Resveratrol protects primary rat hepatocytes against oxidative stress damage: activation of the Nrf2 transcription factor and augmented activities of antioxidant enzymes.

Oxidative stress is recognized as an important factor in the development of liver pathologies. The reactive oxygen species endogenously generated or as a consequence of xenobiotic metabolism are eliminated by enzymatic and nonenzymatic cellular systems. Besides endogen defences, the antioxidant consumption in the diet has an important role in the protection against the development of diseases product of oxidative damage. Resveratrol is a naturally occurring compound which is part of the human diet. This molecule has been shown to have many biological properties, including antioxidant activity. We decided to test if resveratrol could protect primary hepatocytes in culture from oxidative stress damage and if so, to determine if this compound affects the cellular detoxifying systems and their regulation through the Nrf2 transcription factor that regulates the expression of antioxidant and phase II detoxifying enzymes. Cell death by necrosis was detected by measuring the activity of lactate dehydrogenase liberated to the medium. The activities of antioxidant and phase II enzymes were measured using previously described methods. Activation of the Nrf2 transcription factor was studied by confocal microscopy and the Nrf2 and its coding mRNA levels were determined by western blot and quantitative PCR respectively. Resveratrol pre-treatment effectively protected hepatocytes in culture exposed to oxidative stress, increasing the activities of catalase, superoxide dismutase, glutathione peroxidase, NADPH quinone oxidoreductase and glutathione-S-transferase. Resveratrol increases the level of Nrf2 and induces its translocation to the nucleus. Also, it increases the concentration of the coding mRNA for Nrf2. In this work we show that resveratrol could be a useful drug for the protection of liver cells from oxidative stress induced damage.