DHA and vitamin E antagonized the Aβ25–35-mediated neuron oxidative damage through activation of Nrf2 signaling pathways and regulation of CD36, SRB1 and FABP5 expression in PC12 cells

The present study was designed to explore the neuroprotective effects of docosahexaenoic acid (DHA) and/or vitamin E (VE) in vitro. The PC12 cells were pretreated with DHA and/or VE for 4 h, followed by 50 μmol L-1 Aβ25-35 treatments for another 48 h. The cells were then collected and used for the measurements of oxidative stress parameters. Real time-PCR and western blot were applied to measure fatty acid transporters, Nrf2 and its downstream antioxidant targets' gene and protein expression. Our results indicated that the Aβ25-35 treatment inhibited cellular growth, increased intracellular ROS generation and decreased the mitochondrial membrane potential. The Aβ25-35 treatment decreased the total antioxidant capacity (T-AOC), whereas it increased the MDA levels in neuron cells. Pretreatment of cells with VE or DHA could antagonize the Aβ25-35-mediated cell growth inhibition and mitochondrial membrane potential decline. Activation of the Nrf2 signaling pathway and regulation of CD36, SRB1 and FABP5 expression were observed in DHA- and DHA + VE-pretreated cells. Our results indicated a synergistic effect of DHA and VE in antagonizing the oxidative damage caused by Aβ25-35 in the PC12 cells. The results of the present study will shed light on the application of nutritional intervention for DHA and VE in preventing neuronal damage-related diseases.