Ferulic acid protects human umbilical vein endothelial cells from radiation induced oxidative stress by phosphatidylinositol 3-kinase and extracellular signal-regulated kinase pathways.

Ferulic acid (FA) has been demonstrated to have a remarkable antioxidant activity, the mechanism of FA of protecting human umbilical vein endothelial cells (HUVECs) from radiation induced oxidative stress was investigated in the present study. The oxidative protection of FA was assessed by cellular glutathione (GSH) content, nicotinamide adenine dinucleotide phosphate (NADPH) levels, and reactive oxygen species (ROS) analysis. Nuclear factor erythroid 2-related factor 2 (Nrf2) nuclear translocation was detected using Western blotting. The upstream signaling pathway involved in FA mediated Nrf2 activation was determined by signaling inhibitors. FA significantly increased the transcription of antioxidant related genes such as GCLC (glutamate-cysteine ligase catalytic subunit), GCLM (glutamate-cysteine ligase regulatory subunit), NQO1 (NADPH quinone oxidoreductase-1) and heme oxygenase-1 (HO-1) mRNA in radiated cells, and these changes involved in a significant increase of the intracellular GSH content and the expression of NAPDH. FA evidently promoted Nrf2 translocation into nuclei and increased the intracellular GSH and NADPH levels in radiated cells. Phosphatidylinositol 3-kinase (PI3K) and extracellular signal regulated kinase (ERK) pathways were associated with FA-induced Nrf2 activation. The results suggested that FA-induced Nrf2 activation play key role in cytoprotective effect of FA against oxidative stress via PI3K and ERK signaling pathways.