Avaliação da função mitocondrial, do estresse oxidativo e da expressão de sirtuínas em células HEK-293 tratadas com proantocianidinas de semente de uva

Abstract

The grape has an abundant quantity of proanthocyanidins, which are located inside the seeds. Researches has shown proanthocyanidins of the grape seeds act by reducing the oxidative stress, inflammation and act in the modulation of the mitochondrial dysfunction as well. However, it is not known exactly how the proanthocyanidins mechanism foster these effects. Answers to the stress provided by the mitochondria and by the complex electron transport chain activity can be coordinated by a protein family called sirtuins. This way, sirtuins are an important therapeutic target in diseases, which has in their physiopathology, the mitochondrial disfunction, as cancer, neurodegenerative diseases (Parkinson e Alzheimer), atherosclerosis and diabetes. For this purpose, natural products emerge as a strategy to modulate the oxidative stress and the mitochondrial dysfunction. Thus, the study purpose was to evaluate the grape seed proanthocyanidins capacity to modulate the H2O2 effects in terms of oxidative stress, the mitochondrial function, the apoptosis and the sirtuin 1 and sirtuin 3 manifestation in the HEK-293 human kidney’s embryonic cells. In the tests, the HEK-293 cells were treated with different proanthocyanidins concentrations (25, 50 e 100 µg/ml) by 30 minutes, followed by a 24 hour H2O2 (100µM) treatment, known as an oxidative cellular damage inductor. Results reveal that the proanthocyanidins treatment was capable to prevent the cellular death and the oxidative damage occurrence to lipids and proteins into HEK-293 cells. The proanthocyanidins also avoided the depletion of the antioxidant enzyme superoxide dismutase activity, caused by the H2O2. The mitochondrial electron transport chain activity (complexes I, III and IV), as the expression of the 7-subunit of the mitochondrial I complex and the ATP levels, decreased by H2O2, were preserved with the proanthocyanidins treatment. To the complex II, proanthocyanidins reduced its activity, which had suffered an increase due the H2O2 treatment. Proanthocyanidins also avoided the apoptosis occurrence inducted by H2O2 by reducing the PARP, p53 e BAX proteins expression. Sirtuins 1 and 3 expression was also modulated with the proanthocyanidins treatment, through the enhancement of sirtuin 1 expression and the sirtuin 3 depletion. These data points appoint that proanthocyanidins are cells capable to reduce the oxidative stress, the mitochondrial dysfunction and the apoptosis in HEK-293 cells. These markers increase occurred due to the sirtuin 1 expression regulation made by the proanthocyanidins, attested for the first time in our wor [resumo fornecido pelo autor]