activity of antioxidant enzymes.