DHA sensitizes FaO cells to tert-BHP-induced oxidative effects. Protective role of EGCG

Abstract

The excessive production of reactive oxygen species has been implicated in several pathologies, such as atherosclerosis, obesity, hypertension and insulin resistance. Docosahexaenoic acid (DHA) may protect against the above mentioned diseases, but paradoxically the main DHA treated pathologies are also associated with increased ROS levels. Therefore, the aim of this study was to explore if in vitro DHA supplementation may increase the sensitivity of cells to tert-BHP induced oxidative stress, and if the green tea polyphenol epigallocatechin-3-gallate (EGCG) is able to correct such detrimental effect. We found that DHA-enriched cells exacerbate ROS generation, decrease cell viability and increase Nrf2 nuclear translocation and HO-1 expression. Interestingly, cellular EGCG is able to counteract oxidative damage from either tert-BHP or DHA-enriched cells. In consequence, our results suggest that in a ROS enriched environment DHA could not always be beneficial for cells and can be considered a double-edged sword in terms of its benefits vs. risks. In this sense, our results propose that the supplementation with potent antioxidant molecules could be an appropriate strategy to reduce the risks related with the DHA supplementation in an oxidative stress-associated condition.

Keywords: 2′,7′-dichlorofluorescin diacetate; 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazoilum bromide; 5,5′-dithiobis-2-nitrobenzoic acid; ARE; BSA; CAT; CL; DCFH-DA; DHA; DMSO; DTNB; DTT; Docosahexaenoic acid; EGCG; EPA; Epigallocatechin-3-gallate; FBS; GSH; GSSG; H(2)O(2); HO-1; Heme oxygenase-1; LDH; Lipid peroxidation; MDA; MTT; Nrf2; Oxidative stress; PMSF; PPIA; PUFA; PVDF; ROS; TBARS; TBST; WB; Western blot; antioxidant-response element; bovine serum albumin; cardiolipin; catalase; cyclophilin peptidylprolyl isomerase A; dimethyl sulfoxide; dithiothreitol; docosahexaenoic acid; eicosapentaenoic acid; epigallocatechin-3-gallate; fetal bovine serum; heme oxygenase-1; hydrogen Peroxide; lactate dehydrogenase; malondialdheyde; nuclear factor erythroid 2; oxidized glutathione; phenylmethylsulfonyl fluoride; polyunsaturated fatty acids; polyvinylidene difluoride; reactive oxygen species; reduced glutathione; tert-BHP; tert-Butylhydroperoxide; thiobarbituric acid reactive substances; tris-buffered saline with Tween 20.