Gastrodin represses hydrogen peroxide-induced oxidative stress in retinal pigment epithelial cells through p38MAPK/iNOS pathway

Elevated reactive oxygen species (ROS) induce oxidative damage in retinal pigment epithelium (RPE) and contribute to the development of age-related macular degeneration (AMD). Gastrodin plays an antioxidant role in distinct diseases, such as epilepsy, cerebral ischemia, Alzheimer's disease, and cardiovascular diseases. However, the function of gastrodin in AMD remains unclear. Human RPE (ARPE-19) cells were incubated with 300 mu M hydrogen peroxide (H2O2) for 24 hours. The results showed that H2O2 decreased cell viability and promoted the cell apoptosis of ARPE-19 cells. H2O2-induced ARPE-19 cells were then treated with different concentrations of gastrodin. Gastrodin increased cell viability of H2O2-induced ARPE-19 cells, suppressed the cell apoptosis of H2O2-induced ARPE-19 cells with reduced B-cell lymphoma (Bcl)-2 like protein (Bax), and enhanced Bcl-2. The levels of ROS were enhanced, malondialdehyde (MDA) was up-regulated, and superoxide dismutase (SOD) and glutathione (GSH) were down-regulated in H2O2-induced ARPE-19 cells. However, gastrodin reduced the levels of ROS and MDA and elevated SOD and GSH in H2O2-induced ARPE-19 cells. Furthermore, H2O2-induced increase of inducible nitric oxide synthase (iNOS) and p-p38 proteins in ARPE-19 was reversed by gastrodin. In conclusion, gastrodin exerted antiapoptotic and antioxidant capacities to protect against H2O2-induced oxidative stress in RPE, thereby acting as a potential agent for managing AMD.