Abstract

BACKGROUND: The aim of this study was to investigate whether and how sulforaphane (SFN), a novel promising nuclear factor-E2-related factor 2 (Nrf2) activator, exerted antioxidative stress through activating Nrf2 signaling.

MATERIAL AND METHODS: Cultured human trabecular meshwork cells (HTMCs) were treated with SFN for 6 hours after establishing the oxidative stress model by hydrogen peroxide (H₂O₂). The cell viability, the level of intercellular reactive oxygen species (ROS), and the apoptosis rate were observed using various kits. In addition, the gene and protein expression of Nrf2 and the phase II antioxidative enzymes were determined by performing qRT-PCR and western blotting.

RESULTS: In H₂O₂-treated HTMCs, SFN protected HTMCs from oxidative stress damage and decreased the intracellular ROS accumulation, thus inhibiting cell apoptosis. SFN also increased the gene and protein expression of phase II antioxidative enzymes such as NAD(P)H: quinone oxidoreductase 1 (NQO-1), heme oxygenase-1 (HO-1), glutamate-cysteine ligase catalytic subunit (GCLC), and glutamate-cysteine ligase modifier subunit (GCLM) by Nrf2-dependent pathway. Furthermore, investigations of the pathway showed that HTMCs pretreated with LY294002, an inhibitor of phosphatidylinositol 3-kinase (PI3K), downregulated the expression of phase II antioxidative enzymes, partly.

CONCLUSIONS: These results indicated a novel application for SFN in attenuating H₂O₂-induced oxidative stress in HTMCs through activating PI3K/Akt/Nrf2 signaling pathway.

Keywords: Phosphatidylinositol 3-Kinases, Proto-Oncogene Proteins c-akt, Isothiocyanates, NF-E2-Related Factor 2, Oxidants, phosphatidylinositol 3-kinase, Phosphatidylinositols, Sulfoxides, Trabecular Meshwork